From 42e0828f582dcc4ff92d65039910ffe5fa9d881b Mon Sep 17 00:00:00 2001

From: Stefan Liebler <stli@linux.vnet.ibm.com>

Date: Thu, 27 Jul 2017 10:53:58 +0200

Subject: [PATCH 02/10] S390: Use new s390_libc_ifunc_expr macro in s390

 8bit-generic.c.

upstream-commit 51213e2b8d89164527131f3bf6c5946b811c5e3e

This patch adds s390_libc_ifunc_expr macro which uses the __ifunc base macro

(upstream it is in include/libc-symbols.h; this backport implements it

in s390-header) and lets the user define a generic expression to

choose the correct ifunc variant.  Furthermore as the base macro is used,

the ifunc resolver functions are now also using inhibit_stack_protector.

S390 needs its own version due to the hwcap argument of the ifunc resolver.

This new macro is now used in iconv code in 8bit-generic.c instead of using

gcc attribute ifunc directly.

ChangeLog:

	* sysdeps/s390/multiarch/ifunc-resolve.h

	(s390_libc_ifunc_expr_init, s390_libc_ifunc_expr, __ifunc,

	__ifunc_resolver): New Define.

	* sysdeps/s390/multiarch/8bit-generic.c

	(__to_generic, __from_generic): Use s390_libc_ifunc_expr to

	define ifunc resolvers.

---

 sysdeps/s390/multiarch/8bit-generic.c  | 41 ++++++++++------------------------

 sysdeps/s390/multiarch/ifunc-resolve.h | 20 +++++++++++++++++

 2 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/sysdeps/s390/multiarch/8bit-generic.c b/sysdeps/s390/multiarch/8bit-generic.c

index 93565e1..9232240 100644

--- a/sysdeps/s390/multiarch/8bit-generic.c

+++ b/sysdeps/s390/multiarch/8bit-generic.c

@@ -40,8 +40,7 @@

    to translate between multiple generic characters and "1 byte UCS4"

    characters at once. The vector instructions are used to convert between

    the "1 byte UCS4" and UCS4.  */

-# include <unistd.h>

-# include <dl-procinfo.h>

+# include <ifunc-resolve.h>

 # undef FROM_LOOP

 # undef TO_LOOP

@@ -372,33 +371,17 @@

 /* Generate ifunc'ed loop function.  */

-__typeof(__from_generic_c)

-__attribute__ ((ifunc ("__from_generic_resolver")))

-__from_generic;

+s390_libc_ifunc_expr (__from_generic_c, __from_generic,

+		      (sizeof (from_ucs4) / sizeof (from_ucs4[0]) <= 256

+		       && hwcap & HWCAP_S390_VX)

+		      ? __from_generic_vx

+		      : __from_generic_c);

-static void *

-__from_generic_resolver (unsigned long int dl_hwcap)

-{

-  if (sizeof (from_ucs4) / sizeof (from_ucs4[0]) <= 256

-      && dl_hwcap & HWCAP_S390_VX)

-    return &__from_generic_vx;

-  else

-    return &__from_generic_c;

-}

-

-__typeof(__to_generic_c)

-__attribute__ ((ifunc ("__to_generic_resolver")))

-__to_generic;

-

-static void *

-__to_generic_resolver (unsigned long int dl_hwcap)

-{

-  if (sizeof (from_ucs4) / sizeof (from_ucs4[0]) <= 256

-      && dl_hwcap & HWCAP_S390_VX)

-    return &__to_generic_vx;

-  else

-    return &__to_generic_c;

-}

+s390_libc_ifunc_expr (__to_generic_c, __to_generic,

+		      (sizeof (from_ucs4) / sizeof (from_ucs4[0]) <= 256

+		       && hwcap & HWCAP_S390_VX)

+		      ? __to_generic_vx

+		      : __to_generic_c);

 strong_alias (__to_generic_c_single, __to_generic_single)

@@ -410,6 +393,6 @@ strong_alias (__to_generic_c_single, __to_generic_single)

 #else

 /* Generate this module without ifunc if build environment lacks vector

-   support. Instead the common 8bit-generic.c is used.  */

+   support.  Instead the common 8bit-generic.c is used.  */

 # include "iconvdata/8bit-generic.c"

 #endif /* !defined HAVE_S390_VX_ASM_SUPPORT */

diff --git a/sysdeps/s390/multiarch/ifunc-resolve.h b/sysdeps/s390/multiarch/ifunc-resolve.h

index e9fd90e..883365b 100644

--- a/sysdeps/s390/multiarch/ifunc-resolve.h

+++ b/sysdeps/s390/multiarch/ifunc-resolve.h

@@ -92,3 +92,23 @@

       return &RESOLVERFUNC##_c;						\

   }									\

  __asm__ (".type " #FUNC ", %gnu_indirect_function");

+

+/* Helper / base  macros for indirect function symbols

+   (See include/libc-symbols in upstream glibc).  */

+#define __ifunc_resolver(type_name, name, expr, arg, init, classifier)	\

+  classifier void *name##_ifunc (arg)					\

+  {									\

+    init ();								\

+    __typeof (type_name) *res = expr;					\

+    return res;								\

+  }

+

+#define __ifunc(type_name, name, expr, arg, init)			\

+  extern __typeof (type_name) name __attribute__			\

+			      ((ifunc (#name "_ifunc")));		\

+  __ifunc_resolver (type_name, name, expr, arg, init, static)

+

+#define s390_libc_ifunc_expr_init()

+#define s390_libc_ifunc_expr(TYPE_FUNC, FUNC, EXPR)		\

+  __ifunc (TYPE_FUNC, FUNC, EXPR, unsigned long int hwcap,	\

+	   s390_libc_ifunc_expr_init);

-- 

1.8.3.1