[PATCH 045/208] x86/fpu: Eliminate the __thread_has_fpu() wrapper

Ingo Molnar
2015-05-05T16:55:45Z

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: Borislav 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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/fpu-internal.h | 16 ++++------------
arch/x86/kernel/fpu/core.c | 17 ++++++++++-------
2 files changed, 14 insertions(+), 19 deletions(-)

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index e180fb96dd0d..c005d1fc1247 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -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
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 7711539bcda5..c0633ca8fece 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -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);
}
}
--
2.1.0