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authorIngo Molnar <mingo@kernel.org>2017-09-23 15:00:02 +0200
committerIngo Molnar <mingo@kernel.org>2017-09-24 13:04:34 +0200
commit6cf4edbe0526db311a28734609da888fdfcb3604 (patch)
treeae414faeb5a0e91376697a3b54719cc74374dc43 /arch
parentf1c8cd0176078c7bcafdc89cac447cab672a0b5e (diff)
x86/fpu: Decouple fpregs_activate()/fpregs_deactivate() from fpu->fpregs_active
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: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.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> Link: http://lkml.kernel.org/r/20170923130016.21448-20-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/fpu/internal.h7
-rw-r--r--arch/x86/kernel/fpu/core.c3
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 = &current->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);

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