diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-07-29 10:29:20 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-30 19:49:24 +0200 |
| commit | b359e8a434cc3d09847010fc4aeccf48d69740e4 (patch) | |
| tree | 8911c299dc1768c78d5452a1e7e0efd2fc8d5abb /arch/x86/kernel/i387.c | |
| parent | dc1e35c6e95e8923cf1d3510438b63c600fee1e2 (diff) | |
x86, xsave: context switch support using xsave/xrstor
Uses xsave/xrstor (instead of traditional fxsave/fxrstor) in context switch
when available.
Introduces TS_XSAVE flag, which determine the need to use xsave/xrstor
instructions during context switch instead of the legacy fxsave/fxrstor
instructions. Thread-synchronous status word is already in L1 cache during
this code patch and thus minimizes the performance penality compared to
(cpu_has_xsave) checks.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/i387.c')
| -rw-r--r-- | arch/x86/kernel/i387.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index e22a9a9dce8..b778e17e4b0 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -97,7 +97,10 @@ void __cpuinit fpu_init(void) mxcsr_feature_mask_init(); /* clean state in init */ - current_thread_info()->status = 0; + if (cpu_has_xsave) + current_thread_info()->status = TS_XSAVE; + else + current_thread_info()->status = 0; clear_used_math(); } #endif /* CONFIG_X86_64 */ |