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).

1 files changed, 62 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/powerpc/time.c b/sysdeps/unix/sysv/linux/powerpc/time.c
new file mode 100644
index 0000000000..66b4eb3049
--- /dev/null
+++ b/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