linux-stable.git/arch/x86/kernel/cpu/microcode/intel_early.c, branch linux-3.16.y Linux kernel stable tree x86/microcode/intel: Check microcode revision before updating sibling threads 2018-12-16T22:08:58+00:00 Ashok Raj ashok.raj@intel.com 2018-02-28T10:28:41+00:00 1af1e58f16761e3eb7ac759db9ced4ebd6870b3d commit c182d2b7d0ca48e0d6ff16f7d883161238c447ed upstream. After updating microcode on one of the threads of a core, the other thread sibling automatically gets the update since the microcode resources on a hyperthreaded core are shared between the two threads. Check the microcode revision on the CPU before performing a microcode update and thus save us the WRMSR 0x79 because it is a particularly expensive operation. [ Borislav: Massage changelog and coding style. ] Signed-off-by: Ashok Raj <ashok.raj@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Tom Lendacky <thomas.lendacky@amd.com> Tested-by: Ashok Raj <ashok.raj@intel.com> Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com> Link: http://lkml.kernel.org/r/1519352533-15992-2-git-send-email-ashok.raj@intel.com Link: https://lkml.kernel.org/r/20180228102846.13447-3-bp@alien8.de [bwh: Backported to 3.16: - s/mc->/mc_intel->/ - Return 0 in this case - Adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit c182d2b7d0ca48e0d6ff16f7d883161238c447ed upstream.

After updating microcode on one of the threads of a core, the other
thread sibling automatically gets the update since the microcode
resources on a hyperthreaded core are shared between the two threads.

Check the microcode revision on the CPU before performing a microcode
update and thus save us the WRMSR 0x79 because it is a particularly
expensive operation.

[ Borislav: Massage changelog and coding style. ]

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Link: http://lkml.kernel.org/r/1519352533-15992-2-git-send-email-ashok.raj@intel.com
Link: https://lkml.kernel.org/r/20180228102846.13447-3-bp@alien8.de
[bwh: Backported to 3.16:
 - s/mc->/mc_intel->/
 - Return 0 in this case
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86/microcode/intel: Add a helper which gives the microcode revision 2018-12-16T22:08:58+00:00 Borislav Petkov bp@suse.de 2017-01-09T11:41:45+00:00 8acfa7f8ccba01b93b11c8a20fee7dc19106b7a8 commit 4167709bbf826512a52ebd6aafda2be104adaec9 upstream. Since on Intel we're required to do CPUID(1) first, before reading the microcode revision MSR, let's add a special helper which does the required steps so that we don't forget to do them next time, when we want to read the microcode revision. Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20170109114147.5082-4-bp@alien8.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bwh: Backported to 3.16: - Don't touch prev_rev variable in apply_microcode() - Keep using sync_core(), which will alway includes the necessary CPUID - Adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 4167709bbf826512a52ebd6aafda2be104adaec9 upstream.

Since on Intel we're required to do CPUID(1) first, before reading
the microcode revision MSR, let's add a special helper which does the
required steps so that we don't forget to do them next time, when we
want to read the microcode revision.

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20170109114147.5082-4-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.16:
 - Don't touch prev_rev variable in apply_microcode()
 - Keep using sync_core(), which will alway includes the necessary CPUID
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
x86/microcode/intel: Guard against stack overflow in the loader 2015-03-30T10:11:48+00:00 Quentin Casasnovas quentin.casasnovas@oracle.com 2015-02-03T12:00:22+00:00 caccf691912359293bc4dfce740b62b202a5dba6 commit f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 upstream. mc_saved_tmp is a static array allocated on the stack, we need to make sure mc_saved_count stays within its bounds, otherwise we're overflowing the stack in _save_mc(). A specially crafted microcode header could lead to a kernel crash or potentially kernel execution. Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> 
commit f84598bd7c851f8b0bf8cd0d7c3be0d73c432ff4 upstream.

mc_saved_tmp is a static array allocated on the stack, we need to make
sure mc_saved_count stays within its bounds, otherwise we're overflowing
the stack in _save_mc(). A specially crafted microcode header could lead
to a kernel crash or potentially kernel execution.

Signed-off-by: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1422964824-22056-1-git-send-email-quentin.casasnovas@oracle.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
x86, microcode: Move to a proper location 2014-01-13T19:00:12+00:00 Borislav Petkov bp@suse.de 2013-12-01T17:09:58+00:00 bad5fa631fca5466401cd4a48e30cc1f1cb6101e We've grown a bunch of microcode loader files all prefixed with "microcode_". They should be under cpu/ because this is strictly CPU-related functionality so do that and drop the prefix since they're in their own directory now which gives that prefix. :) While at it, drop MICROCODE_INTEL_LIB config item and stash the functionality under CONFIG_MICROCODE_INTEL as it was its only user. Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com> 
We've grown a bunch of microcode loader files all prefixed with
"microcode_". They should be under cpu/ because this is strictly
CPU-related functionality so do that and drop the prefix since they're
in their own directory now which gives that prefix. :)

While at it, drop MICROCODE_INTEL_LIB config item and stash the
functionality under CONFIG_MICROCODE_INTEL as it was its only user.

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