From 01c3d9bb14a1e90159d6999cf3469e62c0c5d4b2 Mon Sep 17 00:00:00 2001

From: Adhemerval Zanella <azanella@linux.vnet.ibm.com>

Date: Fri, 3 May 2013 15:00:31 -0500

Subject: [PATCH 27/42] PowerPC: Add time vDSO support

PowerPC kernel now provides a vDSO implementation for time syscall

(commit fcb41a2030abe0eb716ef0798035ef9562097f42). This patch changes

time syscall wrapper to use the vDSO when available. It also changes

the default non vDSO time on PowerPC to use sysdeps/posix/time.c

(since gettimeofday is a vDSO call).

(cherry picked from commit 83e7640f6bf68708ecf0b09d83c670203167271e)

---

 sysdeps/unix/sysv/linux/powerpc/Versions         |  1 +

 sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h |  6 ++-

 sysdeps/unix/sysv/linux/powerpc/init-first.c     |  4 +-

 sysdeps/unix/sysv/linux/powerpc/time.c           | 62 ++++++++++++++++++++++++

 5 files changed, 81 insertions(+), 3 deletions(-)

 create mode 100644 sysdeps/unix/sysv/linux/powerpc/time.c

diff --git glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/Versions glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/Versions

index 396a423..289c4fe 100644

--- glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/Versions

+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/Versions

@@ -4,5 +4,6 @@ libc {

     __vdso_clock_gettime;

     __vdso_clock_getres;

     __vdso_getcpu;

+    __vdso_time;

   }

 }

diff --git glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h

index e4ae630..f7f635e 100644

--- glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h

+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h

@@ -32,14 +32,16 @@ extern void *__vdso_get_tbfreq;

 extern void *__vdso_getcpu;

+extern void *__vdso_time;

+

 /* This macro is needed for PPC64 to return a skeleton OPD entry of a vDSO

    symbol.  This works because _dl_vdso_vsym always return the function

    address, and no vDSO symbols use the TOC or chain pointers from the OPD

    so we can allow them to be garbage.  */

 #if defined(__PPC64__) || defined(__powerpc64__)

-#define VDSO_IFUNC_RET(value)  &value

+#define VDSO_IFUNC_RET(value)  ((void *) &(value))

 #else

-#define VDSO_IFUNC_RET(value)  value

+#define VDSO_IFUNC_RET(value)  ((void *) (value))

 #endif

 #endif

diff --git glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/init-first.c glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/init-first.c

index 5587e2a..3cefd9b 100644

--- glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/init-first.c

+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/init-first.c

@@ -28,7 +28,7 @@ void *__vdso_clock_gettime;

 void *__vdso_clock_getres;

 void *__vdso_get_tbfreq;

 void *__vdso_getcpu;

-

+void *__vdso_time;

 static inline void

 _libc_vdso_platform_setup (void)

@@ -44,6 +44,8 @@ _libc_vdso_platform_setup (void)

   __vdso_get_tbfreq = _dl_vdso_vsym ("__kernel_get_tbfreq", &linux2615);

   __vdso_getcpu = _dl_vdso_vsym ("__kernel_getcpu", &linux2615);

+

+  __vdso_time = _dl_vdso_vsym ("__kernel_time", &linux2615);

 }

 # define VDSO_SETUP _libc_vdso_platform_setup

diff --git glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/time.c glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/time.c

new file mode 100644

index 0000000..66b4eb3

--- /dev/null

+++ glibc-2.17-c758a686/sysdeps/unix/sysv/linux/powerpc/time.c

@@ -0,0 +1,62 @@

+/* time system call for Linux/PowerPC.

+   Copyright (C) 2013 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

+   modify it under the terms of the GNU Lesser General Public

+   License as published by the Free Software Foundation; either

+   version 2.1 of the License, or (at your option) any later version.

+

+   The GNU C Library is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

+   Lesser General Public License for more details.

+

+   You should have received a copy of the GNU Lesser General Public

+   License along with the GNU C Library; if not, see

+   <http://www.gnu.org/licenses/>.  */

+

+#ifdef SHARED

+

+# include <time.h>

+# include <sysdep.h>

+# include <bits/libc-vdso.h>

+

+void *time_ifunc (void) asm ("time");

+

+static time_t

+time_syscall (time_t *t)

+{

+  struct timeval tv;

+  time_t result;

+

+  if (INLINE_VSYSCALL (gettimeofday, 2, &tv, NULL) < 0)

+    result = (time_t) -1;

+  else

+    result = (time_t) tv.tv_sec;

+

+  if (t != NULL)

+    *t = result;

+  return result;

+}

+

+void *

+time_ifunc (void)

+{

+  /* If the vDSO is not available we fall back to the syscall.  */

+  return (__vdso_time ? VDSO_IFUNC_RET (__vdso_time)

+	  : time_syscall);

+}

+asm (".type time, %gnu_indirect_function");

+

+/* This is doing "libc_hidden_def (time)" but the compiler won't

+ * let us do it in C because it doesn't know we're defining time

+ * here in this file.  */

+asm (".globl __GI_time\n"

+     "__GI_time = time");

+

+#else

+

+#include <sysdeps/posix/time.c>

+

+#endif

-- 

1.7.11.7