Commit 191cf7fa authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86_fpu_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 fpu update from Borislav Petkov:
 "A single x86/fpu update for 5.17:

   - Exclude AVX opmask registers use from AVX512 state tracking as they
     don't contribute to frequency throttling"

* tag 'x86_fpu_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu: Correct AVX512 state tracking
parents 8cc1e207 0fe4ff88

arch/x86/kernel/fpu/core.c

+14 −7
Original line number Diff line number Diff line
@@ -98,6 +98,19 @@ 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;

	}