powerpc: Fix swapcontext system for VSX + old ucontext size

[linux-2.6-omap-h63xx.git] / arch / powerpc / kernel / signal_32.c

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 3e80aa32b8b09e1daf432cb7e112d9a04be7ce4a..a6a43103655e8625865b021b5cf3d59e2cee0221 100644 (file)
--- 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;
        }