Proxmox-Port/linux-loongson
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson synced 2025-08-31 22:23:05 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

x86/cpufeatures: Add X86_FEATURE_APX

Browse Source 
Intel Advanced Performance Extensions (APX) introduce a new set of
general-purpose registers, managed as an extended state component via the
xstate management facility.

Before enabling this new xstate, define a feature flag to clarify the
dependency in xsave_cpuid_features[]. APX is enumerated under CPUID level
7 with EDX=1. Since this CPUID leaf is not yet allocated, place the flag
in a scattered feature word.

While this feature is intended only for userspace, exposing it via
/proc/cpuinfo is unnecessary. Instead, the existing arch_prctl(2)
mechanism with the ARCH_GET_XCOMP_SUPP option can be used to query the
feature availability.

Finally, clarify that APX depends on XSAVE.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250416021720.12305-2-chang.seok.bae@intel.com
This commit is contained in:
Chang S. Bae 2025-04-15 19:16:51 -07:00 committed by Ingo Molnar
parent 4e2547509f
commit b02dc185ee
3 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/cpufeatures.h
View File

@ -481,6 +481,7 @@
#define X86_FEATURE_AMD_HTR_CORES (21*32+ 6) /* Heterogeneous Core Topology */
#define X86_FEATURE_AMD_WORKLOAD_CLASS (21*32+ 7) /* Workload Classification */
#define X86_FEATURE_PREFER_YMM (21*32+ 8) /* Avoid ZMM registers due to downclocking */
#define X86_FEATURE_APX (21*32+ 9) /* Advanced Performance Extensions */
/*
* BUG word(s)

1
arch/x86/kernel/cpu/cpuid-deps.c
View File

@ -28,6 +28,7 @@ static const struct cpuid_dep cpuid_deps[] = {
{ X86_FEATURE_PKU, X86_FEATURE_XSAVE },
{ X86_FEATURE_MPX, X86_FEATURE_XSAVE },
{ X86_FEATURE_XGETBV1, X86_FEATURE_XSAVE },
{ X86_FEATURE_APX, X86_FEATURE_XSAVE },
{ X86_FEATURE_CMOV, X86_FEATURE_FXSR },
{ X86_FEATURE_MMX, X86_FEATURE_FXSR },
{ X86_FEATURE_MMXEXT, X86_FEATURE_MMX },

1
arch/x86/kernel/cpu/scattered.c
View File

@ -27,6 +27,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_APERFMPERF, CPUID_ECX, 0, 0x00000006, 0 },
{ X86_FEATURE_EPB, CPUID_ECX, 3, 0x00000006, 0 },
{ X86_FEATURE_INTEL_PPIN, CPUID_EBX, 0, 0x00000007, 1 },
{ X86_FEATURE_APX, CPUID_EDX, 21, 0x00000007, 1 },
{ X86_FEATURE_RRSBA_CTRL, CPUID_EDX, 2, 0x00000007, 2 },
{ X86_FEATURE_BHI_CTRL, CPUID_EDX, 4, 0x00000007, 2 },
{ X86_FEATURE_CQM_LLC, CPUID_EDX, 1, 0x0000000f, 0 },