Files
android_kernel_xiaomi_sm8450/arch/x86/kernel
H.J. Lu eaa5a99019 x86, fpu: correct the asm constraints for fxsave, unbreak mxcsr.daz
GCC will optimize mxcsr_feature_mask_init in arch/x86/kernel/i387.c:

		memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
		asm volatile("fxsave %0" : : "m" (fx_scratch));
		mask = fx_scratch.mxcsr_mask;
		if (mask == 0)
			mask = 0x0000ffbf;

to

		memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));
		asm volatile("fxsave %0" : : "m" (fx_scratch));
		mask = 0x0000ffbf;

since asm statement doesn’t say it will update fx_scratch.  As the
result, the DAZ bit will be cleared.  This patch fixes it. This bug
dates back to at least kernel 2.6.12.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
2013-07-26 09:11:56 -07:00
..
2013-04-23 13:45:22 +02:00
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2013-07-16 15:14:48 -07:00