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Message-Id: <20080428073037.B649B26F8F0@magilla.localdomain>
Date: Mon, 28 Apr 2008 00:30:37 -0700 (PDT)
From: Roland McGrath <roland@...hat.com>
To: Paul Mackerras <paulus@...ba.org>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org,
akpm@...ux-foundation.org
Subject: Re: [PATCH] powerpc TLF_RESTORE_SIGMASK
> Thanks. That can't go in until some generic changes have gone in
> first, right? So are you going to push the lot in one go via Andrew,
> or should I wait until the generic part is upstream and then push the
> powerpc bit?
>From what I can see, the related patches are in -mm now, but the powerpc
patch is not. Linus already said he approved of the patches, so I hope
they can be merged in real soon. That will simplify the juggling for arch
patches. That said, there is really no hurry for this change for powerpc;
it's a small optimization.
> Oh, and could you please also fix the occurrence of
> TIF_RESTORE_SIGMASK in arch/ppc/kernel/entry.S when this stuff goes
> in?
Oh, I didn't realize that file was in use (or existed).
Third time's the charm (or is this the fifth time?).
Thanks,
Roland
---
[PATCH] powerpc TLF_RESTORE_SIGMASK
Replace TIF_RESTORE_SIGMASK with TLF_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@...hat.com>
---
arch/powerpc/kernel/entry_32.S | 4 ++--
arch/powerpc/kernel/signal.c | 12 ++++++------
arch/powerpc/kernel/signal_32.c | 2 +-
arch/ppc/kernel/entry.S | 4 ++--
include/asm-powerpc/thread_info.h | 17 +++++++++++++----
5 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 84c8686..7e2ecf0 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -667,7 +667,7 @@ user_exc_return: /* r10 contains MSR_KERNEL here */
/* Check current_thread_info()->flags */
rlwinm r9,r1,0,0,(31-THREAD_SHIFT)
lwz r9,TI_FLAGS(r9)
- andi. r0,r9,(_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK|_TIF_NEED_RESCHED)
+ andi. r0,r9,_TIF_USER_WORK_MASK
bne do_work
restore_user:
@@ -924,7 +924,7 @@ recheck:
lwz r9,TI_FLAGS(r9)
andi. r0,r9,_TIF_NEED_RESCHED
bne- do_resched
- andi. r0,r9,_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK
+ andi. r0,r9,_TIF_USER_WORK_MASK
beq restore_user
do_user_signal: /* r10 contains MSR_KERNEL here */
ori r10,r10,MSR_EE
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index a65a44f..ad55488 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -120,7 +120,7 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
int ret;
int is32 = is_32bit_task();
- if (test_thread_flag(TIF_RESTORE_SIGMASK))
+ if (current_thread_info()->local_flags & _TLF_RESTORE_SIGMASK)
oldset = ¤t->saved_sigmask;
else if (!oldset)
oldset = ¤t->blocked;
@@ -131,9 +131,10 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
check_syscall_restart(regs, &ka, signr > 0);
if (signr <= 0) {
+ struct thread_info *ti = current_thread_info();
/* No signal to deliver -- put the saved sigmask back */
- if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
- clear_thread_flag(TIF_RESTORE_SIGMASK);
+ if (ti->local_flags & _TLF_RESTORE_SIGMASK) {
+ ti->local_flags &= ~_TLF_RESTORE_SIGMASK;
sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL);
}
return 0; /* no signals delivered */
@@ -169,10 +170,9 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs)
/*
* A signal was successfully delivered; the saved sigmask is in
- * its frame, and we can clear the TIF_RESTORE_SIGMASK flag.
+ * its frame, and we can clear the TLF_RESTORE_SIGMASK flag.
*/
- if (test_thread_flag(TIF_RESTORE_SIGMASK))
- clear_thread_flag(TIF_RESTORE_SIGMASK);
+ current_thread_info()->local_flags &= ~_TLF_RESTORE_SIGMASK;
}
return ret;
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index ad69434..4ae16d1 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -243,7 +243,7 @@ long sys_sigsuspend(old_sigset_t mask)
current->state = TASK_INTERRUPTIBLE;
schedule();
- set_thread_flag(TIF_RESTORE_SIGMASK);
+ set_restore_sigmask();
return -ERESTARTNOHAND;
}
diff --git a/arch/ppc/kernel/entry.S b/arch/ppc/kernel/entry.S
index 5f3a5d0..fcd830a 100644
--- a/arch/ppc/kernel/entry.S
+++ b/arch/ppc/kernel/entry.S
@@ -647,7 +647,7 @@ user_exc_return: /* r10 contains MSR_KERNEL here */
/* Check current_thread_info()->flags */
rlwinm r9,r1,0,0,18
lwz r9,TI_FLAGS(r9)
- andi. r0,r9,(_TIF_SIGPENDING|_TIF_RESTORE_SIGMASK|_TIF_NEED_RESCHED)
+ andi. r0,r9,_TIF_USER_WORK_MASK
bne do_work
restore_user:
@@ -898,7 +898,7 @@ recheck:
lwz r9,TI_FLAGS(r9)
andi. r0,r9,_TIF_NEED_RESCHED
bne- do_resched
- andi. r0,r9,_TIF_SIGPENDING
+ andi. r0,r9,_TIF_USER_WORK_MASK
beq restore_user
do_user_signal: /* r10 contains MSR_KERNEL here */
ori r10,r10,MSR_EE
diff --git a/include/asm-powerpc/thread_info.h b/include/asm-powerpc/thread_info.h
index d030f5c..e079e81 100644
--- a/include/asm-powerpc/thread_info.h
+++ b/include/asm-powerpc/thread_info.h
@@ -116,7 +116,6 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SECCOMP 10 /* secure computing */
#define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */
#define TIF_NOERROR 12 /* Force successful syscall return */
-#define TIF_RESTORE_SIGMASK 13 /* Restore signal mask in do_signal */
#define TIF_FREEZE 14 /* Freezing for suspend */
#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */
#define TIF_ABI_PENDING 16 /* 32/64 bit switch needed */
@@ -134,21 +133,31 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_RESTOREALL (1<<TIF_RESTOREALL)
#define _TIF_NOERROR (1<<TIF_NOERROR)
-#define _TIF_RESTORE_SIGMASK (1<<TIF_RESTORE_SIGMASK)
#define _TIF_FREEZE (1<<TIF_FREEZE)
#define _TIF_RUNLATCH (1<<TIF_RUNLATCH)
#define _TIF_ABI_PENDING (1<<TIF_ABI_PENDING)
#define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP)
-#define _TIF_USER_WORK_MASK ( _TIF_SIGPENDING | \
- _TIF_NEED_RESCHED | _TIF_RESTORE_SIGMASK)
+#define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED)
#define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR)
/* Bits in local_flags */
/* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
#define TLF_NAPPING 0 /* idle thread enabled NAP mode */
+#define TLF_RESTORE_SIGMASK 1 /* Restore signal mask in do_signal */
#define _TLF_NAPPING (1 << TLF_NAPPING)
+#define _TLF_RESTORE_SIGMASK (1 << TLF_RESTORE_SIGMASK)
+
+#ifndef __ASSEMBLY__
+#define HAVE_SET_RESTORE_SIGMASK 1
+static inline void set_restore_sigmask(void)
+{
+ struct thread_info *ti = current_thread_info();
+ ti->local_flags |= _TLF_RESTORE_SIGMASK;
+ set_bit(TIF_SIGPENDING, &ti->flags);
+}
+#endif /* !__ASSEMBLY__ */
#endif /* __KERNEL__ */
--
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