diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 2c5bef78a484..a5aba4ab0224 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -32,15 +32,29 @@ extern void fpregs_mark_activate(void); * * 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) { - local_bh_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_disable(); + else + preempt_disable(); } static inline void fpregs_unlock(void) { - local_bh_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_bh_enable(); + else + preempt_enable(); } #ifdef CONFIG_X86_DEBUG_FPU |