1 files changed, 15 insertions, 18 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index c6a8f2326b6f..e132891d3cea 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -74,7 +74,8 @@ static const char fmt64[] = KERN_INFO \
  */
 
 static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
-                 int signr, sigset_t *set, unsigned long handler)
+                 int signr, sigset_t *set, unsigned long handler,
+                 int ctx_has_vsx_region)
 {
         /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
          * process never used altivec yet (MSR_VEC is zero in pt_regs of
@@ -121,7 +122,7 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
          * then out to userspace.  Update v_regs to point after the
          * VMX data.
          */
-        if (current->thread.used_vsr) {
+        if (current->thread.used_vsr && ctx_has_vsx_region) {
                 __giveup_vsx(current);
                 v_regs += ELF_NVRREG;
                 err |= copy_vsx_to_user(v_regs, current);
@@ -282,9 +283,10 @@ int sys_swapcontext(struct ucontext __user *old_ctx,
         unsigned char tmp;
         sigset_t set;
         unsigned long new_msr = 0;
+        int ctx_has_vsx_region = 0;
 
         if (new_ctx &&
-            __get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
+            get_user(new_msr, &new_ctx->uc_mcontext.gp_regs[PT_MSR]))
                 return -EFAULT;
         /*
          * Check that the context is not smaller than the original
@@ -299,28 +301,23 @@ int sys_swapcontext(struct ucontext __user *old_ctx,
         if ((ctx_size < sizeof(struct ucontext)) &&
             (new_msr & MSR_VSX))
                 return -EINVAL;
-#ifdef CONFIG_VSX
-        /*
-         * If userspace doesn't provide enough room for VSX data,
-         * but current thread has used VSX, we don't have anywhere
-         * to store the full context back into.
-         */
-        if ((ctx_size < sizeof(struct ucontext)) &&
-            (current->thread.used_vsr && old_ctx))
-                return -EINVAL;
-#endif
+        /* Does the context have enough room to store VSX data? */
+        if (ctx_size >= sizeof(struct ucontext))
+                ctx_has_vsx_region = 1;
+
         if (old_ctx != NULL) {
-                if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
-                    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
+                if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
+                    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0,
+                                        ctx_has_vsx_region)
                     || __copy_to_user(&old_ctx->uc_sigmask,
                                       &current->blocked, sizeof(sigset_t)))
                         return -EFAULT;
         }
         if (new_ctx == NULL)
                 return 0;
-        if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
+        if (!access_ok(VERIFY_READ, new_ctx, ctx_size)
             || __get_user(tmp, (u8 __user *) new_ctx)
-            || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
+            || __get_user(tmp, (u8 __user *) new_ctx + ctx_size - 1))
                 return -EFAULT;
 
         /*
@@ -423,7 +420,7 @@ int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info,
                           &frame->uc.uc_stack.ss_flags);
         err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
         err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL,
-                                (unsigned long)ka->sa.sa_handler);
+                                (unsigned long)ka->sa.sa_handler, 1);
         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
         if (err)
                 goto badframe;