signals: x86 TS_RESTORE_SIGMASK

Replace TIF_RESTORE_SIGMASK with TS_RESTORE_SIGMASK and define our own
set_restore_sigmask() function.  This saves the costly SMP-safe set_bit
operation, which we do not need for the sigmask flag since TIF_SIGPENDING
always has to be set too.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index bbed3a2..cb3856a 100644 (file)
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -128,7 +128,7 @@ asmlinkage long sys32_sigsuspend(int history0, int history1, old_sigset_t mask)
 
        current->state = TASK_INTERRUPTIBLE;
        schedule();
-       set_thread_flag(TIF_RESTORE_SIGMASK);
+       set_restore_sigmask();
        return -ERESTARTNOHAND;
 }
 

diff --git a/arch/x86/kernel/signal_32.c b/arch/x86/kernel/signal_32.c
index 8e05e7f..d923736 100644 (file)
--- a/arch/x86/kernel/signal_32.c
+++ b/arch/x86/kernel/signal_32.c
@@ -57,7 +57,7 @@ sys_sigsuspend(int history0, int history1, old_sigset_t mask)
 
        current->state = TASK_INTERRUPTIBLE;
        schedule();
-       set_thread_flag(TIF_RESTORE_SIGMASK);
+       set_restore_sigmask();
 
        return -ERESTARTNOHAND;
 }
@@ -593,7 +593,7 @@ static void do_signal(struct pt_regs *regs)
        if (!user_mode(regs))
                return;
 
-       if (test_thread_flag(TIF_RESTORE_SIGMASK))
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK)
                oldset = &current->saved_sigmask;
        else
                oldset = &current->blocked;
@@ -612,13 +612,12 @@ static void do_signal(struct pt_regs *regs)
                /* Whee! Actually deliver the signal.  */
                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
                        /*
-                        * a signal was successfully delivered; the saved
+                        * 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
+                        * clear the TS_RESTORE_SIGMASK flag.
                         */
-                       if (test_thread_flag(TIF_RESTORE_SIGMASK))
-                               clear_thread_flag(TIF_RESTORE_SIGMASK);
+                       current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                }
                return;
        }
@@ -645,8 +644,8 @@ static void do_signal(struct pt_regs *regs)
         * 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);
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
+               current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
        }
 }
@@ -665,7 +664,7 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
        }
 
        /* deal with pending signal delivery */
-       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+       if (thread_info_flags & _TIF_SIGPENDING)
                do_signal(regs);
 
        if (thread_info_flags & _TIF_HRTICK_RESCHED)

diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c
index ccb2a45..e53b267 100644 (file)
--- a/arch/x86/kernel/signal_64.c
+++ b/arch/x86/kernel/signal_64.c
@@ -427,7 +427,7 @@ static void do_signal(struct pt_regs *regs)
        if (!user_mode(regs))
                return;
 
-       if (test_thread_flag(TIF_RESTORE_SIGMASK))
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK)
                oldset = &current->saved_sigmask;
        else
                oldset = &current->blocked;
@@ -444,11 +444,13 @@ static void do_signal(struct pt_regs *regs)
 
                /* Whee!  Actually deliver the signal.  */
                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
-                       /* a signal was successfully delivered; the saved
+                       /*
+                        * 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 */
-                       clear_thread_flag(TIF_RESTORE_SIGMASK);
+                        * clear the TS_RESTORE_SIGMASK flag.
+                        */
+                       current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                }
                return;
        }
@@ -476,8 +478,8 @@ static void do_signal(struct pt_regs *regs)
         * 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);
+       if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
+               current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
        }
 }
@@ -498,7 +500,7 @@ void do_notify_resume(struct pt_regs *regs, void *unused,
 #endif /* CONFIG_X86_MCE */
 
        /* deal with pending signal delivery */
-       if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK))
+       if (thread_info_flags & _TIF_SIGPENDING)
                do_signal(regs);
 
        if (thread_info_flags & _TIF_HRTICK_RESCHED)

diff --git a/include/asm-x86/thread_info_32.h b/include/asm-x86/thread_info_32.h
index 5318599..b633882 100644 (file)
--- a/include/asm-x86/thread_info_32.h
+++ b/include/asm-x86/thread_info_32.h
@@ -131,7 +131,6 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SYSCALL_EMU                5       /* syscall emulation active */
 #define TIF_SYSCALL_AUDIT      6       /* syscall auditing active */
 #define TIF_SECCOMP            7       /* secure computing */
-#define TIF_RESTORE_SIGMASK    8       /* restore signal mask in do_signal() */
 #define TIF_HRTICK_RESCHED     9       /* reprogram hrtick timer */
 #define TIF_MEMDIE             16
 #define TIF_DEBUG              17      /* uses debug registers */
@@ -151,7 +150,6 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SYSCALL_EMU       (1 << TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_AUDIT     (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP           (1 << TIF_SECCOMP)
-#define _TIF_RESTORE_SIGMASK   (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_HRTICK_RESCHED    (1 << TIF_HRTICK_RESCHED)
 #define _TIF_DEBUG             (1 << TIF_DEBUG)
 #define _TIF_IO_BITMAP         (1 << TIF_IO_BITMAP)
@@ -188,9 +186,20 @@ static inline struct thread_info *current_thread_info(void)
                                           this quantum (SMP) */
 #define TS_POLLING             0x0002  /* True if in idle loop
                                           and not sleeping */
+#define TS_RESTORE_SIGMASK     0x0004  /* restore signal mask in do_signal() */
 
 #define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
 
+#ifndef __ASSEMBLY__
+#define HAVE_SET_RESTORE_SIGMASK       1
+static inline void set_restore_sigmask(void)
+{
+       struct thread_info *ti = current_thread_info();
+       ti->status |= TS_RESTORE_SIGMASK;
+       set_bit(TIF_SIGPENDING, &ti->flags);
+}
+#endif /* !__ASSEMBLY__ */
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_THREAD_INFO_H */

diff --git a/include/asm-x86/thread_info_64.h b/include/asm-x86/thread_info_64.h
index ed664e8..cb69f70 100644 (file)
--- a/include/asm-x86/thread_info_64.h
+++ b/include/asm-x86/thread_info_64.h
@@ -109,7 +109,6 @@ static inline struct thread_info *stack_thread_info(void)
 #define TIF_IRET               5       /* force IRET */
 #define TIF_SYSCALL_AUDIT      7       /* syscall auditing active */
 #define TIF_SECCOMP            8       /* secure computing */
-#define TIF_RESTORE_SIGMASK    9       /* restore signal mask in do_signal */
 #define TIF_MCE_NOTIFY         10      /* notify userspace of an MCE */
 #define TIF_HRTICK_RESCHED     11      /* reprogram hrtick timer */
 /* 16 free */
@@ -133,7 +132,6 @@ static inline struct thread_info *stack_thread_info(void)
 #define _TIF_IRET              (1 << TIF_IRET)
 #define _TIF_SYSCALL_AUDIT     (1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SECCOMP           (1 << TIF_SECCOMP)
-#define _TIF_RESTORE_SIGMASK   (1 << TIF_RESTORE_SIGMASK)
 #define _TIF_MCE_NOTIFY                (1 << TIF_MCE_NOTIFY)
 #define _TIF_HRTICK_RESCHED    (1 << TIF_HRTICK_RESCHED)
 #define _TIF_IA32              (1 << TIF_IA32)
@@ -178,9 +176,20 @@ static inline struct thread_info *stack_thread_info(void)
 #define TS_COMPAT              0x0002  /* 32bit syscall active */
 #define TS_POLLING             0x0004  /* true if in idle loop
                                           and not sleeping */
+#define TS_RESTORE_SIGMASK     0x0008  /* restore signal mask in do_signal() */
 
 #define tsk_is_polling(t) (task_thread_info(t)->status & TS_POLLING)
 
+#ifndef __ASSEMBLY__
+#define HAVE_SET_RESTORE_SIGMASK       1
+static inline void set_restore_sigmask(void)
+{
+       struct thread_info *ti = current_thread_info();
+       ti->status |= TS_RESTORE_SIGMASK;
+       set_bit(TIF_SIGPENDING, &ti->flags);
+}
+#endif /* !__ASSEMBLY__ */
+
 #endif /* __KERNEL__ */
 
 #endif /* _ASM_THREAD_INFO_H */