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| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2012-09-06 21:58:52 (GMT) |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2012-09-18 22:52:22 (GMT) |
| commit | 5d2bd7009f306c82afddd1ca4d9763ad8473c216 (patch) | |
| tree | 772bc888c48766b892e216c19e938c82657e2b0e /arch/x86/kernel/i387.c | |
| parent | 304bceda6a18ae0b0240b8aac9a6bdf8ce2d2469 (diff) | |
| download | linux-5d2bd7009f306c82afddd1ca4d9763ad8473c216.tar.xz | |
x86, fpu: decouple non-lazy/eager fpu restore from xsave
Decouple non-lazy/eager fpu restore policy from the existence of the xsave
feature. Introduce a synthetic CPUID flag to represent the eagerfpu
policy. "eagerfpu=on" boot paramter will enable the policy.
Requested-by: H. Peter Anvin <hpa@zytor.com>
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1347300665-6209-2-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/i387.c')
| -rw-r--r-- | arch/x86/kernel/i387.c | 25 |
1 files changed, 8 insertions, 17 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c index 5285574..6782e39 100644 --- a/arch/x86/kernel/i387.c +++ b/arch/x86/kernel/i387.c @@ -22,9 +22,8 @@ /* * Were we in an interrupt that interrupted kernel mode? * - * For now, on xsave platforms we will return interrupted - * kernel FPU as not-idle. TBD: As we use non-lazy FPU restore - * for xsave platforms, ideally we can change the return value + * For now, with eagerfpu we will return interrupted kernel FPU + * state as not-idle. TBD: Ideally we can change the return value * to something like __thread_has_fpu(current). But we need to * be careful of doing __thread_clear_has_fpu() before saving * the FPU etc for supporting nested uses etc. For now, take @@ -38,7 +37,7 @@ */ static inline bool interrupted_kernel_fpu_idle(void) { - if (use_xsave()) + if (use_eager_fpu()) return 0; return !__thread_has_fpu(current) && @@ -84,7 +83,7 @@ void kernel_fpu_begin(void) __save_init_fpu(me); __thread_clear_has_fpu(me); /* We do 'stts()' in kernel_fpu_end() */ - } else if (!use_xsave()) { + } else if (!use_eager_fpu()) { this_cpu_write(fpu_owner_task, NULL); clts(); } @@ -93,7 +92,7 @@ EXPORT_SYMBOL(kernel_fpu_begin); void kernel_fpu_end(void) { - if (use_xsave()) + if (use_eager_fpu()) math_state_restore(); else stts(); @@ -122,7 +121,6 @@ static void __cpuinit mxcsr_feature_mask_init(void) { unsigned long mask = 0; - clts(); if (cpu_has_fxsr) { memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct)); asm volatile("fxsave %0" : : "m" (fx_scratch)); @@ -131,7 +129,6 @@ static void __cpuinit mxcsr_feature_mask_init(void) mask = 0x0000ffbf; } mxcsr_feature_mask &= mask; - stts(); } static void __cpuinit init_thread_xstate(void) @@ -185,9 +182,8 @@ void __cpuinit fpu_init(void) init_thread_xstate(); mxcsr_feature_mask_init(); - /* clean state in init */ - current_thread_info()->status = 0; - clear_used_math(); + xsave_init(); + eager_fpu_init(); } void fpu_finit(struct fpu *fpu) @@ -198,12 +194,7 @@ void fpu_finit(struct fpu *fpu) } if (cpu_has_fxsr) { - struct i387_fxsave_struct *fx = &fpu->state->fxsave; - - memset(fx, 0, xstate_size); - fx->cwd = 0x37f; - if (cpu_has_xmm) - fx->mxcsr = MXCSR_DEFAULT; + fx_finit(&fpu->state->fxsave); } else { struct i387_fsave_struct *fp = &fpu->state->fsave; memset(fp, 0, xstate_size); |