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path: root/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S
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Diffstat (limited to 'nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S')
-rw-r--r--nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S27
1 files changed, 25 insertions, 2 deletions
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S
index de9e109f45..3dbb9e81e3 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_signal.S
@@ -31,7 +31,9 @@
#define SYS_futex 202
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
-#define FUTEX_REQUEUE 3
+#define FUTEX_WAKE_OP 5
+
+#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
#define EINVAL 22
@@ -66,9 +68,30 @@ __pthread_cond_signal:
addl $1, (%rdi)
/* Wake up one thread. */
- movl $FUTEX_WAKE, %esi
+ movl $FUTEX_WAKE_OP, %esi
movl $SYS_futex, %eax
movl $1, %edx
+ movl $1, %r10d
+#if cond_lock != 0
+ addq $cond_lock, %r8
+#endif
+ movl $FUTEX_OP_CLEAR_WAKE_IF_GT_ONE, %r9d
+ syscall
+#if cond_lock != 0
+ subq $cond_lock, %r8
+#endif
+ /* For any kind of error, we try again with WAKE.
+ The general test also covers running on old kernels. */
+ cmpq $-4095, %rax
+ jae 7f
+
+ xorl %eax, %eax
+ retq
+
+7: movl $FUTEX_WAKE, %esi
+ movl $SYS_futex, %eax
+ /* %rdx should be 1 already from $FUTEX_WAKE_OP syscall.
+ movl $1, %edx */
syscall
/* Unlock. */