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Commit 4c138410 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Open code PF_USED_MATH usages 



PF_USED_MATH is used directly, but also in a handful of helper inlines.

To ease the elimination of PF_USED_MATH, convert all inline helpers
to open-coded PF_USED_MATH usage.

Reviewed-by: default avatarBorislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 4540d3fa

arch/x86/ia32/ia32_signal.c

+1 −1
Original line number Diff line number Diff line
@@ -321,7 +321,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, 
		 ksig->ka.sa.sa_restorer)

		sp = (unsigned long) ksig->ka.sa.sa_restorer;



	if (used_math()) {

	if (current->flags & PF_USED_MATH) {

		unsigned long fx_aligned, math_size;



		sp = alloc_mathframe(sp, 1, &fx_aligned, &math_size);

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

+3 −2
Original line number Diff line number Diff line
@@ -375,7 +375,8 @@ static inline void drop_fpu(struct task_struct *tsk) 
		__thread_fpu_end(fpu);

	}



	clear_stopped_child_used_math(tsk);

	tsk->flags &= ~PF_USED_MATH;



	preempt_enable();

}
@@ -423,7 +424,7 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta 
	 * If the task has used the math, pre-load the FPU on xsave processors

	 * or if the past 5 consecutive context-switches used math.

	 */

	fpu.preload = tsk_used_math(new) &&

	fpu.preload = (new->flags & PF_USED_MATH) &&

		      (use_eager_fpu() || new->thread.fpu.counter > 5);



	if (old_fpu->has_fpu) {

arch/x86/kernel/fpu/core.c

+8 −6
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ int fpu__copy(struct task_struct *dst, struct task_struct *src) 


	task_disable_lazy_fpu_restore(dst);



	if (tsk_used_math(src)) {

	if (src->flags & PF_USED_MATH) {

		int err = fpstate_alloc(&dst->thread.fpu);



		if (err)
@@ -331,7 +331,7 @@ void fpu__restore(void) 
	struct task_struct *tsk = current;

	struct fpu *fpu = &tsk->thread.fpu;



	if (!tsk_used_math(tsk)) {

	if (!(tsk->flags & PF_USED_MATH)) {

		local_irq_enable();

		/*

		 * does a slab alloc which can sleep
@@ -361,12 +361,14 @@ EXPORT_SYMBOL_GPL(fpu__restore); 


void fpu__flush_thread(struct task_struct *tsk)

{

	WARN_ON(tsk != current);



	if (!use_eager_fpu()) {

		/* FPU state will be reallocated lazily at the first use. */

		drop_fpu(tsk);

		fpstate_free(&tsk->thread.fpu);

	} else {

		if (!tsk_used_math(tsk)) {

		if (!(tsk->flags & PF_USED_MATH)) {

			/* kthread execs. TODO: cleanup this horror. */

		if (WARN_ON(fpstate_alloc_init(tsk)))

				force_sig(SIGKILL, tsk);
@@ -383,12 +385,12 @@ void fpu__flush_thread(struct task_struct *tsk) 
 */

int fpregs_active(struct task_struct *target, const struct user_regset *regset)

{

	return tsk_used_math(target) ? regset->n : 0;

	return (target->flags & PF_USED_MATH) ? regset->n : 0;

}



int xfpregs_active(struct task_struct *target, const struct user_regset *regset)

{

	return (cpu_has_fxsr && tsk_used_math(target)) ? regset->n : 0;

	return (cpu_has_fxsr && (target->flags & PF_USED_MATH)) ? regset->n : 0;

}



int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
@@ -719,7 +721,7 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu) 
	struct task_struct *tsk = current;

	int fpvalid;



	fpvalid = !!used_math();

	fpvalid = !!(tsk->flags & PF_USED_MATH);

	if (fpvalid)

		fpvalid = !fpregs_get(tsk, NULL,

				      0, sizeof(struct user_i387_ia32_struct),

arch/x86/kernel/fpu/xsave.c

+5 −5
Original line number Diff line number Diff line
@@ -349,7 +349,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) 
	if (!access_ok(VERIFY_READ, buf, size))

		return -EACCES;



	if (!used_math() && fpstate_alloc_init(tsk))

	if (!(tsk->flags & PF_USED_MATH) && fpstate_alloc_init(tsk))

		return -1;



	if (!static_cpu_has(X86_FEATURE_FPU))
@@ -384,12 +384,12 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) 
		int err = 0;



		/*

		 * Drop the current fpu which clears used_math(). This ensures

		 * Drop the current fpu which clears PF_USED_MATH. This ensures

		 * that any context-switch during the copy of the new state,

		 * avoids the intermediate state from getting restored/saved.

		 * Thus avoiding the new restored state from getting corrupted.

		 * We will be ready to restore/save the state only after

		 * set_used_math() is again set.

		 * PF_USED_MATH is again set.

		 */

		drop_fpu(tsk);
@@ -401,7 +401,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) 
			sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);

		}



		set_used_math();

		tsk->flags |= PF_USED_MATH;

		if (use_eager_fpu()) {

			preempt_disable();

			fpu__restore();
@@ -685,7 +685,7 @@ void xsave_init(void) 
 */

void __init_refok eager_fpu_init(void)

{

	WARN_ON(used_math());

	WARN_ON(current->flags & PF_USED_MATH);

	current_thread_info()->status = 0;



	if (eagerfpu == ENABLE)

arch/x86/kernel/signal.c

+3 −3
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 
		}

	}



	if (used_math()) {

	if (current->flags & PF_USED_MATH) {

		sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),

				     &buf_fx, &math_size);

		*fpstate = (void __user *)sp;
@@ -233,7 +233,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, 
		return (void __user *)-1L;



	/* save i387 and extended state */

	if (used_math() &&

	if ((current->flags & PF_USED_MATH) &&

	    save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)

		return (void __user *)-1L;
@@ -664,7 +664,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
		/*

		 * Ensure the signal handler starts with the new fpu state.

		 */

		if (used_math())

		if (current->flags & PF_USED_MATH)

			fpu_reset_state(current);

	}

	signal_setup_done(failed, ksig, stepping);