Fenghua Yu facbf4d91a x86/xsaves: Use xsave/xrstor for saving and restoring user space context ... We use legacy xsave/xrstor to save and restore standard form of xsave area in user space context. No xsaveopt or xsaves is used here for two reasons. First, we don't want to use modified optimization which is implemented in xsaveopt and xsaves because xrstor/xrstors might track a wrong user space application. Secondly, we don't use compacted format of xsave area for backward compatibility because legacy user space applications only don't understand the compacted format of the xsave area. Using standard form of the xsave area may allocate more memory for user context than compacted form, but preserves compatibility with legacy applications. Furthermore, even with holes, the relevant cache lines don't get touched and thus the performance impact is limited. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1401387164-43416-11-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>		2014-05-29 14:32:57 -07:00
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asm	x86/xsaves: Use xsave/xrstor for saving and restoring user space context	2014-05-29 14:32:57 -07:00
uapi/asm	x86/xsaves: Detect xsaves/xrstors feature	2014-05-29 14:24:28 -07:00