x86/bugs: Replace CONFIG_SPECTRE_BHI_{ON,OFF} with CONFIG_MITIGATION_SPECTRE_BHI

For consistency with the other CONFIG_MITIGATION_* options, replace the
CONFIG_SPECTRE_BHI_{ON,OFF} options with a single
CONFIG_MITIGATION_SPECTRE_BHI option.

[ mingo: Fix ]

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nikolay Borisov <nik.borisov@suse.com>
Link: https://lore.kernel.org/r/3833812ea63e7fdbe36bf8b932e63f70d18e2a2a.1712813475.git.jpoimboe@kernel.org

x86/bugs: Remove CONFIG_BHI_MITIGATION_AUTO and spectre_bhi=auto

Unlike most other mitigations' "auto" options, spectre_bhi=auto only
mitigates newer systems, which is confusing and not particularly useful.

Remove it.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/412e9dc87971b622bbbaf64740ebc1f140bff343.1712813475.git.jpoimboe@kernel.org

x86/bhi: Add BHI mitigation knob

Branch history clearing software sequences and hardware control
BHI_DIS_S were defined to mitigate Branch History Injection (BHI).

Add cmdline spectre_bhi={on|off|auto} to control BHI mitigation:

auto - Deploy the hardware mitigation BHI_DIS_S, if available.
on - Deploy the hardware mitigation BHI_DIS_S, if available,
otherwise deploy the software sequence at syscall entry and
VMexit.
off - Turn off BHI mitigation.

The default is auto mode which does not deploy the software sequence
mitigation. This is because of the hardening done in the syscall
dispatch path, which is the likely target of BHI.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>

x86/percpu: Disable named address spaces for KCSAN

-fsanitize=thread (KCSAN) is at the moment incompatible
with named address spaces in a similar way as KASAN -
see GCC PR sanitizer/111736:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111736

The patch disables named address spaces with KCSAN.

Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240325110128.615933-1-ubizjak@gmail.com

platform: goldfish: move the separate 'default' propery for CONFIG_GOLDFISH

Currently, there are two entries for CONFIG_GOLDFISH.

In arch/x86/Kconfig:

config GOLDFISH
def_bool y
depends on X86_GOLDFISH

In drivers/platform/goldfish/Kconfig:

menuconfig GOLDFISH
bool "Platform support for Goldfish virtual devices"
depends on HAS_IOMEM && HAS_DMA

While Kconfig allows multiple entries, it generally leads to tricky
code.

Prior to commit bd2f348db503 ("goldfish: refactor goldfish platform
configs"), CONFIG_GOLDFISH was an alias of CONFIG_X86_GOLDFISH.

After the mentioned commit added the second entry with a user prompt,
the former provides the 'default' property that is effective only when
X86_GOLDFISH=y.

Merge them tegether to clarify how it has worked in the past 8 years.

Cc: Greg Hackmann <ghackmann@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240204081004.33871-1-masahiroy@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

treewide: remove CONFIG_HAVE_KVM

It has no users anymore.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

kexec: split crashkernel reservation code out from crash_core.c

Patch series "Split crash out from kexec and clean up related config
items", v3.

Motivation:
=============
Previously, LKP reported a building error. When investigating, it can't
be resolved reasonablly with the present messy kdump config items.

https://lore.kernel.org/oe-kbuild-all/202312182200.Ka7MzifQ-lkp@intel.com/

The kdump (crash dumping) related config items could causes confusions:

Firstly,

CRASH_CORE enables codes including
- crashkernel reservation;
- elfcorehdr updating;
- vmcoreinfo exporting;
- crash hotplug handling;

Now fadump of powerpc, kcore dynamic debugging and kdump all selects
CRASH_CORE, while fadump
- fadump needs crashkernel parsing, vmcoreinfo exporting, and accessing
global variable 'elfcorehdr_addr';
- kcore only needs vmcoreinfo exporting;
- kdump needs all of the current kernel/crash_core.c.

So only enabling PROC_CORE or FA_DUMP will enable CRASH_CORE, this
mislead people that we enable crash dumping, actual it's not.

Secondly,

It's not reasonable to allow KEXEC_CORE select CRASH_CORE.

Because KEXEC_CORE enables codes which allocate control pages, copy
kexec/kdump segments, and prepare for switching. These codes are
shared by both kexec reboot and kdump. We could want kexec reboot,
but disable kdump. In that case, CRASH_CORE should not be selected.

--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------

Thirdly,

It's not reasonable to allow CRASH_DUMP select KEXEC_CORE.

That could make KEXEC_CORE, CRASH_DUMP are enabled independently from
KEXEC or KEXEC_FILE. However, w/o KEXEC or KEXEC_FILE, the KEXEC_CORE
code built in doesn't make any sense because no kernel loading or
switching will happen to utilize the KEXEC_CORE code.
---------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
---------------------

In this case, what is worse, on arch sh and arm, KEXEC relies on MMU,
while CRASH_DUMP can still be enabled when !MMU, then compiling error is
seen as the lkp test robot reported in above link.

------arch/sh/Kconfig------
config ARCH_SUPPORTS_KEXEC
def_bool MMU

config ARCH_SUPPORTS_CRASH_DUMP
def_bool BROKEN_ON_SMP
---------------------------

Changes:
===========
1, split out crash_reserve.c from crash_core.c;
2, split out vmcore_infoc. from crash_core.c;
3, move crash related codes in kexec_core.c into crash_core.c;
4, remove dependency of FA_DUMP on CRASH_DUMP;
5, clean up kdump related config items;
6, wrap up crash codes in crash related ifdefs on all 8 arch-es
which support crash dumping, except of ppc;

Achievement:
===========
With above changes, I can rearrange the config item logic as below (the right
item depends on or is selected by the left item):

PROC_KCORE -----------> VMCORE_INFO

|----------> VMCORE_INFO
FA_DUMP----|
|----------> CRASH_RESERVE

---->VMCORE_INFO
/
|---->CRASH_RESERVE
KEXEC --| /|
|--> KEXEC_CORE--> CRASH_DUMP-->/-|---->PROC_VMCORE
KEXEC_FILE --| \ |
\---->CRASH_HOTPLUG


KEXEC --|
|--> KEXEC_CORE (for kexec reboot only)
KEXEC_FILE --|

Test
========
On all 8 architectures, including x86_64, arm64, s390x, sh, arm, mips,
riscv, loongarch, I did below three cases of config item setting and
building all passed. Take configs on x86_64 as exampmle here:

(1) Both CONFIG_KEXEC and KEXEC_FILE is unset, then all kexec/kdump
items are unset automatically:
# Kexec and crash features
# CONFIG_KEXEC is not set
# CONFIG_KEXEC_FILE is not set
# end of Kexec and crash features

(2) set CONFIG_KEXEC_FILE and 'make olddefconfig':
---------------
# Kexec and crash features
CONFIG_CRASH_RESERVE=y
CONFIG_VMCORE_INFO=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
CONFIG_CRASH_DUMP=y
CONFIG_CRASH_HOTPLUG=y
CONFIG_CRASH_MAX_MEMORY_RANGES=8192
# end of Kexec and crash features
---------------

(3) unset CONFIG_CRASH_DUMP in case 2 and execute 'make olddefconfig':
------------------------
# Kexec and crash features
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC_FILE=y
# end of Kexec and crash features
------------------------

Note:
For ppc, it needs investigation to make clear how to split out crash
code in arch folder. Hope Hari and Pingfan can help have a look, see if
it's doable. Now, I make it either have both kexec and crash enabled, or
disable both of them altogether.


This patch (of 14):

Both kdump and fa_dump of ppc rely on crashkernel reservation. Move the
relevant codes into separate files: crash_reserve.c,
include/linux/crash_reserve.h.

And also add config item CRASH_RESERVE to control its enabling of the
codes. And update config items which has relationship with crashkernel
reservation.

And also change ifdeffery from CONFIG_CRASH_CORE to CONFIG_CRASH_RESERVE
when those scopes are only crashkernel reservation related.

And also rename arch/XXX/include/asm/{crash_core.h => crash_reserve.h} on
arm64, x86 and risc-v because those architectures' crash_core.h is only
related to crashkernel reservation.

[akpm@linux-foundation.org: s/CRASH_RESEERVE/CRASH_RESERVE/, per Klara Modin]
Link: https://lkml.kernel.org/r/20240124051254.67105-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20240124051254.67105-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86: Drop CPU_SUP_INTEL from SCHED_MC_PRIO for the expansion

amd-pstate driver also uses SCHED_MC_PRIO, so decouple the requirement
of CPU_SUP_INTEL from the dependencies to allow compilation in kernels
without Intel CPU support.

Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Meng Li <li.meng@amd.com>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

x86/rfds: Mitigate Register File Data Sampling (RFDS)

RFDS is a CPU vulnerability that may allow userspace to infer kernel
stale data previously used in floating point registers, vector registers
and integer registers. RFDS only affects certain Intel Atom processors.

Intel released a microcode update that uses VERW instruction to clear
the affected CPU buffers. Unlike MDS, none of the affected cores support
SMT.

Add RFDS bug infrastructure and enable the VERW based mitigation by
default, that clears the affected buffers just before exiting to
userspace. Also add sysfs reporting and cmdline parameter
"reg_file_data_sampling" to control the mitigation.

For details see:
Documentation/admin-guide/hw-vuln/reg-file-data-sampling.rst

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>

arch: define CONFIG_PAGE_SIZE_*KB on all architectures

Most architectures only support a single hardcoded page size. In order
to ensure that each one of these sets the corresponding Kconfig symbols,
change over the PAGE_SHIFT definition to the common one and allow
only the hardware page size to be selected.

Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

x86/idle: Sanitize X86_BUG_AMD_E400 handling

amd_e400_idle(), the idle routine for AMD CPUs which are affected by
erratum 400 violates the RCU constraints by invoking tick_broadcast_enter()
and tick_broadcast_exit() after the core code has marked RCU non-idle. The
functions can end up in lockdep or tracing, which rightfully triggers a
RCU warning.

The core code provides now a static branch conditional invocation of the
broadcast functions.

Remove amd_e400_idle(), enforce default_idle() and enable the static branch
on affected CPUs to cure this.

[ bp: Fold in a fix for a IS_ENABLED() check fail missing a "CONFIG_"
prefix which tglx spotted. ]

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/877cim6sis.ffs@tglx

kexec: Allocate kernel above bzImage's pref_address

A relocatable kernel will relocate itself to pref_address if it is
loaded below pref_address. This means a booted kernel may be relocating
itself to an area with reserved memory on modern systems, potentially
clobbering arbitrary data that may be important to the system.

This is often the case, as the default value of PHYSICAL_START is
0x1000000 and kernels are typically loaded at 0x100000 or above by
bootloaders like iPXE or kexec. GRUB behaves like the approach
implemented here.

Also fixes the documentation around pref_address and PHYSICAL_START to
be accurate.

[ dhansen: changelog tweak ]

Co-developed-by: Cloud Hsu <cloudhsu@google.com>
Signed-off-by: Cloud Hsu <cloudhsu@google.com>
Signed-off-by: Chris Koch <chrisko@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Link: https://lore.kernel.org/all/20231215190521.3796022-1-chrisko%40google.com

ubsan: Remove CONFIG_UBSAN_SANITIZE_ALL

For simplicity in splitting out UBSan options into separate rules,
remove CONFIG_UBSAN_SANITIZE_ALL, effectively defaulting to "y", which
is how it is generally used anyway. (There are no ":= y" cases beyond
where a specific file is enabled when a top-level ":= n" is in effect.)

Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kbuild@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

x86/Kconfig: Remove CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT

It was meant well at the time but nothing's using it so get rid of it.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240202163510.GDZb0Zvj8qOndvFOiZ@fat_crate.local

x86/fred: Add Kconfig option for FRED (CONFIG_X86_FRED)

Add the configuration option CONFIG_X86_FRED to enable FRED.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-6-xin3.li@intel.com

x86/bugs: Rename CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK

Step 10/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Added one more case. ]

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-11-leitao@debian.org

x86/bugs: Rename CONFIG_CPU_SRSO => CONFIG_MITIGATION_SRSO

Step 9/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-10-leitao@debian.org

x86/bugs: Rename CONFIG_CPU_IBRS_ENTRY => CONFIG_MITIGATION_IBRS_ENTRY

Step 8/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-9-leitao@debian.org

x86/bugs: Rename CONFIG_CPU_UNRET_ENTRY => CONFIG_MITIGATION_UNRET_ENTRY

Step 7/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-8-leitao@debian.org

x86/bugs: Rename CONFIG_SLS => CONFIG_MITIGATION_SLS

Step 6/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-7-leitao@debian.org

x86/bugs: Rename CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINE

Step 5/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Converted a few more uses in comments/messages as well. ]

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ariel Miculas <amiculas@cisco.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-6-leitao@debian.org

x86/bugs: Rename CONFIG_PAGE_TABLE_ISOLATION => CONFIG_MITIGATION_PAGE_TABLE_ISOLATION

Step 4/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Converted new uses that got added since the series was posted. ]

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-5-leitao@debian.org

x86/bugs: Rename CONFIG_CALL_DEPTH_TRACKING => CONFIG_MITIGATION_CALL_DEPTH_TRACKING

Step 3/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-4-leitao@debian.org

x86/bugs: Rename CONFIG_CPU_IBPB_ENTRY => CONFIG_MITIGATION_IBPB_ENTRY

Step 2/10 of the namespace unification of CPU mitigations related Kconfig options.

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-3-leitao@debian.org

x86/bugs: Rename CONFIG_GDS_FORCE_MITIGATION => CONFIG_MITIGATION_GDS_FORCE

So the CPU mitigations Kconfig entries - there's 10 meanwhile - are named
in a historically idiosyncratic and hence rather inconsistent fashion
and have become hard to relate with each other over the years:

https://lore.kernel.org/lkml/20231011044252.42bplzjsam3qsasz@treble/

When they were introduced we never expected that we'd eventually have
about a dozen of them, and that more organization would be useful,
especially for Linux distributions that want to enable them in an
informed fashion, and want to make sure all mitigations are configured
as expected.

For example, the current CONFIG_SPECULATION_MITIGATIONS namespace is only
halfway populated, where some mitigations have entries in Kconfig, and
they could be modified, while others mitigations do not have Kconfig entries,
and can not be controlled at build time.

Fine-grained control over these Kconfig entries can help in a number of ways:

1) Users can choose and pick only mitigations that are important for
their workloads.

2) Users and developers can choose to disable mitigations that mangle
the assembly code generation, making it hard to read.

3) Separate Kconfigs for just source code readability,
so that we see *which* butt-ugly piece of crap code is for what
reason...

In most cases, if a mitigation is disabled at compilation time, it
can still be enabled at runtime using kernel command line arguments.

This is the first patch of an initial series that renames various
mitigation related Kconfig options, unifying them under a single
CONFIG_MITIGATION_* namespace:

CONFIG_GDS_FORCE_MITIGATION => CONFIG_MITIGATION_GDS_FORCE
CONFIG_CPU_IBPB_ENTRY => CONFIG_MITIGATION_IBPB_ENTRY
CONFIG_CALL_DEPTH_TRACKING => CONFIG_MITIGATION_CALL_DEPTH_TRACKING
CONFIG_PAGE_TABLE_ISOLATION => CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINE
CONFIG_SLS => CONFIG_MITIGATION_SLS
CONFIG_CPU_UNRET_ENTRY => CONFIG_MITIGATION_UNRET_ENTRY
CONFIG_CPU_IBRS_ENTRY => CONFIG_MITIGATION_IBRS_ENTRY
CONFIG_CPU_SRSO => CONFIG_MITIGATION_SRSO
CONFIG_RETHUNK => CONFIG_MITIGATION_RETHUNK

Implement step 1/10 of the namespace unification of CPU mitigations related
Kconfig options and rename CONFIG_GDS_FORCE_MITIGATION to
CONFIG_MITIGATION_GDS_FORCE.

[ mingo: Rewrote changelog for clarity. ]

Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-2-leitao@debian.org

x86/percpu: Disable named address spaces for KASAN

-fsanitize=kernel-address (KASAN) is at the moment incompatible
with named address spaces - see GCC PR sanitizer/111736:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111736

GCC is doing a KASAN check on a percpu address which it shouldn't do,
and didn't used to do because we did the access using inline asm.

But now that GCC does the accesses as normal (albeit special address
space) memory accesses, the KASAN code triggers on them too, and it
all goes to hell in a handbasket very quickly.

Those percpu accessor functions need to disable any KASAN
checking or other sanitizer checking. Not on the percpu address,
because that's not a "real" address, it's obviously just the offset
from the segment register.

And GCC should probably not have generated such code in the first
place, so arguably this is a bug with -fsanitize=kernel-address.

The patch also removes a stale dependency on CONFIG_SMP.

Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20231009151409.53656-1-ubizjak@gmail.com

Closes: https://lore.kernel.org/oe-lkp/202310071301.a5113890-oliver.sang@intel.com

x86/percpu: Enable named address spaces with known compiler version

Enable named address spaces with known compiler versions
(GCC 12.1 and later) in order to avoid possible issues with named
address spaces with older compilers. Set CC_HAS_NAMED_AS when the
compiler satisfies version requirements and set USE_X86_SEG_SUPPORT
to signal when segment qualifiers could be used.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20231004145137.86537-3-ubizjak@gmail.com

x86/virt/tdx: Make TDX host depend on X86_MCE

A build failure was reported that when INTEL_TDX_HOST is enabled but
X86_MCE is not, the tdx_dump_mce_info() function fails to link:

ld: vmlinux.o: in function `tdx_dump_mce_info':
...: undefined reference to `mce_is_memory_error'
...: undefined reference to `mce_usable_address'

The reason is in such configuration, despite there's no caller of
tdx_dump_mce_info() it is still built and there's no implementation for
the two "mce_*()" functions.

Make INTEL_TDX_HOST depend on X86_MCE to fix.

It makes sense to enable MCE support for the TDX host anyway. Because
the only way that TDX has to report integrity errors is an MCE, and it
is not good to silently ignore such MCE. The TDX spec also suggests
the host VMM is expected to implement the MCE handler.

Note it also makes sense to make INTEL_TDX_HOST select X86_MCE but this
generates "recursive dependency detected!" error in the Kconfig.

Closes: https://lore.kernel.org/all/20231212214612.GHZXjUpBFa1IwVMTI7@fat_crate.local/T/
Fixes: 70060463cb2b ("x86/mce: Differentiate real hardware #MCs from TDX erratum ones")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/all/20231212214612.GHZXjUpBFa1IwVMTI7@fat_crate.local/T/#m1a109c29324b2bbd0b3b1d45c218012cd3a13be6
Link: https://lore.kernel.org/all/20231213222825.286809-1-kai.huang%40intel.com

x86/virt/tdx: Disable TDX host support when kexec is enabled

TDX host support currently lacks the ability to handle kexec. Disable TDX
when kexec is enabled.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-20-dave.hansen%40intel.com

iommu: Change kconfig around IOMMU_SVA

Linus suggested that the kconfig here is confusing:

https://lore.kernel.org/all/CAHk-=wgUiAtiszwseM1p2fCJ+sC4XWQ+YN4TanFhUgvUqjr9Xw@mail.gmail.com/

Let's break it into three kconfigs controlling distinct things:

- CONFIG_IOMMU_MM_DATA controls if the mm_struct has the additional
fields for the IOMMU. Currently only PASID, but later patches store
a struct iommu_mm_data *

- CONFIG_ARCH_HAS_CPU_PASID controls if the arch needs the scheduling bit
for keeping track of the ENQCMD instruction. x86 will select this if
IOMMU_SVA is enabled

- IOMMU_SVA controls if the IOMMU core compiles in the SVA support code
for iommu driver use and the IOMMU exported API

This way ARM will not enable CONFIG_ARCH_HAS_CPU_PASID

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20231027000525.1278806-2-tina.zhang@intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

x86/virt/tdx: Allocate and set up PAMTs for TDMRs

The TDX module uses additional metadata to record things like which
guest "owns" a given page of memory. This metadata, referred as
Physical Address Metadata Table (PAMT), essentially serves as the
'struct page' for the TDX module. PAMTs are not reserved by hardware
up front. They must be allocated by the kernel and then given to the
TDX module during module initialization.

TDX supports 3 page sizes: 4K, 2M, and 1G. Each "TD Memory Region"
(TDMR) has 3 PAMTs to track the 3 supported page sizes. Each PAMT must
be a physically contiguous area from a Convertible Memory Region (CMR).
However, the PAMTs which track pages in one TDMR do not need to reside
within that TDMR but can be anywhere in CMRs. If one PAMT overlaps with
any TDMR, the overlapping part must be reported as a reserved area in
that particular TDMR.

Use alloc_contig_pages() since PAMT must be a physically contiguous area
and it may be potentially large (~1/256th of the size of the given TDMR).
The downside is alloc_contig_pages() may fail at runtime. One (bad)
mitigation is to launch a TDX guest early during system boot to get
those PAMTs allocated at early time, but the only way to fix is to add a
boot option to allocate or reserve PAMTs during kernel boot.

It is imperfect but will be improved on later.

TDX only supports a limited number of reserved areas per TDMR to cover
both PAMTs and memory holes within the given TDMR. If many PAMTs are
allocated within a single TDMR, the reserved areas may not be sufficient
to cover all of them.

Adopt the following policies when allocating PAMTs for a given TDMR:

- Allocate three PAMTs of the TDMR in one contiguous chunk to minimize
the total number of reserved areas consumed for PAMTs.
- Try to first allocate PAMT from the local node of the TDMR for better
NUMA locality.

Also dump out how many pages are allocated for PAMTs when the TDX module
is initialized successfully. This helps answer the eternal "where did
all my memory go?" questions.

[ dhansen: merge in error handling cleanup ]

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Yuan Yao <yuan.yao@intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-11-dave.hansen%40intel.com

x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory

Start to transit out the "multi-steps" to initialize the TDX module.

TDX provides increased levels of memory confidentiality and integrity.
This requires special hardware support for features like memory
encryption and storage of memory integrity checksums. Not all memory
satisfies these requirements.

As a result, TDX introduced the concept of a "Convertible Memory Region"
(CMR). During boot, the firmware builds a list of all of the memory
ranges which can provide the TDX security guarantees. The list of these
ranges is available to the kernel by querying the TDX module.

CMRs tell the kernel which memory is TDX compatible. The kernel needs
to build a list of memory regions (out of CMRs) as "TDX-usable" memory
and pass them to the TDX module. Once this is done, those "TDX-usable"
memory regions are fixed during module's lifetime.

To keep things simple, assume that all TDX-protected memory will come
from the page allocator. Make sure all pages in the page allocator
*are* TDX-usable memory.

As TDX-usable memory is a fixed configuration, take a snapshot of the
memory configuration from memblocks at the time of module initialization
(memblocks are modified on memory hotplug). This snapshot is used to
enable TDX support for *this* memory configuration only. Use a memory
hotplug notifier to ensure that no other RAM can be added outside of
this configuration.

This approach requires all memblock memory regions at the time of module
initialization to be TDX convertible memory to work, otherwise module
initialization will fail in a later SEAMCALL when passing those regions
to the module. This approach works when all boot-time "system RAM" is
TDX convertible memory and no non-TDX-convertible memory is hot-added
to the core-mm before module initialization.

For instance, on the first generation of TDX machines, both CXL memory
and NVDIMM are not TDX convertible memory. Using kmem driver to hot-add
any CXL memory or NVDIMM to the core-mm before module initialization
will result in failure to initialize the module. The SEAMCALL error
code will be available in the dmesg to help user to understand the
failure.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-7-dave.hansen%40intel.com

x86/virt/tdx: Make INTEL_TDX_HOST depend on X86_X2APIC

TDX capable platforms are locked to X2APIC mode and cannot fall back to
the legacy xAPIC mode when TDX is enabled by the BIOS. TDX host support
requires x2APIC. Make INTEL_TDX_HOST depend on X86_X2APIC.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/lkml/ba80b303-31bf-d44a-b05d-5c0f83038798@intel.com/
Link: https://lore.kernel.org/all/20231208170740.53979-3-dave.hansen%40intel.com

x86/topology: Switch over to GENERIC_CPU_DEVICES

Now that GENERIC_CPU_DEVICES calls arch_register_cpu(), which can be
overridden by the arch code, switch over to this to allow common code
to choose when the register_cpu() call is made.

x86's struct cpus come from struct x86_cpu, which has no other members
or users. Remove this and use the version defined by common code.

This is an intermediate step to the logic being moved to drivers/acpi,
where GENERIC_CPU_DEVICES will do the work when booting with acpi=off.

This patch also has the effect of moving the registration of CPUs from
subsys to driver core initialisation, prior to any initcalls running.

----
Changes since RFC:
* Fixed the second copy of arch_register_cpu() used for non-hotplug
Changes since RFC v2:
* Remove duplicate of the weak generic arch_register_cpu(), spotted
by Jonathan Cameron. Add note about initialisation order change.
Changes since RFC v3:
* Adapt to removal of EXPORT_SYMBOL()s

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R3l-00Cszm-UA@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI: Move ACPI_HOTPLUG_CPU to be disabled on arm64 and riscv

Neither arm64 nor riscv support physical hotadd of CPUs that were not
present at boot. For arm64 much of the platform description is in static
tables which do not have update methods. arm64 does support HOTPLUG_CPU,
which is backed by a firmware interface to turn CPUs on and off.

acpi_processor_hotadd_init() and acpi_processor_remove() are for adding
and removing CPUs that were not present at boot. arm64 systems that do this
are not supported as there is currently insufficient information in the
platform description. (e.g. did the GICR get removed too?)

arm64 currently relies on the MADT enabled flag check in map_gicc_mpidr()
to prevent CPUs that were not described as present at boot from being
added to the system. Similarly, riscv relies on the same check in
map_rintc_hartid(). Both architectures also rely on the weak 'always fails'
definitions of acpi_map_cpu() and arch_register_cpu().

Subsequent changes will redefine ACPI_HOTPLUG_CPU as making possible
CPUs present. Neither arm64 nor riscv support this.

Disable ACPI_HOTPLUG_CPU for arm64 and riscv by removing 'default y' and
selecting it on the other three ACPI architectures. This allows the weak
definitions of some symbols to be removed.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/E1r5R31-00Csyt-Jq@rmk-PC.armlinux.org.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

mm/mglru: add CONFIG_ARCH_HAS_HW_PTE_YOUNG

Patch series "mm/mglru: Kconfig cleanup", v4.

This series is the result of the following discussion:
https://lore.kernel.org/47066176-bd93-55dd-c2fa-002299d9e034@linux.ibm.com/

It mainly avoids building the code that walks page tables on CPUs that
use it, i.e., those don't support hardware accessed bit. Specifically,
it introduces a new Kconfig to guard some of functions added by
commit bd74fdaea146 ("mm: multi-gen LRU: support page table walks")
on CPUs like POWER9, on which the series was tested.


This patch (of 5):

Some architectures are able to set the accessed bit in PTEs when PTEs
are used as part of linear address translations.

Add CONFIG_ARCH_HAS_HW_PTE_YOUNG for such architectures to be able to
override arch_has_hw_pte_young().

Link: https://lkml.kernel.org/r/20231227141205.2200125-1-kinseyho@google.com
Link: https://lkml.kernel.org/r/20231227141205.2200125-2-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Co-developed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Tested-by: Donet Tom <donettom@linux.vnet.ibm.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile

Remove CONFIG_SLAB, CONFIG_DEBUG_SLAB, CONFIG_SLAB_DEPRECATED and
everything in Kconfig files and mm/Makefile that depends on those. Since
SLUB is the only remaining allocator, remove the allocator choice, make
CONFIG_SLUB a "def_bool y" for now and remove all explicit dependencies
on SLUB or SLAB as it's now always enabled. Make every option's verbose
name and description refer to "the slab allocator" without refering to
the specific implementation. Do not rename the CONFIG_ option names yet.

Everything under #ifdef CONFIG_SLAB, and mm/slab.c is now dead code, all
code under #ifdef CONFIG_SLUB is now always compiled.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

x86/Kconfig: Rework CONFIG_X86_PAE dependency

While looking at a Xen Kconfig dependency issue, I tried to understand the
exact dependencies for CONFIG_X86_PAE, which is selected by CONFIG_HIGHMEM64G
but can also be enabled manually.

Apparently the dependencies for CONFIG_HIGHMEM64G are strictly about CPUs
that do support PAE, but the actual feature can be incorrectly enabled on
older CPUs as well. The CONFIG_X86_CMPXCHG64 dependencies on the other hand
include X86_PAE because cmpxchg8b is requried for PAE to work.

Rework this for readability and correctness, using a positive list of CPUs
that support PAE in a new X86_HAVE_PAE symbol that can serve as a dependency
for both X86_PAE and HIGHMEM64G as well as simplify the X86_CMPXCHG64
dependency list.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231204084722.3789473-2-arnd@kernel.org

x86/Kconfig: Remove obsolete config X86_32_SMP

Commit

0f08c3b22996 ("x86/smp: Reduce code duplication")

removed the only use of CONFIG_X86_32_SMP.

Remove the now obsolete config X86_32_SMP too.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231128090016.29676-1-lukas.bulwahn@gmail.com

kexec: fix KEXEC_FILE dependencies

The cleanup for the CONFIG_KEXEC Kconfig logic accidentally changed the
'depends on CRYPTO=y' dependency to a plain 'depends on CRYPTO', which
causes a link failure when all the crypto support is in a loadable module
and kexec_file support is built-in:

x86_64-linux-ld: vmlinux.o: in function `__x64_sys_kexec_file_load':
(.text+0x32e30a): undefined reference to `crypto_alloc_shash'
x86_64-linux-ld: (.text+0x32e58e): undefined reference to `crypto_shash_update'
x86_64-linux-ld: (.text+0x32e6ee): undefined reference to `crypto_shash_final'

Both s390 and x86 have this problem, while ppc64 and riscv have the
correct dependency already. On riscv, the dependency is only used for the
purgatory, not for the kexec_file code itself, which may be a bit
surprising as it means that with CONFIG_CRYPTO=m, it is possible to enable
KEXEC_FILE but then the purgatory code is silently left out.

Move this into the common Kconfig.kexec file in a way that is correct
everywhere, using the dependency on CRYPTO_SHA256=y only when the
purgatory code is available. This requires reversing the dependency
between ARCH_SUPPORTS_KEXEC_PURGATORY and KEXEC_FILE, but the effect
remains the same, other than making riscv behave like the other ones.

On s390, there is an additional dependency on CRYPTO_SHA256_S390, which
should technically not be required but gives better performance. Remove
this dependency here, noting that it was not present in the initial
Kconfig code but was brought in without an explanation in commit
71406883fd357 ("s390/kexec_file: Add kexec_file_load system call").

[arnd@arndb.de: fix riscv build]
Link: https://lkml.kernel.org/r/67ddd260-d424-4229-a815-e3fcfb864a77@app.fastmail.com
Link: https://lkml.kernel.org/r/20231023110308.1202042-1-arnd@kernel.org
Fixes: 6af5138083005 ("x86/kexec: refactor for kernel/Kconfig.kexec")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Conor Dooley <conor@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/microcode: Prepare for minimal revision check

Applying microcode late can be fatal for the running kernel when the
update changes functionality which is in use already in a non-compatible
way, e.g. by removing a CPUID bit.

There is no way for admins which do not have access to the vendors deep
technical support to decide whether late loading of such a microcode is
safe or not.

Intel has added a new field to the microcode header which tells the
minimal microcode revision which is required to be active in the CPU in
order to be safe.

Provide infrastructure for handling this in the core code and a command
line switch which allows to enforce it.

If the update is considered safe the kernel is not tainted and the annoying
warning message not emitted. If it's enforced and the currently loaded
microcode revision is not safe for late loading then the load is aborted.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211724.079611170@linutronix.de

x86/microcode: Handle "nosmt" correctly

On CPUs where microcode loading is not NMI-safe the SMT siblings which
are parked in one of the play_dead() variants still react to NMIs.

So if an NMI hits while the primary thread updates the microcode the
resulting behaviour is undefined. The default play_dead() implementation on
modern CPUs is using MWAIT which is not guaranteed to be safe against
a microcode update which affects MWAIT.

Take the cpus_booted_once_mask into account to detect this case and
refuse to load late if the vendor specific driver does not advertise
that late loading is NMI safe.

AMD stated that this is safe, so mark the AMD driver accordingly.

This requirement will be partially lifted in later changes.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.087472735@linutronix.de

x86/microcode: Provide CONFIG_MICROCODE_INITRD32

Create an aggregate config switch which covers X86_32, MICROCODE and
BLK_DEV_INITRD to avoid lengthy #ifdeffery in upcoming code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211722.236208250@linutronix.de

x86: kdump: use generic interface to simplify crashkernel reservation code

With the help of newly changed function parse_crashkernel() and generic
reserve_crashkernel_generic(), crashkernel reservation can be simplified
by steps:

1) Add a new header file <asm/crash_core.h>, and define CRASH_ALIGN,
CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX and
DEFAULT_CRASH_KERNEL_LOW_SIZE in <asm/crash_core.h>;

2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
reserve_crashkernel_generic(), and do the ARCH specific work if
needed.

3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
arch/x86/Kconfig.

When adding DEFAULT_CRASH_KERNEL_LOW_SIZE, add crash_low_size_default() to
calculate crashkernel low memory because x86_64 has special requirement.

The old reserve_crashkernel_low() and reserve_crashkernel() can be
removed.

[bhe@redhat.com: move crash_low_size_default() code into <asm/crash_core.h>]
Link: https://lkml.kernel.org/r/ZQpeAjOmuMJBFw1/@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20230914033142.676708-7-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Jiahao <chenjiahao16@huawei.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/virt/tdx: Wire up basic SEAMCALL functions

Intel Trust Domain Extensions (TDX) protects guest VMs from malicious
host and certain physical attacks. A CPU-attested software module
called 'the TDX module' runs inside a new isolated memory range as a
trusted hypervisor to manage and run protected VMs.

TDX introduces a new CPU mode: Secure Arbitration Mode (SEAM). This
mode runs only the TDX module itself or other code to load the TDX
module.

The host kernel communicates with SEAM software via a new SEAMCALL
instruction. This is conceptually similar to a guest->host hypercall,
except it is made from the host to SEAM software instead. The TDX
module establishes a new SEAMCALL ABI which allows the host to
initialize the module and to manage VMs.

The SEAMCALL ABI is very similar to the TDCALL ABI and leverages much
TDCALL infrastructure. Wire up basic functions to make SEAMCALLs for
the basic support of running TDX guests: __seamcall(), __seamcall_ret(),
and __seamcall_saved_ret() for TDH.VP.ENTER. All SEAMCALLs involved in
the basic TDX support don't use "callee-saved" registers as input and
output, except the TDH.VP.ENTER.

To start to support TDX, create a new arch/x86/virt/vmx/tdx/tdx.c for
TDX host kernel support. Add a new Kconfig option CONFIG_INTEL_TDX_HOST
to opt-in TDX host kernel support (to distinguish with TDX guest kernel
support). So far only KVM uses TDX. Make the new config option depend
on KVM_INTEL.

Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Isaku Yamahata <isaku.yamahata@intel.com>
Link: https://lore.kernel.org/all/4db7c3fc085e6af12acc2932294254ddb3d320b3.1692096753.git.kai.huang%40intel.com

x86/numa: Add Devicetree support

Hyper-V has usecases where it needs to fetch NUMA information from
Devicetree. Currently, it is not possible to extract the NUMA information
from Devicetree for the x86 arch.

Add support for Devicetree in the x86_numa_init() function, allowing the
retrieval of NUMA node information from the Devicetree.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/1692949657-16446-2-git-send-email-ssengar@linux.microsoft.com

locking/lockref/x86: Enable ARCH_USE_CMPXCHG_LOCKREF for X86_CMPXCHG64

The following commit:

bc08b449ee14 ("lockref: implement lockless reference count updates using cmpxchg()")

enabled lockless reference count updates using cmpxchg() only for x86_64,
and left x86_32 behind due to inability to detect support for
cmpxchg8b instruction.

Nowadays, we can use CONFIG_X86_CMPXCHG64 for this purpose. Also,
by using try_cmpxchg64() instead of cmpxchg64() in the CMPXCHG_LOOP macro,
the compiler actually produces sane code, improving the
lockref_get_not_zero() main loop from:

eb: 8d 48 01 lea 0x1(%eax),%ecx
ee: 85 c0 test %eax,%eax
f0: 7e 2f jle 121 <lockref_get_not_zero+0x71>
f2: 8b 44 24 10 mov 0x10(%esp),%eax
f6: 8b 54 24 14 mov 0x14(%esp),%edx
fa: 8b 74 24 08 mov 0x8(%esp),%esi
fe: f0 0f c7 0e lock cmpxchg8b (%esi)
102: 8b 7c 24 14 mov 0x14(%esp),%edi
106: 89 c1 mov %eax,%ecx
108: 89 c3 mov %eax,%ebx
10a: 8b 74 24 10 mov 0x10(%esp),%esi
10e: 89 d0 mov %edx,%eax
110: 31 fa xor %edi,%edx
112: 31 ce xor %ecx,%esi
114: 09 f2 or %esi,%edx
116: 75 58 jne 170 <lockref_get_not_zero+0xc0>

to:

350: 8d 4f 01 lea 0x1(%edi),%ecx
353: 85 ff test %edi,%edi
355: 7e 79 jle 3d0 <lockref_get_not_zero+0xb0>
357: f0 0f c7 0e lock cmpxchg8b (%esi)
35b: 75 53 jne 3b0 <lockref_get_not_zero+0x90>

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20230918184050.9180-1-ubizjak@gmail.com

x86: Make IA32_EMULATION boot time configurable

Distributions would like to reduce their attack surface as much as
possible but at the same time they'd want to retain flexibility to cater
to a variety of legacy software. This stems from the conjecture that
compat layer is likely rarely tested and could have latent security
bugs. Ideally distributions will set their default policy and also
give users the ability to override it as appropriate.

To enable this use case, introduce CONFIG_IA32_EMULATION_DEFAULT_DISABLED
compile time option, which controls whether 32bit processes/syscalls
should be allowed or not. This option is aimed mainly at distributions
to set their preferred default behavior in their kernels.

To allow users to override the distro's policy, introduce the 'ia32_emulation'
parameter which allows overriding CONFIG_IA32_EMULATION_DEFAULT_DISABLED
state at boot time.

Signed-off-by: Nikolay Borisov <nik.borisov@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230623111409.3047467-7-nik.borisov@suse.com

efi/x86: Ensure that EFI_RUNTIME_MAP is enabled for kexec

CONFIG_EFI_RUNTIME_MAP needs to be enabled in order for kexec to be able
to provide the required information about the EFI runtime mappings to
the incoming kernel, regardless of whether kexec_load() or
kexec_file_load() is being used. Without this information, kexec boot in
EFI mode is not possible.

The CONFIG_EFI_RUNTIME_MAP option is currently directly configurable if
CONFIG_EXPERT is enabled, so that it can be turned on for debugging
purposes even if KEXEC is not enabled. However, the upshot of this is
that it can also be disabled even when it shouldn't.

So tweak the Kconfig declarations to avoid this situation.

Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

x86/kbuild: Fix Documentation/ reference

x86 documentation moved. Fix the reference.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202307271956.IxoG9X0c-lkp@intel.com/

x86/shstk: Add Kconfig option for shadow stack

Shadow stack provides protection for applications against function return
address corruption. It is active when the processor supports it, the
kernel has CONFIG_X86_SHADOW_STACK enabled, and the application is built
for the feature. This is only implemented for the 64-bit kernel. When it
is enabled, legacy non-shadow stack applications continue to work, but
without protection.

Since there is another feature that utilizes CET (Kernel IBT) that will
share implementation with shadow stacks, create CONFIG_CET to signify
that at least one CET feature is configured.

Co-developed-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-7-rick.p.edgecombe%40intel.com

x86/crash: add x86 crash hotplug support

When CPU or memory is hot un/plugged, or off/onlined, the crash
elfcorehdr, which describes the CPUs and memory in the system, must also
be updated.

A new elfcorehdr is generated from the available CPUs and memory and
replaces the existing elfcorehdr. The segment containing the elfcorehdr
is identified at run-time in crash_core:crash_handle_hotplug_event().

No modifications to purgatory (see 'kexec: exclude elfcorehdr from the
segment digest') or boot_params (as the elfcorehdr= capture kernel command
line parameter pointer remains unchanged and correct) are needed, just
elfcorehdr.

For kexec_file_load(), the elfcorehdr segment size is based on NR_CPUS and
CRASH_MAX_MEMORY_RANGES in order to accommodate a growing number of CPU
and memory resources.

For kexec_load(), the userspace kexec utility needs to size the elfcorehdr
segment in the same/similar manner.

To accommodate kexec_load() syscall in the absence of kexec_file_load()
syscall support, prepare_elf_headers() and dependents are moved outside of
CONFIG_KEXEC_FILE.

[eric.devolder@oracle.com: correct unused function build error]
Link: https://lkml.kernel.org/r/20230821182644.2143-1-eric.devolder@oracle.com
Link: https://lkml.kernel.org/r/20230814214446.6659-6-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Akhil Raj <lf32.dev@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory_hotplug: simplify ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE kconfig

Patch series "Add support for memmap on memory feature on ppc64", v8.

This patch series update memmap on memory feature to fall back to
memmap allocation outside the memory block if the alignment rules are
not met. This makes the feature more useful on architectures like
ppc64 where alignment rules are different with 64K page size.


This patch (of 6):

Instead of adding menu entry with all supported architectures, add
mm/Kconfig variable and select the same from supported architectures.

No functional change in this patch.

Link: https://lkml.kernel.org/r/20230808091501.287660-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20230808091501.287660-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: rename ARCH_HAS_KEXEC_PURGATORY

The Kconfig refactor to consolidate KEXEC and CRASH options utilized
option names of the form ARCH_SUPPORTS_<option>. Thus rename the
ARCH_HAS_KEXEC_PURGATORY to ARCH_SUPPORTS_KEXEC_PURGATORY to follow
the same.

Link: https://lkml.kernel.org/r/20230712161545.87870-15-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/kexec: refactor for kernel/Kconfig.kexec

The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.

Link: https://lkml.kernel.org/r/20230712161545.87870-3-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmemmap optimization: split hugetlb and devdax vmemmap optimization

Arm disabled hugetlb vmemmap optimization [1] because hugetlb vmemmap
optimization includes an update of both the permissions (writeable to
read-only) and the output address (pfn) of the vmemmap ptes. That is not
supported without unmapping of pte(marking it invalid) by some
architectures.

With DAX vmemmap optimization we don't require such pte updates and
architectures can enable DAX vmemmap optimization while having hugetlb
vmemmap optimization disabled. Hence split DAX optimization support into
a different config.

s390, loongarch and riscv don't have devdax support. So the DAX config is
not enabled for them. With this change, arm64 should be able to select
DAX optimization

[1] commit 060a2c92d1b6 ("arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP")

Link: https://lkml.kernel.org/r/20230724190759.483013-8-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/microcode: Hide the config knob

In reality CONFIG_MICROCODE is enabled in any reasonable configuration when
Intel or AMD support is enabled. Accommodate to reality.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230812195727.660453052@linutronix.de

x86/srso: Add a Speculative RAS Overflow mitigation

Add a mitigation for the speculative return address stack overflow
vulnerability found on AMD processors.

The mitigation works by ensuring all RET instructions speculate to
a controlled location, similar to how speculation is controlled in the
retpoline sequence. To accomplish this, the __x86_return_thunk forces
the CPU to mispredict every function return using a 'safe return'
sequence.

To ensure the safety of this mitigation, the kernel must ensure that the
safe return sequence is itself free from attacker interference. In Zen3
and Zen4, this is accomplished by creating a BTB alias between the
untraining function srso_untrain_ret_alias() and the safe return
function srso_safe_ret_alias() which results in evicting a potentially
poisoned BTB entry and using that safe one for all function returns.

In older Zen1 and Zen2, this is accomplished using a reinterpretation
technique similar to Retbleed one: srso_untrain_ret() and
srso_safe_ret().

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>

x86/speculation: Add Kconfig option for GDS

Gather Data Sampling (GDS) is mitigated in microcode. However, on
systems that haven't received the updated microcode, disabling AVX
can act as a mitigation. Add a Kconfig option that uses the microcode
mitigation if available and disables AVX otherwise. Setting this
option has no effect on systems not affected by GDS. This is the
equivalent of setting gather_data_sampling=force.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>

x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL

The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the x86 platform.

We introduce a new structure called fgraph_ret_regs for the x86
platform to hold return registers and the frame pointer. We then
fill its content in the return_to_handler and pass its address
to the function ftrace_return_to_handler to record the return
value.

Link: https://lkml.kernel.org/r/53a506f0f18ff4b7aeb0feb762f1c9a5e9b83ee9.1680954589.git.pengdonglin@sangfor.com.cn

Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

mm: introduce new 'lock_mm_and_find_vma()' page fault helper

.. and make x86 use it.

This basically extracts the existing x86 "find and expand faulting vma"
code, but extends it to also take the mmap lock for writing in case we
actually do need to expand the vma.

We've historically short-circuited that case, and have some rather ugly
special logic to serialize the stack segment expansion (since we only
hold the mmap lock for reading) that doesn't match the normal VM
locking.

That slight violation of locking worked well, right up until it didn't:
the maple tree code really does want proper locking even for simple
extension of an existing vma.

So extract the code for "look up the vma of the fault" from x86, fix it
up to do the necessary write locking, and make it available as a helper
function for other architectures that can use the common helper.

Note: I say "common helper", but it really only handles the normal
stack-grows-down case. Which is all architectures except for PA-RISC
and IA64. So some rare architectures can't use the helper, but if they
care they'll just need to open-code this logic.

It's also worth pointing out that this code really would like to have an
optimistic "mmap_upgrade_trylock()" to make it quicker to go from a
read-lock (for the common case) to taking the write lock (for having to
extend the vma) in the normal single-threaded situation where there is
no other locking activity.

But that _is_ all the very uncommon special case, so while it would be
nice to have such an operation, it probably doesn't matter in reality.
I did put in the skeleton code for such a possible future expansion,
even if it only acts as pseudo-documentation for what we're doing.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/cpu: Switch to arch_cpu_finalize_init()

check_bugs() is a dumping ground for finalizing the CPU bringup. Only parts of
it has to do with actual CPU bugs.

Split it apart into arch_cpu_finalize_init() and cpu_select_mitigations().

Fixup the bogus 32bit comments while at it.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230613224545.019583869@linutronix.de

x86/sev: Add SNP-specific unaccepted memory support

Add SNP-specific hooks to the unaccepted memory support in the boot
path (__accept_memory()) and the core kernel (accept_memory()) in order
to support booting SNP guests when unaccepted memory is present. Without
this support, SNP guests will fail to boot and/or panic() when unaccepted
memory is present in the EFI memory map.

The process of accepting memory under SNP involves invoking the hypervisor
to perform a page state change for the page to private memory and then
issuing a PVALIDATE instruction to accept the page.

Since the boot path and the core kernel paths perform similar operations,
move the pvalidate_pages() and vmgexit_psc() functions into sev-shared.c
to avoid code duplication.

Create the new header file arch/x86/boot/compressed/sev.h because adding
the function declaration to any of the existing SEV related header files
pulls in too many other header files, causing the build to fail.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/a52fa69f460fd1876d70074b20ad68210dfc31dd.1686063086.git.thomas.lendacky@amd.com

x86/tdx: Add unaccepted memory support

Hookup TDX-specific code to accept memory.

Accepting the memory is done with ACCEPT_PAGE module call on every page
in the range. MAP_GPA hypercall is not required as the unaccepted memory
is considered private already.

Extract the part of tdx_enc_status_changed() that does memory acceptance
in a new helper. Move the helper tdx-shared.c. It is going to be used by
both main kernel and decompressor.

[ bp: Fix the INTEL_TDX_GUEST=y, KVM_GUEST=n build. ]

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230606142637.5171-10-kirill.shutemov@linux.intel.com

x86/cpu: Remove X86_FEATURE_NAMES

While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.

As the need for really tiny kernel images has gone away and kernel images
with !X86_FEATURE_NAMES are hardly tested, remove this config and the whole
ifdeffery in the source code.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/
Link: https://lore.kernel.org/r/20230510065713.10996-3-lukas.bulwahn@gmail.com

x86/Kconfig: Make X86_FEATURE_NAMES non-configurable in prompt

While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.

As a first step, make X86_FEATURE_NAMES disappear from Kconfig. So, as
X86_FEATURE_NAMES defaults to yes, to disable it, one now needs to
modify the .config file before compiling the kernel.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/

x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it

Implement the validation function which tells the core code whether
parallel bringup is possible.

The only condition for now is that the kernel does not run in an encrypted
guest as these will trap the RDMSR via #VC, which cannot be handled at that
point in early startup.

There was an earlier variant for AMD-SEV which used the GHBC protocol for
retrieving the APIC ID via CPUID, but there is no guarantee that the
initial APIC ID in CPUID is the same as the real APIC ID. There is no
enforcement from the secure firmware and the hypervisor can assign APIC IDs
as it sees fit as long as the ACPI/MADT table is consistent with that
assignment.

Unfortunately there is no RDMSR GHCB protocol at the moment, so enabling
AMD-SEV guests for parallel startup needs some more thought.

Intel-TDX provides a secure RDMSR hypercall, but supporting that is outside
the scope of this change.

Fixup announce_cpu() as e.g. on Hyper-V CPU1 is the secondary sibling of
CPU0, which makes the @cpu == 1 logic in announce_cpu() fall apart.

[ mikelley: Reported the announce_cpu() fallout

Originally-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.467571745@linutronix.de

x86/smpboot: Enable split CPU startup

The x86 CPU bringup state currently does AP wake-up, wait for AP to
respond and then release it for full bringup.

It is safe to be split into a wake-up and and a separate wait+release
state.

Provide the required functions and enable the split CPU bringup, which
prepares for parallel bringup, where the bringup of the non-boot CPUs takes
two iterations: One to prepare and wake all APs and the second to wait and
release them. Depending on timing this can eliminate the wait time
completely.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205257.133453992@linutronix.de

x86/smpboot: Switch to hotplug core state synchronization

The new AP state tracking and synchronization mechanism in the CPU hotplug
core code allows to remove quite some x86 specific code:

1) The AP alive synchronization based on cpumasks

2) The decision whether an AP can be brought up again

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.529657366@linutronix.de

x86/topology: Remove CPU0 hotplug option

This was introduced together with commit e1c467e69040 ("x86, hotplug: Wake
up CPU0 via NMI instead of INIT, SIPI, SIPI") to eventually support
physical hotplug of CPU0:

"We'll change this code in the future to wake up hard offlined CPU0 if
real platform and request are available."

11 years later this has not happened and physical hotplug is not officially
supported. Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205255.715707999@linutronix.de

mm/hugetlb_vmemmap: rename ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP

Now we use ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP config option to
indicate devdax and hugetlb vmemmap optimization support. Hence rename
that to a generic ARCH_WANT_OPTIMIZE_VMEMMAP

Link: https://lkml.kernel.org/r/20230412050025.84346-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Tarun Sahu <tsahu@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/mm: try VMA lock-based page fault handling first

Attempt VMA lock-based page fault handling first, and fall back to the
existing mmap_lock-based handling if that fails.

Link: https://lkml.kernel.org/r/20230227173632.3292573-30-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86: CPUID and CR3/CR4 flags for Linear Address Masking

Enumerate Linear Address Masking and provide defines for CR3 and CR4
flags.

The new CONFIG_ADDRESS_MASKING option enables the feature support in
kernel.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-4-kirill.shutemov%40linux.intel.com

Kconfig: introduce HAS_IOPORT option and select it as necessary

We introduce a new HAS_IOPORT Kconfig option to indicate support for I/O
Port access. In a future patch HAS_IOPORT=n will disable compilation of
the I/O accessor functions inb()/outb() and friends on architectures
which can not meaningfully support legacy I/O spaces such as s390.

The following architectures do not select HAS_IOPORT:

* ARC
* C-SKY
* Hexagon
* Nios II
* OpenRISC
* s390
* User-Mode Linux
* Xtensa

All other architectures select HAS_IOPORT at least conditionally.

The "depends on" relations on HAS_IOPORT in drivers as well as ifdefs
for HAS_IOPORT specific sections will be added in subsequent patches on
a per subsystem basis.

Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net> # for ARCH=um
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/x86: Remove "select SRCU"

Now that the SRCU Kconfig option is unconditionally selected, there is
no longer any point in selecting it. Therefore, remove the "select SRCU"
Kconfig statements.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>

docs: move x86 documentation into Documentation/arch/

Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.

All in-kernel references to the old paths have been updated.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

x86/Kconfig: Fix spellos & punctuation

Fix spelling (reported by codespell) & punctuation in arch/x86/ Kconfig.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230124181753.19309-1-rdunlap@infradead.org

mm: Rename GUP_GET_PTE_LOW_HIGH

Since it no longer applies to only PTEs, rename it to PXX.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221022114424.776404066%40infradead.org

objtool: Add --mnop as an option to --mcount

Some architectures (powerpc) may not support ftrace locations being nop'ed
out at build time. Introduce CONFIG_HAVE_OBJTOOL_NOP_MCOUNT for objtool, as
a means for architectures to enable nop'ing of ftrace locations. Add --mnop
as an option to objtool --mcount, to indicate support for the same.

Also, make sure that --mnop can be passed as an option to objtool only when
--mcount is passed.

Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221114175754.1131267-12-sv@linux.ibm.com

x86/Kconfig: Enable kernel IBT by default

The kernel IBT defense strongly mitigates the common "first step" of ROP
attacks, by eliminating arbitrary stack pivots (that appear either at
the end of a function or in immediate values), which cannot be reached
if indirect calls must be to marked function entry addresses. IBT is
also required to be enabled to gain the FineIBT feature when built with
Kernel Control Flow Integrity.

Additionally, given that this feature is runtime enabled via CPU ID,
it clearly should be built in by default; it will only be enabled if the
CPU supports it. The build takes 2 seconds longer, which seems a small
price to pay for gaining this coverage by default.

Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221101172503.gonna.094-kees@kernel.org

x86/ibt: Implement FineIBT

Implement an alternative CFI scheme that merges both the fine-grained
nature of kCFI but also takes full advantage of the coarse grained
hardware CFI as provided by IBT.

To contrast:

kCFI is a pure software CFI scheme and relies on being able to read
text -- specifically the instruction *before* the target symbol, and
does the hash validation *before* doing the call (otherwise control
flow is compromised already).

FineIBT is a software and hardware hybrid scheme; by ensuring every
branch target starts with a hash validation it is possible to place
the hash validation after the branch. This has several advantages:

o the (hash) load is avoided; no memop; no RX requirement.

o IBT WAIT-FOR-ENDBR state is a speculation stop; by placing
the hash validation in the immediate instruction after
the branch target there is a minimal speculation window
and the whole is a viable defence against SpectreBHB.

o Kees feels obliged to mention it is slightly more vulnerable
when the attacker can write code.

Obviously this patch relies on kCFI, but additionally it also relies
on the padding from the call-depth-tracking patches. It uses this
padding to place the hash-validation while the call-sites are
re-written to modify the indirect target to be 16 bytes in front of
the original target, thus hitting this new preamble.

Notably, there is no hardware that needs call-depth-tracking (Skylake)
and supports IBT (Tigerlake and onwards).

Suggested-by: Joao Moreira (Intel) <joao@overdrivepizza.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20221027092842.634714496@infradead.org

x86: Add prefix symbols for function padding

When code is compiled with:

-fpatchable-function-entry=${PADDING_BYTES},${PADDING_BYTES}

functions will have PADDING_BYTES of NOP in front of them. Unwinders
and other things that symbolize code locations will typically
attribute these bytes to the preceding function.

Given that these bytes nominally belong to the following symbol this
mis-attribution is confusing.

Inspired by the fact that CFI_CLANG emits __cfi_##name symbols to
claim these bytes, use objtool to emit __pfx_##name symbols to do
the same when CFI_CLANG is not used.

This then shows the callthunk for symbol 'name' as:

__pfx_##name+0x6/0x10

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Link: https://lkml.kernel.org/r/20221028194453.592512209@infradead.org

x86/callthunks: Add call patching for call depth tracking

Mitigating the Intel SKL RSB underflow issue in software requires to
track the call depth. That is every CALL and every RET need to be
intercepted and additional code injected.

The existing retbleed mitigations already include means of redirecting
RET to __x86_return_thunk; this can be re-purposed and RET can be
redirected to another function doing RET accounting.

CALL accounting will use the function padding introduced in prior
patches. For each CALL instruction, the destination symbol's padding
is rewritten to do the accounting and the CALL instruction is adjusted
to call into the padding.

This ensures only affected CPUs pay the overhead of this accounting.
Unaffected CPUs will leave the padding unused and have their 'JMP
__x86_return_thunk' replaced with an actual 'RET' instruction.

Objtool has been modified to supply a .call_sites section that lists
all the 'CALL' instructions. Additionally the paravirt instruction
sites are iterated since they will have been patched from an indirect
call to direct calls (or direct instructions in which case it'll be
ignored).

Module handling and the actual thunk code for SKL will be added in
subsequent steps.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.470877038@infradead.org

x86/retbleed: Add X86_FEATURE_CALL_DEPTH

Intel SKL CPUs fall back to other predictors when the RSB underflows. The
only microcode mitigation is IBRS which is insanely expensive. It comes
with performance drops of up to 30% depending on the workload.

A way less expensive, but nevertheless horrible mitigation is to track the
call depth in software and overeagerly fill the RSB when returns underflow
the software counter.

Provide a configuration symbol and a CPU misfeature bit.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111147.056176424@infradead.org

x86/Kconfig: Introduce function padding

Now that all functions are 16 byte aligned, add 16 bytes of NOP
padding in front of each function. This prepares things for software
call stack tracking and kCFI/FineIBT.

This significantly increases kernel .text size, around 5.1% on a
x86_64-defconfig-ish build.

However, per the random access argument used for alignment, these 16
extra bytes are code that wouldn't be used. Performance measurements
back this up by showing no significant performance regressions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.950884492@infradead.org

x86/Kconfig: Add CONFIG_CALL_THUNKS

In preparation for mitigating the Intel SKL RSB underflow issue in
software, add a new configuration symbol which allows to build the
required call thunk infrastructure conditionally.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111146.849523555@infradead.org

arch: Introduce CONFIG_FUNCTION_ALIGNMENT

Generic function-alignment infrastructure.

Architectures can select FUNCTION_ALIGNMENT_xxB symbols; the
FUNCTION_ALIGNMENT symbol is then set to the largest such selected
size, 0 otherwise.

From this the -falign-functions compiler argument and __ALIGN macro
are set.

This incorporates the DEBUG_FORCE_FUNCTION_ALIGN_64B knob and future
alignment requirements for x86_64 (later in this series) into a single
place.

NOTE: also removes the 0x90 filler byte from the generic __ALIGN
primitive, that value makes no sense outside of x86.

NOTE: .balign 0 reverts to a no-op.

Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220915111143.719248727@infradead.org

x86: Remove CONFIG_ARCH_NR_GPIO

CONFIG_ARCH_NR_GPIO is not used anymore, remove it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

x86/apic: Handle no CONFIG_X86_X2APIC on systems with x2APIC enabled by BIOS

A kernel that was compiled without CONFIG_X86_X2APIC was unable to boot on
platforms that have x2APIC already enabled in the BIOS before starting the
kernel.

The kernel was supposed to panic with an approprite error message in
validate_x2apic() due to the missing X2APIC support.

However, validate_x2apic() was run too late in the boot cycle, and the
kernel tried to initialize the APIC nonetheless. This resulted in an
earlier panic in setup_local_APIC() because the APIC was not registered.

In my experiments, a panic message in setup_local_APIC() was not visible
in the graphical console, which resulted in a hang with no indication
what has gone wrong.

Instead of calling panic(), disable the APIC, which results in a somewhat
working system with the PIC only (and no SMP). This way the user is able to
diagnose the problem more easily.

Disabling X2APIC mode is not an option because it's impossible on systems
with locked x2APIC.

The proper place to disable the APIC in this case is in check_x2apic(),
which is called early from setup_arch(). Doing this in
__apic_intr_mode_select() is too late.

Make check_x2apic() unconditionally available and remove the empty stub.

Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reported-by: Robert Elliott (Servers) <elliott@hpe.com>
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/d573ba1c-0dc4-3016-712a-cc23a8a33d42@molgen.mpg.de
Link: https://lore.kernel.org/lkml/20220911084711.13694-3-mat.jonczyk@o2.pl
Link: https://lore.kernel.org/all/20221129215008.7247-1-mat.jonczyk@o2.pl

x86/efi: Make the deprecated EFI handover protocol optional

The EFI handover protocol permits a bootloader to invoke the kernel as a
EFI PE/COFF application, while passing a bootparams struct as a third
argument to the entrypoint function call.

This has no basis in the UEFI specification, and there are better ways
to pass additional data to a UEFI application (UEFI configuration
tables, UEFI variables, UEFI protocols) than going around the
StartImage() boot service and jumping to a fixed offset in the loaded
image, just to call a different function that takes a third parameter.

The reason for handling struct bootparams in the bootloader was that the
EFI stub could only load initrd images from the EFI system partition,
and so passing it via struct bootparams was needed for loaders like
GRUB, which pass the initrd in memory, and may load it from anywhere,
including from the network. Another motivation was EFI mixed mode, which
could not use the initrd loader in the EFI stub at all due to 32/64 bit
incompatibilities (which will be fixed shortly [0]), and could not
invoke the ordinary PE/COFF entry point either, for the same reasons.

Given that loaders such as GRUB already carried the bootparams handling
in order to implement non-EFI boot, retaining that code and just passing
bootparams to the EFI stub was a reasonable choice (although defining an
alternate entrypoint could have been avoided.) However, the GRUB side
changes never made it upstream, and are only shipped by some of the
distros in their downstream versions.

In the meantime, EFI support has been added to other Linux architecture
ports, as well as to U-boot and systemd, including arch-agnostic methods
for passing initrd images in memory [1], and for doing mixed mode boot
[2], none of them requiring anything like the EFI handover protocol. So
given that only out-of-tree distro GRUB relies on this, let's permit it
to be omitted from the build, in preparation for retiring it completely
at a later date. (Note that systemd-boot does have an implementation as
well, but only uses it as a fallback for booting images that do not
implement the LoadFile2 based initrd loading method, i.e., v5.8 or older)

[0] https://lore.kernel.org/all/20220927085842.2860715-1-ardb@kernel.org/
[1] ec93fc371f01 ("efi/libstub: Add support for loading the initrd from a device path")
[2] 97aa276579b2 ("efi/x86: Add true mixed mode entry point into .compat section")

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221122161017.2426828-18-ardb@kernel.org

efi: x86: Move EFI runtime map sysfs code to arch/x86

The EFI runtime map code is only wired up on x86, which is the only
architecture that has a need for it in its implementation of kexec.

So let's move this code under arch/x86 and drop all references to it
from generic code. To ensure that the efi_runtime_map_init() is invoked
at the appropriate time use a 'sync' subsys_initcall() that will be
called right after the EFI initcall made from generic code where the
original invocation of efi_runtime_map_init() resided.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dave Young <dyoung@redhat.com>

efi: memmap: Move EFI fake memmap support into x86 arch tree

The EFI fake memmap support is specific to x86, which manipulates the
EFI memory map in various different ways after receiving it from the EFI
stub. On other architectures, we have managed to push back on this, and
the EFI memory map is kept pristine.

So let's move the fake memmap code into the x86 arch tree, where it
arguably belongs.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

PCI/MSI: Get rid of PCI_MSI_IRQ_DOMAIN

What a zoo:

PCI_MSI
select GENERIC_MSI_IRQ

PCI_MSI_IRQ_DOMAIN
def_bool y
depends on PCI_MSI
select GENERIC_MSI_IRQ_DOMAIN

Ergo PCI_MSI enables PCI_MSI_IRQ_DOMAIN which in turn selects
GENERIC_MSI_IRQ_DOMAIN. So all the dependencies on PCI_MSI_IRQ_DOMAIN are
just an indirection to PCI_MSI.

Match the reality and just admit that PCI_MSI requires
GENERIC_MSI_IRQ_DOMAIN.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122014.467556921@linutronix.de

memregion: Add cpu_cache_invalidate_memregion() interface

With CXL security features, and CXL dynamic provisioning, global CPU
cache flushing nvdimm requirements are no longer specific to that
subsystem, even beyond the scope of security_ops. CXL will need such
semantics for features not necessarily limited to persistent memory.

The functionality this is enabling is to be able to instantaneously
secure erase potentially terabytes of memory at once and the kernel
needs to be sure that none of the data from before the erase is still
present in the cache. It is also used when unlocking a memory device
where speculative reads and firmware accesses could have cached poison
from before the device was unlocked. Lastly this facility is used when
mapping new devices, or new capacity into an established physical
address range. I.e. when the driver switches DeviceA mapping AddressX to
DeviceB mapping AddressX then any cached data from DeviceA:AddressX
needs to be invalidated.

This capability is typically only used once per-boot (for unlock), or
once per bare metal provisioning event (secure erase), like when handing
off the system to another tenant or decommissioning a device. It may
also be used for dynamic CXL region provisioning.

Users must first call cpu_cache_has_invalidate_memregion() to know
whether this functionality is available on the architecture. On x86 this
respects the constraints of when wbinvd() is tolerable. It is already
the case that wbinvd() is problematic to allow in VMs due its global
performance impact and KVM, for example, has been known to just trap and
ignore the call. With confidential computing guest execution of wbinvd()
may even trigger an exception. Given guests should not be messing with
the bare metal address map via CXL configuration changes
cpu_cache_has_invalidate_memregion() returns false in VMs.

While this global cache invalidation facility, is exported to modules,
since NVDIMM and CXL support can be built as a module, it is not for
general use. The intent is that this facility is not available outside
of specific "device-memory" use cases. To make that expectation as clear
as possible the API is scoped to a new "DEVMEM" module namespace that
only the NVDIMM and CXL subsystems are expected to import.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Co-developed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

arch/x86: Add ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option

The x86 architecture uses an add-to-memory instruction to implement
this_cpu_add(), which is NMI safe. This means that the old and
more-efficient srcu_read_lock() may be used in NMI context, without
the need for srcu_read_lock_nmisafe(). Therefore, add the new Kconfig
option ARCH_HAS_NMI_SAFE_THIS_CPU_OPS to arch/x86/Kconfig, which will
cause NEED_SRCU_NMI_SAFE to be deselected, thus preserving the current
srcu_read_lock() behavior.

Link: https://lore.kernel.org/all/20220910221947.171557773@linutronix.de/

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: <x86@kernel.org>

x86/Kconfig: Drop check for -mabi=ms for CONFIG_EFI_STUB

A recent change in LLVM made CONFIG_EFI_STUB unselectable because it no
longer pretends to support -mabi=ms, breaking the dependency in
Kconfig. Lack of CONFIG_EFI_STUB can prevent kernels from booting via
EFI in certain circumstances.

This check was added by

8f24f8c2fc82 ("efi/libstub: Annotate firmware routines as __efiapi")

to ensure that __attribute__((ms_abi)) was available, as -mabi=ms is
not actually used in any cflags.

According to the GCC documentation, this attribute has been supported
since GCC 4.4.7. The kernel currently requires GCC 5.1 so this check is
not necessary; even when that change landed in 5.6, the kernel required
GCC 4.9 so it was unnecessary then as well.

Clang supports __attribute__((ms_abi)) for all versions that are
supported for building the kernel so no additional check is needed.
Remove the 'depends on' line altogether to allow CONFIG_EFI_STUB to be
selected when CONFIG_EFI is enabled, regardless of compiler.

Fixes: 8f24f8c2fc82 ("efi/libstub: Annotate firmware routines as __efiapi")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org
Link: https://github.com/llvm/llvm-project/commit/d1ad006a8f64bdc17f618deffa9e7c91d82c444d

x86: kmsan: enable KMSAN builds for x86

Make KMSAN usable by adding the necessary Kconfig bits.

Also declare x86-specific functions checking address validity in
arch/x86/include/asm/kmsan.h.

Link: https://lkml.kernel.org/r/20220915150417.722975-44-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS

dentry_string_cmp() calls read_word_at_a_time(), which might read
uninitialized bytes to optimize string comparisons. Disabling
CONFIG_DCACHE_WORD_ACCESS should prohibit this optimization, as well as
(probably) similar ones.

Link: https://lkml.kernel.org/r/20220915150417.722975-39-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN

This is needed to allow memory tools like KASAN and KMSAN see the memory
accesses from the checksum code. Without CONFIG_GENERIC_CSUM the tools
can't see memory accesses originating from handwritten assembly code.

For KASAN it's a question of detecting more bugs, for KMSAN using the C
implementation also helps avoid false positives originating from seemingly
uninitialized checksum values.

Link: https://lkml.kernel.org/r/20220915150417.722975-38-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG

Some architectures support the accessed bit in non-leaf PMD entries, e.g.,
x86 sets the accessed bit in a non-leaf PMD entry when using it as part of
linear address translation [1]. Page table walkers that clear the
accessed bit may use this capability to reduce their search space.

Note that:
1. Although an inline function is preferable, this capability is added
as a configuration option for consistency with the existing macros.
2. Due to the little interest in other varieties, this capability was
only tested on Intel and AMD CPUs.

Thanks to the following developers for their efforts [2][3].
Randy Dunlap <rdunlap@infradead.org>
Stephen Rothwell <sfr@canb.auug.org.au>

[1]: Intel 64 and IA-32 Architectures Software Developer's Manual
Volume 3 (June 2021), section 4.8
[2] https://lore.kernel.org/r/bfdcc7c8-922f-61a9-aa15-7e7250f04af7@infradead.org/
[3] https://lore.kernel.org/r/20220413151513.5a0d7a7e@canb.auug.org.au/

Link: https://lkml.kernel.org/r/20220918080010.2920238-3-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

bpf: Move bpf_dispatcher function out of ftrace locations

The dispatcher function is attached/detached to trampoline by
dispatcher update function. At the same time it's available as
ftrace attachable function.

After discussion [1] the proposed solution is to use compiler
attributes to alter bpf_dispatcher_##name##_func function:

- remove it from being instrumented with __no_instrument_function__
attribute, so ftrace has no track of it

- but still generate 5 nop instructions with patchable_function_entry(5)
attribute, which are expected by bpf_arch_text_poke used by
dispatcher update function

Enabling HAVE_DYNAMIC_FTRACE_NO_PATCHABLE option for x86, so
__patchable_function_entries functions are not part of ftrace/mcount
locations.

Adding attributes to bpf_dispatcher_XXX function on x86_64 so it's
kept out of ftrace locations and has 5 byte nop generated at entry.

These attributes need to be arch specific as pointed out by Ilya
Leoshkevic in here [2].

The dispatcher image is generated only for x86_64 arch, so the
code can stay as is for other archs.

[1] https://lore.kernel.org/bpf/20220722110811.124515-1-jolsa@kernel.org/
[2] https://lore.kernel.org/bpf/969a14281a7791c334d476825863ee449964dd0c.camel@linux.ibm.com/

Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/bpf/20220903131154.420467-3-jolsa@kernel.org

x86/Kconfig: Specify idle=poll instead of no-hlt

Commit 27be45700021 ("x86 idle: remove 32-bit-only "no-hlt" parameter,
hlt_works_ok flag") removed no-hlt, but CONFIG_APM still refers to
it. Suggest "idle=poll" instead, based on the commit message:

> If a user wants to avoid HLT, then "idle=poll"
> is much more useful, as it avoids invocation of HLT
> in idle, while "no-hlt" failed to do so.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220713160840.1577569-1-steve@sk2.org

x86/apic: Don't disable x2APIC if locked

The APIC supports two modes, legacy APIC (or xAPIC), and Extended APIC
(or x2APIC). X2APIC mode is mostly compatible with legacy APIC, but
it disables the memory-mapped APIC interface in favor of one that uses
MSRs. The APIC mode is controlled by the EXT bit in the APIC MSR.

The MMIO/xAPIC interface has some problems, most notably the APIC LEAK
[1]. This bug allows an attacker to use the APIC MMIO interface to
extract data from the SGX enclave.

Introduce support for a new feature that will allow the BIOS to lock
the APIC in x2APIC mode. If the APIC is locked in x2APIC mode and the
kernel tries to disable the APIC or revert to legacy APIC mode a GP
fault will occur.

Introduce support for a new MSR (IA32_XAPIC_DISABLE_STATUS) and handle
the new locked mode when the LEGACY_XAPIC_DISABLED bit is set by
preventing the kernel from trying to disable the x2APIC.

On platforms with the IA32_XAPIC_DISABLE_STATUS MSR, if SGX or TDX are
enabled the LEGACY_XAPIC_DISABLED will be set by the BIOS. If
legacy APIC is required, then it SGX and TDX need to be disabled in the
BIOS.

[1]: https://aepicleak.com/aepicleak.pdf

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Neelima Krishnan <neelima.krishnan@intel.com>
Link: https://lkml.kernel.org/r/20220816231943.1152579-1-daniel.sneddon@linux.intel.com

x86: enable initial Rust support

Note that only x86_64 is covered and not all features nor mitigations
are handled, but it is enough as a starting point and showcases
the basics needed to add Rust support for a new architecture.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com>
Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com>
Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Co-developed-by: David Gow <davidgow@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

x86: Add support for CONFIG_CFI_CLANG

With CONFIG_CFI_CLANG, the compiler injects a type preamble immediately
before each function and a check to validate the target function type
before indirect calls:

; type preamble
__cfi_function:
mov <id>, %eax
function:
...
; indirect call check
mov -<id>,%r10d
add -0x4(%r11),%r10d
je .Ltmp1
ud2
.Ltmp1:
call __x86_indirect_thunk_r11

Add error handling code for the ud2 traps emitted for the checks, and
allow CONFIG_CFI_CLANG to be selected on x86_64.

This produces the following oops on CFI failure (generated using lkdtm):

[ 21.441706] CFI failure at lkdtm_indirect_call+0x16/0x20 [lkdtm]
(target: lkdtm_increment_int+0x0/0x10 [lkdtm]; expected type: 0x7e0c52a)
[ 21.444579] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 21.445296] CPU: 0 PID: 132 Comm: sh Not tainted
5.19.0-rc8-00020-g9f27360e674c #1
[ 21.445296] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 21.445296] RIP: 0010:lkdtm_indirect_call+0x16/0x20 [lkdtm]
[ 21.445296] Code: 52 1c c0 48 c7 c1 c5 50 1c c0 e9 25 48 2a cc 0f 1f
44 00 00 49 89 fb 48 c7 c7 50 b4 1c c0 41 ba 5b ad f3 81 45 03 53 f8
[ 21.445296] RSP: 0018:ffffa9f9c02ffdc0 EFLAGS: 00000292
[ 21.445296] RAX: 0000000000000027 RBX: ffffffffc01cb300 RCX: 385cbbd2e070a700
[ 21.445296] RDX: 0000000000000000 RSI: c0000000ffffdfff RDI: ffffffffc01cb450
[ 21.445296] RBP: 0000000000000006 R08: 0000000000000000 R09: ffffffff8d081610
[ 21.445296] R10: 00000000bcc90825 R11: ffffffffc01c2fc0 R12: 0000000000000000
[ 21.445296] R13: ffffa31b827a6000 R14: 0000000000000000 R15: 0000000000000002
[ 21.445296] FS: 00007f08b42216a0(0000) GS:ffffa31b9f400000(0000)
knlGS:0000000000000000
[ 21.445296] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 21.445296] CR2: 0000000000c76678 CR3: 0000000001940000 CR4: 00000000000006f0
[ 21.445296] Call Trace:
[ 21.445296] <TASK>
[ 21.445296] lkdtm_CFI_FORWARD_PROTO+0x30/0x50 [lkdtm]
[ 21.445296] direct_entry+0x12d/0x140 [lkdtm]
[ 21.445296] full_proxy_write+0x5d/0xb0
[ 21.445296] vfs_write+0x144/0x460
[ 21.445296] ? __x64_sys_wait4+0x5a/0xc0
[ 21.445296] ksys_write+0x69/0xd0
[ 21.445296] do_syscall_64+0x51/0xa0
[ 21.445296] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 21.445296] RIP: 0033:0x7f08b41a6fe1
[ 21.445296] Code: be 07 00 00 00 41 89 c0 e8 7e ff ff ff 44 89 c7 89
04 24 e8 91 c6 02 00 8b 04 24 48 83 c4 68 c3 48 63 ff b8 01 00 00 03
[ 21.445296] RSP: 002b:00007ffcdf65c2e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 21.445296] RAX: ffffffffffffffda RBX: 00007f08b4221690 RCX: 00007f08b41a6fe1
[ 21.445296] RDX: 0000000000000012 RSI: 0000000000c738f0 RDI: 0000000000000001
[ 21.445296] RBP: 0000000000000001 R08: fefefefefefefeff R09: fefefefeffc5ff4e
[ 21.445296] R10: 00007f08b42222b0 R11: 0000000000000246 R12: 0000000000c738f0
[ 21.445296] R13: 0000000000000012 R14: 00007ffcdf65c401 R15: 0000000000c70450
[ 21.445296] </TASK>
[ 21.445296] Modules linked in: lkdtm
[ 21.445296] Dumping ftrace buffer:
[ 21.445296] (ftrace buffer empty)
[ 21.471442] ---[ end trace 0000000000000000 ]---
[ 21.471811] RIP: 0010:lkdtm_indirect_call+0x16/0x20 [lkdtm]
[ 21.472467] Code: 52 1c c0 48 c7 c1 c5 50 1c c0 e9 25 48 2a cc 0f 1f
44 00 00 49 89 fb 48 c7 c7 50 b4 1c c0 41 ba 5b ad f3 81 45 03 53 f8
[ 21.474400] RSP: 0018:ffffa9f9c02ffdc0 EFLAGS: 00000292
[ 21.474735] RAX: 0000000000000027 RBX: ffffffffc01cb300 RCX: 385cbbd2e070a700
[ 21.475664] RDX: 0000000000000000 RSI: c0000000ffffdfff RDI: ffffffffc01cb450
[ 21.476471] RBP: 0000000000000006 R08: 0000000000000000 R09: ffffffff8d081610
[ 21.477127] R10: 00000000bcc90825 R11: ffffffffc01c2fc0 R12: 0000000000000000
[ 21.477959] R13: ffffa31b827a6000 R14: 0000000000000000 R15: 0000000000000002
[ 21.478657] FS: 00007f08b42216a0(0000) GS:ffffa31b9f400000(0000)
knlGS:0000000000000000
[ 21.479577] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 21.480307] CR2: 0000000000c76678 CR3: 0000000001940000 CR4: 00000000000006f0
[ 21.481460] Kernel panic - not syncing: Fatal exception

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-23-samitolvanen@google.com

mm/mmap: drop ARCH_HAS_VM_GET_PAGE_PROT

Now all the platforms enable ARCH_HAS_GET_PAGE_PROT. They define and
export own vm_get_page_prot() whether custom or standard
DECLARE_VM_GET_PAGE_PROT. Hence there is no need for default generic
fallback for vm_get_page_prot(). Just drop this fallback and also
ARCH_HAS_GET_PAGE_PROT mechanism.

Link: https://lkml.kernel.org/r/20220711070600.2378316-27-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/*/: remove CONFIG_VIRT_TO_BUS

All architecture-independent users of virt_to_bus() and bus_to_virt()
have been fixed to use the dma mapping interfaces or have been
removed now. This means the definitions on most architectures, and the
CONFIG_VIRT_TO_BUS symbol are now obsolete and can be removed.

The only exceptions to this are a few network and scsi drivers for m68k
Amiga and VME machines and ppc32 Macintosh. These drivers work correctly
with the old interfaces and are probably not worth changing.

On alpha and parisc, virt_to_bus() were still used in asm/floppy.h.
alpha can use isa_virt_to_bus() like x86 does, and parisc can just
open-code the virt_to_phys() here, as this is architecture specific
code.

I tried updating the bus-virt-phys-mapping.rst documentation, which
started as an email from Linus to explain some details of the Linux-2.0
driver interfaces. The bits about virt_to_bus() were declared obsolete
backin 2000, and the rest is not all that relevant any more, so in the
end I just decided to remove the file completely.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

random: remove CONFIG_ARCH_RANDOM

When RDRAND was introduced, there was much discussion on whether it
should be trusted and how the kernel should handle that. Initially, two
mechanisms cropped up, CONFIG_ARCH_RANDOM, a compile time switch, and
"nordrand", a boot-time switch.

Later the thinking evolved. With a properly designed RNG, using RDRAND
values alone won't harm anything, even if the outputs are malicious.
Rather, the issue is whether those values are being *trusted* to be good
or not. And so a new set of options were introduced as the real
ones that people use -- CONFIG_RANDOM_TRUST_CPU and "random.trust_cpu".
With these options, RDRAND is used, but it's not always credited. So in
the worst case, it does nothing, and in the best case, maybe it helps.

Along the way, CONFIG_ARCH_RANDOM's meaning got sort of pulled into the
center and became something certain platforms force-select.

The old options don't really help with much, and it's a bit odd to have
special handling for these instructions when the kernel can deal fine
with the existence or untrusted existence or broken existence or
non-existence of that CPU capability.

Simplify the situation by removing CONFIG_ARCH_RANDOM and using the
ordinary asm-generic fallback pattern instead, keeping the two options
that are actually used. For now it leaves "nordrand" for now, as the
removal of that will take a different route.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

context_tracking: Split user tracking Kconfig

Context tracking is going to be used not only to track user transitions
but also idle/IRQs/NMIs. The user tracking part will then become a
separate feature. Prepare Kconfig for that.

[ frederic: Apply Max Filippov feedback. ]

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>

x86/purgatory: Omit use of bin2c

The .incbin assembler directive is much faster than bin2c + $(CC).

Do similar refactoring as in

4c0f032d4963 ("s390/purgatory: Omit use of bin2c").

Please note the .quad directive matches to size_t in C (both 8
byte) because the purgatory is compiled only for the 64-bit kernel.
(KEXEC_FILE depends on X86_64).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220725020812.622255-2-masahiroy@kernel.org

x86/Kconfig: Fix CONFIG_CC_HAS_SANE_STACKPROTECTOR when cross compiling with clang

Chimera Linux notes that CONFIG_CC_HAS_SANE_STACKPROTECTOR cannot be
enabled when cross compiling an x86_64 kernel with clang, even though it
does work when natively compiling.

When building on aarch64:

$ make -sj"$(nproc)" ARCH=x86_64 LLVM=1 defconfig

$ grep STACKPROTECTOR .config

When building on x86_64:

$ make -sj"$(nproc)" ARCH=x86_64 LLVM=1 defconfig

$ grep STACKPROTECTOR .config
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
CONFIG_HAVE_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR_STRONG=y

When clang is invoked without a '--target' flag, code is generated for
the default target, which is usually the host (it is configurable via
cmake). As a result, the has-stack-protector scripts will generate code
for the default target but check for x86 specific segment registers,
which cannot succeed if the default target is not x86.

$(CLANG_FLAGS) contains an explicit '--target' flag so pass that
variable along to the has-stack-protector scripts so that the stack
protector can be enabled when cross compiling with clang. The 32-bit
stack protector cannot currently be enabled with clang, as it does not
support '-mstack-protector-guard-symbol', so this results in no
functional change for ARCH=i386 when cross compiling.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://github.com/chimera-linux/cports/commit/0fb7e506d5f83fdf2104feb22cdac34934561226
Link: https://github.com/llvm/llvm-project/issues/48553
Link: https://lkml.kernel.org/r/20220617180845.2788442-1-nathan@kernel.org

x86/kexec: Carry forward IMA measurement log on kexec

On kexec file load, the Integrity Measurement Architecture (IMA)
subsystem may verify the IMA signature of the kernel and initramfs, and
measure it. The command line parameters passed to the kernel in the
kexec call may also be measured by IMA.

A remote attestation service can verify a TPM quote based on the TPM
event log, the IMA measurement list and the TPM PCR data. This can
be achieved only if the IMA measurement log is carried over from the
current kernel to the next kernel across the kexec call.

PowerPC and ARM64 both achieve this using device tree with a
"linux,ima-kexec-buffer" node. x86 platforms generally don't make use of
device tree, so use the setup_data mechanism to pass the IMA buffer to
the new kernel.

Signed-off-by: Jonathan McDowell <noodles@fb.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> # IMA function definitions
Link: https://lore.kernel.org/r/YmKyvlF3my1yWTvK@noodles-fedora-PC23Y6EG

arch: make TRACE_IRQFLAGS_NMI_SUPPORT generic

On most architectures, IRQ flag tracing is disabled in NMI context, and
architectures need to define and select TRACE_IRQFLAGS_NMI_SUPPORT in
order to enable this.

Commit:

859d069ee1ddd878 ("lockdep: Prepare for NMI IRQ state tracking")

Permitted IRQ flag tracing in NMI context, allowing lockdep to work in
NMI context where an architecture had suitable entry logic. At the time,
most architectures did not have such suitable entry logic, and this broke
lockdep on such architectures. Thus, this was partially disabled in
commit:

ed00495333ccc80f ("locking/lockdep: Fix TRACE_IRQFLAGS vs. NMIs")

... with architectures needing to select TRACE_IRQFLAGS_NMI_SUPPORT to
enable IRQ flag tracing in NMI context.

Currently TRACE_IRQFLAGS_NMI_SUPPORT is defined under
arch/x86/Kconfig.debug. Move it to arch/Kconfig so architectures can
select it without having to provide their own definition.

Since the regular TRACE_IRQFLAGS_SUPPORT is selected by
arch/x86/Kconfig, the select of TRACE_IRQFLAGS_NMI_SUPPORT is moved
there too.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220511131733.4074499-2-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

x86/speculation: Make all RETbleed mitigations 64-bit only

The mitigations for RETBleed are currently ineffective on x86_32 since
entry_32.S does not use the required macros. However, for an x86_32
target, the kconfig symbols for them are still enabled by default and
/sys/devices/system/cpu/vulnerabilities/retbleed will wrongly report
that mitigations are in place.

Make all of these symbols depend on X86_64, and only enable RETHUNK by
default on X86_64.

Fixes: f43b9876e857 ("x86/retbleed: Add fine grained Kconfig knobs")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/YtwSR3NNsWp1ohfV@decadent.org.uk

mmu_gather: Remove per arch tlb_{start,end}_vma()

Scattered across the archs are 3 basic forms of tlb_{start,end}_vma().
Provide two new MMU_GATHER_knobs to enumerate them and remove the per
arch tlb_{start,end}_vma() implementations.

- MMU_GATHER_NO_FLUSH_CACHE indicates the arch has flush_cache_range()
but does *NOT* want to call it for each VMA.

- MMU_GATHER_MERGE_VMAS indicates the arch wants to merge the
invalidate across multiple VMAs if possible.

With these it is possible to capture the three forms:

1) empty stubs;
select MMU_GATHER_NO_FLUSH_CACHE and MMU_GATHER_MERGE_VMAS

2) start: flush_cache_range(), end: empty;
select MMU_GATHER_MERGE_VMAS

3) start: flush_cache_range(), end: flush_tlb_range();
default

Obviously, if the architecture does not have flush_cache_range() then
it also doesn't need to select MMU_GATHER_NO_FLUSH_CACHE.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/retbleed: Add fine grained Kconfig knobs

Do fine-grained Kconfig for all the various retbleed parts.

NOTE: if your compiler doesn't support return thunks this will
silently 'upgrade' your mitigation to IBPB, you might not like this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>

x86/bugs: Add AMD retbleed= boot parameter

Add the "retbleed=<value>" boot parameter to select a mitigation for
RETBleed. Possible values are "off", "auto" and "unret"
(JMP2RET mitigation). The default value is "auto".

Currently, "retbleed=auto" will select the unret mitigation on
AMD and Hygon and no mitigation on Intel (JMP2RET is not effective on
Intel).

[peterz: rebase; add hygon]
[jpoimboe: cleanups]

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>

virtio: replace arch_has_restricted_virtio_memory_access()

Instead of using arch_has_restricted_virtio_memory_access() together
with CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS, replace those
with platform_has() and a new platform feature
PLATFORM_VIRTIO_RESTRICTED_MEM_ACCESS.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Tested-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Arm64 only
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Borislav Petkov <bp@suse.de>

x86/microcode: Default-disable late loading

It is dangerous and it should not be used anyway - there's a nice early
loading already.

Requested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220525161232.14924-3-bp@alien8.de

x86/microcode: Rip out the OLD_INTERFACE

Everything should be using the early initrd loading by now.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20220525161232.14924-2-bp@alien8.de

objtool: Add CONFIG_HAVE_UACCESS_VALIDATION

Allow an arch specify that it has objtool uaccess validation with
CONFIG_HAVE_UACCESS_VALIDATION. For now, doing so unconditionally
selects CONFIG_OBJTOOL.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d393d5e2fe73aec6e8e41d5c24f4b6fe8583f2d8.1650384225.git.jpoimboe@redhat.com

x86/Kconfig: Fix indentation and add endif comments to arch/x86/Kconfig

The convention for indentation seems to be a single tab. Help text is
further indented by an additional two whitespaces. Fix the lines that
violate these rules.

While add it, add missing trailing endif comments and squeeze multiple
empty lines.

Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20220525133203.52463-2-juerg.haefliger@canonical.com

arch: Add SYSVIPC_COMPAT for all architectures

The existing per-arch definitions are pretty much historic cruft.
Move SYSVIPC_COMPAT into init/Kconfig.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Link: https://lore.kernel.org/r/20220405071314.3225832-5-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP*

The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize". In this patch , cheanup configs to make code more
expressive.

Link: https://lkml.kernel.org/r/20220404074652.68024-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

x86/mm: enable ARCH_HAS_VM_GET_PAGE_PROT

This defines and exports a platform specific custom vm_get_page_prot() via
subscribing ARCH_HAS_VM_GET_PAGE_PROT. This also unsubscribes from config
ARCH_HAS_FILTER_PGPROT, after dropping off arch_filter_pgprot() and
arch_vm_get_page_prot().

Link: https://lkml.kernel.org/r/20220414062125.609297-6-anshuman.khandual@arm.com
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm: hugetlb_vmemmap: introduce ARCH_WANT_HUGETLB_PAGE_FREE_VMEMMAP

The feature of minimizing overhead of struct page associated with each
HugeTLB page is implemented on x86_64, however, the infrastructure of this
feature is already there, we could easily enable it for other
architectures. Introduce ARCH_WANT_HUGETLB_PAGE_FREE_VMEMMAP for other
architectures to be easily enabled. Just select this config if they want
to enable this feature.

Link: https://lkml.kernel.org/r/20220331065640.5777-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Barry Song <baohua@kernel.org>
Tested-by: Barry Song <baohua@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

objtool: Add HAVE_NOINSTR_VALIDATION

Remove CONFIG_NOINSTR_VALIDATION's dependency on HAVE_OBJTOOL, since
other arches might want to implement objtool without it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/488e94f69db4df154499bc098573d90e5db1c826.1650300597.git.jpoimboe@redhat.com

objtool: Make noinstr hacks optional

Objtool has some hacks in place to workaround toolchain limitations
which otherwise would break no-instrumentation rules. Make the hacks
explicit (and optional for other arches) by turning it into a cmdline
option and kernel config option.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/b326eeb9c33231b9dfbb925f194ed7ee40edcd7c.1650300597.git.jpoimboe@redhat.com

objtool: Make jump label hack optional

Objtool secretly does a jump label hack to overcome the limitations of
the toolchain. Make the hack explicit (and optional for other arches)
by turning it into a cmdline option and kernel config option.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/3bdcbfdd27ecb01ddec13c04bdf756a583b13d24.1650300597.git.jpoimboe@redhat.com

objtool: Add CONFIG_OBJTOOL

Now that stack validation is an optional feature of objtool, add
CONFIG_OBJTOOL and replace most usages of CONFIG_STACK_VALIDATION with
it.

CONFIG_STACK_VALIDATION can now be considered to be frame-pointer
specific. CONFIG_UNWINDER_ORC is already inherently valid for live
patching, so no need to "validate" it.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/939bf3d85604b2a126412bf11af6e3bd3b872bcb.1650300597.git.jpoimboe@redhat.com

sysfb: Enable boot time VESA graphic mode selection

Since switch to simplefb/simpledrm VESA graphic mode selection with vga=
kernel parameter is no longer available with legacy BIOS.

The x86 realmode boot code enables the VESA graphic modes when option
FB_BOOT_VESA_SUPPORT is enabled.

This option is selected by vesafb but not simplefb/simpledrm.

To enable use of VESA modes with simplefb in legacy BIOS boot mode drop
dependency of BOOT_VESA_SUPPORT on FB, also drop the FB_ prefix. Select
the option from sysfb rather than the drivers that depend on it.

The BOOT_VESA_SUPPORT is not specific to framebuffer but rather to x86
platform, move it from fbdev to x86 Kconfig.

Fixes: e3263ab389a7 ("x86: provide platform-devices for boot-framebuffers")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/948c39940a4e99f5b43bdbcbe537faae71a43e1d.1645822213.git.msuchanek@suse.de

x86/microcode: Add explicit CPU vendor dependency

Add an explicit dependency to the respective CPU vendor so that the
respective microcode support for it gets built only when that support is
enabled.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/8ead0da9-9545-b10d-e3db-7df1a1f219e4@infradead.org

x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATE

CONFIG_LEGACY_VSYSCALL_EMULATE is, as far as I know, only needed for the
combined use of exotic and outdated debugging mechanisms with outdated
binaries. At this point, no one should be using it. Eventually, dynamic
switching of vsyscalls will be implemented, but this is much more
complicated to support in EMULATE mode than XONLY mode.

So let's force all the distros off of EMULATE mode. If anyone actually
needs it, they can set vsyscall=emulate, and the kernel can then get
away with refusing to support newer security models if that option is
set.

[ bp: Remove "we"s. ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Florian Weimer <fweimer@redhat.com>
Link: https://lore.kernel.org/r/898932fe61db6a9d61bc2458fa2f6049f1ca9f5c.1652290558.git.luto@kernel.org

x86: Remove a.out support

Commit

eac616557050 ("x86: Deprecate a.out support")

deprecated a.out support with the promise to remove it a couple of
releases later. That commit landed in v5.1.

Now it is more than a couple of releases later, no one has complained so
remove it.

Fold in a hunk removing the reference to arch/x86/ia32/ia32_aout.c in
MAINTAINERS:

https://lore.kernel.org/r/20220316050828.17255-1-lukas.bulwahn@gmail.com

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220113160115.5375-1-bp@alien8.de

x86/mm: Make DMA memory shared for TD guest

Intel TDX doesn't allow VMM to directly access guest private memory.
Any memory that is required for communication with the VMM must be
shared explicitly. The same rule applies for any DMA to and from the
TDX guest. All DMA pages have to be marked as shared pages. A generic way
to achieve this without any changes to device drivers is to use the
SWIOTLB framework.

The previous patch ("Add support for TDX shared memory") gave TDX guests
the _ability_ to make some pages shared, but did not make any pages
shared. This actually marks SWIOTLB buffers *as* shared.

Start returning true for cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT) in
TDX guests. This has several implications:

- Allows the existing mem_encrypt_init() to be used for TDX which
sets SWIOTLB buffers shared (aka. "decrypted").
- Ensures that all DMA is routed via the SWIOTLB mechanism (see
pci_swiotlb_detect())

Stop selecting DYNAMIC_PHYSICAL_MASK directly. It will get set
indirectly by selecting X86_MEM_ENCRYPT.

mem_encrypt_init() is currently under an AMD-specific #ifdef. Move it to
a generic area of the header.

Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220405232939.73860-28-kirill.shutemov@linux.intel.com

x86/boot: Avoid #VE during boot for TDX platforms

There are a few MSRs and control register bits that the kernel
normally needs to modify during boot. But, TDX disallows
modification of these registers to help provide consistent security
guarantees. Fortunately, TDX ensures that these are all in the correct
state before the kernel loads, which means the kernel does not need to
modify them.

The conditions to avoid are:

* Any writes to the EFER MSR
* Clearing CR4.MCE

This theoretically makes the guest boot more fragile. If, for instance,
EFER was set up incorrectly and a WRMSR was performed, it will trigger
early exception panic or a triple fault, if it's before early
exceptions are set up. However, this is likely to trip up the guest
BIOS long before control reaches the kernel. In any case, these kinds
of problems are unlikely to occur in production environments, and
developers have good debug tools to fix them quickly.

Change the common boot code to work on TDX and non-TDX systems.
This should have no functional effect on non-TDX systems.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-24-kirill.shutemov@linux.intel.com

x86/tdx: Exclude shared bit from __PHYSICAL_MASK

In TDX guests, by default memory is protected from host access. If a
guest needs to communicate with the VMM (like the I/O use case), it uses
a single bit in the physical address to communicate the protected/shared
attribute of the given page.

In the x86 ARCH code, __PHYSICAL_MASK macro represents the width of the
physical address in the given architecture. It is used in creating
physical PAGE_MASK for address bits in the kernel. Since in TDX guest,
a single bit is used as metadata, it needs to be excluded from valid
physical address bits to avoid using incorrect addresses bits in the
kernel.

Enable DYNAMIC_PHYSICAL_MASK to support updating the __PHYSICAL_MASK.

Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-6-kirill.shutemov@linux.intel.com

x86/tdx: Extend the confidential computing API to support TDX guests

Confidential Computing (CC) features (like string I/O unroll support,
memory encryption/decryption support, etc) are conditionally enabled
in the kernel using cc_platform_has() API. Since TDX guests also need
to use these CC features, extend cc_platform_has() API and add TDX
guest-specific CC attributes support.

CC API also provides an interface to deal with encryption mask. Extend
it to cover TDX.

Details about which bit in the page table entry to be used to indicate
shared/private state is determined by using the TDINFO TDCALL.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-5-kirill.shutemov@linux.intel.com

x86/tdx: Detect running as a TDX guest in early boot

In preparation of extending cc_platform_has() API to support TDX guest,
use CPUID instruction to detect support for TDX guests in the early
boot code (via tdx_early_init()). Since copy_bootdata() is the first
user of cc_platform_has() API, detect the TDX guest status before it.

Define a synthetic feature flag (X86_FEATURE_TDX_GUEST) and set this
bit in a valid TDX guest platform.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-2-kirill.shutemov@linux.intel.com

x86/cpu: Remove CONFIG_X86_SMAP and "nosmap"

Those were added as part of the SMAP enablement but SMAP is currently
an integral part of kernel proper and there's no need to disable it
anymore.

Rip out that functionality. Leave --uaccess default on for objtool as
this is what objtool should do by default anyway.

If still needed - clearcpuid=smap.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220127115626.14179-4-bp@alien8.de

x86/Kconfig: fix the spelling of 'becoming' in X86_KERNEL_IBT config

There is only one m in becoming.

Signed-off-by: Nur Hussein <hussein@unixcat.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220417192454.10247-1-hussein@unixcat.org

Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"

Revert commit bf9ad37dc8a. It needs to be better encapsulated and
generalized.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

x86,rethook,kprobes: Replace kretprobe with rethook on x86

Replaces the kretprobe code with rethook on x86. With this patch,
kretprobe on x86 uses the rethook instead of kretprobe specific
trampoline code.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/164826163692.2455864.13745421016848209527.stgit@devnote2

x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0

With CONFIG_X86_KERNEL_IBT=y and a version of ld.lld prior to 14.0.0,
there are numerous objtool warnings along the lines of:

warning: objtool: .plt+0x6: indirect jump found in RETPOLINE build

This is a known issue that has been resolved in ld.lld 14.0.0. Prevent
CONFIG_X86_KERNEL_IBT from being selectable when using one of these
problematic ld.lld versions.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220318230747.3900772-3-nathan@kernel.org

x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0

Commit 156ff4a544ae ("x86/ibt: Base IBT bits") added a check for a crash
with 'clang -fcf-protection=branch -mfentry -pg', which intended to
exclude Clang versions older than 14.0.0 from selecting
CONFIG_X86_KERNEL_IBT.

clang-11 does not have the issue that the check is testing for, so
CONFIG_X86_KERNEL_IBT is selectable. Unfortunately, there is a different
crash in clang-11 that was fixed in clang-12. To make matters worse,
that crash does not appear to be entirely deterministic, as the same
input to the compiler will sometimes crash and other times not, which
makes dynamically checking for the crash like the '-pg' one unreliable.

To make everything work properly for all common versions of clang, use a
hard version check of 14.0.0, as that will be the first release upstream
that has both bugs properly fixed.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220318230747.3900772-2-nathan@kernel.org

x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy

There are two outstanding issues with CONFIG_X86_X32_ABI and
llvm-objcopy, with similar root causes:

1. llvm-objcopy does not properly convert .note.gnu.property when going
from x86_64 to x86_x32, resulting in a corrupted section when
linking:

https://github.com/ClangBuiltLinux/linux/issues/1141

2. llvm-objcopy produces corrupted compressed debug sections when going
from x86_64 to x86_x32, also resulting in an error when linking:

https://github.com/ClangBuiltLinux/linux/issues/514

After commit 41c5ef31ad71 ("x86/ibt: Base IBT bits"), the
.note.gnu.property section is always generated when
CONFIG_X86_KERNEL_IBT is enabled, which causes the first issue to become
visible with an allmodconfig build:

ld.lld: error: arch/x86/entry/vdso/vclock_gettime-x32.o:(.note.gnu.property+0x1c): program property is too short

To avoid this error, do not allow CONFIG_X86_X32_ABI to be selected when
using llvm-objcopy. If the two issues ever get fixed in llvm-objcopy,
this can be turned into a feature check.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-3-nathan@kernel.org

x86: Remove toolchain check for X32 ABI capability

Commit 0bf6276392e9 ("x32: Warn and disable rather than error if
binutils too old") added a small test in arch/x86/Makefile because
binutils 2.22 or newer is needed to properly support elf32-x86-64. This
check is no longer necessary, as the minimum supported version of
binutils is 2.23, which is enforced at configuration time with
scripts/min-tool-version.sh.

Remove this check and replace all uses of CONFIG_X86_X32 with
CONFIG_X86_X32_ABI, as two symbols are no longer necessary.

[nathan: Rebase, fix up a few places where CONFIG_X86_X32 was still
used, and simplify commit message to satisfy -tip requirements]

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220314194842.3452-2-nathan@kernel.org

x86/alternative: Use .ibt_endbr_seal to seal indirect calls

Objtool's --ibt option generates .ibt_endbr_seal which lists
superfluous ENDBR instructions. That is those instructions for which
the function is never indirectly called.

Overwrite these ENDBR instructions with a NOP4 such that these
function can never be indirect called, reducing the number of viable
ENDBR targets in the kernel.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org

x86/ibt: Base IBT bits

Add Kconfig, Makefile and basic instruction support for x86 IBT.

(Ab)use __DISABLE_EXPORTS to disable IBT since it's already employed
to mark compressed and purgatory. Additionally mark realmode with it
as well to avoid inserting ENDBR instructions there. While ENDBR is
technically a NOP, inserting them was causing some grief due to code
growth. There's also a problem with using __noendbr in code compiled
without -fcf-protection=branch.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154317.519875203@infradead.org

mm: generalize ARCH_HAS_FILTER_PGPROT

ARCH_HAS_FILTER_PGPROT config has duplicate definitions on platforms that
subscribe it. Instead make it a generic config option which can be
selected on applicable platforms when required.

Link: https://lkml.kernel.org/r/1643004823-16441-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Revert "rethook: x86: Add rethook x86 implementation"

This reverts commit 75caf33eda242e2f34f61e475d666359749ae5ff.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

rethook: x86: Add rethook x86 implementation

Add rethook for x86 implementation. Most of the code has been copied from
kretprobes on x86.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Tested-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/164735286243.1084943.7477055110527046644.stgit@devnote2

x86: Disable HAVE_ARCH_HUGE_VMALLOC on 32-bit x86

kernel test robot reported kernel BUG like:

[ 44.587744][ T1] kernel BUG at arch/x86/mm/physaddr.c:76!
[ 44.590151][ T1] __vmalloc_area_node (mm/vmalloc.c:622 mm/vmalloc.c:2995)
[ 44.590151][ T1] __vmalloc_node_range (mm/vmalloc.c:3108)
[ 44.590151][ T1] __vmalloc_node (mm/vmalloc.c:3157)

which is triggered with HAVE_ARCH_HUGE_VMALLOC on 32-bit x86. Since BPF
only uses HAVE_ARCH_HUGE_VMALLOC for x86_64, turn it off for 32-bit x86.

Fixes: fac54e2bfb5b ("x86/Kconfig: Select HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220302175126.247459-2-song@kernel.org

x86/Kconfig: Select HAVE_ARCH_HUGE_VMALLOC with HAVE_ARCH_HUGE_VMAP

This enables module_alloc() to allocate huge page for 2MB+ requests.
To check the difference of this change, we need enable config
CONFIG_PTDUMP_DEBUGFS, and call module_alloc(2MB). Before the change,
/sys/kernel/debug/page_tables/kernel shows pte for this map. With the
change, /sys/kernel/debug/page_tables/ show pmd for thie map.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220204185742.271030-2-song@kernel.org

mm/hugetlb: generalize ARCH_WANT_GENERAL_HUGETLB

ARCH_WANT_GENERAL_HUGETLB config has duplicate definitions on platforms
that subscribe it. Instead make it a generic config option which can be
selected on applicable platforms when required.

Link: https://lkml.kernel.org/r/1643718465-4324-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sched/preempt: Add PREEMPT_DYNAMIC using static keys

Where an architecture selects HAVE_STATIC_CALL but not
HAVE_STATIC_CALL_INLINE, each static call has an out-of-line trampoline
which will either branch to a callee or return to the caller.

On such architectures, a number of constraints can conspire to make
those trampolines more complicated and potentially less useful than we'd
like. For example:

* Hardware and software control flow integrity schemes can require the
addition of "landing pad" instructions (e.g. `BTI` for arm64), which
will also be present at the "real" callee.

* Limited branch ranges can require that trampolines generate or load an
address into a register and perform an indirect branch (or at least
have a slow path that does so). This loses some of the benefits of
having a direct branch.

* Interaction with SW CFI schemes can be complicated and fragile, e.g.
requiring that we can recognise idiomatic codegen and remove
indirections understand, at least until clang proves more helpful
mechanisms for dealing with this.

For PREEMPT_DYNAMIC, we don't need the full power of static calls, as we
really only need to enable/disable specific preemption functions. We can
achieve the same effect without a number of the pain points above by
using static keys to fold early returns into the preemption functions
themselves rather than in an out-of-line trampoline, effectively
inlining the trampoline into the start of the function.

For arm64, this results in good code generation. For example, the
dynamic_cond_resched() wrapper looks as follows when enabled. When
disabled, the first `B` is replaced with a `NOP`, resulting in an early
return.

| <dynamic_cond_resched>:
| bti c
| b <dynamic_cond_resched+0x10> // or `nop`
| mov w0, #0x0
| ret
| mrs x0, sp_el0
| ldr x0, [x0, #8]
| cbnz x0, <dynamic_cond_resched+0x8>
| paciasp
| stp x29, x30, [sp, #-16]!
| mov x29, sp
| bl <preempt_schedule_common>
| mov w0, #0x1
| ldp x29, x30, [sp], #16
| autiasp
| ret

... compared to the regular form of the function:

| <__cond_resched>:
| bti c
| mrs x0, sp_el0
| ldr x1, [x0, #8]
| cbz x1, <__cond_resched+0x18>
| mov w0, #0x0
| ret
| paciasp
| stp x29, x30, [sp, #-16]!
| mov x29, sp
| bl <preempt_schedule_common>
| mov w0, #0x1
| ldp x29, x30, [sp], #16
| autiasp
| ret

Any architecture which implements static keys should be able to use this
to implement PREEMPT_DYNAMIC with similar cost to non-inlined static
calls. Since this is likely to have greater overhead than (inlined)
static calls, PREEMPT_DYNAMIC is only defaulted to enabled when
HAVE_PREEMPT_DYNAMIC_CALL is selected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220214165216.2231574-6-mark.rutland@arm.com

signal, x86: Delay calling signals in atomic on RT enabled kernels

On x86_64 we must disable preemption before we enable interrupts
for stack faults, int3 and debugging, because the current task is using
a per CPU debug stack defined by the IST. If we schedule out, another task
can come in and use the same stack and cause the stack to be corrupted
and crash the kernel on return.

When CONFIG_PREEMPT_RT is enabled, spinlock_t locks become sleeping, and
one of these is the spin lock used in signal handling.

Some of the debug code (int3) causes do_trap() to send a signal.
This function calls a spinlock_t lock that has been converted to a
sleeping lock. If this happens, the above issues with the corrupted
stack is possible.

Instead of calling the signal right away, for PREEMPT_RT and x86,
the signal information is stored on the stacks task_struct and
TIF_NOTIFY_RESUME is set. Then on exit of the trap, the signal resume
code will send the signal when preemption is enabled.

[ rostedt: Switched from #ifdef CONFIG_PREEMPT_RT to
ARCH_RT_DELAYS_SIGNAL_SEND and added comments to the code. ]
[bigeasy: Add on 32bit as per Yang Shi, minor rewording. ]
[ tglx: Use a config option ]

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/Ygq5aBB/qMQw6aP5@linutronix.de

x86/Kconfig: move and modify CONFIG_I8K

In Kconfig, inside the "Processor type and features" menu, there is
the CONFIG_I8K option: "Dell i8k legacy laptop support". This is
very confusing - enabling CONFIG_I8K is not required for the kernel to
support old Dell laptops. This option is specific to the dell-smm-hwmon
driver, which mostly exports some hardware monitoring information and
allows the user to change fan speed.

This option is misplaced, so move CONFIG_I8K to drivers/hwmon/Kconfig,
where it belongs.

Also, modify the dependency order - change
select SENSORS_DELL_SMM
to
depends on SENSORS_DELL_SMM
as it is just a configuration option of dell-smm-hwmon. This includes
changing the option type from tristate to bool. It was tristate because
it could select CONFIG_SENSORS_DELL_SMM=m .

When running "make oldconfig" on configurations with
CONFIG_SENSORS_DELL_SMM enabled , this change will result in an
additional question (which could be printed several times during
bisecting). I think that tidying up the configuration is worth it,
though.

Next patch tweaks the description of CONFIG_I8K.

Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Pali Rohár <pali@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Mark Gross <markgross@kernel.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220212125654.357408-1-mat.jonczyk@o2.pl
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

usercopy: Check valid lifetime via stack depth

One of the things that CONFIG_HARDENED_USERCOPY sanity-checks is whether
an object that is about to be copied to/from userspace is overlapping
the stack at all. If it is, it performs a number of inexpensive
bounds checks. One of the finer-grained checks is whether an object
crosses stack frames within the stack region. Doing this on x86 with
CONFIG_FRAME_POINTER was cheap/easy. Doing it with ORC was deemed too
heavy, and was left out (a while ago), leaving the courser whole-stack
check.

The LKDTM tests USERCOPY_STACK_FRAME_TO and USERCOPY_STACK_FRAME_FROM
try to exercise these cross-frame cases to validate the defense is
working. They have been failing ever since ORC was added (which was
expected). While Muhammad was investigating various LKDTM failures[1],
he asked me for additional details on them, and I realized that when
exact stack frame boundary checking is not available (i.e. everything
except x86 with FRAME_POINTER), it could check if a stack object is at
least "current depth valid", in the sense that any object within the
stack region but not between start-of-stack and current_stack_pointer
should be considered unavailable (i.e. its lifetime is from a call no
longer present on the stack).

Introduce ARCH_HAS_CURRENT_STACK_POINTER to track which architectures
have actually implemented the common global register alias.

Additionally report usercopy bounds checking failures with an offset
from current_stack_pointer, which may assist with diagnosing failures.

The LKDTM USERCOPY_STACK_FRAME_TO and USERCOPY_STACK_FRAME_FROM tests
(once slightly adjusted in a separate patch) pass again with this fixed.

[1] https://github.com/kernelci/kernelci-project/issues/84

Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v1: https://lore.kernel.org/lkml/20220216201449.2087956-1-keescook@chromium.org
v2: https://lore.kernel.org/lkml/20220224060342.1855457-1-keescook@chromium.org
v3: https://lore.kernel.org/lkml/20220225173345.3358109-1-keescook@chromium.org
v4: - improve commit log (akpm)

x86/Kconfig: Select ARCH_SELECT_MEMORY_MODEL only if FLATMEM and SPARSEMEM are possible

x86-64 supports only CONFIG_SPARSEMEM; there is nothing users can select.
So enable the memory model selection (via CONFIG_ARCH_SELECT_MEMORY_MODEL)
only if both, SPARSEMEM and FLATMEM are possible, which isn't the case
on x86-64.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20210929144321.50411-1-david@redhat.com

ftrace: Have architectures opt-in for mcount build time sorting

First S390 complained that the sorting of the mcount sections at build
time caused the kernel to crash on their architecture. Now PowerPC is
complaining about it too. And also ARM64 appears to be having issues.

It may be necessary to also update the relocation table for the values
in the mcount table. Not only do we have to sort the table, but also
update the relocations that may be applied to the items in the table.

If the system is not relocatable, then it is fine to sort, but if it is,
some architectures may have issues (although x86 does not as it shifts all
addresses the same).

Add a HAVE_BUILDTIME_MCOUNT_SORT that an architecture can set to say it is
safe to do the sorting at build time.

Also update the config to compile in build time sorting in the sorttable
code in scripts/ to depend on CONFIG_BUILDTIME_MCOUNT_SORT.

Link: https://lore.kernel.org/all/944D10DA-8200-4BA9-8D0A-3BED9AA99F82@linux.ibm.com/
Link: https://lkml.kernel.org/r/20220127153821.3bc1ac6e@gandalf.local.home

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Yinan Liu <yinan@linux.alibaba.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Fixes: 72b3942a173c ("scripts: ftrace - move the sort-processing in ftrace_init")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

arch: remove GENERIC_FIND_FIRST_BIT entirely

In 5.12 cycle we enabled GENERIC_FIND_FIRST_BIT config option for ARM64
and MIPS. It increased performance and shrunk .text size; and so far
I didn't receive any negative feedback on the change.

https://lore.kernel.org/linux-arch/20210225135700.1381396-1-yury.norov@gmail.com/

Now I think it's a good time to switch all architectures to use
find_{first,last}_bit() unconditionally, and so remove corresponding
config option.

The patch does't introduce functioal changes for arc, arm, arm64, mips,
m68k, s390 and x86, for other architectures I expect improvement both in
performance and .text size.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Alexander Lobakin <alobakin@pm.me> (mips)
Reviewed-by: Alexander Lobakin <alobakin@pm.me> (mips)
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Will Deacon <will@kernel.org>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR

Until recent versions of GCC and Clang, it was not possible to disable
KCOV instrumentation via a function attribute. The relevant function
attribute was introduced in 540540d06e9d9 ("kcov: add
__no_sanitize_coverage to fix noinstr for all architectures").

x86 was the first architecture to want a working noinstr, and at the
time no compiler support for the attribute existed yet. Therefore,
commit 0f1441b44e823 ("objtool: Fix noinstr vs KCOV") introduced the
ability to NOP __sanitizer_cov_*() calls in .noinstr.text.

However, this doesn't work for other architectures like arm64 and s390
that want a working noinstr per ARCH_WANTS_NO_INSTR.

At the time of 0f1441b44e823, we didn't yet have ARCH_WANTS_NO_INSTR,
but now we can move the Kconfig dependency checks to the generic KCOV
option. KCOV will be available if:

- architecture does not care about noinstr, OR
- we have objtool support (like on x86), OR
- GCC is 12.0 or newer, OR
- Clang is 13.0 or newer.

Link: https://lkml.kernel.org/r/20211201152604.3984495-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: percpu: generalize percpu related config

Patch series "mm: percpu: Cleanup percpu first chunk function".

When supporting page mapping percpu first chunk allocator on arm64, we
found there are lots of duplicated codes in percpu embed/page first chunk
allocator. This patchset is aimed to cleanup them and should no function
change.

The currently supported status about 'embed' and 'page' in Archs shows
below,

embed: NEED_PER_CPU_PAGE_FIRST_CHUNK
page: NEED_PER_CPU_EMBED_FIRST_CHUNK

embed page
------------------------
arm64 Y Y
mips Y N
powerpc Y Y
riscv Y N
sparc Y Y
x86 Y Y
------------------------

There are two interfaces about percpu first chunk allocator,

extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
size_t atom_size,
pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
- pcpu_fc_alloc_fn_t alloc_fn,
- pcpu_fc_free_fn_t free_fn);
+ pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);

extern int __init pcpu_page_first_chunk(size_t reserved_size,
- pcpu_fc_alloc_fn_t alloc_fn,
- pcpu_fc_free_fn_t free_fn,
- pcpu_fc_populate_pte_fn_t populate_pte_fn);
+ pcpu_fc_cpu_to_node_fn_t cpu_to_nd_fn);

The pcpu_fc_alloc_fn_t/pcpu_fc_free_fn_t is killed, we provide generic
pcpu_fc_alloc() and pcpu_fc_free() function, which are called in the
pcpu_embed/page_first_chunk().

1) For pcpu_embed_first_chunk(), pcpu_fc_cpu_to_node_fn_t is needed to be
provided when archs supported NUMA.

2) For pcpu_page_first_chunk(), the pcpu_fc_populate_pte_fn_t is killed too,
a generic pcpu_populate_pte() which marked '__weak' is provided, if you
need a different function to populate pte on the arch(like x86), please
provide its own implementation.

[1] https://github.com/kevin78/linux.git percpu-cleanup

This patch (of 4):

The HAVE_SETUP_PER_CPU_AREA/NEED_PER_CPU_EMBED_FIRST_CHUNK/
NEED_PER_CPU_PAGE_FIRST_CHUNK/USE_PERCPU_NUMA_NODE_ID configs, which have
duplicate definitions on platforms that subscribe it.

Move them into mm, drop these redundant definitions and instead just
select it on applicable platforms.

Link: https://lkml.kernel.org/r/20211216112359.103822-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20211216112359.103822-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86: mm: add x86_64 support for page table check

Add page table check hooks into routines that modify user page tables.

Link: https://lkml.kernel.org/r/20211221154650.1047963-5-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/mmx_32: Remove X86_USE_3DNOW

This code puts an exception table entry on the PREFETCH instruction to
overwrite it with a JMP.d8 when it triggers an exception. Except of
course, our code is no longer writable, also SMP.

Instead of fixing this broken mess, simply take it out.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/YZKQzUmeNuwyvZpk@hirez.programming.kicks-ass.net

x86: Add straight-line-speculation mitigation

Make use of an upcoming GCC feature to mitigate
straight-line-speculation for x86:

https://gcc.gnu.org/g:53a643f8568067d7700a9f2facc8ba39974973d3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952
https://bugs.llvm.org/show_bug.cgi?id=52323

It's built tested on x86_64-allyesconfig using GCC-12 and GCC-11.

Maintenance overhead of this should be fairly low due to objtool
validation.

Size overhead of all these additional int3 instructions comes to:

text data bss dec hex filename
22267751 6933356 2011368 31212475 1dc43bb defconfig-build/vmlinux
22804126 6933356 1470696 31208178 1dc32f2 defconfig-build/vmlinux.sls

Or roughly 2.4% additional text.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134908.140103474@infradead.org

x86/sgx: Add an attribute for the amount of SGX memory in a NUMA node

== Problem ==

The amount of SGX memory on a system is determined by the BIOS and it
varies wildly between systems. It can be as small as dozens of MB's
and as large as many GB's on servers. Just like how applications need
to know how much regular RAM is available, enclave builders need to
know how much SGX memory an enclave can consume.

== Solution ==

Introduce a new sysfs file:

/sys/devices/system/node/nodeX/x86/sgx_total_bytes

to enumerate the amount of SGX memory available in each NUMA node.
This serves the same function for SGX as /proc/meminfo or
/sys/devices/system/node/nodeX/meminfo does for normal RAM.

'sgx_total_bytes' is needed today to help drive the SGX selftests.
SGX-specific swap code is exercised by creating overcommitted enclaves
which are larger than the physical SGX memory on the system. They
currently use a CPUID-based approach which can diverge from the actual
amount of SGX memory available. 'sgx_total_bytes' ensures that the
selftests can work efficiently and do not attempt stupid things like
creating a 100,000 MB enclave on a system with 128 MB of SGX memory.

== Implementation Details ==

Introduce CONFIG_HAVE_ARCH_NODE_DEV_GROUP opt-in flag to expose an
arch specific attribute group, and add an attribute for the amount of
SGX memory in bytes to each NUMA node:

== ABI Design Discussion ==

As opposed to the per-node ABI, a single, global ABI was considered.
However, this would prevent enclaves from being able to size
themselves so that they fit on a single NUMA node. Essentially, a
single value would rule out NUMA optimizations for enclaves.

Create a new "x86/" directory inside each "nodeX/" sysfs directory.
'sgx_total_bytes' is expected to be the first of at least a few
sgx-specific files to be placed in the new directory. Just scanning
/proc/meminfo, these are the no-brainers that we have for RAM, but we
need for SGX:

MemTotal: xxxx kB // sgx_total_bytes (implemented here)
MemFree: yyyy kB // sgx_free_bytes
SwapTotal: zzzz kB // sgx_swapped_bytes

So, at *least* three. I think we will eventually end up needing
something more along the lines of a dozen. A new directory (as
opposed to being in the nodeX/ "root") directory avoids cluttering the
root with several "sgx_*" files.

Place the new file in a new "nodeX/x86/" directory because SGX is
highly x86-specific. It is very unlikely that any other architecture
(or even non-Intel x86 vendor) will ever implement SGX. Using "sgx/"
as opposed to "x86/" was also considered. But, there is a real chance
this can get used for other arch-specific purposes.

[ dhansen: rewrite changelog ]

Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211116162116.93081-2-jarkko@kernel.org

x86/sev: Move common memory encryption code to mem_encrypt.c

SEV and TDX both protect guest memory from host accesses. They both use
guest physical address bits to communicate to the hardware which pages
receive protection or not. SEV and TDX both assume that all I/O (real
devices and virtio) must be performed to pages *without* protection.

To add this support, AMD SEV code forces force_dma_unencrypted() to
decrypt DMA pages when DMA pages were allocated for I/O. It also uses
swiotlb_update_mem_attributes() to update decryption bits in SWIOTLB DMA
buffers.

Since TDX also uses a similar memory sharing design, all the above
mentioned changes can be reused. So move force_dma_unencrypted(),
SWIOTLB update code and virtio changes out of mem_encrypt_amd.c to
mem_encrypt.c.

Introduce a new config option X86_MEM_ENCRYPT that can be selected by
platforms which use x86 memory encryption features (needed in both AMD
SEV and Intel TDX guest platforms).

Since the code is moved from mem_encrypt_amd.c, inherit the same make
flags.

This is preparation for enabling TDX memory encryption support and it
has no functional changes.

Co-developed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20211206135505.75045-4-kirill.shutemov@linux.intel.com

x86/sgx: Add infrastructure to identify SGX EPC pages

X86 machine check architecture reports a physical address when there
is a memory error. Handling that error requires a method to determine
whether the physical address reported is in any of the areas reserved
for EPC pages by BIOS.

SGX EPC pages do not have Linux "struct page" associated with them.

Keep track of the mapping from ranges of EPC pages to the sections
that contain them using an xarray. N.B. adds CONFIG_XARRAY_MULTI to
the SGX dependecies. So "select" that in arch/x86/Kconfig for X86/SGX.

Create a function arch_is_platform_page() that simply reports whether an
address is an EPC page for use elsewhere in the kernel. The ACPI error
injection code needs this function and is typically built as a module,
so export it.

Note that arch_is_platform_page() will be slower than other similar
"what type is this page" functions that can simply check bits in the
"struct page". If there is some future performance critical user of
this function it may need to be implemented in a more efficient way.

Note also that the current implementation of xarray allocates a few
hundred kilobytes for this usage on a system with 4GB of SGX EPC memory
configured. This isn't ideal, but worth it for the code simplicity.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/20211026220050.697075-3-tony.luck@intel.com

x86/sme: Explicitly map new EFI memmap table as encrypted

Reserving memory using efi_mem_reserve() calls into the x86
efi_arch_mem_reserve() function. This function will insert a new EFI
memory descriptor into the EFI memory map representing the area of
memory to be reserved and marking it as EFI runtime memory. As part
of adding this new entry, a new EFI memory map is allocated and mapped.
The mapping is where a problem can occur. This new memory map is mapped
using early_memremap() and generally mapped encrypted, unless the new
memory for the mapping happens to come from an area of memory that is
marked as EFI_BOOT_SERVICES_DATA memory. In this case, the new memory will
be mapped unencrypted. However, during replacement of the old memory map,
efi_mem_type() is disabled, so the new memory map will now be long-term
mapped encrypted (in efi.memmap), resulting in the map containing invalid
data and causing the kernel boot to crash.

Since it is known that the area will be mapped encrypted going forward,
explicitly map the new memory map as encrypted using early_memremap_prot().

Cc: <stable@vger.kernel.org> # 4.14.x
Fixes: 8f716c9b5feb ("x86/mm: Add support to access boot related data in the clear")
Link: https://lore.kernel.org/all/ebf1eb2940405438a09d51d121ec0d02c8755558.1634752931.git.thomas.lendacky@amd.com/
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
[ardb: incorporate Kconfig fix by Arnd]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

ftrace/samples: add missing Kconfig option for ftrace direct multi sample

Currently it is not possible to build the ftrace direct multi example
anymore due to broken config dependencies. Fix this by adding
SAMPLE_FTRACE_DIRECT_MULTI config option.

This broke when merging s390-5.16-1 due to an incorrect merge conflict
resolution proposed by me.

Also rename SAMPLE_FTRACE_MULTI_DIRECT to SAMPLE_FTRACE_DIRECT_MULTI
so it matches the module name.

Fixes: 0b707e572a19 ("Merge tag 's390-5.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux")
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211115195614.3173346-2-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

x86: remove memory hotplug support on X86_32

CONFIG_MEMORY_HOTPLUG was marked BROKEN over one year and we just
restricted it to 64 bit. Let's remove the unused x86 32bit
implementation and simplify the Kconfig.

Link: https://lkml.kernel.org/r/20210929143600.49379-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Alex Shi <alexs@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

samples: add HAVE_SAMPLE_FTRACE_DIRECT config option

Add HAVE_SAMPLE_FTRACE_DIRECT config option which can be selected by
architectures which have support for ftrace direct call samples.

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20211012133802.2460757-4-hca@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

kprobes: Add a test case for stacktrace from kretprobe handler

Add a test case for stacktrace from kretprobe handler and
nested kretprobe handlers.

This test checks both of stack trace inside kretprobe handler
and stack trace from pt_regs. Those stack trace must include
actual function return address instead of kretprobe trampoline.
The nested kretprobe stacktrace test checks whether the unwinder
can correctly unwind the call frame on the stack which has been
modified by the kretprobe.

Since the stacktrace on kretprobe is correctly fixed only on x86,
this introduces a meta kconfig ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
which tells user that the stacktrace on kretprobe is correct or not.

The test results will be shown like below;

TAP version 14
1..1
# Subtest: kprobes_test
1..6
ok 1 - test_kprobe
ok 2 - test_kprobes
ok 3 - test_kretprobe
ok 4 - test_kretprobes
ok 5 - test_stacktrace_on_kretprobe
ok 6 - test_stacktrace_on_nested_kretprobe
# kprobes_test: pass:6 fail:0 skip:0 total:6
# Totals: pass:6 fail:0 skip:0 total:6
ok 1 - kprobes_test

Link: https://lkml.kernel.org/r/163516211244.604541.18350507860972214415.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

x86/signal: Implement sigaltstack size validation

For historical reasons MINSIGSTKSZ is a constant which became already too
small with AVX512 support.

Add a mechanism to enforce strict checking of the sigaltstack size against
the real size of the FPU frame.

The strict check can be enabled via a config option and can also be
controlled via the kernel command line option 'strict_sas_size' independent
of the config switch.

Enabling it might break existing applications which allocate a too small
sigaltstack but 'work' because they never get a signal delivered. Though it
can be handy to filter out binaries which are not yet aware of
AT_MINSIGSTKSZ.

Also the upcoming support for dynamically enabled FPU features requires a
strict sanity check to ensure that:

- Enabling of a dynamic feature, which changes the sigframe size fits
into an enabled sigaltstack

- Installing a too small sigaltstack after a dynamic feature has been
added is not possible.

Implement the base check which is controlled by config and command line
options.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-3-chang.seok.bae@intel.com

ftrace/x86_64: Have function graph tracer depend on DYNAMIC_FTRACE

The function graph tracer is going to now depend on
ARCH_SUPPORTS_FTRACE_OPS, as that also means that it can support ftrace
args. Since ARCH_SUPPORTS_FTRACE_OPS depends on DYNAMIC_FTRACE, this
means that the function graph tracer for x86_64 will need to depend on
DYNAMIC_FTRACE.

Link: https://lkml.kernel.org/r/20211020233555.16b0dbf2@rorschach.local.home

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

sched: Add cluster scheduler level for x86

There are x86 CPU architectures (e.g. Jacobsville) where L2 cahce is
shared among a cluster of cores instead of being exclusive to one
single core.

To prevent oversubscription of L2 cache, load should be balanced
between such L2 clusters, especially for tasks with no shared data.
On benchmark such as SPECrate mcf test, this change provides a boost
to performance especially on medium load system on Jacobsville. on a
Jacobsville that has 24 Atom cores, arranged into 6 clusters of 4
cores each, the benchmark number is as follow:

Improvement over baseline kernel for mcf_r
copies run time base rate
1 -0.1% -0.2%
6 25.1% 25.1%
12 18.8% 19.0%
24 0.3% 0.3%

So this looks pretty good. In terms of the system's task distribution,
some pretty bad clumping can be seen for the vanilla kernel without
the L2 cluster domain for the 6 and 12 copies case. With the extra
domain for cluster, the load does get evened out between the clusters.

Note this patch isn't an universal win as spreading isn't necessarily
a win, particually for those workload who can benefit from packing.

Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210924085104.44806-4-21cnbao@gmail.com

x86/Kconfig: Remove references to obsolete Kconfig symbols

Remove two symbols referenced in Kconfig which have been removed
previously by:

ef3c67b6454b ("mfd: intel_msic: Remove driver for deprecated platform")
1b79fc4f2bfd ("x86/apb_timer: Remove driver for deprecated platform")

Detected by scripts/checkkconfigsymbols.py.

[ bp: Merge into a single patch. ]

Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210803113531.30720-5-lukas.bulwahn@gmail.com

x86/sev: Add an x86 version of cc_platform_has()

Introduce an x86 version of the cc_platform_has() function. This will be
used to replace vendor specific calls like sme_active(), sev_active(),
etc.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210928191009.32551-4-bp@alien8.de

x86/Kconfig: Fix an unused variable error in dell-smm-hwmon

When CONFIG_PROC_FS is not set, there is a build warning (turned
into an error):

../drivers/hwmon/dell-smm-hwmon.c: In function 'i8k_init_procfs':
../drivers/hwmon/dell-smm-hwmon.c:624:24: error: unused variable 'data' [-Werror=unused-variable]
struct dell_smm_data *data = dev_get_drvdata(dev);

Make I8K depend on PROC_FS and HWMON (instead of selecting HWMON -- it
is strongly preferred to not select entire subsystems).

Build tested in all possible combinations of SENSORS_DELL_SMM, I8K, and
PROC_FS.

Fixes: 039ae58503f3 ("hwmon: Allow to compile dell-smm-hwmon driver without /proc/i8k")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Pali Rohár <pali@kernel.org>
Link: https://lkml.kernel.org/r/20210910071921.16777-1-rdunlap@infradead.org

x86/Kconfig: Do not enable AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT automatically

This Kconfig option was added initially so that memory encryption is
enabled by default on machines which support it.

However, devices which have DMA masks that are less than the bit
position of the encryption bit, aka C-bit, require the use of an IOMMU
or the use of SWIOTLB.

If the IOMMU is disabled or in passthrough mode, the kernel would switch
to SWIOTLB bounce-buffering for those transfers.

In order to avoid that,

2cc13bb4f59f ("iommu: Disable passthrough mode when SME is active")

disables the default IOMMU passthrough mode so that devices for which the
default 256K DMA is insufficient, can use the IOMMU instead.

However 2, there are cases where the IOMMU is disabled in the BIOS, etc.
(think the usual hardware folk "oops, I dropped the ball there" cases) or a
driver doesn't properly use the DMA APIs or a device has a firmware or
hardware bug, e.g.:

ea68573d408f ("drm/amdgpu: Fail to load on RAVEN if SME is active")

However 3, in the above GPU use case, there are APIs like Vulkan and
some OpenGL/OpenCL extensions which are under the assumption that
user-allocated memory can be passed in to the kernel driver and both the
GPU and CPU can do coherent and concurrent access to the same memory.
That cannot work with SWIOTLB bounce buffers, of course.

So, in order for those devices to function, drop the "default y" for the
SME by default active option so that users who want to have SME enabled,
will need to either enable it in their config or use "mem_encrypt=on" on
the kernel command line.

[ tlendacky: Generalize commit message. ]

Fixes: 7744ccdbc16f ("x86/mm: Add Secure Memory Encryption (SME) support")
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/8bbacd0e-4580-3194-19d2-a0ecad7df09c@molgen.mpg.de

firmware: include drivers/firmware/Kconfig unconditionally

Compile-testing drivers that require access to a firmware layer
fails when that firmware symbol is unavailable. This happened
twice this week:

- My proposed to change to rework the QCOM_SCM firmware symbol
broke on ppc64 and others.

- The cs_dsp firmware patch added device specific firmware loader
into drivers/firmware, which broke on the same set of
architectures.

We should probably do the same thing for other subsystems as well,
but fix this one first as this is a dependency for other patches
getting merged.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: Simon Trimmer <simont@opensource.cirrus.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

x86/Kconfig: Correct reference to MWINCHIP3D

Commit in Fixes intended to exclude the Winchip series and referred to
CONFIG_WINCHIP3D, but the config symbol is called CONFIG_MWINCHIP3D.

Hence, scripts/checkkconfigsymbols.py warns:

WINCHIP3D
Referencing files: arch/x86/Kconfig

Correct the reference to the intended config symbol.

Fixes: 69b8d3fcabdc ("x86/Kconfig: Exclude i586-class CPUs lacking PAE support from the HIGHMEM64G Kconfig group")
Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20210803113531.30720-4-lukas.bulwahn@gmail.com

swiotlb-xen: this is PV-only on x86

The code is unreachable for HVM or PVH, and it also makes little sense
in auto-translated environments. On Arm, with
xen_{create,destroy}_contiguous_region() both being stubs, I have a hard
time seeing what good the Xen specific variant does - the generic one
ought to be fine for all purposes there. Still Arm code explicitly
references symbols here, so the code will continue to be included there.

Instead of making PCI_XEN's "select" conditional, simply drop it -
SWIOTLB_XEN will be available unconditionally in the PV case anyway, and
is - as explained above - dead code in non-PV environments.

This in turn allows dropping the stubs for
xen_{create,destroy}_contiguous_region(), the former of which was broken
anyway - it failed to set the DMA handle output.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

Link: https://lore.kernel.org/r/5947b8ae-fdc7-225c-4838-84712265fc1e@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>

x86/platform: Increase maximum GPIO number for X86_64

By default the 512 GPIOs is the maximum on any x86 platform.
With, for example, Intel Tiger Lake-H the SoC based controller
occupies up to 480 pins. This leaves only 32 available for
GPIO expanders or other drivers, like PMIC. Hence, bump the
maximum GPIO number to 1024 for X86_64 and leave 512 for X86_32.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20210826150317.29435-1-andriy.shevchenko@linux.intel.com

tracing: Refactor TRACE_IRQFLAGS_SUPPORT in Kconfig

Make architectures select TRACE_IRQFLAGS_SUPPORT instead of
having many defines.

Link: https://lkml.kernel.org/r/20210731052233.4703-2-masahiroy@kernel.org

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>   #arch/arc
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols

Most architectures do not need a custom implementation, and in most
cases the generic implementation is preferred, so change the polariy
on these Kconfig symbols to require architectures to select them when
they provide their own version.

The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER.

The remaining architectures at the moment are: ia64, mips, parisc,
um and xtensa. We should probably convert these as well, but
I was not sure how far to take this series. Thomas Bogendoerfer
had some concerns about converting mips but may still do some
more detailed measurements to see which version is better.

Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-xtensa@linux-xtensa.org
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/firmware: move x86 Generic System Framebuffers support

The x86 architecture has generic support to register a system framebuffer
platform device. It either registers a "simple-framebuffer" if the config
option CONFIG_X86_SYSFB is enabled, or a legacy VGA/VBE/EFI FB device.

But the code is generic enough to be reused by other architectures and can
be moved out of the arch/x86 directory.

This will allow to also support the simple{fb,drm} drivers on non-x86 EFI
platforms, such as aarch64 where these drivers are only supported with DT.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20210625130947.1803678-2-javierm@redhat.com

x86/mm: Prepare for opt-in based L1D flush in switch_mm()

The goal of this is to allow tasks that want to protect sensitive
information, against e.g. the recently found snoop assisted data sampling
vulnerabilites, to flush their L1D on being switched out. This protects
their data from being snooped or leaked via side channels after the task
has context switched out.

This could also be used to wipe L1D when an untrusted task is switched in,
but that's not a really well defined scenario while the opt-in variant is
clearly defined.

The mechanism is default disabled and can be enabled on the kernel command
line.

Prepare for the actual prctl based opt-in:

1) Provide the necessary setup functionality similar to the other
mitigations and enable the static branch when the command line option
is set and the CPU provides support for hardware assisted L1D
flushing. Software based L1D flush is not supported because it's CPU
model specific and not really well defined.

This does not come with a sysfs file like the other mitigations
because it is not bound to any specific vulnerability.

Support has to be queried via the prctl(2) interface.

2) Add TIF_SPEC_L1D_FLUSH next to L1D_SPEC_IB so the two bits can be
mangled into the mm pointer in one go which allows to reuse the
existing mechanism in switch_mm() for the conditional IBPB speculation
barrier efficiently.

3) Add the L1D flush specific functionality which flushes L1D when the
outgoing task opted in.

Also check whether the incoming task has requested L1D flush and if so
validate that it is not accidentaly running on an SMT sibling as this
makes the whole excercise moot because SMT siblings share L1D which
opens tons of other attack vectors. If that happens schedule task work
which signals the incoming task on return to user/guest with SIGBUS as
this is part of the paranoid L1D flush contract.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Balbir Singh <sblbir@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210108121056.21940-1-sblbir@amazon.com

arch: Kconfig: clean up obsolete use of HAVE_IDE

The arch-specific Kconfig files use HAVE_IDE to indicate if IDE is
supported.

As IDE support and the HAVE_IDE config vanishes with commit b7fb14d3ac63
("ide: remove the legacy ide driver"), there is no need to mention
HAVE_IDE in all those arch-specific Kconfig files.

The issue was identified with ./scripts/checkkconfigsymbols.py.

Fixes: b7fb14d3ac63 ("ide: remove the legacy ide driver")
Suggested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210728182115.4401-1-lukas.bulwahn@gmail.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

mm: generalize ZONE_[DMA|DMA32]

ZONE_[DMA|DMA32] configs have duplicate definitions on platforms that
subscribe to them. Instead, just make them generic options which can be
selected on applicable platforms.

Also only x86/arm64 architectures could enable both ZONE_DMA and
ZONE_DMA32 if EXPERT, add ARCH_HAS_ZONE_DMA_SET to make dma zone
configurable and visible on the two architectures.

Link: https://lkml.kernel.org/r/20210528074557.17768-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> [RISC-V]
Acked-by: Michal Simek <michal.simek@xilinx.com> [microblaze]
Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/thp: make ARCH_ENABLE_SPLIT_PMD_PTLOCK dependent on PGTABLE_LEVELS > 2

ARCH_ENABLE_SPLIT_PMD_PTLOCK is irrelevant unless there are more than two
page table levels including PMD (also per
Documentation/vm/split_page_table_lock.rst). Make this dependency
explicit on remaining platforms i.e x86 and s390 where
ARCH_ENABLE_SPLIT_PMD_PTLOCK is subscribed.

Link: https://lkml.kernel.org/r/1622013501-20409-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> # s390
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR

We don't want compiler instrumentation to touch noinstr functions,
which are annotated with the no_profile_instrument_function function
attribute. Add a Kconfig test for this and make GCOV depend on it, and
in the future, PGO.

If an architecture is using noinstr, it should denote that via this
Kconfig value. That makes Kconfigs that depend on noinstr able to express
dependencies in an architecturally agnostic way.

Cc: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/lkml/YMTn9yjuemKFLbws@hirez.programming.kicks-ass.net/
Link: https://lore.kernel.org/lkml/YMcssV%2Fn5IBGv4f0@hirez.programming.kicks-ass.net/
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210621231822.2848305-4-ndesaulniers@google.com

x86, lto: Enable Clang LTO for 32-bit as well

Commit b33fff07e3e3 ("x86, build: allow LTO to be selected") enabled
support for LTO for x86_64 but 32-bit works fine as well.

I tested the following config combinations:

* i386_defconfig + CONFIG_LTO_CLANG_FULL=y

* i386_defconfig + CONFIG_LTO_CLANG_THIN=y

* ARCH=i386 allmodconfig + CONFIG_LTO_CLANG_THIN=y

with LLVM 11.1.0, 12.0.0, and 13.0.0 from git without any build
failures. The defconfigs boot in QEMU with no new warnings.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210429232611.3966964-1-nathan@kernel.org

mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA

After removal of DISCINTIGMEM the NEED_MULTIPLE_NODES and NUMA
configuration options are equivalent.

Drop CONFIG_NEED_MULTIPLE_NODES and use CONFIG_NUMA instead.

Done with

$ sed -i 's/CONFIG_NEED_MULTIPLE_NODES/CONFIG_NUMA/' \
$(git grep -wl CONFIG_NEED_MULTIPLE_NODES)
$ sed -i 's/NEED_MULTIPLE_NODES/NUMA/' \
$(git grep -wl NEED_MULTIPLE_NODES)

with manual tweaks afterwards.

[rppt@linux.ibm.com: fix arm boot crash]
Link: https://lkml.kernel.org/r/YMj9vHhHOiCVN4BF@linux.ibm.com

Link: https://lkml.kernel.org/r/20210608091316.3622-9-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options

The CONFIG_X86_RESERVE_LOW build time and reservelow= command line option
allowed to control the amount of memory under 1M that would be reserved at
boot to avoid using memory that can be potentially clobbered by BIOS.

Since the entire range under 1M is always reserved there is no need for
these options anymore and they can be removed.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210601075354.5149-3-rppt@kernel.org

locking/atomic: delete !ARCH_ATOMIC remnants

Now that all architectures implement ARCH_ATOMIC, we can make it
mandatory, removing the Kconfig symbol and logic for !ARCH_ATOMIC.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-33-mark.rutland@arm.com

locking/atomic: make ARCH_ATOMIC a Kconfig symbol

Subsequent patches will move architectures over to the ARCH_ATOMIC API,
after preparing the asm-generic atomic implementations to function with
or without ARCH_ATOMIC.

As some architectures use the asm-generic implementations exclusively
(and don't have a local atomic.h), and to avoid the risk that
ARCH_ATOMIC isn't defined in some cases we expect, let's make the
ARCH_ATOMIC macro a Kconfig symbol instead, so that we can guarantee it
is consistently available where needed.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-2-mark.rutland@arm.com

x86/Kconfig: introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE

Enable x86_64 platform to use the MHP_MEMMAP_ON_MEMORY feature.

Link: https://lkml.kernel.org/r/20210421102701.25051-8-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: drop redundant ARCH_ENABLE_SPLIT_PMD_PTLOCK

ARCH_ENABLE_SPLIT_PMD_PTLOCKS has duplicate definitions on platforms
that subscribe it. Drop these redundant definitions and instead just
select it on applicable platforms.

Link: https://lkml.kernel.org/r/1617259448-22529-6-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Heiko Carstens <hca@linux.ibm.com> [s390]
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: drop redundant ARCH_ENABLE_[HUGEPAGE|THP]_MIGRATION

ARCH_ENABLE_[HUGEPAGE|THP]_MIGRATION configs have duplicate definitions on
platforms that subscribe them. Drop these reduntant definitions and
instead just select them appropriately.

[akpm@linux-foundation.org: s/x86_64/X86_64/, per Oscar]

Link: https://lkml.kernel.org/r/1617259448-22529-5-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: generalize ARCH_ENABLE_MEMORY_[HOTPLUG|HOTREMOVE]

ARCH_ENABLE_MEMORY_[HOTPLUG|HOTREMOVE] configs have duplicate
definitions on platforms that subscribe them. Instead, just make them
generic options which can be selected on applicable platforms.

Link: https://lkml.kernel.org/r/1617259448-22529-4-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Heiko Carstens <hca@linux.ibm.com> [s390]
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: generalize ARCH_HAS_CACHE_LINE_SIZE

Patch series "mm: some config cleanups", v2.

This series contains config cleanup patches which reduces code
duplication across platforms and also improves maintainability. There
is no functional change intended with this series.

This patch (of 6):

ARCH_HAS_CACHE_LINE_SIZE config has duplicate definitions on platforms
that subscribe it. Instead, just make it a generic option which can be
selected on applicable platforms. This change reduces code duplication
and makes it cleaner.

Link: https://lkml.kernel.org/r/1617259448-22529-1-git-send-email-anshuman.khandual@arm.com
Link: https://lkml.kernel.org/r/1617259448-22529-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

userfaultfd: add minor fault registration mode

Patch series "userfaultfd: add minor fault handling", v9.

Overview
========

This series adds a new userfaultfd feature, UFFD_FEATURE_MINOR_HUGETLBFS.
When enabled (via the UFFDIO_API ioctl), this feature means that any
hugetlbfs VMAs registered with UFFDIO_REGISTER_MODE_MISSING will *also*
get events for "minor" faults. By "minor" fault, I mean the following
situation:

Let there exist two mappings (i.e., VMAs) to the same page(s) (shared
memory). One of the mappings is registered with userfaultfd (in minor
mode), and the other is not. Via the non-UFFD mapping, the underlying
pages have already been allocated & filled with some contents. The UFFD
mapping has not yet been faulted in; when it is touched for the first
time, this results in what I'm calling a "minor" fault. As a concrete
example, when working with hugetlbfs, we have huge_pte_none(), but
find_lock_page() finds an existing page.

We also add a new ioctl to resolve such faults: UFFDIO_CONTINUE. The idea
is, userspace resolves the fault by either a) doing nothing if the
contents are already correct, or b) updating the underlying contents using
the second, non-UFFD mapping (via memcpy/memset or similar, or something
fancier like RDMA, or etc...). In either case, userspace issues
UFFDIO_CONTINUE to tell the kernel "I have ensured the page contents are
correct, carry on setting up the mapping".

Use Case
========

Consider the use case of VM live migration (e.g. under QEMU/KVM):

1. While a VM is still running, we copy the contents of its memory to a
target machine. The pages are populated on the target by writing to the
non-UFFD mapping, using the setup described above. The VM is still running
(and therefore its memory is likely changing), so this may be repeated
several times, until we decide the target is "up to date enough".

2. We pause the VM on the source, and start executing on the target machine.
During this gap, the VM's user(s) will *see* a pause, so it is desirable to
minimize this window.

3. Between the last time any page was copied from the source to the target, and
when the VM was paused, the contents of that page may have changed - and
therefore the copy we have on the target machine is out of date. Although we
can keep track of which pages are out of date, for VMs with large amounts of
memory, it is "slow" to transfer this information to the target machine. We
want to resume execution before such a transfer would complete.

4. So, the guest begins executing on the target machine. The first time it
touches its memory (via the UFFD-registered mapping), userspace wants to
intercept this fault. Userspace checks whether or not the page is up to date,
and if not, copies the updated page from the source machine, via the non-UFFD
mapping. Finally, whether a copy was performed or not, userspace issues a
UFFDIO_CONTINUE ioctl to tell the kernel "I have ensured the page contents
are correct, carry on setting up the mapping".

We don't have to do all of the final updates on-demand. The userfaultfd manager
can, in the background, also copy over updated pages once it receives the map of
which pages are up-to-date or not.

Interaction with Existing APIs
==============================

Because this is a feature, a registered VMA could potentially receive both
missing and minor faults. I spent some time thinking through how the
existing API interacts with the new feature:

UFFDIO_CONTINUE cannot be used to resolve non-minor faults, as it does not
allocate a new page. If UFFDIO_CONTINUE is used on a non-minor fault:

- For non-shared memory or shmem, -EINVAL is returned.
- For hugetlb, -EFAULT is returned.

UFFDIO_COPY and UFFDIO_ZEROPAGE cannot be used to resolve minor faults.
Without modifications, the existing codepath assumes a new page needs to
be allocated. This is okay, since userspace must have a second
non-UFFD-registered mapping anyway, thus there isn't much reason to want
to use these in any case (just memcpy or memset or similar).

- If UFFDIO_COPY is used on a minor fault, -EEXIST is returned.
- If UFFDIO_ZEROPAGE is used on a minor fault, -EEXIST is returned (or -EINVAL
in the case of hugetlb, as UFFDIO_ZEROPAGE is unsupported in any case).
- UFFDIO_WRITEPROTECT simply doesn't work with shared memory, and returns
-ENOENT in that case (regardless of the kind of fault).

Future Work
===========

This series only supports hugetlbfs. I have a second series in flight to
support shmem as well, extending the functionality. This series is more
mature than the shmem support at this point, and the functionality works
fully on hugetlbfs, so this series can be merged first and then shmem
support will follow.

This patch (of 6):

This feature allows userspace to intercept "minor" faults. By "minor"
faults, I mean the following situation:

Let there exist two mappings (i.e., VMAs) to the same page(s). One of the
mappings is registered with userfaultfd (in minor mode), and the other is
not. Via the non-UFFD mapping, the underlying pages have already been
allocated & filled with some contents. The UFFD mapping has not yet been
faulted in; when it is touched for the first time, this results in what
I'm calling a "minor" fault. As a concrete example, when working with
hugetlbfs, we have huge_pte_none(), but find_lock_page() finds an existing
page.

This commit adds the new registration mode, and sets the relevant flag on
the VMAs being registered. In the hugetlb fault path, if we find that we
have huge_pte_none(), but find_lock_page() does indeed find an existing
page, then we have a "minor" fault, and if the VMA has the userfaultfd
registration flag, we call into userfaultfd to handle it.

This is implemented as a new registration mode, instead of an API feature.
This is because the alternative implementation has significant drawbacks
[1].

However, doing it this was requires we allocate a VM_* flag for the new
registration mode. On 32-bit systems, there are no unused bits, so this
feature is only supported on architectures with
CONFIG_ARCH_USES_HIGH_VMA_FLAGS. When attempting to register a VMA in
MINOR mode on 32-bit architectures, we return -EINVAL.

[1] https://lore.kernel.org/patchwork/patch/1380226/

[peterx@redhat.com: fix minor fault page leak]
Link: https://lkml.kernel.org/r/20210322175132.36659-1-peterx@redhat.com

Link: https://lkml.kernel.org/r/20210301222728.176417-1-axelrasmussen@google.com
Link: https://lkml.kernel.org/r/20210301222728.176417-2-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shawn Anastasio <shawn@anastas.io>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Adam Ruprecht <ruprecht@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Cannon Matthews <cannonmatthews@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>