This patch adds the ability to be able to save the VEC 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 registers in the
thread copy path to avoid a possibly pointless reload of VEC state.
Signed-off-by: Cyril Bur <cyril...@gmail.com>
---
arch/powerpc/include/asm/switch_to.h | 3 ++-
arch/powerpc/kernel/process.c | 12 +++++++++++-
arch/powerpc/kernel/vector.S | 24 ++++--------------------
3 files changed, 17 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/switch_to.h
b/arch/powerpc/include/asm/switch_to.h
index 6a201e8..9028822 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -43,12 +43,13 @@ static inline void flush_fp_to_thread(struct task_struct
*t) { }
extern void enable_kernel_altivec(void);
extern void flush_altivec_to_thread(struct task_struct *);
extern void giveup_altivec(struct task_struct *);
-extern void __giveup_altivec(struct task_struct *);
+extern void save_altivec(struct task_struct *);
static inline void disable_kernel_altivec(void)
{
msr_check_and_clear(MSR_VEC);
}
#else
+static inline void save_altivec(struct task_struct *t) { }
static inline void __giveup_altivec(struct task_struct *t) { }
#endif
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a3411ce..fef5b7d 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -213,6 +213,16 @@ static int restore_fp(struct task_struct *tsk) { return 0;
}
#ifdef CONFIG_ALTIVEC
#define loadvec(thr) ((thr).load_vec)
+static void __giveup_altivec(struct task_struct *tsk)
+{
+ save_altivec(tsk);
+ tsk->thread.regs->msr &= ~MSR_VEC;
+#ifdef CONFIG_VSX
+ if (cpu_has_feature(CPU_FTR_VSX))
+ tsk->thread.regs->msr &= ~MSR_VSX;
+#endif
+}
+
void giveup_altivec(struct task_struct *tsk)
{
check_if_tm_restore_required(tsk);
@@ -476,7 +486,7 @@ void save_all(struct task_struct *tsk)
save_fpu(tsk);
if (usermsr & MSR_VEC)
- __giveup_altivec(tsk);
+ save_altivec(tsk);
if (usermsr & MSR_VSX)
__giveup_vsx(tsk);
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index 038cff8..51b0c17 100644
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -106,36 +106,20 @@ _GLOBAL(load_up_altivec)
blr
/*
- * __giveup_altivec(tsk)
- * Disable VMX for the task given as the argument,
- * and save the vector registers in its thread_struct.
+ * save_altivec(tsk)
+ * Save the vector registers to its thread_struct
*/
-_GLOBAL(__giveup_altivec)
+_GLOBAL(save_altivec)
addi r3,r3,THREAD /* want THREAD of task */
PPC_LL r7,THREAD_VRSAVEAREA(r3)
PPC_LL r5,PT_REGS(r3)
PPC_LCMPI 0,r7,0
bne 2f
addi r7,r3,THREAD_VRSTATE
-2: PPC_LCMPI 0,r5,0
- SAVE_32VRS(0,r4,r7)
+2: SAVE_32VRS(0,r4,r7)
mfvscr v0
li r4,VRSTATE_VSCR
stvx v0,r4,r7
- beq 1f
- PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
-#ifdef CONFIG_VSX
-BEGIN_FTR_SECTION
- lis r3,(MSR_VEC|MSR_VSX)@h
-FTR_SECTION_ELSE
- lis r3,MSR_VEC@h
-ALT_FTR_SECTION_END_IFSET(CPU_FTR_VSX)
-#else
- lis r3,MSR_VEC@h
-#endif
- andc r4,r4,r3 /* disable FP for previous task */
- PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
-1:
blr
#ifdef CONFIG_VSX
--
2.7.0
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