[v3,9/9] Use libc_ifunc macro for siglongjmp, longjmp in libpthread.
Commit Message
This patch uses the libc_ifunc macro to create already existing ifunc functions
longjmp_ifunc, siglongjmp_ifunc if HAVE_IFUNC is defined.
The s390 pt-longjmp.c includes the common pt-longjmp.c and uses strong_alias
to create the longjmp, siglongjmp symbols for glibc version 2.19.
ChangeLog:
* nptl/pt-longjmp.c (DEFINE_LONGJMP): Use libc_ifunc macro.
* sysdeps/unix/sysv/linux/s390/pt-longjmp.c (longjmp, siglongjmp):
Use strong_alias to create symbols for glibc verison 2.19.
---
nptl/pt-longjmp.c | 24 ++++++------------------
sysdeps/unix/sysv/linux/s390/pt-longjmp.c | 4 ++--
2 files changed, 8 insertions(+), 20 deletions(-)
Comments
On 08/24/2016 04:04 PM, Stefan Liebler wrote:
> This patch uses the libc_ifunc macro to create already existing ifunc functions
> longjmp_ifunc, siglongjmp_ifunc if HAVE_IFUNC is defined.
> The s390 pt-longjmp.c includes the common pt-longjmp.c and uses strong_alias
> to create the longjmp, siglongjmp symbols for glibc version 2.19.
>
> ChangeLog:
>
> * nptl/pt-longjmp.c (DEFINE_LONGJMP): Use libc_ifunc macro.
> * sysdeps/unix/sysv/linux/s390/pt-longjmp.c (longjmp, siglongjmp):
> Use strong_alias to create symbols for glibc verison 2.19.
This is okay for now.
Once this is in, I'm going to submit a patch which replaces the IFUNC
resolver with a direct call (similar to what we did for fork) because of
the relocation ordering issue that can cause those IFUNC resolvers to go
wrong.
Thanks,
Florian
@@ -32,24 +32,12 @@
# if HAVE_IFUNC
-static __typeof (longjmp) *
-__attribute__ ((used))
-longjmp_resolve (void)
-{
- return &__libc_longjmp;
-}
+# undef INIT_ARCH
+# define INIT_ARCH()
+# define DEFINE_LONGJMP(name) libc_ifunc (name, &__libc_longjmp)
-# ifdef HAVE_ASM_SET_DIRECTIVE
-# define DEFINE_LONGJMP(name) \
- asm (".set " #name ", longjmp_resolve\n" \
- ".globl " #name "\n" \
- ".type " #name ", %gnu_indirect_function");
-# else
-# define DEFINE_LONGJMP(name) \
- asm (#name " = longjmp_resolve\n" \
- ".globl " #name "\n" \
- ".type " #name ", %gnu_indirect_function");
-# endif
+extern __typeof(longjmp) longjmp_ifunc;
+extern __typeof(siglongjmp) siglongjmp_ifunc;
# else /* !HAVE_IFUNC */
@@ -66,7 +54,7 @@ longjmp_compat (jmp_buf env, int val)
DEFINE_LONGJMP (longjmp_ifunc)
compat_symbol (libpthread, longjmp_ifunc, longjmp, GLIBC_2_0);
-DEFINE_LONGJMP (siglongjmp_ifunc)
+strong_alias (longjmp_ifunc, siglongjmp_ifunc)
compat_symbol (libpthread, siglongjmp_ifunc, siglongjmp, GLIBC_2_0);
#endif
@@ -26,8 +26,8 @@
/* In glibc release 2.19 new versions of longjmp-functions were introduced,
but were reverted before 2.20. Thus both versions are the same function. */
-DEFINE_LONGJMP (__v2longjmp)
+strong_alias (longjmp_ifunc, __v2longjmp)
compat_symbol (libpthread, __v2longjmp, longjmp, GLIBC_2_19);
-DEFINE_LONGJMP (__v2siglongjmp)
+strong_alias (siglongjmp_ifunc, __v2siglongjmp)
compat_symbol (libpthread, __v2siglongjmp, siglongjmp, GLIBC_2_19);
#endif /* SHLIB_COMPAT (libpthread, GLIBC_2_19, GLIBC_2_20)) */