forge/linux-pinenote
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

x86, xsave: Use xsaveopt in context-switch path when supported

Browse source 
xsaveopt is a more optimized form of xsave specifically designed
for the context switch usage. xsaveopt doesn't save the state that's not
modified from the prior xrstor. And if a specific feature state gets
modified to the init state, then xsaveopt just updates the header bit
in the xsave memory layout without updating the corresponding memory
layout.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100719230205.604014179@sbs-t61.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Suresh Siddha 2010-07-19 16:05:52 -07:00 • committed by H. Peter Anvin
parent 29104e101d
commit 6bad06b768
3 changed files with 15 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/include/asm/i387.h
View file

@ -60,7 +60,7 @@ extern int restore_i387_xstate_ia32(void __user *buf);
static __always_inline __pure bool use_xsaveopt(void)
{
return 0;
return static_cpu_has(X86_FEATURE_XSAVEOPT);
}
static __always_inline __pure bool use_xsave(void)