1 files changed, 34 insertions, 6 deletions

diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index 7347bb14e306..1c83e5124c65 100644
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -295,7 +295,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	   see include/asm-x86_64/uaccess.h for details. */
 	set_fs(USER_DS);
 
-	regs->flags &= ~X86_EFLAGS_TF;
+	regs->flags &= ~(X86_EFLAGS_TF | X86_EFLAGS_DF);
 	if (test_thread_flag(TIF_SINGLESTEP))
 		ptrace_notify(SIGTRAP);
 #ifdef DEBUG_SIG
@@ -311,6 +311,35 @@ give_sigsegv:
 }
 
 /*
+ * Return -1L or the syscall number that @regs is executing.
+ */
+static long current_syscall(struct pt_regs *regs)
+{
+	/*
+	 * We always sign-extend a -1 value being set here,
+	 * so this is always either -1L or a syscall number.
+	 */
+	return regs->orig_ax;
+}
+
+/*
+ * Return a value that is -EFOO if the system call in @regs->orig_ax
+ * returned an error.  This only works for @regs from @current.
+ */
+static long current_syscall_ret(struct pt_regs *regs)
+{
+#ifdef CONFIG_IA32_EMULATION
+	if (test_thread_flag(TIF_IA32))
+		/*
+		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
+		 * and will match correctly in comparisons.
+		 */
+		return (int) regs->ax;
+#endif
+	return regs->ax;
+}
+
+/*
  * OK, we're invoking a handler
  */	
 
@@ -327,9 +356,9 @@ handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
 #endif
 
 	/* Are we from a system call? */
-	if ((long)regs->orig_ax >= 0) {
+	if (current_syscall(regs) >= 0) {
 		/* If so, check system call restarting.. */
-		switch (regs->ax) {
+		switch (current_syscall_ret(regs)) {
 		        case -ERESTART_RESTARTBLOCK:
 			case -ERESTARTNOHAND:
 				regs->ax = -EINTR;
@@ -426,10 +455,9 @@ static void do_signal(struct pt_regs *regs)
 	}
 
 	/* Did we come from a system call? */
-	if ((long)regs->orig_ax >= 0) {
+	if (current_syscall(regs) >= 0) {
 		/* Restart the system call - no handlers present */
-		long res = regs->ax;
-		switch (res) {
+		switch (current_syscall_ret(regs)) {
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR: