[MIPS] Add support for TIF_RESTORE_SIGMASK for signal32

    
Following the recent implementation of TIF_RESTORE_SIGMASK in
arch/mips/kernel/signal.c, 64-bit kernels with 32-bit user-land
compatibility oops when starting init.  signal32.c needs to be
converted to use TIF_RESTORE_SIGMASK too.
    
Signed-off-by: Martin Michlmayr <tbm@cyrius.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 41 insertions, 27 deletions

diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index 8a8b8dd9041..c0701957521 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -106,8 +106,6 @@ typedef struct compat_siginfo {
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
-extern int do_signal32(sigset_t *oldset, struct pt_regs *regs);
-
 /* 32-bit compatibility types */
 
 #define _NSIG_BPW32     32
@@ -198,7 +196,7 @@ __attribute_used__ noinline static int
 _sys32_sigsuspend(nabi_no_regargs struct pt_regs regs)
 {
         compat_sigset_t *uset;
-        sigset_t newset, saveset;
+        sigset_t newset;
 
         uset = (compat_sigset_t *) regs.regs[4];
         if (get_sigset(&newset, uset))
@@ -206,19 +204,15 @@ _sys32_sigsuspend(nabi_no_regargs struct pt_regs regs)
         sigdelsetmask(&newset, ~_BLOCKABLE);
 
         spin_lock_irq(&current->sighand->siglock);
-        saveset = current->blocked;
+        current->saved_sigmask = current->blocked;
         current->blocked = newset;
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        regs.regs[2] = EINTR;
-        regs.regs[7] = 1;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (do_signal32(&saveset, &regs))
-                        return -EINTR;
-        }
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
 }
 
 save_static_function(sys32_rt_sigsuspend);
@@ -226,7 +220,7 @@ __attribute_used__ noinline static int
 _sys32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
 {
         compat_sigset_t *uset;
-        sigset_t newset, saveset;
+        sigset_t newset;
         size_t sigsetsize;
 
         /* XXX Don't preclude handling different sized sigset_t's.  */
@@ -240,19 +234,15 @@ _sys32_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
         sigdelsetmask(&newset, ~_BLOCKABLE);
 
         spin_lock_irq(&current->sighand->siglock);
-        saveset = current->blocked;
+        current->saved_sigmask = current->blocked;
         current->blocked = newset;
         recalc_sigpending();
         spin_unlock_irq(&current->sighand->siglock);
 
-        regs.regs[2] = EINTR;
-        regs.regs[7] = 1;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (do_signal32(&saveset, &regs))
-                        return -EINTR;
-        }
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
 }
 
 asmlinkage int sys32_sigaction(int sig, const struct sigaction32 *act,
@@ -783,7 +773,7 @@ static inline int handle_signal(unsigned long sig, siginfo_t *info,
                 regs->regs[2] = EINTR;
                 break;
         case ERESTARTSYS:
-                if(!(ka->sa.sa_flags & SA_RESTART)) {
+                if (!(ka->sa.sa_flags & SA_RESTART)) {
                         regs->regs[2] = EINTR;
                         break;
                 }
@@ -810,9 +800,10 @@ static inline int handle_signal(unsigned long sig, siginfo_t *info,
         return ret;
 }
 
-int do_signal32(sigset_t *oldset, struct pt_regs *regs)
+int do_signal32(struct pt_regs *regs)
 {
         struct k_sigaction ka;
+        sigset_t *oldset;
         siginfo_t info;
         int signr;
 
@@ -827,12 +818,25 @@ int do_signal32(sigset_t *oldset, struct pt_regs *regs)
         if (try_to_freeze())
                 goto no_signal;
 
-        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)
-                return handle_signal(signr, &info, &ka, oldset, regs);
+        if (signr > 0) {
+                /* Whee! Actually deliver the signal. */
+                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
+                        /*
+                        * 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);
+                }
+        }
 
 no_signal:
         /*
@@ -853,6 +857,16 @@ no_signal:
                         regs->cp0_epc -= 4;
                 }
         }
+
+        /*
+        * 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);
+        }
+
         return 0;
 }