From: Anton Blanchard <an...@samba.org>
In setup_sigcontext(), we set current->thread.vrsave then use it
straight after. Since current is hidden from the compiler via inline
assembly, it cannot optimise this and we end up with a load hit store.
Fix this by using a temporary.
Signed-off-by: Anton Blanchard <an...@samba.org>
---
arch/powerpc/kernel/signal_64.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 2552079..7e49984 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -104,6 +104,7 @@ static long setup_sigcontext(struct sigcontext __user *sc,
struct pt_regs *regs,
*/
#ifdef CONFIG_ALTIVEC
elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
+ unsigned long vrsave;
#endif
unsigned long msr = regs->msr;
long err = 0;
@@ -125,9 +126,13 @@ static long setup_sigcontext(struct sigcontext __user *sc,
struct pt_regs *regs,
/* We always copy to/from vrsave, it's 0 if we don't have or don't
* use altivec.
*/
- if (cpu_has_feature(CPU_FTR_ALTIVEC))
- current->thread.vrsave = mfspr(SPRN_VRSAVE);
- err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+ vrsave = 0;
+ if (cpu_has_feature(CPU_FTR_ALTIVEC)) {
+ vrsave = mfspr(SPRN_VRSAVE);
+ current->thread.vrsave = vrsave;
+ }
+
+ err |= __put_user(vrsave, (u32 __user *)&v_regs[33]);
#else /* CONFIG_ALTIVEC */
err |= __put_user(0, &sc->v_regs);
#endif /* CONFIG_ALTIVEC */
--
2.7.4
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