From 7e7814180b334dff97ef8f56c7c40c277ad4531c Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Tue, 2 Aug 2016 14:05:36 -0700 Subject: signal: consolidate {TS,TLF}_RESTORE_SIGMASK code In general, there's no need for the "restore sigmask" flag to live in ti->flags. alpha, ia64, microblaze, powerpc, sh, sparc (64-bit only), tile, and x86 use essentially identical alternative implementations, placing the flag in ti->status. Replace those optimized implementations with an equally good common implementation that stores it in a bitfield in struct task_struct and drop the custom implementations. Additional architectures can opt in by removing their TIF_RESTORE_SIGMASK defines. Link: http://lkml.kernel.org/r/8a14321d64a28e40adfddc90e18a96c086a6d6f9.1468522723.git.luto@kernel.org Signed-off-by: Andy Lutomirski Tested-by: Michael Ellerman [powerpc] Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Tony Luck Cc: Fenghua Yu Cc: Michal Simek Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Yoshinori Sato Cc: Rich Felker Cc: "David S. Miller" Cc: Chris Metcalf Cc: Peter Zijlstra Cc: Borislav Petkov Cc: Brian Gerst Cc: Dmitry Safonov Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 63 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/thread_info.h | 41 ----------------------------- 2 files changed, 63 insertions(+), 41 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index 553af2923824..62c68e513e39 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1547,6 +1547,9 @@ struct task_struct { /* unserialized, strictly 'current' */ unsigned in_execve:1; /* bit to tell LSMs we're in execve */ unsigned in_iowait:1; +#if !defined(TIF_RESTORE_SIGMASK) + unsigned restore_sigmask:1; +#endif #ifdef CONFIG_MEMCG unsigned memcg_may_oom:1; #ifndef CONFIG_SLOB @@ -2680,6 +2683,66 @@ extern void sigqueue_free(struct sigqueue *); extern int send_sigqueue(struct sigqueue *, struct task_struct *, int group); extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *); +#ifdef TIF_RESTORE_SIGMASK +/* + * Legacy restore_sigmask accessors. These are inefficient on + * SMP architectures because they require atomic operations. + */ + +/** + * set_restore_sigmask() - make sure saved_sigmask processing gets done + * + * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code + * will run before returning to user mode, to process the flag. For + * all callers, TIF_SIGPENDING is already set or it's no harm to set + * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the + * arch code will notice on return to user mode, in case those bits + * are scarce. We set TIF_SIGPENDING here to ensure that the arch + * signal code always gets run when TIF_RESTORE_SIGMASK is set. + */ +static inline void set_restore_sigmask(void) +{ + set_thread_flag(TIF_RESTORE_SIGMASK); + WARN_ON(!test_thread_flag(TIF_SIGPENDING)); +} +static inline void clear_restore_sigmask(void) +{ + clear_thread_flag(TIF_RESTORE_SIGMASK); +} +static inline bool test_restore_sigmask(void) +{ + return test_thread_flag(TIF_RESTORE_SIGMASK); +} +static inline bool test_and_clear_restore_sigmask(void) +{ + return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); +} + +#else /* TIF_RESTORE_SIGMASK */ + +/* Higher-quality implementation, used if TIF_RESTORE_SIGMASK doesn't exist. */ +static inline void set_restore_sigmask(void) +{ + current->restore_sigmask = true; + WARN_ON(!test_thread_flag(TIF_SIGPENDING)); +} +static inline void clear_restore_sigmask(void) +{ + current->restore_sigmask = false; +} +static inline bool test_restore_sigmask(void) +{ + return current->restore_sigmask; +} +static inline bool test_and_clear_restore_sigmask(void) +{ + if (!current->restore_sigmask) + return false; + current->restore_sigmask = false; + return true; +} +#endif + static inline void restore_saved_sigmask(void) { if (test_and_clear_restore_sigmask()) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index b4c2a485b28a..352b1542f5cc 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -105,47 +105,6 @@ static inline int test_ti_thread_flag(struct thread_info *ti, int flag) #define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED) -#if defined TIF_RESTORE_SIGMASK && !defined HAVE_SET_RESTORE_SIGMASK -/* - * An arch can define its own version of set_restore_sigmask() to get the - * job done however works, with or without TIF_RESTORE_SIGMASK. - */ -#define HAVE_SET_RESTORE_SIGMASK 1 - -/** - * set_restore_sigmask() - make sure saved_sigmask processing gets done - * - * This sets TIF_RESTORE_SIGMASK and ensures that the arch signal code - * will run before returning to user mode, to process the flag. For - * all callers, TIF_SIGPENDING is already set or it's no harm to set - * it. TIF_RESTORE_SIGMASK need not be in the set of bits that the - * arch code will notice on return to user mode, in case those bits - * are scarce. We set TIF_SIGPENDING here to ensure that the arch - * signal code always gets run when TIF_RESTORE_SIGMASK is set. - */ -static inline void set_restore_sigmask(void) -{ - set_thread_flag(TIF_RESTORE_SIGMASK); - WARN_ON(!test_thread_flag(TIF_SIGPENDING)); -} -static inline void clear_restore_sigmask(void) -{ - clear_thread_flag(TIF_RESTORE_SIGMASK); -} -static inline bool test_restore_sigmask(void) -{ - return test_thread_flag(TIF_RESTORE_SIGMASK); -} -static inline bool test_and_clear_restore_sigmask(void) -{ - return test_and_clear_thread_flag(TIF_RESTORE_SIGMASK); -} -#endif /* TIF_RESTORE_SIGMASK && !HAVE_SET_RESTORE_SIGMASK */ - -#ifndef HAVE_SET_RESTORE_SIGMASK -#error "no set_restore_sigmask() provided and default one won't work" -#endif - #endif /* __KERNEL__ */ #endif /* _LINUX_THREAD_INFO_H */ -- cgit v1.2.3