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Commit 276983f8 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Eliminate the __thread_has_fpu() wrapper 



Start migrating FPU methods towards using 'struct fpu *fpu'
directly. __thread_has_fpu() is just a trivial wrapper around
fpu->has_fpu, eliminate it.

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 9a89b029

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

+4 −12
Original line number Diff line number Diff line
@@ -323,16 +323,6 @@ static inline int restore_fpu_checking(struct task_struct *tsk) 
	return fpu_restore_checking(&tsk->thread.fpu);

}



/*

 * Software FPU state helpers. Careful: these need to

 * be preemption protection *and* they need to be

 * properly paired with the CR0.TS changes!

 */

static inline int __thread_has_fpu(struct task_struct *tsk)

{

	return tsk->thread.fpu.has_fpu;

}



/* Must be paired with an 'stts' after! */

static inline void __thread_clear_has_fpu(struct task_struct *tsk)

{
@@ -370,13 +360,14 @@ static inline void __thread_fpu_begin(struct task_struct *tsk) 


static inline void drop_fpu(struct task_struct *tsk)

{

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

	/*

	 * Forget coprocessor state..

	 */

	preempt_disable();

	tsk->thread.fpu.counter = 0;



	if (__thread_has_fpu(tsk)) {

	if (fpu->has_fpu) {

		/* Ignore delayed exceptions from user space */

		asm volatile("1: fwait\n"

			     "2:\n"
@@ -424,6 +415,7 @@ typedef struct { int preload; } fpu_switch_t; 


static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct task_struct *new, int cpu)

{

	struct fpu *old_fpu = &old->thread.fpu;

	fpu_switch_t fpu;



	/*
@@ -433,7 +425,7 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta 
	fpu.preload = tsk_used_math(new) &&

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



	if (__thread_has_fpu(old)) {

	if (old_fpu->has_fpu) {

		if (!fpu_save_init(&old->thread.fpu))

			task_disable_lazy_fpu_restore(old);

		else

arch/x86/kernel/fpu/core.c

+10 −7
Original line number Diff line number Diff line
@@ -57,8 +57,7 @@ static bool interrupted_kernel_fpu_idle(void) 
	if (use_eager_fpu())

		return true;



	return !__thread_has_fpu(current) &&

		(read_cr0() & X86_CR0_TS);

	return !current->thread.fpu.has_fpu && (read_cr0() & X86_CR0_TS);

}



/*
@@ -93,11 +92,12 @@ EXPORT_SYMBOL(irq_fpu_usable); 
void __kernel_fpu_begin(void)

{

	struct task_struct *me = current;

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



	kernel_fpu_disable();



	if (__thread_has_fpu(me)) {

		fpu_save_init(&me->thread.fpu);

	if (fpu->has_fpu) {

		fpu_save_init(fpu);

	} else {

		this_cpu_write(fpu_owner_task, NULL);

		if (!use_eager_fpu())
@@ -109,8 +109,9 @@ EXPORT_SYMBOL(__kernel_fpu_begin); 
void __kernel_fpu_end(void)

{

	struct task_struct *me = current;

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



	if (__thread_has_fpu(me)) {

	if (fpu->has_fpu) {

		if (WARN_ON(restore_fpu_checking(me)))

			fpu_reset_state(me);

	} else if (!use_eager_fpu()) {
@@ -128,14 +129,16 @@ EXPORT_SYMBOL(__kernel_fpu_end); 
 */

void fpu__save(struct task_struct *tsk)

{

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



	WARN_ON(tsk != current);



	preempt_disable();

	if (__thread_has_fpu(tsk)) {

	if (fpu->has_fpu) {

		if (use_eager_fpu()) {

			__save_fpu(tsk);

		} else {

			fpu_save_init(&tsk->thread.fpu);

			fpu_save_init(fpu);

			__thread_fpu_end(tsk);

		}

	}