From a8509ca540427502bd955f35296ff7b727c7a8a1 Mon Sep 17 00:00:00 2001
From: Ulrich Drepper <drepper@gmail.com>
Date: Fri, 27 May 2011 16:09:52 -0400
Subject: [PATCH] Use getcpu definition from vDSO on x86-64

---
 ChangeLog                                     |  7 +++++++
 NEWS                                          |  2 +-
 sysdeps/unix/sysv/linux/x86_64/init-first.c   | 12 +++++++++++-
 sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S |  7 ++++++-
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 34df6baeae..5e5261728f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2011-05-27  Ulrich Drepper  <drepper@gmail.com>
 
+	[BZ #12813]
+	* sysdeps/unix/sysv/linux/x86_64/init-first.c (__vdso_getcpu):
+	Retrieve getcpu symbol from vDSO.  Substitute with vsyscall if not
+	available.
+	* sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S [SHARED]: Use
+	__vdso_getcpu.
+
 	[BZ #12814]
 	* iconvdata/Makefile (tests): Add bug-iconv9.
 	* iconvdata/bug-iconv9.c: New file.
diff --git a/NEWS b/NEWS
index 2cdb0cc425..d899685be1 100644
--- a/NEWS
+++ b/NEWS
@@ -17,7 +17,7 @@ Version 2.14
   12545, 12551, 12582, 12583, 12587, 12597, 12601, 12611, 12625, 12626,
   12631, 12650, 12653, 12655, 12660, 12671, 12681, 12685, 12711, 12713,
   12714, 12717, 12723, 12724, 12734, 12738, 12746, 12766, 12775, 12777,
-  12782, 12788, 12792, 12795, 12814
+  12782, 12788, 12792, 12795, 12813, 12814
 
 * The RPC implementation in libc is obsoleted.  Old programs keep working
   but new programs cannot be linked with the routines in libc anymore.
diff --git a/sysdeps/unix/sysv/linux/x86_64/init-first.c b/sysdeps/unix/sysv/linux/x86_64/init-first.c
index ead7dbcc38..23934fc857 100644
--- a/sysdeps/unix/sysv/linux/x86_64/init-first.c
+++ b/sysdeps/unix/sysv/linux/x86_64/init-first.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 2007 Free Software Foundation, Inc.
+/* Copyright (C) 2007, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -26,6 +26,8 @@ long int (*__vdso_clock_gettime) (clockid_t, struct timespec *)
   __attribute__ ((nocommon));
 strong_alias (__vdso_clock_gettime, __GI___vdso_clock_gettime attribute_hidden)
 
+long int (*__vdso_getcpu) (unsigned *, unsigned *, void *);
+
 
 static inline void
 _libc_vdso_platform_setup (void)
@@ -43,6 +45,14 @@ _libc_vdso_platform_setup (void)
   p = _dl_vdso_vsym ("clock_gettime", &linux26);
   PTR_MANGLE (p);
   __GI___vdso_clock_gettime = p;
+
+  p = _dl_vdso_vsym ("getcpu", &linux26);
+  /* If the vDSO is not available we fall back on the old vsyscall.  */
+#define VSYSCALL_ADDR_vgetcpu	0xffffffffff600800
+  if (p == NULL)
+    p = (void *) VSYSCALL_ADDR_vgetcpu;
+  PTR_MANGLE (p);
+  __vdso_getcpu = p;
 }
 
 # define VDSO_SETUP _libc_vdso_platform_setup
diff --git a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
index a950990627..8ec7d3fcd2 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
+++ b/sysdeps/unix/sysv/linux/x86_64/sched_getcpu.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2007 Free Software Foundation, Inc.
+/* Copyright (C) 2007, 2011 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -35,7 +35,12 @@ ENTRY (sched_getcpu)
 	movl	$VGETCPU_CACHE_OFFSET, %edx
 	addq	%fs:0, %rdx
 
+#ifdef SHARED
+	movq	__vdso_getcpu(%rip), %rax
+	PTR_DEMANGLE (%rax)
+#else
 	movq	$VSYSCALL_ADDR_vgetcpu, %rax
+#endif
 	callq	*%rax
 
 	cmpq	$-4095, %rax