Messages in this thread Patch in this message | | | From | Ingo Molnar <> | Subject | [PATCH 19/33] x86/fpu: Decouple fpregs_activate()/fpregs_deactivate() from fpu->fpregs_active | Date | Sat, 23 Sep 2017 15:00:02 +0200 |
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The fpregs_activate()/fpregs_deactivate() are currently called in such a pattern:
if (!fpu->fpregs_active) fpregs_activate(fpu);
...
if (fpu->fpregs_active) fpregs_deactivate(fpu);
But note that it's actually safe to call them without checking the flag first.
This further decouples the fpu->fpregs_active flag from actual FPU logic.
Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/include/asm/fpu/internal.h | 7 +------ arch/x86/kernel/fpu/core.c | 3 +-- 2 files changed, 2 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 7fa676f93ac1..42a601673c09 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -526,8 +526,6 @@ static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu) */ static inline void fpregs_deactivate(struct fpu *fpu) { - WARN_ON_FPU(!fpu->fpregs_active); - fpu->fpregs_active = 0; this_cpu_write(fpu_fpregs_owner_ctx, NULL); trace_x86_fpu_regs_deactivated(fpu); @@ -535,8 +533,6 @@ static inline void fpregs_deactivate(struct fpu *fpu) static inline void fpregs_activate(struct fpu *fpu) { - WARN_ON_FPU(fpu->fpregs_active); - fpu->fpregs_active = 1; this_cpu_write(fpu_fpregs_owner_ctx, fpu); trace_x86_fpu_regs_activated(fpu); @@ -604,8 +600,7 @@ static inline void user_fpu_begin(void) struct fpu *fpu = ¤t->thread.fpu; preempt_disable(); - if (!fpu->fpregs_active) - fpregs_activate(fpu); + fpregs_activate(fpu); preempt_enable(); } diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index eab244622402..01a47e9edfb4 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -426,8 +426,7 @@ void fpu__drop(struct fpu *fpu) asm volatile("1: fwait\n" "2:\n" _ASM_EXTABLE(1b, 2b)); - if (fpu->fpregs_active) - fpregs_deactivate(fpu); + fpregs_deactivate(fpu); } } else { WARN_ON_FPU(fpu->fpregs_active); -- 2.11.0
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