1 files changed, 11 insertions, 9 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 5462bef898f..7b9d999e211 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -207,10 +207,20 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
 
         if (!sig)
                 regs->gpr[13] = save_r13;
-        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
         if (set != NULL)
                 err |=  __get_user(set->sig[0], &sc->oldmask);
 
+        /*
+         * Do this before updating the thread state in
+         * current->thread.fpr/vr.  That way, if we get preempted
+         * and another task grabs the FPU/Altivec, it won't be
+         * tempted to save the current CPU state into the thread_struct
+         * and corrupt what we are writing there.
+         */
+        discard_lazy_cpu_state();
+
+        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
+
 #ifdef CONFIG_ALTIVEC
         err |= __get_user(v_regs, &sc->v_regs);
         err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
@@ -229,14 +239,6 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
                 current->thread.vrsave = 0;
 #endif /* CONFIG_ALTIVEC */
 
-#ifndef CONFIG_SMP
-        preempt_disable();
-        if (last_task_used_math == current)
-                last_task_used_math = NULL;
-        if (last_task_used_altivec == current)
-                last_task_used_altivec = NULL;
-        preempt_enable();
-#endif
         /* Force reload of FP/VEC */
         regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);