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| 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 | |
| parent | dc1e35c6e95e8923cf1d3510438b63c600fee1e2 (diff) | |
| download | kernel_samsung_smdk4412-b359e8a434cc3d09847010fc4aeccf48d69740e4.zip kernel_samsung_smdk4412-b359e8a434cc3d09847010fc4aeccf48d69740e4.tar.gz kernel_samsung_smdk4412-b359e8a434cc3d09847010fc4aeccf48d69740e4.tar.bz2 | |
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')
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/i387.c | 5 | ||||
| -rw-r--r-- | arch/x86/kernel/traps_64.c | 2 |
3 files changed, 9 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index fabbcb7..6c2b9e7 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -709,7 +709,10 @@ void __cpuinit cpu_init(void) /* * Force FPU initialization: */ - current_thread_info()->status = 0; + if (cpu_has_xsave) + current_thread_info()->status = TS_XSAVE; + else + current_thread_info()->status = 0; clear_used_math(); mxcsr_feature_mask_init(); diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index e22a9a9..b778e17 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 */ diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c index 3580a79..38eb761 100644 --- a/arch/x86/kernel/traps_64.c +++ b/arch/x86/kernel/traps_64.c @@ -1134,7 +1134,7 @@ asmlinkage void math_state_restore(void) /* * Paranoid restore. send a SIGSEGV if we fail to restore the state. */ - if (unlikely(restore_fpu_checking(&me->thread.xstate->fxsave))) { + if (unlikely(restore_fpu_checking(me))) { stts(); force_sig(SIGSEGV, me); return; |