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| author | Kevin Hao <haokexin@gmail.com> | 2013-07-14 17:02:05 +0800 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-08-14 14:59:44 +1000 |
| commit | 037f0eed57c3f35367ac32275e45f24e297549e9 (patch) | |
| tree | 87dbec64efb721dae5fd8b0a5c2b634f882631dd | |
| parent | 662499d04b6bc73d0ecab0ab876bacd5bbe7d6a7 (diff) | |
| download | linux-037f0eed57c3f35367ac32275e45f24e297549e9.tar.gz linux-037f0eed57c3f35367ac32275e45f24e297549e9.tar.bz2 linux-037f0eed57c3f35367ac32275e45f24e297549e9.zip | |
powerpc: Make flush_fp_to_thread() nop when CONFIG_PPC_FPU is disabled
In the current kernel, the function flush_fp_to_thread() is not
dependent on CONFIG_PPC_FPU. So most invocations of this function
is not wrapped by CONFIG_PPC_FPU. Even through we don't really
save the FPRs to the thread struct if CONFIG_PPC_FPU is not enabled,
but there does have some runtime overhead such as the check for
tsk->thread.regs and preempt disable and enable. It really make
no sense to do that. So make it a nop when CONFIG_PPC_FPU is
disabled. Also remove the wrapped #ifdef CONFIG_PPC_FPU
when invoking this function.
Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/include/asm/switch_to.h | 7 | ||||
| -rw-r--r-- | arch/powerpc/kernel/process.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/math-emu/math.c | 3 |
3 files changed, 9 insertions, 3 deletions
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 33e1cd823585..39cf0f6cc373 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -19,7 +19,6 @@ extern struct task_struct *_switch(struct thread_struct *prev, extern void giveup_fpu(struct task_struct *); extern void load_up_fpu(void); extern void enable_kernel_fp(void); -extern void flush_fp_to_thread(struct task_struct *); extern void enable_kernel_altivec(void); extern void load_up_altivec(struct task_struct *); extern int emulate_altivec(struct pt_regs *); @@ -37,6 +36,12 @@ static inline void discard_lazy_cpu_state(void) } #endif +#ifdef CONFIG_PPC_FPU +extern void flush_fp_to_thread(struct task_struct *); +#else +static inline void flush_fp_to_thread(struct task_struct *t) { } +#endif + #ifdef CONFIG_ALTIVEC extern void flush_altivec_to_thread(struct task_struct *); extern void giveup_altivec(struct task_struct *); diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index c517dbe705fd..0ec255a81c66 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -74,6 +74,7 @@ struct task_struct *last_task_used_vsx = NULL; struct task_struct *last_task_used_spe = NULL; #endif +#ifdef CONFIG_PPC_FPU /* * Make sure the floating-point register state in the * the thread_struct is up to date for task tsk. @@ -107,6 +108,7 @@ void flush_fp_to_thread(struct task_struct *tsk) } } EXPORT_SYMBOL_GPL(flush_fp_to_thread); +#endif void enable_kernel_fp(void) { diff --git a/arch/powerpc/math-emu/math.c b/arch/powerpc/math-emu/math.c index 49eb2ac08fd3..bc901623d8df 100644 --- a/arch/powerpc/math-emu/math.c +++ b/arch/powerpc/math-emu/math.c @@ -7,6 +7,7 @@ #include <asm/uaccess.h> #include <asm/reg.h> +#include <asm/switch_to.h> #include <asm/sfp-machine.h> #include <math-emu/double.h> @@ -433,9 +434,7 @@ do_mathemu(struct pt_regs *regs) * is flushed into the thread_struct before attempting * emulation */ -#ifdef CONFIG_PPC_FPU flush_fp_to_thread(current); -#endif eflag = func(op0, op1, op2, op3); |