1 files changed, 53 insertions, 37 deletions

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index cb839831764..0340224cf73 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -597,19 +597,13 @@ setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
         return err;
 }
 
-static inline void setup_syscall_restart(struct pt_regs *regs)
-{
-        regs->ARM_r0 = regs->ARM_ORIG_r0;
-        regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
-}
-
 /*
  * OK, we're invoking a handler
  */     
 static int
 handle_signal(unsigned long sig, struct k_sigaction *ka,
               siginfo_t *info, sigset_t *oldset,
-              struct pt_regs * regs, int syscall)
+              struct pt_regs * regs)
 {
         struct thread_info *thread = current_thread_info();
         struct task_struct *tsk = current;
@@ -617,26 +611,6 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
         int ret;
 
         /*
-         * If we were from a system call, check for system call restarting...
-         */
-        if (syscall) {
-                switch (regs->ARM_r0) {
-                case -ERESTART_RESTARTBLOCK:
-                case -ERESTARTNOHAND:
-                        regs->ARM_r0 = -EINTR;
-                        break;
-                case -ERESTARTSYS:
-                        if (!(ka->sa.sa_flags & SA_RESTART)) {
-                                regs->ARM_r0 = -EINTR;
-                                break;
-                        }
-                        /* fallthrough */
-                case -ERESTARTNOINTR:
-                        setup_syscall_restart(regs);
-                }
-        }
-
-        /*
          * translate the signal
          */
         if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap)
@@ -685,6 +659,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
  */
 static void do_signal(struct pt_regs *regs, int syscall)
 {
+        unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
         struct k_sigaction ka;
         siginfo_t info;
         int signr;
@@ -698,18 +673,61 @@ static void do_signal(struct pt_regs *regs, int syscall)
         if (!user_mode(regs))
                 return;
 
+        /*
+         * If we were from a system call, check for system call restarting...
+         */
+        if (syscall) {
+                continue_addr = regs->ARM_pc;
+                restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
+                retval = regs->ARM_r0;
+
+                /*
+                 * Prepare for system call restart.  We do this here so that a
+                 * debugger will see the already changed PSW.
+                 */
+                switch (retval) {
+                case -ERESTARTNOHAND:
+                case -ERESTARTSYS:
+                case -ERESTARTNOINTR:
+                        regs->ARM_r0 = regs->ARM_ORIG_r0;
+                        regs->ARM_pc = restart_addr;
+                        break;
+                case -ERESTART_RESTARTBLOCK:
+                        regs->ARM_r0 = -EINTR;
+                        break;
+                }
+        }
+
         if (try_to_freeze())
                 goto no_signal;
 
+        /*
+         * Get the signal to deliver.  When running under ptrace, at this
+         * point the debugger may change all our registers ...
+         */
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
         if (signr > 0) {
                 sigset_t *oldset;
 
+                /*
+                 * Depending on the signal settings we may need to revert the
+                 * decision to restart the system call.  But skip this if a
+                 * debugger has chosen to restart at a different PC.
+                 */
+                if (regs->ARM_pc == restart_addr) {
+                        if (retval == -ERESTARTNOHAND
+                            || (retval == -ERESTARTSYS
+                                && !(ka.sa.sa_flags & SA_RESTART))) {
+                                regs->ARM_r0 = -EINTR;
+                                regs->ARM_pc = continue_addr;
+                        }
+                }
+
                 if (test_thread_flag(TIF_RESTORE_SIGMASK))
                         oldset = &current->saved_sigmask;
                 else
                         oldset = &current->blocked;
-                if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) {
+                if (handle_signal(signr, &ka, &info, oldset, regs) == 0) {
                         /*
                          * A signal was successfully delivered; the saved
                          * sigmask will have been stored in the signal frame,
@@ -723,11 +741,14 @@ static void do_signal(struct pt_regs *regs, int syscall)
         }
 
  no_signal:
-        /*
-         * No signal to deliver to the process - restart the syscall.
-         */
         if (syscall) {
-                if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) {
+                /*
+                 * Handle restarting a different system call.  As above,
+                 * if a debugger has chosen to restart at a different PC,
+                 * ignore the restart.
+                 */
+                if (retval == -ERESTART_RESTARTBLOCK
+                    && regs->ARM_pc == continue_addr) {
                         if (thumb_mode(regs)) {
                                 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE;
                                 regs->ARM_pc -= 2;
@@ -750,11 +771,6 @@ static void do_signal(struct pt_regs *regs, int syscall)
 #endif
                         }
                 }
-                if (regs->ARM_r0 == -ERESTARTNOHAND ||
-                    regs->ARM_r0 == -ERESTARTSYS ||
-                    regs->ARM_r0 == -ERESTARTNOINTR) {
-                        setup_syscall_restart(regs);
-                }
 
                 /* If there's no signal to deliver, we just put the saved sigmask
                  * back.