Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (c93eceda) · Commits · 戴 / test

arch/x86/include/asm/fpu-internal.h

+6 −4

Original line number	Diff line number	Diff line
		@@ -207,7 +207,7 @@ static inline void fpu_fxsave(struct fpu *fpu)
		if (config_enabled(CONFIG_X86_32))
		asm volatile( "fxsave %[fx]" : [fx] "=m" (fpu->state->fxsave));
		else if (config_enabled(CONFIG_AS_FXSAVEQ))
		asm volatile("fxsaveq %0" : "=m" (fpu->state->fxsave));
		asm volatile("fxsaveq %[fx]" : [fx] "=m" (fpu->state->fxsave));
		else {
		/* Using "rex64; fxsave %0" is broken because, if the memory
		* operand uses any extended registers for addressing, a second
		@@ -290,9 +290,11 @@ static inline int fpu_restore_checking(struct fpu *fpu)

		static inline int restore_fpu_checking(struct task_struct *tsk)
		{
		/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
		is pending. Clear the x87 state here by setting it to fixed
		values. "m" is a random variable that should be in L1 */
		/*
		* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is
		* pending. Clear the x87 state here by setting it to fixed values.
		* "m" is a random variable that should be in L1.
		*/
		if (unlikely(static_cpu_has_bug_safe(X86_BUG_FXSAVE_LEAK))) {
		asm volatile(
		"fnclex\n\t"

arch/x86/include/asm/i387.h

+5 −1

Original line number	Diff line number	Diff line
		@@ -40,8 +40,8 @@ extern void __kernel_fpu_end(void);

		static inline void kernel_fpu_begin(void)
		{
		WARN_ON_ONCE(!irq_fpu_usable());
		preempt_disable();
		WARN_ON_ONCE(!irq_fpu_usable());
		__kernel_fpu_begin();
		}

		@@ -51,6 +51,10 @@ static inline void kernel_fpu_end(void)
		preempt_enable();
		}

		/* Must be called with preempt disabled */
		extern void kernel_fpu_disable(void);
		extern void kernel_fpu_enable(void);

		/*
		* Some instructions like VIA's padlock instructions generate a spurious
		* DNA fault but don't modify SSE registers. And these instructions

arch/x86/kernel/i387.c

+26 −13

Original line number	Diff line number	Diff line
		@@ -19,6 +19,19 @@
		#include <asm/fpu-internal.h>
		#include <asm/user.h>

		static DEFINE_PER_CPU(bool, in_kernel_fpu);

		void kernel_fpu_disable(void)
		{
		WARN_ON(this_cpu_read(in_kernel_fpu));
		this_cpu_write(in_kernel_fpu, true);
		}

		void kernel_fpu_enable(void)
		{
		this_cpu_write(in_kernel_fpu, false);
		}

		/*
		* Were we in an interrupt that interrupted kernel mode?
		*
		@@ -33,6 +46,9 @@
		*/
		static inline bool interrupted_kernel_fpu_idle(void)
		{
		if (this_cpu_read(in_kernel_fpu))
		return false;

		if (use_eager_fpu())
		return __thread_has_fpu(current);

		@@ -73,10 +89,10 @@ void __kernel_fpu_begin(void)
		{
		struct task_struct *me = current;

		this_cpu_write(in_kernel_fpu, true);

		if (__thread_has_fpu(me)) {
		__thread_clear_has_fpu(me);
		__save_init_fpu(me);
		/* We do 'stts()' in __kernel_fpu_end() */
		} else if (!use_eager_fpu()) {
		this_cpu_write(fpu_owner_task, NULL);
		clts();
		@@ -86,19 +102,16 @@ EXPORT_SYMBOL(__kernel_fpu_begin);

		void __kernel_fpu_end(void)
		{
		if (use_eager_fpu()) {
		/*
		* For eager fpu, most the time, tsk_used_math() is true.
		* Restore the user math as we are done with the kernel usage.
		* At few instances during thread exit, signal handling etc,
		* tsk_used_math() is false. Those few places will take proper
		* actions, so we don't need to restore the math here.
		*/
		if (likely(tsk_used_math(current)))
		math_state_restore();
		} else {
		struct task_struct *me = current;

		if (__thread_has_fpu(me)) {
		if (WARN_ON(restore_fpu_checking(me)))
		drop_init_fpu(me);
		} else if (!use_eager_fpu()) {
		stts();
		}

		this_cpu_write(in_kernel_fpu, false);
		}
		EXPORT_SYMBOL(__kernel_fpu_end);

arch/x86/kernel/traps.c

+5 −7

Original line number	Diff line number	Diff line
		@@ -859,19 +859,17 @@ void math_state_restore(void)
		local_irq_disable();
		}

		/* Avoid __kernel_fpu_begin() right after __thread_fpu_begin() */
		kernel_fpu_disable();
		__thread_fpu_begin(tsk);

		/*
		* Paranoid restore. send a SIGSEGV if we fail to restore the state.
		*/
		if (unlikely(restore_fpu_checking(tsk))) {
		drop_init_fpu(tsk);
		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
		return;
		}

		} else {
		tsk->thread.fpu_counter++;
		}
		kernel_fpu_enable();
		}
		EXPORT_SYMBOL_GPL(math_state_restore);

		dotraplinkage void

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