From 223b642762d639bca416cc3e99af98d21074fcd7 Mon Sep 17 00:00:00 2001
From: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Thu, 4 Aug 2016 18:46:23 +0200
Subject: [PATCH 4/8] ppc: Use libc_ifunc macro for time, gettimeofday.
This patch uses the libc_ifunc_hidden macro to create already existing ifunc functions
time and gettimeofday on power. This way, the libc_hidden_def macro can be used
instead of inline assemblies.
On ppc32, the __GI_* symbols do not target the ifunc symbol and thus the
redirection construct has to be applied here.
ChangeLog:
* sysdeps/unix/sysv/linux/powerpc/gettimeofday.c (__gettimeofday):
Use libc_ifunc_hidden and libc_hidden_def macro. Redirect ifunced function
in header for using it as type for ifunc function because __GI_* symbols
for ppc32 do not target the ifunc symbols.
* sysdeps/unix/sysv/linux/powerpc/time.c (time): Likewise.
---
sysdeps/unix/sysv/linux/powerpc/gettimeofday.c | 60 ++++++++++++-----------
sysdeps/unix/sysv/linux/powerpc/time.c | 67 +++++++++++++-------------
2 files changed, 65 insertions(+), 62 deletions(-)
@@ -15,6 +15,11 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#if defined SHARED && !defined __powerpc64__
+# define __gettimeofday __redirect___gettimeofday
+#else
+# define __redirect___gettimeofday __gettimeofday
+#endif
#include <sys/time.h>
@@ -24,30 +29,14 @@
# include <libc-vdso.h>
# include <dl-machine.h>
-void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
-
-static int
-__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
-{
- return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
-}
+# ifndef __powerpc64__
+# undef __gettimeofday
-void *
-gettimeofday_ifunc (void)
+int
+__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)
{
- PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565);
-
- /* If the vDSO is not available we fall back syscall. */
- void *vdso_gettimeofday = _dl_vdso_vsym ("__kernel_gettimeofday", &linux2615);
- return (vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
- : (void*)__gettimeofday_syscall);
+ return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
}
-asm (".type __gettimeofday, %gnu_indirect_function");
-
-/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
- let us do it in C because it doesn't know we're defining __gettimeofday
- here in this file. */
-asm (".globl __GI___gettimeofday");
/* __GI___gettimeofday is defined as hidden and for ppc32 it enables the
compiler make a local call (symbol@local) for internal GLIBC usage. It
@@ -55,16 +44,29 @@ asm (".globl __GI___gettimeofday");
For ppc64 a call to a function in another translation unit might use a
different toc pointer thus disallowing direct branchess and making internal
ifuncs calls safe. */
-#ifdef __powerpc64__
-asm ("__GI___gettimeofday = __gettimeofday");
-#else
-int
-__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)
+# undef libc_hidden_def
+# define libc_hidden_def(name) \
+ __hidden_ver1 (__gettimeofday_vsyscall, __GI___gettimeofday, \
+ __gettimeofday_vsyscall);
+
+# endif /* !__powerpc64__ */
+
+static int
+__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
{
- return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
+ return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
}
-asm ("__GI___gettimeofday = __gettimeofday_vsyscall");
-#endif
+
+# define INIT_ARCH() \
+ PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); \
+ void *vdso_gettimeofday = _dl_vdso_vsym ("__kernel_gettimeofday", &linux2615);
+
+/* If the vDSO is not available we fall back syscall. */
+libc_ifunc_hidden (__redirect___gettimeofday, __gettimeofday,
+ vdso_gettimeofday
+ ? VDSO_IFUNC_RET (vdso_gettimeofday)
+ : (void *) __gettimeofday_syscall);
+libc_hidden_def (__gettimeofday)
#else
@@ -17,6 +17,11 @@
<http://www.gnu.org/licenses/>. */
#ifdef SHARED
+# ifndef __powerpc64__
+# define time __redirect_time
+# else
+# define __redirect_time time
+# endif
# include <time.h>
# include <sysdep.h>
@@ -24,7 +29,26 @@
# include <libc-vdso.h>
# include <dl-machine.h>
-void *time_ifunc (void) asm ("time");
+# ifndef __powerpc64__
+# undef time
+
+time_t
+__time_vsyscall (time_t *t)
+{
+ return INLINE_VSYSCALL (time, 1, t);
+}
+
+/* __GI_time is defined as hidden and for ppc32 it enables the
+ compiler make a local call (symbol@local) for internal GLIBC usage. It
+ means the PLT won't be used and the ifunc resolver will be called directly.
+ For ppc64 a call to a function in another translation unit might use a
+ different toc pointer thus disallowing direct branchess and making internal
+ ifuncs calls safe. */
+# undef libc_hidden_def
+# define libc_hidden_def(name) \
+ __hidden_ver1 (__time_vsyscall, __GI_time, __time_vsyscall);
+
+# endif /* !__powerpc64__ */
static time_t
time_syscall (time_t *t)
@@ -42,42 +66,19 @@ time_syscall (time_t *t)
return result;
}
-void *
-time_ifunc (void)
-{
- PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565);
-
- /* If the vDSO is not available we fall back to the syscall. */
+# define INIT_ARCH() \
+ PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); \
void *vdso_time = _dl_vdso_vsym ("__kernel_time", &linux2615);
- return (vdso_time ? VDSO_IFUNC_RET (vdso_time)
- : (void*)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");
-
-/* __GI_time is defined as hidden and for ppc32 it enables the
- compiler make a local call (symbol@local) for internal GLIBC usage. It
- means the PLT won't be used and the ifunc resolver will be called directly.
- For ppc64 a call to a function in another translation unit might use a
- different toc pointer thus disallowing direct branchess and making internal
- ifuncs calls safe. */
-#ifdef __powerpc64__
-asm ("__GI_time = time");
-#else
-time_t
-__time_vsyscall (time_t *t)
-{
- return INLINE_VSYSCALL (time, 1, t);
-}
-asm ("__GI_time = __time_vsyscall");
-#endif
+/* If the vDSO is not available we fall back to the syscall. */
+libc_ifunc_hidden (__redirect_time, time,
+ vdso_time
+ ? VDSO_IFUNC_RET (vdso_time)
+ : (void *) time_syscall);
+libc_hidden_def (time)
#else
#include <sysdeps/posix/time.c>
-#endif
+#endif /* !SHARED */
--
2.3.0