Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.
All in-kernel references to the old paths have been updated.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The AMD side of the loader has always claimed to support mixed
steppings. But somewhere along the way, it broke that by assuming that
the cached patch blob is a single one instead of it being one per
*node*.
So turn it into a per-node one so that each node can stash the blob
relevant for it.
[ NB: Fixes tag is not really the exactly correct one but it is good
enough. ]
Fixes: fe055896c0 ("x86/microcode: Merge the early microcode loader")
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org> # 2355370cd9 ("x86/microcode/amd: Remove load_microcode_amd()'s bsp parameter")
Cc: <stable@kernel.org> # a5ad92134b ("x86/microcode/AMD: Add a @cpu parameter to the reloading functions")
Link: https://lore.kernel.org/r/20230130161709.11615-4-bp@alien8.de
It can happen that - especially during testing - the microcode
blobs of all families are all glued together in the initrd. The
current code doesn't check whether the current container matched
a microcode patch and continues to the next one, which leads to
save_microcode_in_initrd_amd() to look at the next and thus wrong one:
microcode: parse_container: ucode: 0xffff88807e9d9082
microcode: verify_patch: buf: 0xffff88807e9d90ce, buf_size: 26428
microcode: verify_patch: proc_id: 0x8082, patch_fam: 0x17, this family: 0x17
microcode: verify_patch: buf: 0xffff88807e9d9d56, buf_size: 23220
microcode: verify_patch: proc_id: 0x8012, patch_fam: 0x17, this family: 0x17
microcode: parse_container: MATCH: eq_id: 0x8012, patch proc_rev_id: 0x8012
<-- matching patch found
microcode: verify_patch: buf: 0xffff88807e9da9de, buf_size: 20012
microcode: verify_patch: proc_id: 0x8310, patch_fam: 0x17, this family: 0x17
microcode: verify_patch: buf: 0xffff88807e9db666, buf_size: 16804
microcode: Invalid type field (0x414d44) in container file section header.
microcode: Patch section fail
<-- checking chokes on the microcode magic value of the next container.
microcode: parse_container: saving container 0xffff88807e9d9082
microcode: save_microcode_in_initrd_amd: scanned containers, data: 0xffff88807e9d9082, size: 9700a
and now if there's a next (and last container) it'll use that in
save_microcode_in_initrd_amd() and not find a proper patch, ofc.
Fix that by moving the out: label up, before the desc->mc check which
jots down the pointer of the matching patch and is used to signal to the
caller that it has found a matching patch in the current container.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20221219210656.5140-2-bp@alien8.de
- Rename apply_microcode_early_amd() to early_apply_microcode():
simplify the name so that it is clear what it does and when does it do
it.
- Rename __load_ucode_amd() to find_blobs_in_containers(): the new name
actually explains what it does.
Document some.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20221219210656.5140-1-bp@alien8.de
driver in order to be able to run multiple different test patterns.
Rework things and remove the BROKEN dependency so that the driver can be
enabled (Jithu Joseph)
- Remove the subsys interface usage in the microcode loader because it
is not really needed
- A couple of smaller fixes and cleanups
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Merge tag 'x86_microcode_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 microcode and IFS updates from Borislav Petkov:
"The IFS (In-Field Scan) stuff goes through tip because the IFS driver
uses the same structures and similar functionality as the microcode
loader and it made sense to route it all through this branch so that
there are no conflicts.
- Add support for multiple testing sequences to the Intel In-Field
Scan driver in order to be able to run multiple different test
patterns. Rework things and remove the BROKEN dependency so that
the driver can be enabled (Jithu Joseph)
- Remove the subsys interface usage in the microcode loader because
it is not really needed
- A couple of smaller fixes and cleanups"
* tag 'x86_microcode_for_v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/microcode/intel: Do not retry microcode reloading on the APs
x86/microcode/intel: Do not print microcode revision and processor flags
platform/x86/intel/ifs: Add missing kernel-doc entry
Revert "platform/x86/intel/ifs: Mark as BROKEN"
Documentation/ABI: Update IFS ABI doc
platform/x86/intel/ifs: Add current_batch sysfs entry
platform/x86/intel/ifs: Remove reload sysfs entry
platform/x86/intel/ifs: Add metadata validation
platform/x86/intel/ifs: Use generic microcode headers and functions
platform/x86/intel/ifs: Add metadata support
x86/microcode/intel: Use a reserved field for metasize
x86/microcode/intel: Add hdr_type to intel_microcode_sanity_check()
x86/microcode/intel: Reuse microcode_sanity_check()
x86/microcode/intel: Use appropriate type in microcode_sanity_check()
x86/microcode/intel: Reuse find_matching_signature()
platform/x86/intel/ifs: Remove memory allocation from load path
platform/x86/intel/ifs: Remove image loading during init
platform/x86/intel/ifs: Return a more appropriate error code
platform/x86/intel/ifs: Remove unused selection
x86/microcode: Drop struct ucode_cpu_info.valid
...
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
Currently, the patch application logic checks whether the revision
needs to be applied on each logical CPU (SMT thread). Therefore, on SMT
designs where the microcode engine is shared between the two threads,
the application happens only on one of them as that is enough to update
the shared microcode engine.
However, there are microcode patches which do per-thread modification,
see Link tag below.
Therefore, drop the revision check and try applying on each thread. This
is what the BIOS does too so this method is very much tested.
Btw, change only the early paths. On the late loading paths, there's no
point in doing per-thread modification because if is it some case like
in the bugzilla below - removing a CPUID flag - the kernel cannot go and
un-use features it has detected are there early. For that, one should
use early loading anyway.
[ bp: Fixes does not contain the oldest commit which did check for
equality but that is good enough. ]
Fixes: 8801b3fcb5 ("x86/microcode/AMD: Rework container parsing")
Reported-by: Ștefan Talpalaru <stefantalpalaru@yahoo.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Ștefan Talpalaru <stefantalpalaru@yahoo.com>
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216211
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: 757885e94a ("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/
181b6f40e9 ("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
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>
The dummy variable is the high part of the microcode revision MSR which
is defined as reserved. Mark it unused so that W=1 builds don't trigger
the above warning.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20190928162559.26294-1-bp@alien8.de
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Merge tag 'v5.2-rc4' into mauro
We need to pick up post-rc1 changes to various document files so they don't
get lost in Mauro's massive RST conversion push.
Mostly due to x86 and acpi conversion, several documentation
links are still pointing to the old file. Fix them.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Reviewed-by: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Based on 1 normalized pattern(s):
licensed under the terms of the gnu general public license version 2
see file copying for details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 1 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081035.403801661@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The load_microcode_amd() function searches for microcode patches and
attempts to apply a microcode patch if it is of different level than the
currently installed level.
While the processor won't actually load a level that is less than
what is already installed, the logic wrongly returns UCODE_NEW thus
signaling to its caller reload_store() that a late loading should be
attempted.
If the file-system contains an older microcode revision than what is
currently running, such a late microcode reload can result in these
misleading messages:
x86/CPU: CPU features have changed after loading microcode, but might not take effect.
x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.
These messages were issued on a system where SME/SEV are not
enabled by the BIOS (MSR C001_0010[23] = 0b) because during boot,
early_detect_mem_encrypt() is called and cleared the SME and SEV
features in this case.
However, after the wrong late load attempt, get_cpu_cap() is called and
reloads the SME and SEV feature bits, resulting in the messages.
Update the microcode level check to not attempt microcode loading if the
current level is greater than(!) and not only equal to the current patch
level.
[ bp: massage commit message. ]
Fixes: 2613f36ed9 ("x86/microcode: Attempt late loading only when new microcode is present")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/154894518427.9406.8246222496874202773.stgit@tlendack-t1.amdoffice.net
Currently, the code scanning the CPU equivalence table read from a
microcode container file assumes that it actually contains a terminating
zero entry.
Check also the size of this table to make sure that no reads past its
end happen, in case there's no terminating zero entry at the end of the
table.
[ bp: Adjust to new changes. ]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-16-bp@alien8.de
Convert the CPU equivalence table into a proper struct in preparation
for tracking also the size of this table.
[ bp: Have functions deal with struct equiv_cpu_table pointers only. Rediff. ]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-15-bp@alien8.de
Convert the late loading path to use the newly introduced microcode
container data checking functions as it was previously done for the
early loader.
[ bp: Keep header length addition in install_equiv_cpu_table() and rediff. ]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-14-bp@alien8.de
Make it size_t everywhere as this is what we get from cpio.
[ bp: Fix a smatch warning. ]
Originally-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20181107170218.7596-13-bp@alien8.de
Now that they have the required functionality, use them to verify the
equivalence table and each patch, thus making parse_container() more
readable.
Originally-by: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-12-bp@alien8.de
Add a verify_patch() function which tries to sanity-check many aspects
of a microcode patch supplied by an outside container before attempting
a load.
Prepend all sub-functions' names which verify an aspect of a microcode
patch with "__".
Call it in verify_and_add_patch() *before* looking at the microcode
header.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-7-bp@alien8.de
Rename the variable which contains the patch size read out from the
section header to sh_psize for better differentiation of all the "sizes"
in that function.
Also, improve the comment above it.
No functional changes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-6-bp@alien8.de
Starting with family 0x15, the patch size verification is not needed
anymore. Thus get rid of the need to update this checking function with
each new family.
Keep the check for older families.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20181107170218.7596-5-bp@alien8.de
Add container and patch verification functions to the AMD microcode
update driver.
These functions check whether a passed buffer contains the relevant
structure, whether it isn't truncated and (for actual microcode patches)
whether the size of a patch is not too large for a particular CPU family.
By adding these checks as separate functions the actual microcode loading
code won't get interspersed with a lot of checks and so will be more
readable.
[ bp: Make all pr_err() calls into pr_debug() and drop the
verify_patch() bits. ]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/3014e96c82cd90761b4601bd2cfe59c4119e46a7.1529424596.git.mail@maciej.szmigiero.name
verify_patch_size() verifies whether the remaining size of the microcode
container file is large enough to contain a patch of the indicated size.
However, the section header length is not included in this indicated
size but it is present in the leftover file length so it should be
subtracted from the leftover file length before passing this value to
verify_patch_size().
[ bp: Split comment. ]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/6df43f4f6a28186a13a66e8d7e61143c5e1a2324.1529424596.git.mail@maciej.szmigiero.name
Handle the case where microcode gets loaded on the BSP's hyperthread
sibling first and the boot_cpu_data's microcode revision doesn't get
updated because of early exit due to the siblings sharing a microcode
engine.
For that, simply write the updated revision on all CPUs unconditionally.
Signed-off-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: prarit@redhat.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1533050970-14385-1-git-send-email-sironi@amazon.de
When preparing an MCE record for logging, boot_cpu_data.microcode is used
to read out the microcode revision on the box.
However, on systems where late microcode update has happened, the microcode
revision output in a MCE log record is wrong because
boot_cpu_data.microcode is not updated when the microcode gets updated.
But, the microcode revision saved in boot_cpu_data's microcode member
should be kept up-to-date, regardless, for consistency.
Make it so.
Fixes: fa94d0c6e0 ("x86/MCE: Save microcode revision in machine check records")
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: sironi@amazon.de
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20180731112739.32338-1-prarit@redhat.com
The file Documentation/x86/early-microcode.txt was renamed to
Documentation/x86/microcode.txt in 0e3258753f, but it was still
referenced by its old name in a three places:
* Documentation/x86/00-INDEX
* arch/x86/Kconfig
* arch/x86/kernel/cpu/microcode/amd.c
This commit updates these references accordingly.
Fixes: 0e3258753f ("x86/microcode: Document the three loading methods")
Signed-off-by: Jaak Ristioja <jaak@ristioja.ee>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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
... 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>
The size for the Microcode Patch Block (MPB) for an AMD family 17h
processor is 3200 bytes. Add a #define for fam17h so that it does
not default to 2048 bytes and fail a microcode load/update.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171130224640.15391.40247.stgit@tlendack-t1.amdoffice.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
verify_and_add_patch() allocates memory for a microcode patch and hands
it down to be added to the cache of patches. However, if the cache
already has the latest patch, the newly allocated one needs to be freed
before returning. Do that.
This issue has been found by kmemleak:
unreferenced object 0xffff88010e780b40 (size 32):
comm "bash", pid 860, jiffies 4294690939 (age 29.297s)
backtrace:
kmemleak_alloc
kmem_cache_alloc_trace
load_microcode_amd.isra.0
request_microcode_amd
reload_store
dev_attr_store
sysfs_kf_write
kernfs_fop_write
__vfs_write
vfs_write
SyS_write
do_syscall_64
return_from_SYSCALL_64
0xffffffffffffffff
(gdb) list *0xffffffff81050d60
0xffffffff81050d60 is in load_microcode_amd
(arch/x86/kernel/cpu/microcode/amd.c:616).
which is this:
patch = kzalloc(sizeof(*patch), GFP_KERNEL);
--> if (!patch) {
pr_err("Patch allocation failure.\n");
return -EINVAL;
}
Signed-off-by: Shu Wang <shuwang@redhat.com>
[ Rewrite commit message. ]
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>
Cc: chuhu@redhat.com
Cc: liwang@redhat.com
Link: http://lkml.kernel.org/r/20170724101228.17326-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The helper function __load_ucode_amd() and pointer intel_ucode_patch do
not need to be in global scope, so make them static.
Fixes those sparse warnings:
"symbol '__load_ucode_amd' was not declared. Should it be static?"
"symbol 'intel_ucode_patch' was not declared. Should it be static?"
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170622095736.11937-1-colin.king@canonical.com
With CONFIG_DEBUG_PREEMPT enabled, I get:
BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is debug_smp_processor_id
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc2+ #2
Call Trace:
dump_stack
check_preemption_disabled
debug_smp_processor_id
save_microcode_in_initrd_amd
? microcode_init
save_microcode_in_initrd
...
because, well, it says it above, we're using smp_processor_id() in
preemptible code.
But passing the CPU number is not really needed. It is only used to
determine whether we're on the BSP, and, if so, to save the microcode
patch for early loading.
[ We don't absolutely need to do it on the BSP but we do that
customarily there. ]
Instead, convert that function parameter to a boolean which denotes
whether the patch should be saved or not, thereby avoiding the use of
smp_processor_id() in preemptible code.
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/20170528200414.31305-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
mc is a pointer to the static u8 array amd_ucode_patch and
therefore can never be null, so the check is redundant. Remove it.
Detected by CoverityScan, CID#1372871 ("Logically Dead Code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: kernel-janitors@vger.kernel.org
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20170315171010.17536-1-colin.king@canonical.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The equivalence ID was needed outside of the container scanning logic
but now, after this has been cleaned up, not anymore. Now, cont_desc.mc
is used to denote whether the container we're looking at has the proper
microcode patch for this CPU or not.
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-17-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The idea was to not scan the microcode blob on each AP (Application
Processor) during boot and thus save us some milliseconds. However, on
architectures where the microcode engine is shared between threads, this
doesn't work. Here's why:
The microcode on CPU0, i.e., the first thread, gets updated. The second
thread, i.e., CPU1, i.e., the first AP walks into load_ucode_amd_ap(),
sees that there's no container cached and goes and scans for the proper
blob.
It finds it and as a last step of apply_microcode_early_amd(), it tries
to apply the patch but that core has already the updated microcode
revision which it has received through CPU0's update. So it returns
false and we do desc->size = -1 to prevent other APs from scanning.
However, the next AP, CPU2, has a different microcode engine which
hasn't been updated yet. The desc->size == -1 test prevents it from
scanning the blob anew and we fail to update it.
The fix is much more straight-forward than it looks: the BSP
(BootStrapping Processor), i.e., CPU0, caches the microcode patch
in amd_ucode_patch. We use that on the AP and try to apply it.
In the 99.9999% of cases where we have homogeneous cores - *not*
mixed-steppings - the application will be successful and we're good to
go.
In the remaining small set of systems, we will simply rescan the blob
and find (or not, if none present) the proper patch and apply it then.
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-16-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
