Merge tag 'x86-fpu-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (eb0ea741) · Commits · 戴 / test

arch/x86/include/asm/fpu/api.h

+19 −4

Original line number	Diff line number	Diff line
		@@ -29,16 +29,31 @@ extern void fpregs_mark_activate(void);
		* A context switch will (and softirq might) save CPU's FPU registers to
		* 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)
		{
		preempt_disable();
		if (!IS_ENABLED(CONFIG_PREEMPT_RT))
		local_bh_disable();
		else
		preempt_disable();
		}

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