powerpc: Fix swapcontext system for VSX + old ucontext size

[linux-2.6-omap-h63xx.git] / arch / powerpc / kernel / signal_64.c

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index c6a8f2326b6f246fc077b25c2b7b1d9460f9e6cc..e132891d3cea00e947750aa53ec97288a6f4c839 100644 (file)
--- 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;