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| author | Ingo Molnar <mingo@kernel.org> | 2025-04-11 12:13:27 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-11 12:13:27 +0300 |
| commit | 9f13acb2406a3aed90c6738b3a2f1c0e43118cbd (patch) | |
| tree | cf37d241e85bf8fea4d13cb8d64ad6602c745b72 /arch/x86/kernel/cpu/intel.c | |
| parent | d02c83d75f9f76dda046edbd9f39b911427677c9 (diff) | |
| parent | 0af2f6be1b4281385b618cb86ad946eded089ac8 (diff) | |
| download | linux-9f13acb2406a3aed90c6738b3a2f1c0e43118cbd.tar.xz | |
Merge tag 'v6.15-rc1' into x86/cpu, to refresh the branch with upstream changes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu/intel.c')
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index e5d814703406..a6493f60b3f2 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -514,6 +514,25 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c) wrmsrl(MSR_MISC_FEATURES_ENABLES, msr); } +/* + * This is a list of Intel CPUs that are known to suffer from downclocking when + * ZMM registers (512-bit vectors) are used. On these CPUs, when the kernel + * executes SIMD-optimized code such as cryptography functions or CRCs, it + * should prefer 256-bit (YMM) code to 512-bit (ZMM) code. + */ +static const struct x86_cpu_id zmm_exclusion_list[] = { + X86_MATCH_VFM(INTEL_SKYLAKE_X, 0), + X86_MATCH_VFM(INTEL_ICELAKE_X, 0), + X86_MATCH_VFM(INTEL_ICELAKE_D, 0), + X86_MATCH_VFM(INTEL_ICELAKE, 0), + X86_MATCH_VFM(INTEL_ICELAKE_L, 0), + X86_MATCH_VFM(INTEL_ICELAKE_NNPI, 0), + X86_MATCH_VFM(INTEL_TIGERLAKE_L, 0), + X86_MATCH_VFM(INTEL_TIGERLAKE, 0), + /* Allow Rocket Lake and later, and Sapphire Rapids and later. */ + {}, +}; + static void init_intel(struct cpuinfo_x86 *c) { early_init_intel(c); @@ -592,6 +611,9 @@ static void init_intel(struct cpuinfo_x86 *c) } #endif + if (x86_match_cpu(zmm_exclusion_list)) + set_cpu_cap(c, X86_FEATURE_PREFER_YMM); + /* Work around errata */ srat_detect_node(c); |