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Re: [PATCH 8/8] Use libc_ifunc macro for siglongjmp, longjmp in libpthread.


This updated patch first undefines INIT_ARCH before it is defined.

On 06/23/2016 01:55 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.
---
  nptl/pt-longjmp.c                         | 23 +++++------------------
  sysdeps/unix/sysv/linux/s390/pt-longjmp.c |  4 ++--
  2 files changed, 7 insertions(+), 20 deletions(-)

diff --git a/nptl/pt-longjmp.c b/nptl/pt-longjmp.c
index a1cc286..7c452cb 100644
--- a/nptl/pt-longjmp.c
+++ b/nptl/pt-longjmp.c
@@ -32,24 +32,11 @@

  # if HAVE_IFUNC

-static __typeof (longjmp) *
-__attribute__ ((used))
-longjmp_resolve (void)
-{
-  return &__libc_longjmp;
-}
+#  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 +53,7 @@ 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
diff --git a/sysdeps/unix/sysv/linux/s390/pt-longjmp.c b/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
index 10e825c..2abf112 100644
--- a/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
+++ b/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
@@ -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))  */

>From 7f756e0e39a90324d84dd7eba0e0ba5c2c90ee2a Mon Sep 17 00:00:00 2001
From: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Mon, 4 Jul 2016 15:33:57 +0200
Subject: [PATCH 8/8] Use libc_ifunc macro for siglongjmp, longjmp in
 libpthread.

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(-)

diff --git a/nptl/pt-longjmp.c b/nptl/pt-longjmp.c
index a1cc286..a19cd59 100644
--- a/nptl/pt-longjmp.c
+++ b/nptl/pt-longjmp.c
@@ -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
diff --git a/sysdeps/unix/sysv/linux/s390/pt-longjmp.c b/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
index 10e825c..2abf112 100644
--- a/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
+++ b/sysdeps/unix/sysv/linux/s390/pt-longjmp.c
@@ -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))  */
-- 
2.3.0


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