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Subject[PATCH 2/3] x86/fpu: Make FPU protection reuse common helper
Date
The newly-introduced preempt_{enable, disable}_bh() helpers are an exact
stand-in for fpregs_{lock, unlock}(). Use them there.

No change in behaviour intended.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
arch/x86/include/asm/fpu/api.h | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 62cf3e4c06fb..ffebb9316bfd 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -54,31 +54,16 @@ static inline void kernel_fpu_begin(void)
* fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in
* a random state.
*
- * local_bh_disable() protects against both preemption and soft interrupts
- * on !RT kernels.
- *
- * On RT kernels local_bh_disable() is not sufficient because it only
- * serializes soft interrupt related sections via a local lock, but stays
- * preemptible. Disabling preemption is the right choice here as bottom
- * half processing is always in thread context on RT kernels so it
- * implicitly prevents bottom half processing as well.
- *
* Disabling preemption also serializes against kernel_fpu_begin().
*/
static inline void fpregs_lock(void)
{
- if (!IS_ENABLED(CONFIG_PREEMPT_RT))
- local_bh_disable();
- else
- preempt_disable();
+ preempt_disable_bh();
}

static inline void fpregs_unlock(void)
{
- if (!IS_ENABLED(CONFIG_PREEMPT_RT))
- local_bh_enable();
- else
- preempt_enable();
+ preempt_enable_bh();
}

#ifdef CONFIG_X86_DEBUG_FPU
--
2.25.1
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