x86/trampoline: Bypass compat mode in trampoline_start64() if not needed

The trampoline_start64() vector is used when a secondary CPU starts in
64-bit mode. The current implementation directly enters compatibility
mode. It is necessary to disable paging and re-enable it in the correct
paging mode: either 4- or 5-level, depending on the configuration.

The X86S[1] ISA does not support compatibility mode in ring 0, and
paging cannot be disabled.

Rework the trampoline_start64() function to only enter compatibility
mode if it is necessary to change the paging mode. If the CPU is
already in the desired paging mode, proceed in long mode.

This allows a secondary CPU to boot on an X86S machine as long as the
CPU is already in the correct paging mode.

In the future, there will be a mechanism to switch between paging modes
without disabling paging.

[1] https://www.intel.com/content/www/us/en/developer/articles/technical/envisioning-future-simplified-architecture.html

[ dhansen: changelog tweaks ]

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: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/20240126100101.689090-1-kirill.shutemov%40linux.intel.com

x86/realmode: Make stack lock work in trampoline_compat()

The stack locking and stack assignment macro LOAD_REALMODE_ESP fails to
work when invoked from the 64bit trampoline entry point:

trampoline_start64
trampoline_compat
LOAD_REALMODE_ESP <- lock

Accessing tr_lock is only possible from 16bit mode. For the compat entry
point this needs to be pa_tr_lock so that the required relocation entry is
generated. Otherwise it locks the non-relocated address which is
aside of being wrong never cleared in secondary_startup_64() causing all
but the first CPU to get stuck on the lock.

Make the macro take an argument lock_pa which defaults to 0 and rename it
to LOCK_AND_LOAD_REALMODE_ESP to make it clear what this is about.

Fixes: f6f1ae9128d2 ("x86/smpboot: Implement a bit spinlock to protect the realmode stack")
Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: https://lore.kernel.org/r/87h6rujdvl.ffs@tglx

x86/smpboot: Implement a bit spinlock to protect the realmode stack

Parallel AP bringup requires that the APs can run fully parallel through
the early startup code including the real mode trampoline.

To prepare for this implement a bit-spinlock to serialize access to the
real mode stack so that parallel upcoming APs are not going to corrupt each
others stack while going through the real mode startup code.

Co-developed-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-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/20230512205257.355425551@linutronix.de

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/boot: Set CR0.NE early and keep it set during the boot

TDX guest requires CR0.NE to be set. Clearing the bit triggers #GP(0).

If CR0.NE is 0, the MS-DOS compatibility mode for handling floating-point
exceptions is selected. In this mode, the software exception handler for
floating-point exceptions is invoked externally using the processor’s
FERR#, INTR, and IGNNE# pins.

Using FERR# and IGNNE# to handle floating-point exception is deprecated.
CR0.NE=0 also limits newer processors to operate with one logical
processor active.

Kernel uses CR0_STATE constant to initialize CR0. It has NE bit set.
But during early boot kernel has more ad-hoc approach to setting bit
in the register. During some of this ad-hoc manipulation, CR0.NE is
cleared. This causes a #GP in TDX guests and makes it die in early boot.

Make CR0 initialization consistent, deriving the initial value of CR0
from CR0_STATE. Since CR0_STATE always has CR0.NE=1, this ensures that
CR0.NE is never 0 and avoids the #GP.

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: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-23-kirill.shutemov@linux.intel.com

x86/boot: Add a trampoline for booting APs via firmware handoff

Historically, x86 platforms have booted secondary processors (APs)
using INIT followed by the start up IPI (SIPI) messages. In regular
VMs, this boot sequence is supported by the VMM emulation. But such a
wakeup model is fatal for secure VMs like TDX in which VMM is an
untrusted entity. To address this issue, a new wakeup model was added
in ACPI v6.4, in which firmware (like TDX virtual BIOS) will help boot
the APs. More details about this wakeup model can be found in ACPI
specification v6.4, the section titled "Multiprocessor Wakeup Structure".

Since the existing trampoline code requires processors to boot in real
mode with 16-bit addressing, it will not work for this wakeup model
(because it boots the AP in 64-bit mode). To handle it, extend the
trampoline code to support 64-bit mode firmware handoff. Also, extend
IDT and GDT pointers to support 64-bit mode hand off.

There is no TDX-specific detection for this new boot method. The kernel
will rely on it as the sole boot method whenever the new ACPI structure
is present.

The ACPI table parser for the MADT multiprocessor wake up structure and
the wakeup method that uses this structure will be added by the following
patch in this series.

Signed-off-by: Sean Christopherson <sean.j.christopherson@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: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20220405232939.73860-21-kirill.shutemov@linux.intel.com

x86/msr: Rename MSR_K8_SYSCFG to MSR_AMD64_SYSCFG

The SYSCFG MSR continued being updated beyond the K8 family; drop the K8
name from it.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Joerg Roedel <jroedel@suse.de>
Link: https://lkml.kernel.org/r/20210427111636.1207-4-brijesh.singh@amd.com

x86/realmode: Add SEV-ES specific trampoline entry point

The code at the trampoline entry point is executed in real-mode. In
real-mode, #VC exceptions can't be handled so anything that might cause
such an exception must be avoided.

In the standard trampoline entry code this is the WBINVD instruction and
the call to verify_cpu(), which are both not needed anyway when running
as an SEV-ES guest.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-66-joro@8bytes.org

x86/asm/64: Add ENDs to some functions and relabel with SYM_CODE_*

All these are functions which are invoked from elsewhere but they are
not typical C functions. So annotate them using the new SYM_CODE_START.
All these were not balanced with any END, so mark their ends by
SYM_CODE_END appropriately too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> [xen bits]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [power mgmt]
Cc: Andy Shevchenko <andy@infradead.org>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: platform-driver-x86@vger.kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Huang <wei@redhat.com>
Cc: x86-ml <x86@kernel.org>
Cc: xen-devel@lists.xenproject.org
Cc: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Link: https://lkml.kernel.org/r/20191011115108.12392-23-jslaby@suse.cz

x86/asm/realmode: Use SYM_DATA_* instead of GLOBAL

GLOBAL had several meanings and is going away. Convert all the data
marked using GLOBAL to use SYM_DATA_START or SYM_DATA instead.

Note that SYM_DATA_END_LABEL is used to generate tr_gdt_end too.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191011115108.12392-19-jslaby@suse.cz

x86/realmode: Remove trampoline_status

There is no reader of trampoline_status, it's only written.

It turns out that after commit ce4b1b16502b ("x86/smpboot: Initialize
secondary CPU only if master CPU will wait for it"), trampoline_status is
not needed any more.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1563266424-3472-1-git-send-email-kernelfans@gmail.com

x86-64/realmode: Add instruction suffix

Omitting suffixes from instructions in AT&T mode is bad practice when
operand size cannot be determined by the assembler from register
operands, and is likely going to be warned about by upstream GAS in the
future (mine does already). Add the single missing suffix here.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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>
Link: http://lkml.kernel.org/r/5A8AF5F602000078001A9230@prv-mh.provo.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/boot/realmode: Check for memory encryption on the APs

Add support to check if memory encryption is active in the kernel and that
it has been enabled on the AP. If memory encryption is active in the kernel
but has not been enabled on the AP, then set the memory encryption bit (bit
23) of MSR_K8_SYSCFG to enable memory encryption on that AP and allow the
AP to continue start up.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/37e29b99c395910f56ca9f8ecf7b0439b28827c8.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86: Delete non-required instances of include <linux/init.h>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>. Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

[ hpa: undid incorrect removal from arch/x86/kernel/head_32.S ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: http://lkml.kernel.org/r/1389054026-12947-1-git-send-email-paul.gortmaker@windriver.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, realmode: Change EFER to a single u64 field

Change EFER to be a single u64 field instead of two u32 fields; change
the order to maintain alignment. Note that on x86-64 cr4 is really
also a 64-bit quantity, although we can only set the low 32 bits from
the trampoline code since it is still executing in 32-bit mode at that
point.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>

x86, realmode: Move not-common bits out of trampoline_common.S

Move the bits that aren't actually common out of trampoline_common.S
and into the arch-specific files. Furthermore, make sure the page
directory is first in the .bss section for trampoline_64.S in order to
not waste an entire page of memory.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@intel.com>

x86, realmode: read cr4 and EFER from kernel for 64-bit trampoline

This patch changes 64-bit trampoline so that CR4 and
EFER are provided by the kernel instead of using fixed
values.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-24-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, realmode: header for trampoline code

Added header for trampoline code that can be used to supply
input data to it. This makes interface between real mode code
and kernel cleaner and simpler. Replaced two confusing pointers
to level4 pgt in trampoline_64.S with a single pointer to the
beginning of the page table.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-21-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, realmode: fix 64-bit wakeup sequence

There were number of issues in wakeup sequence:

- Wakeup stack was placed in hardcoded address.
- NX bit in EFER was not enabled.
- Initialization incorrectly set physical address
of secondary_startup_64.
- Some alignment issues.

This patch fixes these issues and in addition:

- Unifies coding conventions in .S files.
- Sets alignments of code and data right.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-18-git-send-email-jarkko.sakkinen@intel.com
Originally-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, realmode: Replace open-coded ljmpw with a macro

We cannot code an ljmpw to the real-mode segment directly, because gas
refuses to assemble an ljmp with a symbolic segment. Instead of
open-coding it everywhere, define a macro and use it for this case.

This is specifically an ljmpw from a 16-bit segment. This is okay, as
one should never enter real mode from a 32-bit segment: if one do, the
CPU ends up in a bizarre (and useless) mode sometimes called "unreal
mode" where segments behave like real mode but the default address and
operand sizes is 32 bits.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-15-git-send-email-jarkko.sakkinen@intel.com

x86, realmode: Remove indirect jumps in trampoline_64.S

Remove indirect jumps in trampoline_64.S which are no longer
necessary: the realmode code can relocate the absolute jumps
correctly from the start.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-13-git-send-email-jarkko.sakkinen@intel.com

x86, realmode: Move bits to the proper sections in trampoline_64.S

Move various bits to the sections they really belong in in
trampoline_64.S. Use GLOBAL() rather than ENTRY() for data objects:
ENTRY() should only be used with code and forces alignment to 16
bytes.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-11-git-send-email-jarkko.sakkinen@intel.com

x86, realmode: Move SMP trampoline to unified realmode code

Migrated SMP trampoline code to the real mode blob.
SMP trampoline code is not yet removed from
.x86_trampoline because it is needed by the wakeup
code.

[ hpa: always enable compiling startup_32_smp in head_32.S... it is
only a few instructions which go into .init on UP builds, and it makes
the rest of the code less #ifdef ugly. ]

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-6-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>