Add support for time syscall in vDSO

diff --git a/ChangeLog b/ChangeLog
index 1f474df77fc2b7658df93569ddaed40d9eca0d27..188fc9065d8084337a66730283a98df99804f707 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2011-05-28  Ulrich Drepper  <drepper@gmail.com>
 
+       [BZ #12813]
+       * sysdeps/unix/sysv/linux/x86_64/init-first.c (__vdso_time): Retrieve
+       time symbol from vDSO.  Substitute with vsyscall if not available.
+       * sysdeps/unix/sysv/linux/x86_64/time.S [SHARED]: Use
+       __vdso_time.
+
        * sysdeps/unix/sysv/linux/internal_sendmmsg.S: New file.
        * sysdeps/unix/sysv/linux/sendmmsg.c: New file.
        * sysdeps/unix/sysv/linux/Makefile [subdir=socket] (sysdep_routines):

diff --git a/sysdeps/unix/sysv/linux/x86_64/init-first.c b/sysdeps/unix/sysv/linux/x86_64/init-first.c
index 23934fc857fef6bc7db9d6d62575be4c001d6daf..e676f623e1a7462f8273de74f8eef7b6a267ab02 100644 (file)
--- a/sysdeps/unix/sysv/linux/x86_64/init-first.c
+++ b/sysdeps/unix/sysv/linux/x86_64/init-first.c
@@ -28,6 +28,8 @@ strong_alias (__vdso_clock_gettime, __GI___vdso_clock_gettime attribute_hidden)
 
 long int (*__vdso_getcpu) (unsigned *, unsigned *, void *);
 
+long int (*__vdso_time) (time_t *) attribute_hidden;
+
 
 static inline void
 _libc_vdso_platform_setup (void)
@@ -53,6 +55,14 @@ _libc_vdso_platform_setup (void)
     p = (void *) VSYSCALL_ADDR_vgetcpu;
   PTR_MANGLE (p);
   __vdso_getcpu = p;
+
+  p = _dl_vdso_vsym ("time", &linux26);
+  /* If the vDSO is not available we fall back on the old vsyscall.  */
+#define VSYSCALL_ADDR_vtime    0xffffffffff600400
+  if (p == NULL)
+    p = (void *) VSYSCALL_ADDR_vtime;
+  PTR_MANGLE (p);
+  __vdso_time = p;
 }
 
 # define VDSO_SETUP _libc_vdso_platform_setup

diff --git a/sysdeps/unix/sysv/linux/x86_64/time.S b/sysdeps/unix/sysv/linux/x86_64/time.S
index e3f326876492e3e3552f20149c9d9538c342289d..66d7498cef18cf0350c928783c99abc6edbe487c 100644 (file)
--- a/sysdeps/unix/sysv/linux/x86_64/time.S
+++ b/sysdeps/unix/sysv/linux/x86_64/time.S
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001,02, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2001,02, 2003, 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
@@ -32,7 +32,12 @@ ENTRY (time)
        sub     $0x8, %rsp
        cfi_adjust_cfa_offset(8)
 
+#ifdef SHARED
+       movq    __vdso_time(%rip), %rax
+       PTR_DEMANGLE (%rax)
+#else
        movq    $VSYSCALL_ADDR_vtime, %rax
+#endif
        callq   *%rax
 
        add     $0x8, %rsp