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PowerPC: gettimeofday optimization by using IFUNC

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This commit is contained in:
Adhemerval Zanella
2013-03-15 10:58:56 -03:00
parent 8cfdb7e056
commit ef26eece63
4 changed files with 53 additions and 54 deletions
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10
sysdeps/unix/sysv/linux/powerpc/bits/libc-vdso.h
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@@ -32,6 +32,16 @@ extern void *__vdso_get_tbfreq;
extern void *__vdso_getcpu;
/* 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
#else
#define VDSO_IFUNC_RET(value) value
#endif
#endif
#endif /* _LIBC_VDSO_H */

48
sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
View File

@@ -15,25 +15,49 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <stddef.h>
#include <sys/time.h>
#include <time.h>
#include <hp-timing.h>
#include <bits/libc-vdso.h>
#ifdef SHARED
/* Get the current time of day and timezone information,
putting it into *TV and *TZ. If TZ is NULL, *TZ is not filled.
Returns 0 on success, -1 on errors. */
# include <dl-vdso.h>
# include <bits/libc-vdso.h>
void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
static int
__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
{
return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
}
void *
gettimeofday_ifunc (void)
{
/* If the vDSO is not available we fall back syscall. */
return (__vdso_gettimeofday ? VDSO_IFUNC_RET (__vdso_gettimeofday)
: __gettimeofday_syscall);
}
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\n"
"__GI___gettimeofday = __gettimeofday");
#else
# include <sysdep.h>
# include <errno.h>
int
__gettimeofday (tv, tz)
struct timeval *tv;
struct timezone *tz;
__gettimeofday (struct timeval *tv, struct timezone *tz)
{
return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
}
libc_hidden_def (__gettimeofday)
#endif
weak_alias (__gettimeofday, gettimeofday)
libc_hidden_weak (gettimeofday)