x86/boot: Remove redundant initialization of the 'delta' variable in strcmp()

The 'delta' variable is zero-initialized, but never
read before the real initialization happens.

The assignment is redundant and can be removed.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231219141304.367200-1-colin.i.king@gmail.com

x86/boot: Repair kernel-doc for boot_kstrtoul()

Adjust the kernel-doc comment to have the proper function name:
boot_kstrtoul().

[ bp: Massage commit message. ]

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221031094835.15923-1-lukas.bulwahn@gmail.com

x86/boot: Add kstrtoul() from lib/

Add kstrtoul() to ../boot/ to be used by facilities there too.

[
bp: Massage, make _kstrtoul() static. Prepend function names with
"boot_". This is a temporary workaround for build errors like:

ld: arch/x86/boot/compressed/acpi.o: in function `count_immovable_mem_regions':
acpi.c:(.text+0x463): undefined reference to `_kstrtoul'
make[2]: *** [arch/x86/boot/compressed/Makefile:117: arch/x86/boot/compressed/vmlinux] Error 1

due to the namespace clash between x86/boot/ and kernel proper.
Future reorg will get rid of the linux/linux/ namespace as much as
possible so that x86/boot/ can be independent from kernel proper. ]

Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/1587645588-7130-2-git-send-email-vamshi.k.sthambamkadi@gmail.com

x86/purgatory: Do not use __builtin_memcpy and __builtin_memset

Implementing memcpy and memset in terms of __builtin_memcpy and
__builtin_memset is problematic.

GCC at -O2 will replace calls to the builtins with calls to memcpy and
memset (but will generate an inline implementation at -Os). Clang will
replace the builtins with these calls regardless of optimization level.
$ llvm-objdump -dr arch/x86/purgatory/string.o | tail

0000000000000339 memcpy:
339: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax
000000000000033b: R_X86_64_64 memcpy
343: ff e0 jmpq *%rax

0000000000000345 memset:
345: 48 b8 00 00 00 00 00 00 00 00 movabsq $0, %rax
0000000000000347: R_X86_64_64 memset
34f: ff e0

Such code results in infinite recursion at runtime. This is observed
when doing kexec.

Instead, reuse an implementation from arch/x86/boot/compressed/string.c.
This requires to implement a stub function for warn(). Also, Clang may
lower memcmp's that compare against 0 to bcmp's, so add a small definition,
too. See also: commit 5f074f3e192f ("lib/string.c: implement a basic bcmp")

Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality")
Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Debugged-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Debugged-by: Manoj Gupta <manojgupta@google.com>
Suggested-by: Alistair Delva <adelva@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Cc: stable@vger.kernel.org
Link: https://bugs.chromium.org/p/chromium/issues/detail?id=984056
Link: https://lkml.kernel.org/r/20190807221539.94583-1-ndesaulniers@google.com

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497

Based on 1 normalized pattern(s):

this file is part of the linux kernel and is made available under
the terms of the gnu general public license version 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 28 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.534229504@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/boot: Restrict header scope to make Clang happy

The inclusion of <linux/kernel.h> was causing issue as the definition of
__arch_hweight64 from arch/x86/include/asm/arch_hweight.h eventually gets
included. The definition is problematic when compiled with -m16 (all code
in arch/x86/boot/ is) as the "D" inline assembly constraint is rejected
by both compilers when passed an argument of type long long (regardless
of signedness, anything smaller is fine).

Because GCC performs inlining before semantic analysis, and
__arch_hweight64 is dead in this translation unit, GCC does not report
any issues at compile time. Clang does the semantic analysis in the
front end, before inlining (run in the middle) can determine the code is
dead. I consider this another case of PR33587, which I think we can do
more work to solve.

It turns out that arch/x86/boot/string.c doesn't actually need
linux/kernel.h, simply linux/limits.h and linux/compiler.h.

Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: bp@alien8.de
Cc: niravd@google.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Link: https://bugs.llvm.org/show_bug.cgi?id=33587
Link: https://github.com/ClangBuiltLinux/linux/issues/347
Link: https://lkml.kernel.org/r/20190314221458.83047-1-ndesaulniers@google.com

x86/boot: Copy kstrtoull() to boot/string.c

Copy kstrtoull() and the other necessary functions from lib/kstrtox.c
to boot/string.c so that code in boot/ can use kstrtoull() and the old
simple_strtoull() can gradually be phased out.

Using div_u64() from math64.h directly will cause the dividend to be
handled as a 64-bit value and cause the infamous __divdi3 linker error
due to gcc trying to use its library function for the 64-bit division.

Therefore, separate the dividend into an upper and lower part.

[ bp: Rewrite commit message. ]

Signed-off-by: Chao Fan <fanc.fnst@cn.fujitsu.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: bhe@redhat.com
Cc: caoj.fnst@cn.fujitsu.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: indou.takao@jp.fujitsu.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kasong@redhat.com
Cc: Kees Cook <keescook@chromium.org>
Cc: msys.mizuma@gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190123110850.12433-2-fanc.fnst@cn.fujitsu.com

x86/boot: Use CC_SET()/CC_OUT() instead of open coding it

Remove open-coded uses of set instructions with CC_SET()/CC_OUT().

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20180629142844.15200-1-ubizjak@gmail.com

x86/boot: #undef memcpy() et al in string.c

undef memcpy() and friends in boot/string.c so that the functions
defined here will have the correct names, otherwise we end up
up trying to redefine __builtin_memcpy() etc.

Surprisingly, GCC allows this (and, helpfully, discards the
__builtin_ prefix from the function name when compiling it),
but clang does not.

Adding these #undef's appears to preserve what I assume was
the original intent of the code.

Signed-off-by: Michael Davidson <md@google.com>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bernhard.Rosenkranzer@linaro.org
Cc: Greg Hackmann <ghackmann@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170724235155.79255-1-mka@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/KASLR: Parse all 'memmap=' boot option entries

In commit:

f28442497b5c ("x86/boot: Fix KASLR and memmap= collision")

... the memmap= option is parsed so that KASLR can avoid those reserved
regions. It uses cmdline_find_option() to get the value if memmap=
is specified, however the problem is that cmdline_find_option() can only
find the last entry if multiple memmap entries are provided. This
is not correct.

Address this by checking each command line token for a "memmap=" match
and parse each instance instead of using cmdline_find_option().

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Cc: douly.fnst@cn.fujitsu.com
Cc: dyoung@redhat.com
Cc: m.mizuma@jp.fujitsu.com
Link: http://lkml.kernel.org/r/1494654390-23861-2-git-send-email-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/boot: Fix KASLR and memmap= collision

CONFIG_RANDOMIZE_BASE=y relocates the kernel to a random base address.

However it does not take into account the memmap= parameter passed in from
the kernel command line. This results in the kernel sometimes being put in
the middle of memmap.

Teach KASLR to not insert the kernel in memmap defined regions. We support
up to 4 memmap regions: any additional regions will cause KASLR to disable.

The mem_avoid set has been augmented to add up to 4 unusable regions of
memmaps provided by the user to exclude those regions from the set of valid
address range to insert the uncompressed kernel image.

The nn@ss ranges will be skipped by the mem_avoid set since it indicates
that memory is useable.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: dan.j.williams@intel.com
Cc: david@fromorbit.com
Cc: linux-nvdimm@lists.01.org
Link: http://lkml.kernel.org/r/148417664156.131935.2248592164852799738.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/boot: Add missing declaration of string functions

Add the missing declarations of basic string functions to string.h to allow
a clean build.

Fixes: 5be865661516 ("String-handling functions for the new x86 setup code.")
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Link: http://lkml.kernel.org/r/1483781911-21399-1-git-send-email-hofrat@osadl.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86, asm: use bool for bitops and other assembly outputs

The gcc people have confirmed that using "bool" when combined with
inline assembly always is treated as a byte-sized operand that can be
assumed to be 0 or 1, which is exactly what the SET instruction
emits. Change the output types and intermediate variables of as many
operations as practical to "bool".

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-3-git-send-email-hpa@linux.intel.com
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

x86/boot: Standardize strcmp()

strcmp() is always expected to return 0 when arguments are equal,
negative when its first argument @str1 is less than its second argument
@str2 and a positive value otherwise. Previously strcmp("a", "b")
returned 1. Now it gives -1, as it is supposed to.

Until now this bug never triggered, because all uses for strcmp() in the
boot code tested for nonzero:

triton:~/tip> git grep strcmp arch/x86/boot/
arch/x86/boot/boot.h:int strcmp(const char *str1, const char *str2);
arch/x86/boot/edd.c: if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip")) {
arch/x86/boot/edd.c: else if (!strcmp(eddarg, "off"))
arch/x86/boot/edd.c: else if (!strcmp(eddarg, "on"))

should in the future strcmp() be used in a comparative way in the boot
code, it might have led to (not so subtle) bugs.

Signed-off-by: Arjun Sreedharan <arjun024@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1426520267-1803-1-git-send-email-arjun024@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86, boot: Remove misc.h inclusion from compressed/string.c

Given the fact that we removed inclusion of boot.h from boot/string.c
does not look like we need misc.h inclusion in compressed/string.c. So
remove it.

misc.h was also pulling in string_32.h which in turn had macros for
memcmp and memcpy. So we don't need to #undef memcmp and memcpy anymore.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1398447972-27896-3-git-send-email-vgoyal@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, boot: Do not include boot.h in string.c

string.c does not require whole of boot.h. Just inclusion of linux/types.h
and ctypes.h seems to be sufficient.

Keep list of stuff being included in string.c to bare minimal so that
string.c can be included in other places easily.

For example, Currently boot/compressed/string.c includes boot/string.c
but looks like it does not want boot/boot.h. Hence there is a define
in boot/compressed/misc.h "define BOOT_BOOT_H" which prevents inclusion
of boot.h in compressed/string.c. And compressed/string.c is forced to
include misc.h just for that reason.

So by removing inclusion of boot.h, we can also get rid of inclusion of
misch.h in compressed/misc.c.

This also enables including of boot/string.c in purgatory/ code relatively
easily.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1398447972-27896-2-git-send-email-vgoyal@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, boot: Move memcmp() into string.h and string.c

Try to treat memcmp() in same way as memcpy() and memset(). Provide a
declaration in boot/string.h and by default user gets a memcmp() which
maps to builtin function.

Move optimized definition of memcmp() in boot/string.c. Now a user can
do #undef memcmp and link against string.c to use optimzied memcmp().

It also simplifies boot/compressed/string.c where we had to redefine
memcmp(). That extra definition is gone now.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1395170800-11059-5-git-send-email-vgoyal@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, efi: EFI boot stub support

There is currently a large divide between kernel development and the
development of EFI boot loaders. The idea behind this patch is to give
the kernel developers full control over the EFI boot process. As
H. Peter Anvin put it,

"The 'kernel carries its own stub' approach been very successful in
dealing with BIOS, and would make a lot of sense to me for EFI as
well."

This patch introduces an EFI boot stub that allows an x86 bzImage to
be loaded and executed by EFI firmware. The bzImage appears to the
firmware as an EFI application. Luckily there are enough free bits
within the bzImage header so that it can masquerade as an EFI
application, thereby coercing the EFI firmware into loading it and
jumping to its entry point. The beauty of this masquerading approach
is that both BIOS and EFI boot loaders can still load and run the same
bzImage, thereby allowing a single kernel image to work in any boot
environment.

The EFI boot stub supports multiple initrds, but they must exist on
the same partition as the bzImage. Command-line arguments for the
kernel can be appended after the bzImage name when run from the EFI
shell, e.g.

Shell> bzImage console=ttyS0 root=/dev/sdb initrd=initrd.img

v7:
- Fix checkpatch warnings.

v6:

- Try to allocate initrd memory just below hdr->inird_addr_max.

v5:

- load_options_size is UTF-16, which needs dividing by 2 to convert
to the corresponding ASCII size.

v4:

- Don't read more than image->load_options_size

v3:

- Fix following warnings when compiling CONFIG_EFI_STUB=n

arch/x86/boot/tools/build.c: In function ‘main’:
arch/x86/boot/tools/build.c:138:24: warning: unused variable ‘pe_header’
arch/x86/boot/tools/build.c:138:15: warning: unused variable ‘file_sz’

- As reported by Matthew Garrett, some Apple machines have GOPs that
don't have hardware attached. We need to weed these out by
searching for ones that handle the PCIIO protocol.

- Don't allocate memory if no initrds are on cmdline
- Don't trust image->load_options_size

Maarten Lankhorst noted:
- Don't strip first argument when booted from efibootmgr
- Don't allocate too much memory for cmdline
- Don't update cmdline_size, the kernel considers it read-only
- Don't accept '\n' for initrd names

v2:

- File alignment was too large, was 8192 should be 512. Reported by
Maarten Lankhorst on LKML.
- Added UGA support for graphics
- Use VIDEO_TYPE_EFI instead of hard-coded number.
- Move linelength assignment until after we've assigned depth
- Dynamically fill out AddressOfEntryPoint in tools/build.c
- Don't use magic number for GDT/TSS stuff. Requested by Andi Kleen
- The bzImage may need to be relocated as it may have been loaded at
a high address address by the firmware. This was required to get my
macbook booting because the firmware loaded it at 0x7cxxxxxx, which
triggers this error in decompress_kernel(),

if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
error("Destination address too large");

Cc: Mike Waychison <mikew@google.com>
Cc: Matthew Garrett <mjg@redhat.com>
Tested-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/1321383097.2657.9.camel@mfleming-mobl1.ger.corp.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, setup: Make the setup code also accept console=uart8250

Make the boot code also accept the console=uart8250,io,0x2f8,115200n
form of early console.

Also add back simple_guess_base(), otherwise those simple_strtoull(,,0)
are not going to work.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4C3CCE05.4090505@kernel.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, setup: Early-boot serial I/O support

This patch adds serial I/O support to the real-mode setup (very early
boot) printf(). It's useful for debugging boot code when running Linux
under KVM, for example. The actual code was lifted from early printk.

Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
LKML-Reference: <1278835617-11368-1-git-send-email-penberg@cs.helsinki.fi>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86: remove pointless comments

Remove old comments that include the old arch/i386 directory.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

i386: move boot

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>