diff options
| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2021-11-16 17:14:21 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-11-16 17:19:41 +0100 |
| commit | 0fe4ff885f8a50082d9dc241b657472894caba16 (patch) | |
| tree | 08466886f8c59b329ab793d62f01b1047794ca34 /arch/x86/kernel/fpu/core.c | |
| parent | fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff) | |
| download | linux-0fe4ff885f8a50082d9dc241b657472894caba16.tar.bz2 | |
x86/fpu: Correct AVX512 state tracking
Add a separate, local mask for tracking AVX512 usage which does not
include the opmask xfeature set. Opmask registers usage does not cause
frequency throttling so it is a completely unnecessary false positive.
While at it, carve it out into a separate function to keep that
abomination extracted out.
[ bp: Rediff and cleanup ontop of 5.16-rc1. ]
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20210920053951.4093668-1-goldstein.w.n@gmail.com
Diffstat (limited to 'arch/x86/kernel/fpu/core.c')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 8ea306b1bf8e..dd3777ac0443 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -99,6 +99,19 @@ bool irq_fpu_usable(void) EXPORT_SYMBOL(irq_fpu_usable); /* + * Track AVX512 state use because it is known to slow the max clock + * speed of the core. + */ +static void update_avx_timestamp(struct fpu *fpu) +{ + +#define AVX512_TRACKING_MASK (XFEATURE_MASK_ZMM_Hi256 | XFEATURE_MASK_Hi16_ZMM) + + if (fpu->fpstate->regs.xsave.header.xfeatures & AVX512_TRACKING_MASK) + fpu->avx512_timestamp = jiffies; +} + +/* * Save the FPU register state in fpu->fpstate->regs. The register state is * preserved. * @@ -116,13 +129,7 @@ void save_fpregs_to_fpstate(struct fpu *fpu) { if (likely(use_xsave())) { os_xsave(fpu->fpstate); - - /* - * AVX512 state is tracked here because its use is - * known to slow the max clock speed of the core. - */ - if (fpu->fpstate->regs.xsave.header.xfeatures & XFEATURE_MASK_AVX512) - fpu->avx512_timestamp = jiffies; + update_avx_timestamp(fpu); return; } |