x86/cpufeatures: Add LbrExtV2 feature bit

Browse source

CPUID leaf 0x80000022 i.e. ExtPerfMonAndDbg advertises some new performance
monitoring features for AMD processors.

Bit 1 of EAX indicates support for Last Branch Record Extension Version 2
(LbrExtV2) features. If found to be set during PMU initialization, the EBX
bits of the same leaf can be used to determine the number of available LBR
entries.

For better utilization of feature words, LbrExtV2 is added as a scattered
feature bit.

[peterz: Rename to AMD_LBR_V2]
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/172d2b0df39306ed77221c45ee1aa62e8ae0548d.1660211399.git.sandipan.das@amd.com

...

This commit is contained in:

Sandipan Das 2022-08-11 17:59:52 +05:30 • committed by Peter Zijlstra

parent 706460a96f

commit 257449c6a5

2 changed files with 2 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

arch/x86/include/asm/cpufeatures.h

View file

1

arch/x86/kernel/cpu/scattered.c

View file