From bf6a4d5b75d1ea87897fe68d0e45d35a2996c678 Mon Sep 17 00:00:00 2001 From: Cyril Bur Date: Mon, 29 Feb 2016 17:53:51 +1100 Subject: [PATCH] powerpc: Add the ability to save VSX without giving it up This patch adds the ability to be able to save the VSX registers to the thread struct without giving up (disabling the facility) next time the process returns to userspace. This patch builds on a previous optimisation for the FPU and VEC registers in the thread copy path to avoid a possibly pointless reload of VSX state. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/switch_to.h | 4 --- arch/powerpc/kernel/ppc_ksyms.c | 4 --- arch/powerpc/kernel/process.c | 42 ++++++++++++++++++++-------- arch/powerpc/kernel/vector.S | 17 ----------- 4 files changed, 30 insertions(+), 37 deletions(-) diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h index 9028822bb73f..17c8380673a6 100644 --- a/arch/powerpc/include/asm/switch_to.h +++ b/arch/powerpc/include/asm/switch_to.h @@ -56,14 +56,10 @@ static inline void __giveup_altivec(struct task_struct *t) { } #ifdef CONFIG_VSX extern void enable_kernel_vsx(void); extern void flush_vsx_to_thread(struct task_struct *); -extern void giveup_vsx(struct task_struct *); -extern void __giveup_vsx(struct task_struct *); 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 diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c index 41e1607e800c..ef7024dacff7 100644 --- a/arch/powerpc/kernel/ppc_ksyms.c +++ b/arch/powerpc/kernel/ppc_ksyms.c @@ -28,10 +28,6 @@ EXPORT_SYMBOL(load_vr_state); EXPORT_SYMBOL(store_vr_state); #endif -#ifdef CONFIG_VSX -EXPORT_SYMBOL_GPL(__giveup_vsx); -#endif - #ifdef CONFIG_EPAPR_PARAVIRT EXPORT_SYMBOL(epapr_hypercall_start); #endif diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 14c09d25de98..d7a9df51b974 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -280,19 +280,31 @@ static inline int restore_altivec(struct task_struct *tsk) { return 0; } #endif /* CONFIG_ALTIVEC */ #ifdef CONFIG_VSX -void giveup_vsx(struct task_struct *tsk) +static void __giveup_vsx(struct task_struct *tsk) { - check_if_tm_restore_required(tsk); - - msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX); if (tsk->thread.regs->msr & MSR_FP) __giveup_fpu(tsk); if (tsk->thread.regs->msr & MSR_VEC) __giveup_altivec(tsk); + tsk->thread.regs->msr &= ~MSR_VSX; +} + +static void giveup_vsx(struct task_struct *tsk) +{ + check_if_tm_restore_required(tsk); + + msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX); __giveup_vsx(tsk); msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX); } -EXPORT_SYMBOL(giveup_vsx); + +static void save_vsx(struct task_struct *tsk) +{ + if (tsk->thread.regs->msr & MSR_FP) + save_fpu(tsk); + if (tsk->thread.regs->msr & MSR_VEC) + save_altivec(tsk); +} void enable_kernel_vsx(void) { @@ -335,6 +347,7 @@ static int restore_vsx(struct task_struct *tsk) } #else static inline int restore_vsx(struct task_struct *tsk) { return 0; } +static inline void save_vsx(struct task_struct *tsk) { } #endif /* CONFIG_VSX */ #ifdef CONFIG_SPE @@ -478,14 +491,19 @@ void save_all(struct task_struct *tsk) msr_check_and_set(msr_all_available); - if (usermsr & MSR_FP) - save_fpu(tsk); - - if (usermsr & MSR_VEC) - save_altivec(tsk); + /* + * Saving the way the register space is in hardware, save_vsx boils + * down to a save_fpu() and save_altivec() + */ + if (usermsr & MSR_VSX) { + save_vsx(tsk); + } else { + if (usermsr & MSR_FP) + save_fpu(tsk); - if (usermsr & MSR_VSX) - __giveup_vsx(tsk); + if (usermsr & MSR_VEC) + save_altivec(tsk); + } if (usermsr & MSR_SPE) __giveup_spe(tsk); diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S index 51b0c175ea8c..1c2e7a343bf5 100644 --- a/arch/powerpc/kernel/vector.S +++ b/arch/powerpc/kernel/vector.S @@ -151,23 +151,6 @@ _GLOBAL(load_up_vsx) std r12,_MSR(r1) b fast_exception_return -/* - * __giveup_vsx(tsk) - * Disable VSX for the task given as the argument. - * Does NOT save vsx registers. - */ -_GLOBAL(__giveup_vsx) - addi r3,r3,THREAD /* want THREAD of task */ - ld r5,PT_REGS(r3) - cmpdi 0,r5,0 - beq 1f - ld r4,_MSR-STACK_FRAME_OVERHEAD(r5) - lis r3,MSR_VSX@h - andc r4,r4,r3 /* disable VSX for previous task */ - std r4,_MSR-STACK_FRAME_OVERHEAD(r5) -1: - blr - #endif /* CONFIG_VSX */ -- 2.20.1