Merge branch 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/…

…git/vgupta/arc

Pull ARC fix from Vineet Gupta:
 "Chrisitian found/fixed issue with SA_SIGINFO based signal handler
  corrupting the user space registers post after signal handling"

* 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Fix signal frame management for SA_SIGINFO

arch/arc/kernel/signal.c

@@ -101,7 +101,6 @@ SYSCALL_DEFINE0(rt_sigreturn)
 {
 	struct rt_sigframe __user *sf;
 	unsigned int magic;
-	int err;
 	struct pt_regs *regs = current_pt_regs();
 
 	/* Always make any pending restarted system calls return -EINTR */
@@ -119,15 +118,16 @@ SYSCALL_DEFINE0(rt_sigreturn)
 	if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
 		goto badframe;
 
-	err = restore_usr_regs(regs, sf);
-	err |= __get_user(magic, &sf->sigret_magic);
-	if (err)
+	if (__get_user(magic, &sf->sigret_magic))
 		goto badframe;
 
 	if (unlikely(is_do_ss_needed(magic)))
 		if (restore_altstack(&sf->uc.uc_stack))
 			goto badframe;
 
+	if (restore_usr_regs(regs, sf))
+		goto badframe;
+
 	/* Don't restart from sigreturn */
 	syscall_wont_restart(regs);
 
@@ -190,6 +190,15 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
 	if (!sf)
 		return 1;
 
+	/*
+	 * w/o SA_SIGINFO, struct ucontext is partially populated (only
+	 * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
+	 * during signal handler execution. This works for SA_SIGINFO as well
+	 * although the semantics are now overloaded (the same reg state can be
+	 * inspected by userland: but are they allowed to fiddle with it ?
+	 */
+	err |= stash_usr_regs(sf, regs, set);
+
 	/*
 	 * SA_SIGINFO requires 3 args to signal handler:
 	 *  #1: sig-no (common to any handler)
@@ -213,14 +222,6 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
 		magic = MAGIC_SIGALTSTK;
 	}
 
-	/*
-	 * w/o SA_SIGINFO, struct ucontext is partially populated (only
-	 * uc_mcontext/uc_sigmask) for kernel's normal user state preservation
-	 * during signal handler execution. This works for SA_SIGINFO as well
-	 * although the semantics are now overloaded (the same reg state can be
-	 * inspected by userland: but are they allowed to fiddle with it ?
-	 */
-	err |= stash_usr_regs(sf, regs, set);
 	err |= __put_user(magic, &sf->sigret_magic);
 	if (err)
 		return err;