x86/microcode/intel: Add a minimum required revision for late loading

In general users, don't have the necessary information to determine
whether late loading of a new microcode version is safe and does not
modify anything which the currently running kernel uses already, e.g.
removal of CPUID bits or behavioural changes of MSRs.

To address this issue, Intel has added a "minimum required version"
field to a previously reserved field in the microcode header. Microcode
updates should only be applied if the current microcode version is equal
to, or greater than this minimum required version.

Thomas made some suggestions on how meta-data in the microcode file could
provide Linux with information to decide if the new microcode is suitable
candidate for late loading. But even the "simpler" option requires a lot of
metadata and corresponding kernel code to parse it, so the final suggestion
was to add the 'minimum required version' field in the header.

When microcode changes visible features, microcode will set the minimum
required version to its own revision which prevents late loading.

Old microcode blobs have the minimum revision field always set to 0, which
indicates that there is no information and the kernel considers it
unsafe.

This is a pure OS software mechanism. The hardware/firmware ignores this
header field.

For early loading there is no restriction because OS visible features
are enumerated after the early load and therefore a change has no
effect.

The check is always enabled, but by default not enforced. It can be
enforced via Kconfig or kernel command line.

If enforced, the kernel refuses to late load microcode with a minimum
required version field which is zero or when the currently loaded
microcode revision is smaller than the minimum required revision.

If not enforced the load happens independent of the revision check to
stay compatible with the existing behaviour, but it influences the
decision whether the kernel is tainted or not. If the check signals that
the late load is safe, then the kernel is not tainted.

Early loading is not affected by this.

[ tglx: Massaged changelog and fixed up the implementation ]

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.776467264@linutronix.de

x86/microcode: Handle "offline" CPUs correctly

Offline CPUs need to be parked in a safe loop when microcode update is
in progress on the primary CPU. Currently, offline CPUs are parked in
mwait_play_dead(), and for Intel CPUs, its not a safe instruction,
because the MWAIT instruction can be patched in the new microcode update
that can cause instability.

- Add a new microcode state 'UCODE_OFFLINE' to report status on per-CPU
basis.
- Force NMI on the offline CPUs.

Wake up offline CPUs while the update is in progress and then return
them back to mwait_play_dead() after microcode update is complete.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.660850472@linutronix.de

x86/microcode: Rendezvous and load in NMI

stop_machine() does not prevent the spin-waiting sibling from handling
an NMI, which is obviously violating the whole concept of rendezvous.

Implement a static branch right in the beginning of the NMI handler
which is nopped out except when enabled by the late loading mechanism.

The late loader enables the static branch before stop_machine() is
invoked. Each CPU has an nmi_enable in its control structure which
indicates whether the CPU should go into the update routine.

This is required to bridge the gap between enabling the branch and
actually being at the point where it is required to enter the loader
wait loop.

Each CPU which arrives in the stopper thread function sets that flag and
issues a self NMI right after that. If the NMI function sees the flag
clear, it returns. If it's set it clears the flag and enters the
rendezvous.

This is safe against a real NMI which hits in between setting the flag
and sending the NMI to itself. The real NMI will be swallowed by the
microcode update and the self NMI will then let stuff continue.
Otherwise this would end up with a spurious NMI.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231002115903.489900814@linutronix.de

x86/microcode/32: Move early loading after paging enable

32-bit loads microcode before paging is enabled. The commit which
introduced that has zero justification in the changelog. The cover
letter has slightly more content, but it does not give any technical
justification either:

"The problem in current microcode loading method is that we load a
microcode way, way too late; ideally we should load it before turning
paging on. This may only be practical on 32 bits since we can't get
to 64-bit mode without paging on, but we should still do it as early
as at all possible."

Handwaving word salad with zero technical content.

Someone claimed in an offlist conversation that this is required for
curing the ATOM erratum AAE44/AAF40/AAG38/AAH41. That erratum requires
an microcode update in order to make the usage of PSE safe. But during
early boot, PSE is completely irrelevant and it is evaluated way later.

Neither is it relevant for the AP on single core HT enabled CPUs as the
microcode loading on the AP is not doing anything.

On dual core CPUs there is a theoretical problem if a split of an
executable large page between enabling paging including PSE and loading
the microcode happens. But that's only theoretical, it's practically
irrelevant because the affected dual core CPUs are 64bit enabled and
therefore have paging and PSE enabled before loading the microcode on
the second core. So why would it work on 64-bit but not on 32-bit?

The erratum:

"AAG38 Code Fetch May Occur to Incorrect Address After a Large Page is
Split Into 4-Kbyte Pages

Problem: If software clears the PS (page size) bit in a present PDE
(page directory entry), that will cause linear addresses mapped through
this PDE to use 4-KByte pages instead of using a large page after old
TLB entries are invalidated. Due to this erratum, if a code fetch uses
this PDE before the TLB entry for the large page is invalidated then it
may fetch from a different physical address than specified by either the
old large page translation or the new 4-KByte page translation. This
erratum may also cause speculative code fetches from incorrect addresses."

The practical relevance for this is exactly zero because there is no
splitting of large text pages during early boot-time, i.e. between paging
enable and microcode loading, and neither during CPU hotplug.

IOW, this load microcode before paging enable is yet another voodoo
programming solution in search of a problem. What's worse is that it causes
at least two serious problems:

1) When stackprotector is enabled, the microcode loader code has the
stackprotector mechanics enabled. The read from the per CPU variable
__stack_chk_guard is always accessing the virtual address either
directly on UP or via %fs on SMP. In physical address mode this
results in an access to memory above 3GB. So this works by chance as
the hardware returns the same value when there is no RAM at this
physical address. When there is RAM populated above 3G then the read
is by chance the same as nothing changes that memory during the very
early boot stage. That's not necessarily true during runtime CPU
hotplug.

2) When function tracing is enabled, the relevant microcode loader
functions and the functions invoked from there will call into the
tracing code and evaluate global and per CPU variables in physical
address mode. What could potentially go wrong?

Cure this and move the microcode loading after the early paging enable, use
the new temporary initrd mapping and remove the gunk in the microcode
loader which is required to handle physical address mode.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211722.348298216@linutronix.de

x86/boot/32: Temporarily map initrd for microcode loading

Early microcode loading on 32-bit runs in physical address mode because
the initrd is not covered by the initial page tables. That results in
a horrible mess all over the microcode loader code.

Provide a temporary mapping for the initrd in the initial page tables by
appending it to the actual initial mapping starting with a new PGD or
PMD depending on the configured page table levels ([non-]PAE).

The page table entries are located after _brk_end so they are not
permanently using memory space. The mapping is invalidated right away in
i386_start_kernel() after the early microcode loader has run.

This prepares for removing the physical address mode oddities from all
over the microcode loader code, which in turn allows further cleanups.

Provide the map and unmap code and document the place where the
microcode loader needs to be invoked with a comment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211722.292291436@linutronix.de

x86/microcode: Move core specific defines to local header

There is no reason to expose all of this globally. Move everything which is
not required outside of the microcode specific code to local header files
and into the respective source files.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230812195727.952876381@linutronix.de

x86/microcode: Make reload_early_microcode() static

fe055896c040 ("x86/microcode: Merge the early microcode loader") left this
needlessly public. Git archaeology provided by Borislav.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230812195727.834943153@linutronix.de

x86/microcode: Include vendor headers into microcode.h

Currently vendor specific headers are included explicitly when used in
common code. Instead, include the vendor specific headers in
microcode.h, and include that in all usages.

No functional change.

Suggested-by: Boris Petkov <bp@alien8.de>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230812195727.776541545@linutronix.de

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/cpu/amd: Add a Zenbleed fix

Add a fix for the Zen2 VZEROUPPER data corruption bug where under
certain circumstances executing VZEROUPPER can cause register
corruption or leak data.

The optimal fix is through microcode but in the case the proper
microcode revision has not been applied, enable a fallback fix using
a chicken bit.

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

x86/microcode/AMD: Add a @cpu parameter to the reloading functions

Will be used in a subsequent change.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230130161709.11615-3-bp@alien8.de

x86/microcode: Drop struct ucode_cpu_info.valid

It is not needed anymore.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-6-bp@alien8.de

x86/microcode: Kill refresh_fw

request_microcode_fw() can always request firmware now so drop this
superfluous argument.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lore.kernel.org/r/20221028142638.28498-4-bp@alien8.de

x86/microcode/AMD: Track patch allocation size explicitly

In preparation for reducing the use of ksize(), record the actual
allocation size for later memcpy(). This avoids copying extra
(uninitialized!) bytes into the patch buffer when the requested
allocation size isn't exactly the size of a kmalloc bucket.
Additionally, fix potential future issues where runtime bounds checking
will notice that the buffer was allocated to a smaller value than
returned by ksize().

Fixes: 757885e94a22 ("x86, microcode, amd: Early microcode patch loading support for AMD")
Suggested-by: Daniel Micay <danielmicay@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/lkml/CA+DvKQ+bp7Y7gmaVhacjv9uF6Ar-o4tet872h4Q8RPYPJjcJQA@mail.gmail.com/

x86/microcode: Remove ->request_microcode_user()

181b6f40e9ea ("x86/microcode: Rip out the OLD_INTERFACE")

removed the old microcode loading interface but forgot to remove the
related ->request_microcode_user() functionality which it uses.

Rip it out now too.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220825075445.28171-1-bp@alien8.de

x86/cpu: Load microcode during restore_processor_state()

When resuming from system sleep state, restore_processor_state()
restores the boot CPU MSRs. These MSRs could be emulated by microcode.
If microcode is not loaded yet, writing to emulated MSRs leads to
unchecked MSR access error:

...
PM: Calling lapic_suspend+0x0/0x210
unchecked MSR access error: WRMSR to 0x10f (tried to write 0x0...0) at rIP: ... (native_write_msr)
Call Trace:
<TASK>
? restore_processor_state
x86_acpi_suspend_lowlevel
acpi_suspend_enter
suspend_devices_and_enter
pm_suspend.cold
state_store
kobj_attr_store
sysfs_kf_write
kernfs_fop_write_iter
new_sync_write
vfs_write
ksys_write
__x64_sys_write
do_syscall_64
entry_SYSCALL_64_after_hwframe
RIP: 0033:0x7fda13c260a7

To ensure microcode emulated MSRs are available for restoration, load
the microcode on the boot CPU before restoring these MSRs.

[ Pawan: write commit message and productize it. ]

Fixes: e2a1256b17b1 ("x86/speculation: Restore speculation related MSRs during S3 resume")
Reported-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Tested-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215841
Link: https://lore.kernel.org/r/4350dfbf785cd482d3fafa72b2b49c83102df3ce.1650386317.git.pawan.kumar.gupta@linux.intel.com

x86/microcode: Use the firmware_loader built-in API

The microcode loader has been looping through __start_builtin_fw down to
__end_builtin_fw to look for possibly built-in firmware for microcode
updates.

Now that the firmware loader code has exported an API for looping
through the kernel's built-in firmware section, use it and drop the x86
implementation in favor.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211021155843.1969401-4-mcgrof@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

x86/microcode: Make microcode_init() static

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201230122147.26938-1-bp@alien8.de

x86/microcode: Attempt late loading only when new microcode is present

Return UCODE_NEW from the scanning functions to denote that new microcode
was found and only then attempt the expensive synchronization dance.

Reported-by: Emanuel Czirai <xftroxgpx@protonmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Emanuel Czirai <xftroxgpx@protonmail.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lkml.kernel.org/r/20180314183615.17629-1-bp@alien8.de

x86/MSR: Move native_* variants to msr.h

... where they belong.

No functional change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Cc: kvm@vger.kernel.org
Link: https://lkml.kernel.org/r/20180301151336.12948-1-bp@alien8.de

x86/microcode: Propagate return value from updating functions

... so that callers can know when microcode was updated and act
accordingly.

Tested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180216112640.11554-2-bp@alien8.de
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/microcode: Do not access the initrd after it has been freed

When we look for microcode blobs, we first try builtin and if that
doesn't succeed, we fallback to the initrd supplied to the kernel.

However, at some point doing boot, that initrd gets jettisoned and we
shouldn't access it anymore. But we do, as the below KASAN report shows.
That's because find_microcode_in_initrd() doesn't check whether the
initrd is still valid or not.

So do that.

==================================================================
BUG: KASAN: use-after-free in find_cpio_data
Read of size 1 by task swapper/1/0
page:ffffea0000db9d40 count:0 mapcount:0 mapping: (null) index:0x1
flags: 0x100000000000000()
raw: 0100000000000000 0000000000000000 0000000000000001 00000000ffffffff
raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.10.0-rc5-debug-00075-g2dbde22 #3
Hardware name: Dell Inc. XPS 13 9360/0839Y6, BIOS 1.2.3 12/01/2016
Call Trace:
dump_stack
? _atomic_dec_and_lock
? __dump_page
kasan_report_error
? pointer
? find_cpio_data
__asan_report_load1_noabort
? find_cpio_data
find_cpio_data
? vsprintf
? dump_stack
? get_ucode_user
? print_usage_bug
find_microcode_in_initrd
__load_ucode_intel
? collect_cpu_info_early
? debug_check_no_locks_freed
load_ucode_intel_ap
? collect_cpu_info
? trace_hardirqs_on
? flat_send_IPI_mask_allbutself
load_ucode_ap
? get_builtin_firmware
? flush_tlb_func
? do_raw_spin_trylock
? cpumask_weight
cpu_init
? trace_hardirqs_off
? play_dead_common
? native_play_dead
? hlt_play_dead
? syscall_init
? arch_cpu_idle_dead
? do_idle
start_secondary
start_cpu
Memory state around the buggy address:
ffff880036e74f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff880036e74f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff880036e75000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff880036e75080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff880036e75100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Tested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170126165833.evjemhbqzaepirxo@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Convert to bare minimum MSR accessors

Having tracepoints to the MSR accessors makes them unsuitable for early
microcode loading: think 32-bit before paging is enabled and us chasing
pointers to test whether a tracepoint is enabled or not. Results in a
reliable triple fault.

Convert to the bare ones.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-4-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

x86/microcode: Rework microcode loading

Yeah, I know, I know, this is a huuge patch and reviewing it is hard.

Sorry but this is the only way I could think of in which I can rewrite
the microcode patches loading procedure without breaking (knowingly) the
driver.

So maybe this patch is easier to review if one looks at the files after
the patch has been applied instead at the diff. Because then it becomes
pretty obvious:

* The BSP-loading path - load_ucode_bsp() is working independently from
the AP path now and it doesn't save any pointers or patches anymore -
it solely parses the builtin or initrd microcode and applies the patch.
That's it.

This fixes the CONFIG_RANDOMIZE_MEMORY offset fun more solidly.

* The AP-loading path - load_ucode_ap() then goes and scans
builtin/initrd *again* for the microcode patches but it caches them this
time so that we don't have to do that scan on each AP but only once.

This simplifies the code considerably.

Then, when we save the microcode from the initrd/builtin, we go and
add the relevant patches to our own cache. The AMD side did do that
and now the Intel side does it too. So no more pointer copying and
blabla, we save the microcode patches ourselves and are independent from
initrd/builtin.

This whole conversion gives us other benefits like unifying the
initrd parsing into a single function: find_microcode_in_initrd() is
used by both.

The diffstat speaks for itself: 456 insertions(+), 695 deletions(-)

Signed-off-by: Borislav Petkov <bp@suse.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>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161025095522.11964-12-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Export the microcode cache linked list

It will be used by both drivers so move it to core.c.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.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>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161025095522.11964-6-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Remove one #ifdef clause

Move the function declaration to the other #ifdef CONFIG_MICROCODE
together with the other functions.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.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>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161025095522.11964-5-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Fix suspend to RAM with builtin microcode

Usually, after we have found the proper microcode blob for the current
machine, we stash it away for later use with save_microcode_in_initrd().

However, with builtin microcode which doesn't come from the initrd, we
don't call that function because CONFIG_BLK_DEV_INITRD=n and even if
set, we don't have a valid initrd.

In order to fix this, let's make save_microcode_in_initrd() an
fs_initcall which runs before rootfs_initcall() as this was the time it
was called previously through:

rootfs_initcall(populate_rootfs)
|-> free_initrd()
|-> free_initrd_mem()
|-> save_microcode_in_initrd()

Also, we make it run independently from initrd functionality being
present or not.

And since it is called in the microcode loader only now, we can also
make it static.

Reported-and-tested-by: Jim Bos <jim876@xs4all.nl>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # v4.6
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465225850-7352-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Fix loading precedence

So it can happen that even with builtin microcode,
CONFIG_BLK_DEV_INITRD=y gets forgotten enabled.

Or, even with that disabled, an initrd image gets supplied by the boot
loader, by omission or is simply forgotten there. And since we do look
at boot_params.hdr.ramdisk_* to know whether we have received an initrd,
we might get puzzled.

So let's just make the loader look for builtin microcode first and if
found, ignore the ramdisk image.

If no builtin found, it falls back to scanning the supplied initrd, of
course.

For that, we move all the initrd scanning in a separate
__scan_microcode_initrd() function and fall back to it only if
load_builtin_intel_microcode() has failed.

Reported-and-tested-by: Gabriel Craciunescu <nix.or.die@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465225850-7352-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Untangle from BLK_DEV_INITRD

Thomas Voegtle reported that doing oldconfig with a .config which has
CONFIG_MICROCODE enabled but BLK_DEV_INITRD disabled prevents the
microcode loading mechanism from being built.

So untangle it from the BLK_DEV_INITRD dependency so that oldconfig
doesn't turn it off and add an explanatory text to its Kconfig help what
the supported methods for supplying microcode are.

Reported-by: Thomas Voegtle <tv@lio96.de>
Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.4
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1454499225-21544-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/cpu: Unify CPU family, model, stepping calculation

Add generic functions which calc family, model and stepping from
the CPUID_1.EAX leaf and stick them into the library we have.

Rename those which do call CPUID with the prefix "x86_cpuid" as
suggested by Paolo Bonzini.

No functionality change.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1448273546-2567-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Remove modularization leftovers

Remove the remaining module functionality leftovers. Make
"dis_ucode_ldr" an early_param and make it static again. Drop
module aliases, autoloading table, description, etc.

Bump version number, while at it.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1445334889-300-4-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Merge the early microcode loader

Merge the early loader functionality into the driver proper. The
diff is huge but logically, it is simply moving code from the
_early.c files into the main driver.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1445334889-300-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Unmodularize the microcode driver

Make CONFIG_MICROCODE a bool. It was practically a bool already anyway,
since early loader was forcing it to =y.

Regardless, there's no real reason to have something be a module which
gets built-in on the majority of installations out there. And its not
like there's noticeable change in functionality - we still can load late
microcode - just the module glue disappears.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/1445334889-300-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Parse built-in microcode early

Apparently, people do build microcode into the kernel image, i.e.
CONFIG_FIRMWARE_IN_KERNEL=y.

Make that work in the early loader which is where microcode should be
preferably loaded anyway.

Note that you need to specify the microcode filename with the path
relative to the toplevel firmware directory (the same like the late
loading method) in CONFIG_EXTRA_FIRMWARE=y so that early loader can
find it.

I.e., something like this (Intel variant):

CONFIG_FIRMWARE_IN_KERNEL=y
CONFIG_EXTRA_FIRMWARE="intel-ucode/06-3a-09"
CONFIG_EXTRA_FIRMWARE_DIR="/lib/firmware/"

While at it, add me to the loader copyright boilerplate.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

x86/microcode: Consolidate family,model, ... code

... to the header. Split the family acquiring function into a
main one, doing CPUID and a helper which computes the extended
family and is used in multiple places. Get rid of the locally-grown
get_x86_{family,model}().

While at it, rename local variables to something more descriptive and
vertically align assignments for better readability.

There should be no functionality change resulting from this patch.

Signed-off-by: Borislav Petkov <bp@suse.de>

x86, microcode: Reload microcode on resume

Normally, we do reapply microcode on resume. However, in the cases where
that microcode comes from the early loader and the late loader hasn't
been utilized yet, there's no easy way for us to go and apply the patch
applied during boot by the early loader.

Thus, reuse the patch stashed by the early loader for the BSP.

Signed-off-by: Borislav Petkov <bp@suse.de>

x86, microcode: Add a disable chicken bit

Add a cmdline param which disables the microcode loader. This is useful
mostly in debugging situations where we want to turn off microcode
loading, both early from the initrd and late, as a means to be able to
rule out its influence on the machine.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1400525957-11525-3-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, microcode: Share native MSR accessing variants

We want to use those in AMD's early loading path too. Also, add a
native_wrmsrl variant.

Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>

x86: delete __cpuinit usage from all x86 files

The __cpuinit type of throwaway sections might have made sense
some time ago when RAM was more constrained, but now the savings
do not offset the cost and complications. For example, the fix in
commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
is a good example of the nasty type of bugs that can be created
with improper use of the various __init prefixes.

After a discussion on LKML[1] it was decided that cpuinit should go
the way of devinit and be phased out. Once all the users are gone,
we can then finally remove the macros themselves from linux/init.h.

Note that some harmless section mismatch warnings may result, since
notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
are flagged as __cpuinit -- so if we remove the __cpuinit from
arch specific callers, we will also get section mismatch warnings.
As an intermediate step, we intend to turn the linux/init.h cpuinit
content into no-ops as early as possible, since that will get rid
of these warnings. In any case, they are temporary and harmless.

This removes all the arch/x86 uses of the __cpuinit macros from
all C files. x86 only had the one __CPUINIT used in assembly files,
and it wasn't paired off with a .previous or a __FINIT, so we can
delete it directly w/o any corresponding additional change there.

[1] https://lkml.org/lkml/2013/5/20/589

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

x86: Fix section mismatch on load_ucode_ap

We are in the process of removing all the __cpuinit annotations.
While working on making that change, an existing problem was
made evident:

WARNING: arch/x86/kernel/built-in.o(.text+0x198f2): Section mismatch
in reference from the function cpu_init() to the function
.init.text:load_ucode_ap() The function cpu_init() references
the function __init load_ucode_ap(). This is often because cpu_init
lacks a __init annotation or the annotation of load_ucode_ap is wrong.

This now appears because in my working tree, cpu_init() is no longer
tagged as __cpuinit, and so the audit picks up the mismatch. The 2nd
hypothesis from the audit is the correct one, as there was an incorrect
__init tag on the prototype in the header (but __cpuinit was used on
the function itself.)

The audit is telling us that the prototype's __init annotation took
effect and the function did land in the .init.text section. Checking
with objdump on a mainline tree that still has __cpuinit shows that
the __cpuinit on the function takes precedence over the __init on the
prototype, but that won't be true once we make __cpuinit a no-op.

Even though we are removing __cpuinit, we temporarily align both
the function and the prototype on __cpuinit so that the changeset
can be applied to stable trees if desired.

[ hpa: build fix only, no object code change ]

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable <stable@vger.kernel.org> # 3.9+
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: http://lkml.kernel.org/r/1371654926-11729-1-git-send-email-paul.gortmaker@windriver.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86/microcode_core_early.c: Define interfaces for early loading ucode

Define interfaces load_ucode_bsp() and load_ucode_ap() to load ucode on BSP and
AP in early boot time. These are generic interfaces. Internally they call
vendor specific implementations.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1356075872-3054-6-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, microcode: Add a refresh firmware flag to ->request_microcode_fw

This is done in preparation for teaching the ucode driver to either load
a new ucode patches container from userspace or use an already cached
version. No functionality change in this patch.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-10-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, microcode, AMD: Remove useless get_ucode_data wrapper

get_ucode_data was a trivial memcpy wrapper. Remove it so as not to
obfuscate code unnecessarily with no obvious gain.

No functional change.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-7-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

x86, microcode, AMD: Add a vendor-specific exit function

This will be used to do cleanup work before the driver exits.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

x86, microcode, AMD: Cleanup code a bit

get_ucode_data is a memcpy() wrapper which always returns 0. Move it
into the header and make it an inline. Remove all code checking its
return value and turn it into a void.

There should be no functionality change resulting from this patch.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

Revert "x86: ucode-amd: Load ucode-patches once ..."

Commit d1c84f79a6ba992dc01e312c44a21496303874d6
leads to a regression when microcode_amd.c is compiled into the kernel.
It causes a big boot delay because the firmware is not available.
See http://marc.info/?l=linux-kernel&m=126267290920060

It also renders the reload sysfs attribute useless.
Fixing this is too intrusive for an -rc5 kernel.

Thus I'd like to restore the microcode loading behaviour of kernel
2.6.32.

CC: Gene Heskett <gene.heskett@verizon.net>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100122203456.GB13792@alberich.amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86: ucode-amd: Load ucode-patches once and not separately of each CPU

This also implies that corresponding log messages, e.g.

platform microcode: firmware: requesting amd-ucode/microcode_amd.bin

show up only once on module load and not when ucode is updated
for each CPU.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: dimm <dmitry.adamushko@gmail.com>
LKML-Reference: <20091110110723.GH30802@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

x86: microcode: use smp_call_function_single instead of set_cpus_allowed, cleanup of synchronization logic

* Solve issues described in 6f66cbc63081fd70e3191b4dbb796746780e5ae1
in a way that doesn't resort to set_cpus_allowed();

* in fact, only collect_cpu_info and apply_microcode callbacks
must run on a target cpu, others will do just fine on any other.
smp_call_function_single() (as suggested by Ingo) is used to run
these callbacks on a target cpu.

* cleanup of synchronization logic of the 'microcode_core' part

The generic 'microcode_core' part guarantees that only a single cpu
(be it a full-fledged cpu, one of the cores or HT)
is being updated at any particular moment of time.

In general, there is no need for any additional sync. mechanism in
arch-specific parts (the patch removes existing spinlocks).

See also the "Synchronization" section in microcode_core.c.

* return -EINVAL instead of -1 (which is translated into -EPERM) in
microcode_write(), reload_cpu() and mc_sysdev_add(). Other suggestions
for an error code?

* use 'enum ucode_state' as return value of request_microcode_{fw, user}
to gain more flexibility by distinguishing between real error cases
and situations when an appropriate ucode was not found (which is not an
error per-se).

* some minor cleanups

Thanks a lot to Hugh Dickins for review/suggestions/testing!

Reference: http://marc.info/?l=linux-kernel&m=124025889012541&w=2

[ Impact: refactor and clean up microcode driver locking code ]

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Peter Oruba <peter.oruba@amd.com>
Cc: Arjan van de Ven <arjan@infradead.org>
LKML-Reference: <1242078507.5560.9.camel@earth>
[ did some more cleanups ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/include/asm/microcode.h | 25 ++
arch/x86/kernel/microcode_amd.c | 58 ++----
arch/x86/kernel/microcode_core.c | 326 +++++++++++++++++++++-----------------
arch/x86/kernel/microcode_intel.c | 92 +++-------
4 files changed, 261 insertions(+), 240 deletions(-)

(~20 new comment lines)

x86: Fix ASM_X86__ header guards

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>