[PATCH] uml: add TIF_RESTORE_SIGMASK support

Add support for TIF_RESTORE_SIGMASK.  I copy the i386 handling of the flag.
sys_sigsuspend is also changed to follow i386.
Also a bit of cleanup -
   turn an if into a switch
   get rid of a couple more emacs formatting comments

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 43 insertions, 49 deletions

diff --git a/arch/um/kernel/signal_kern.c b/arch/um/kernel/signal_kern.c
index 7b0e0e81c161..7a54708db50c 100644
--- a/arch/um/kernel/signal_kern.c
+++ b/arch/um/kernel/signal_kern.c
@@ -99,31 +99,46 @@ static int handle_signal(struct pt_regs *regs, unsigned long signr,
         return err;
 }
 
-static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
+static int kern_do_signal(struct pt_regs *regs)
 {
         struct k_sigaction ka_copy;
         siginfo_t info;
+        sigset_t *oldset;
         int sig, handled_sig = 0;
 
+        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                oldset = &current->saved_sigmask;
+        else
+                oldset = &current->blocked;
+
         while((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0){
                 handled_sig = 1;
                 /* Whee!  Actually deliver the signal.  */
-                if(!handle_signal(regs, sig, &ka_copy, &info, oldset))
+                if(!handle_signal(regs, sig, &ka_copy, &info, oldset)){
+                        /* 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);
                         break;
+                }
         }
 
         /* Did we come from a system call? */
         if(!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)){
                 /* Restart the system call - no handlers present */
-                if(PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOHAND ||
-                   PT_REGS_SYSCALL_RET(regs) == -ERESTARTSYS ||
-                   PT_REGS_SYSCALL_RET(regs) == -ERESTARTNOINTR){
+                switch(PT_REGS_SYSCALL_RET(regs)){
+                case -ERESTARTNOHAND:
+                case -ERESTARTSYS:
+                case -ERESTARTNOINTR:
                         PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
                         PT_REGS_RESTART_SYSCALL(regs);
-                }
-                else if(PT_REGS_SYSCALL_RET(regs) == -ERESTART_RESTARTBLOCK){
+                        break;
+                case -ERESTART_RESTARTBLOCK:
                         PT_REGS_SYSCALL_RET(regs) = __NR_restart_syscall;
                         PT_REGS_RESTART_SYSCALL(regs);
+                        break;
                 }
         }
 
@@ -137,12 +152,19 @@ static int kern_do_signal(struct pt_regs *regs, sigset_t *oldset)
         if(current->ptrace & PT_DTRACE)
                 current->thread.singlestep_syscall =
                         is_syscall(PT_REGS_IP(&current->thread.regs));
+
+        /* if there's no signal to deliver, we just put the saved sigmask
+         * back */
+        if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
+                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+        }
         return(handled_sig);
 }
 
 int do_signal(void)
 {
-        return(kern_do_signal(&current->thread.regs, &current->blocked));
+        return(kern_do_signal(&current->thread.regs));
 }
 
 /*
@@ -150,27 +172,22 @@ int do_signal(void)
  */
 long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 {
-        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);
 
-        PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if(kern_do_signal(&current->thread.regs, &saveset))
-                        return(-EINTR);
-        }
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
 }
 
 long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
 {
-        sigset_t saveset, newset;
+        sigset_t newset;
 
         /* XXX: Don't preclude handling different sized sigset_t's.  */
         if (sigsetsize != sizeof(sigset_t))
@@ -181,32 +198,18 @@ long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize)
         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);
 
-        PT_REGS_SYSCALL_RET(&current->thread.regs) = -EINTR;
-        while (1) {
-                current->state = TASK_INTERRUPTIBLE;
-                schedule();
-                if (kern_do_signal(&current->thread.regs, &saveset))
-                        return(-EINTR);
-        }
+        current->state = TASK_INTERRUPTIBLE;
+        schedule();
+        set_thread_flag(TIF_RESTORE_SIGMASK);
+        return -ERESTARTNOHAND;
 }
 
 long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
 {
         return(do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs)));
 }
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
diff --git a/include/asm-um/thread_info.h b/include/asm-um/thread_info.h
index 705c71972c32..17b6b07c4332 100644
--- a/include/asm-um/thread_info.h
+++ b/include/asm-um/thread_info.h
@@ -69,6 +69,7 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_RESTART_BLOCK       4
 #define TIF_MEMDIE              5
 #define TIF_SYSCALL_AUDIT       6
+#define TIF_RESTORE_SIGMASK     7
 
 #define _TIF_SYSCALL_TRACE      (1 << TIF_SYSCALL_TRACE)
 #define _TIF_SIGPENDING         (1 << TIF_SIGPENDING)
@@ -76,16 +77,6 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_POLLING_NRFLAG     (1 << TIF_POLLING_NRFLAG)
 #define _TIF_MEMDIE             (1 << TIF_MEMDIE)
 #define _TIF_SYSCALL_AUDIT      (1 << TIF_SYSCALL_AUDIT)
+#define _TIF_RESTORE_SIGMASK    (1 << TIF_RESTORE_SIGMASK)
 
 #endif
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */