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authorUlrich Drepper <drepper@redhat.com>2009-07-19 00:00:17 -0700
committerUlrich Drepper <drepper@redhat.com>2009-07-19 00:00:17 -0700
commite2dca2fea3f1a0a7b05fd10589f469496f9c42a3 (patch)
tree5bfac45ae82c8ee580e5082cda7fc17950558172 /nptl
parent3d77b2687f984700f40e26e0fb06c99eeea1c033 (diff)
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Extend x86-64 __lll_robust_timedlock_wait to use futex syscall with absolute timeout.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/ChangeLog4
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S78
2 files changed, 80 insertions, 2 deletions
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index dc576a7..e9cac73 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,5 +1,9 @@
2009-07-18 Ulrich Drepper <drepper@redhat.com>
+ * sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S
+ (__lll_robust_timedlock_wait): If possible use FUTEX_WAIT_BITSET to
+ directly use absolute timeout.
+
* tst-sem5.c (do_test): Add test for premature timeout.
* Makefile: Linu tst-sem5 with librt.
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S
index fa7516e..02db0a4 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007
+/* Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2009
Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
@@ -32,6 +32,8 @@
#ifdef __ASSUME_PRIVATE_FUTEX
# define LOAD_FUTEX_WAIT(reg) \
xorl $(FUTEX_WAIT | FUTEX_PRIVATE_FLAG), reg
+# define LOAD_FUTEX_WAIT_ABS(reg) \
+ xorl $(FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME), reg
#else
# if FUTEX_WAIT == 0
# define LOAD_FUTEX_WAIT(reg) \
@@ -43,6 +45,10 @@
andl %fs:PRIVATE_FUTEX, reg ; \
orl $FUTEX_WAIT, reg
# endif
+# define LOAD_FUTEX_WAIT_ABS(reg) \
+ xorl $FUTEX_PRIVATE_FLAG, reg ; \
+ andl %fs:PRIVATE_FUTEX, reg ; \
+ orl $FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME, reg
#endif
/* For the calculation see asm/vsyscall.h. */
@@ -110,6 +116,73 @@ __lll_robust_lock_wait:
.align 16
__lll_robust_timedlock_wait:
cfi_startproc
+# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
+# ifdef PIC
+ cmpl $0, __have_futex_clock_realtime(%rip)
+# else
+ cmpl $0, __have_futex_clock_realtime
+# endif
+ je .Lreltmo
+# endif
+
+ pushq %r9
+ cfi_adjust_cfa_offset(8)
+ cfi_rel_offset(%r9, 0)
+ movq %rdx, %r10
+ movl $0xffffffff, %r9d
+ LOAD_FUTEX_WAIT_ABS (%esi)
+
+1: testl $FUTEX_OWNER_DIED, %eax
+ jnz 3f
+
+ movl %eax, %edx
+ orl $FUTEX_WAITERS, %edx
+
+ cmpl %eax, %edx
+ je 5f
+
+ LOCK
+ cmpxchgl %edx, (%rdi)
+ movq $0, %rcx /* Must use mov to avoid changing cc. */
+ jnz 6f
+
+5: movl $SYS_futex, %eax
+ syscall
+ movl %eax, %ecx
+
+ movl (%rdi), %eax
+
+6: testl %eax, %eax
+ jne 2f
+
+ movl %fs:TID, %edx
+ orl $FUTEX_WAITERS, %edx
+ LOCK
+ cmpxchgl %edx, (%rdi)
+ jnz 2f
+
+3: popq %r9
+ cfi_adjust_cfa_offset(-8)
+ cfi_restore(%r9)
+ retq
+
+ cfi_adjust_cfa_offset(8)
+ cfi_rel_offset(%r9, 0)
+ /* Check whether the time expired. */
+2: cmpl $-ETIMEDOUT, %ecx
+ je 4f
+ cmpl $-EINVAL, %ecx
+ jne 1b
+
+4: movl %ecx, %eax
+ negl %eax
+ jmp 3b
+ cfi_adjust_cfa_offset(-8)
+ cfi_restore(%r9)
+
+
+# ifndef __ASSUME_FUTEX_CLOCK_REALTIME
+.Lreltmo:
/* Check for a valid timeout value. */
cmpq $1000000000, 8(%rdx)
jae 3f
@@ -223,10 +296,11 @@ __lll_robust_timedlock_wait:
cfi_offset(%r12, -32)
cfi_offset(%r13, -40)
/* Check whether the time expired. */
-7: cmpq $-ETIMEDOUT, %rcx
+7: cmpl $-ETIMEDOUT, %ecx
jne 1b
8: movl $ETIMEDOUT, %eax
jmp 6b
+#endif
cfi_endproc
.size __lll_robust_timedlock_wait,.-__lll_robust_timedlock_wait