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authorCyril Bur <cyrilbur@gmail.com>2016-02-29 17:53:51 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2016-03-02 23:34:50 +1100
commitbf6a4d5b75d1ea87897fe68d0e45d35a2996c678 (patch)
tree8e967bdd1fe1dcd8bda0b38baa212c945c40cab1 /arch/powerpc/kernel
parent6f515d842e8e1b205e54f44b9013bf14870b97a7 (diff)
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 <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/ppc_ksyms.c4
-rw-r--r--arch/powerpc/kernel/process.c42
-rw-r--r--arch/powerpc/kernel/vector.S17
3 files changed, 30 insertions, 33 deletions
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 */