[POWERPC] Fix subtle FP state corruption bug in signal return on SMP

[pandora-kernel.git] / arch / powerpc / kernel / signal_64.c

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 1ce0ae3..b27e268 100644 (file)
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -176,6 +176,13 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
         */
        discard_lazy_cpu_state();
 
+       /*
+        * Force reload of FP/VEC.
+        * This has to be done before copying stuff into current->thread.fpr/vr
+        * for the reasons explained in the previous comment.
+        */
+       regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
+
        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
 
 #ifdef CONFIG_ALTIVEC
@@ -197,9 +204,6 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
                current->thread.vrsave = 0;
 #endif /* CONFIG_ALTIVEC */
 
-       /* Force reload of FP/VEC */
-       regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
-
        return err;
 }