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authorAndy Lutomirski <luto@kernel.org>2016-08-02 14:05:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-08-02 19:35:23 -0400
commit7e7814180b334dff97ef8f56c7c40c277ad4531c (patch)
tree8f2f0ce6b3aca6dcce64a46047c42df63f43a7e9 /include/linux/sched.h
parent0a11b9aae49adf1f952427ef1a1d9e793dd6ffb6 (diff)
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 <luto@kernel.org> Tested-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Rich Felker <dalias@libc.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h63
1 files changed, 63 insertions, 0 deletions
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())