diff options
| author | Cyril Bur <cyrilbur@gmail.com> | 2016-02-29 17:53:48 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-03-02 23:34:48 +1100 |
| commit | de2a20aa7237b45d3c14a2505804a8daa95a8f53 (patch) | |
| tree | 13593cbcaa3c487fa1a8a9ce76c1bdc5e50b602f | |
| parent | 70fe3d980f5f14d8125869125ba9a0ea95e09c6b (diff) | |
powerpc: Prepare for splitting giveup_{fpu, altivec, vsx} in two
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 <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
| -rw-r--r-- | arch/powerpc/include/asm/reg.h | 8 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/switch_to.h | 7 | ||||
| -rw-r--r-- | arch/powerpc/kernel/process.c | 31 |
3 files changed, 45 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index 11a81bd5dabd..52ed654d01ba 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -75,6 +75,14 @@ #define MSR_HV 0 #endif +/* + * To be used in shared book E/book S, this avoids needing to worry about + * book S/book E in shared code + */ +#ifndef MSR_SPE +#define MSR_SPE 0 +#endif + #define MSR_VEC __MASK(MSR_VEC_LG) /* Enable AltiVec */ #define MSR_VSX __MASK(MSR_VSX_LG) /* Enable VSX */ #define MSR_POW __MASK(MSR_POW_LG) /* Enable Power Management */ diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 5b268b6be74c..3690041c126a 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 55c1eb0465af..29da07fb3b4a 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -444,12 +444,41 @@ 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) |