From e2dca2fea3f1a0a7b05fd10589f469496f9c42a3 Mon Sep 17 00:00:00 2001
From: Ulrich Drepper <drepper@redhat.com>
Date: Sun, 19 Jul 2009 00:00:17 -0700
Subject: [PATCH] Extend x86-64 __lll_robust_timedlock_wait to use futex
 syscall with absolute timeout.

---
 nptl/ChangeLog                                     |  4 ++
 .../unix/sysv/linux/x86_64/lowlevelrobustlock.S    | 78 +++++++++++++++++++++-
 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
-- 
2.7.4