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ppc: Use libc_ifunc macro for time, gettimeofday.

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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.
This commit is contained in:
Stefan Liebler
2016-10-07 09:56:47 +02:00
parent e23faea6ae
commit a4d7fe35cd
3 changed files with 73 additions and 62 deletions
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67
sysdeps/unix/sysv/linux/powerpc/time.c
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@ -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 */