1 files changed, 15 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 3e80aa32b8b0..a6a43103655e 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -410,7 +410,7 @@ inline unsigned long copy_fpr_from_user(struct task_struct *task,
  * altivec/spe instructions at some point.
  */
 static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
-                int sigret)
+                int sigret, int ctx_has_vsx_region)
 {
         unsigned long msr = regs->msr;
 
@@ -451,7 +451,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
          * the saved MSR value to indicate that frame->mc_vregs
          * contains valid data
          */
-        if (current->thread.used_vsr) {
+        if (current->thread.used_vsr && ctx_has_vsx_region) {
                 __giveup_vsx(current);
                 if (copy_vsx_to_user(&frame->mc_vsregs, current))
                         return 1;
@@ -858,11 +858,11 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
         frame = &rt_sf->uc.uc_mcontext;
         addr = frame;
         if (vdso32_rt_sigtramp && current->mm->context.vdso_base) {
-                if (save_user_regs(regs, frame, 0))
+                if (save_user_regs(regs, frame, 0, 1))
                         goto badframe;
                 regs->link = current->mm->context.vdso_base + vdso32_rt_sigtramp;
         } else {
-                if (save_user_regs(regs, frame, __NR_rt_sigreturn))
+                if (save_user_regs(regs, frame, __NR_rt_sigreturn, 1))
                         goto badframe;
                 regs->link = (unsigned long) frame->tramp;
         }
@@ -936,12 +936,13 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
                      int ctx_size, int r6, int r7, int r8, struct pt_regs *regs)
 {
         unsigned char tmp;
+        int ctx_has_vsx_region = 0;
 
 #ifdef CONFIG_PPC64
         unsigned long new_msr = 0;
 
         if (new_ctx &&
-            __get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR]))
+            get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR]))
                 return -EFAULT;
         /*
          * Check that the context is not smaller than the original
@@ -956,16 +957,9 @@ long 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;
 #else
         /* Context size is for future use. Right now, we only make sure
          * we are passed something we understand
@@ -985,17 +979,17 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
                  */
                 mctx = (struct mcontext __user *)
                         ((unsigned long) &old_ctx->uc_mcontext & ~0xfUL);
-                if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
-                    || save_user_regs(regs, mctx, 0)
+                if (!access_ok(VERIFY_WRITE, old_ctx, ctx_size)
+                    || save_user_regs(regs, mctx, 0, ctx_has_vsx_region)
                     || put_sigset_t(&old_ctx->uc_sigmask, &current->blocked)
                     || __put_user(to_user_ptr(mctx), &old_ctx->uc_regs))
                         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;
 
         /*
@@ -1196,11 +1190,11 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka,
                 goto badframe;
 
         if (vdso32_sigtramp && current->mm->context.vdso_base) {
-                if (save_user_regs(regs, &frame->mctx, 0))
+                if (save_user_regs(regs, &frame->mctx, 0, 1))
                         goto badframe;
                 regs->link = current->mm->context.vdso_base + vdso32_sigtramp;
         } else {
-                if (save_user_regs(regs, &frame->mctx, __NR_sigreturn))
+                if (save_user_regs(regs, &frame->mctx, __NR_sigreturn, 1))
                         goto badframe;
                 regs->link = (unsigned long) frame->mctx.tramp;
         }