[PATCH v3 6/9] powerpc: Prepare for splitting giveup_{fpu, altivec, vsx} in two
flat view
STALE3901d
SUPERSEDED
From: Cyril Bur <hidden>
Date: 2016-01-21 00:58:53
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Revision v3 of 6 in this series.
Revisions (6)
This prepares for the decoupling of saving {fpu,altivec,vsx} registers and
marking {fpu,altivec,vsx} as being unused by a thread.
Currently giveup_{fpu,altivec,vsx}() does both however optimisations to
task switching can be made if these two operations are decoupled.
save_all() will permit the saving of registers to thread structs and leave
threads MSR with bits enabled.
This patch introduces no functional change.
Signed-off-by: Cyril Bur <redacted>
---
arch/powerpc/include/asm/switch_to.h | 7 +++++++
arch/powerpc/kernel/process.c | 39 +++++++++++++++++++++++++++++++++++-
2 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 5b268b6..3690041 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h@@ -34,6 +34,7 @@ static inline void disable_kernel_fp(void) msr_check_and_clear(MSR_FP); } #else +static inline void __giveup_fpu(struct task_struct *t) { } static inline void flush_fp_to_thread(struct task_struct *t) { } #endif
@@ -46,6 +47,8 @@ static inline void disable_kernel_altivec(void) { msr_check_and_clear(MSR_VEC); } +#else +static inline void __giveup_altivec(struct task_struct *t) { } #endif #ifdef CONFIG_VSX
@@ -57,6 +60,8 @@ static inline void disable_kernel_vsx(void) { msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX); } +#else +static inline void __giveup_vsx(struct task_struct *t) { } #endif #ifdef CONFIG_SPE
@@ -68,6 +73,8 @@ static inline void disable_kernel_spe(void) { msr_check_and_clear(MSR_SPE); } +#else +static inline void __giveup_spe(struct task_struct *t) { } #endif static inline void clear_task_ebb(struct task_struct *t)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 0955b7c..45e37c0 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c@@ -349,6 +349,14 @@ void flush_spe_to_thread(struct task_struct *tsk) preempt_enable(); } } +#else +/* + * save_all() is going to test MSR_SPE, rather than pull in all the + * booke definitions all the time on a books kernel just ensure it exists + * but acts as a nop. + */ + +#define MSR_SPE 0 #endif /* CONFIG_SPE */ static unsigned long msr_all_available;
@@ -440,12 +448,41 @@ void restore_math(struct pt_regs *regs) regs->msr = msr; } +void save_all(struct task_struct *tsk) +{ + unsigned long usermsr; + + if (!tsk->thread.regs) + return; + + usermsr = tsk->thread.regs->msr; + + if ((usermsr & msr_all_available) == 0) + return; + + msr_check_and_set(msr_all_available); + + if (usermsr & MSR_FP) + __giveup_fpu(tsk); + + if (usermsr & MSR_VEC) + __giveup_altivec(tsk); + + if (usermsr & MSR_VSX) + __giveup_vsx(tsk); + + if (usermsr & MSR_SPE) + __giveup_spe(tsk); + + msr_check_and_clear(msr_all_available); +} + void flush_all_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); BUG_ON(tsk != current); - giveup_all(tsk); + save_all(tsk); #ifdef CONFIG_SPE if (tsk->thread.regs->msr & MSR_SPE)
--
2.7.0