CRIS v32: Update signal handling in kernel/signal.c

- do_signal now returns void, and does not have the previous signal set
  as a parameter.
- Remove sys_rt_sigsuspend, we can use the common one instead.
- Change sys_sigsuspend to be more like x86, don't call do_signal here.
- handle_signal, setup_frame and setup_rt_frame now return -EFAULT
  if we've delivered a segfault, which is used by callers to perform
  necessary cleanup.
- Break long lines, correct whitespace and formatting errors.

1 files changed, 56 insertions, 88 deletions

diff --git a/arch/cris/arch-v32/kernel/signal.c b/arch/cris/arch-v32/kernel/signal.c
index 024cc6901974..58c1866804e3 100644
--- a/arch/cris/arch-v32/kernel/signal.c
+++ b/arch/cris/arch-v32/kernel/signal.c
@@ -50,7 +50,7 @@ struct rt_signal_frame {
         unsigned char retcode[8];       /* Trampoline code. */
 };
 
-int do_signal(int restart, sigset_t *oldset, struct pt_regs *regs);
+void do_signal(int restart, struct pt_regs *regs);
 void keep_debug_flags(unsigned long oldccs, unsigned long oldspc,
                       struct pt_regs *regs);
 /*
@@ -61,74 +61,16 @@ int
 sys_sigsuspend(old_sigset_t mask, long r11, long r12, long r13, long mof,
                long srp, struct pt_regs *regs)
 {
-        sigset_t saveset;
-
         mask &= _BLOCKABLE;
-
         spin_lock_irq(&current->sighand->siglock);
-
-        saveset = current->blocked;
-
+        current->saved_sigmask = current->blocked;
         siginitset(&current->blocked, mask);
-
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
-
-        regs->r10 = -EINTR;
-
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-
-                if (do_signal(0, &saveset, regs)) {
-                        /*
-                         * This point is reached twice: once to call
-                         * the signal handler, then again to return
-                         * from the sigsuspend system call. When
-                         * calling the signal handler, R10 hold the
-                         * signal number as set by do_signal(). The
-                         * sigsuspend  call will always return with
-                         * the restored value above; -EINTR.
-                         */
-                        return regs->r10;
-                }
-        }
-}
-
-/* Define some dummy arguments to be able to reach the regs argument. */
-int
-sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, long r12, long r13,
-                  long mof, long srp, struct pt_regs *regs)
-{
-        sigset_t saveset;
-        sigset_t newset;
-
-        if (sigsetsize != sizeof(sigset_t))
-                return -EINVAL;
-
-        if (copy_from_user(&newset, unewset, sizeof(newset)))
-                return -EFAULT;
-
-        sigdelsetmask(&newset, ~_BLOCKABLE);
-        spin_lock_irq(&current->sighand->siglock);
-
-        saveset = current->blocked;
-        current->blocked = newset;
-
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
-
-        regs->r10 = -EINTR;
-
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-
-                if (do_signal(0, &saveset, regs)) {
-                        /* See comment in function above. */
-                        return regs->r10;
-                }
-        }
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
 }
 
 int
@@ -290,7 +232,7 @@ sys_rt_sigreturn(long r10, long r11, long r12, long r13, long mof, long srp,
                 goto badframe;
 
         if (do_sigaltstack(&frame->uc.uc_stack, NULL, rdusp()) == -EFAULT)
-                goto badframe;
+                goto badframe;
 
         keep_debug_flags(oldccs, oldspc, regs);
 
@@ -347,11 +289,11 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 /* Grab and setup a signal frame.
  *
  * Basically a lot of state-info is stacked, and arranged for the
- * user-mode program to return to the kernel using either a trampoline
+ * user-mode program to return to the kernel using either a trampiline
  * which performs the syscall sigreturn(), or a provided user-mode
  * trampoline.
   */
-static void
+static int
 setup_frame(int sig, struct k_sigaction *ka,  sigset_t *set,
             struct pt_regs * regs)
 {
@@ -417,16 +359,17 @@ setup_frame(int sig, struct k_sigaction *ka,  sigset_t *set,
         /* Actually move the USP to reflect the stacked frame. */
         wrusp((unsigned long)frame);
 
-        return;
+        return 0;
 
 give_sigsegv:
         if (sig == SIGSEGV)
                 ka->sa.sa_handler = SIG_DFL;
 
         force_sig(SIGSEGV, current);
+        return -EFAULT;
 }
 
-static void
+static int
 setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
                sigset_t *set, struct pt_regs * regs)
 {
@@ -503,21 +446,24 @@ setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
         /* Actually move the usp to reflect the stacked frame. */
         wrusp((unsigned long)frame);
 
-        return;
+        return 0;
 
 give_sigsegv:
         if (sig == SIGSEGV)
                 ka->sa.sa_handler = SIG_DFL;
 
         force_sig(SIGSEGV, current);
+        return -EFAULT;
 }
 
 /* Invoke a singal handler to, well, handle the signal. */
-static inline void
+static inline int
 handle_signal(int canrestart, unsigned long sig,
               siginfo_t *info, struct k_sigaction *ka,
               sigset_t *oldset, struct pt_regs * regs)
 {
+        int ret;
+
         /* Check if this got called from a system call. */
         if (canrestart) {
                 /* If so, check system call restarting. */
@@ -561,19 +507,24 @@ handle_signal(int canrestart, unsigned long sig,
 
         /* Set up the stack frame. */
         if (ka->sa.sa_flags & SA_SIGINFO)
-                setup_rt_frame(sig, ka, info, oldset, regs);
+                ret = setup_rt_frame(sig, ka, info, oldset, regs);
         else
-                setup_frame(sig, ka, oldset, regs);
+                ret = setup_frame(sig, ka, oldset, regs);
 
         if (ka->sa.sa_flags & SA_ONESHOT)
                 ka->sa.sa_handler = SIG_DFL;
 
-        spin_lock_irq(&current->sighand->siglock);
-        sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
-        if (!(ka->sa.sa_flags & SA_NODEFER))
-                sigaddset(&current->blocked,sig);
-        recalc_sigpending();
-        spin_unlock_irq(&current->sighand->siglock);
+        if (ret == 0) {
+                spin_lock_irq(&current->sighand->siglock);
+                sigorsets(&current->blocked, &current->blocked,
+                        &ka->sa.sa_mask);
+                if (!(ka->sa.sa_flags & SA_NODEFER))
+                        sigaddset(&current->blocked, sig);
+                recalc_sigpending();
+                spin_unlock_irq(&current->sighand->siglock);
+        }
+
+        return ret;
 }
 
 /*
@@ -587,12 +538,13 @@ handle_signal(int canrestart, unsigned long sig,
  * we can use user_mode(regs) to see if we came directly from kernel or user
  * mode below.
  */
-int
-do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
+void
+do_signal(int canrestart, struct pt_regs *regs)
 {
         int signr;
         siginfo_t info;
         struct k_sigaction ka;
+        sigset_t *oldset;
 
         /*
          * The common case should go fast, which is why this point is
@@ -600,17 +552,28 @@ do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
          * without doing anything.
          */
         if (!user_mode(regs))
-                return 1;
+                return;
 
-        if (!oldset)
+        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                oldset = &current->saved_sigmask;
+        else
                 oldset = &current->blocked;
 
         signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 
         if (signr > 0) {
-                /* Deliver the signal. */
-                handle_signal(canrestart, signr, &info, &ka, oldset, regs);
-                return 1;
+                /* Whee!  Actually deliver the signal.  */
+                if (handle_signal(canrestart, signr, &info, &ka,
+                                oldset, regs)) {
+                        /* a signal was successfully delivered; the saved
+                         * sigmask will have been stored in the signal frame,
+                         * and will be restored by sigreturn, so we can simply
+                         * clear the TIF_RESTORE_SIGMASK flag */
+                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                }
+
+                return;
         }
 
         /* Got here from a system call? */
@@ -628,7 +591,12 @@ do_signal(int canrestart, sigset_t *oldset, struct pt_regs *regs)
                 }
         }
 
-        return 0;
+        /* if there's no signal to deliver, we just put the saved sigmask
+         * back */
+        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+        }
 }
 
 asmlinkage void
@@ -641,7 +609,7 @@ ugdb_trap_user(struct thread_info *ti, int sig)
                 user_regs(ti)->spc = 0;
         }
         /* FIXME: Filter out false h/w breakpoint hits (i.e. EDA
-           not within any configured h/w breakpoint range). Synchronize with
+           not withing any configured h/w breakpoint range). Synchronize with
            what already exists for kernel debugging.  */
         if (((user_regs(ti)->exs & 0xff00) >> 8) == BREAK_8_INTR_VECT) {
                 /* Break 8: subtract 2 from ERP unless in a delay slot. */