From 91ac3a7d8474480685632cd25f844d3154c69fdf Mon Sep 17 00:00:00 2001
From: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Date: Mon, 17 Jul 2017 17:48:59 -0300
Subject: powerpc: Fix float128 IFUNC relocations [BZ #21707]

The patch proposed by Peter Bergner [1] to libgcc in order to fix
[BZ #21707] adds a dependency on a symbol provided by the loader,
forcing the loader to be linked to tests after libgcc was linked.

It also requires to read the thread pointer during IRELA relocations.

Tested on powerpc, powerpc64, powerpc64le, s390x and x86_64.

[1] https://sourceware.org/ml/libc-alpha/2017-06/msg01383.html

	[BZ #21707]
	* csu/libc-start.c (LIBC_START_MAIN): Perform IREL{,A}
	relocations before or after initializing the TCB on statically
	linked executables.  That's a per-architecture definition.
	* elf/rtld.c (dl_main): Add a comment about thread-local
	variables initialization.
	* sysdeps/generic/libc-start.h: New file.  Define
	ARCH_APPLY_IREL and ARCH_SETUP_IREL.
	* sysdeps/powerpc/Makefile:
	[$(subdir) = elf && $(multi-arch) != no] (tests-static-internal): Add tst-tlsifunc-static.
	[$(subdir) = elf && $(multi-arch) != no && $(build-shared) == yes]
	(tests-internal): Add tst-tlsifunc.
	* sysdeps/powerpc/tst-tlsifunc.c: New file.
	* sysdeps/powerpc/tst-tlsifunc-static.c: Likewise.
	* sysdeps/powerpc/powerpc64le/Makefile (f128-loader-link): New
	variable.
	[$(subdir) = math] (test-float128% test-ifloat128%): Force
	linking to the loader after linking to libgcc.
	[$(subdir) = wcsmbs || $(subdir) = stdlib] (bug-strtod bug-strtod2)
	(bug-strtod2 tst-strtod-round tst-wcstod-round tst-strtod6 tst-strrom)
	(tst-strfrom-locale strfrom-skeleton): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/libc-start.h: New file.  Define
	ARCH_APPLY_IREL and ARCH_SETUP_IREL.
---
 csu/libc-start.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

(limited to 'csu')

diff --git a/csu/libc-start.c b/csu/libc-start.c
index c2dd1593eb..6720617188 100644
--- a/csu/libc-start.c
+++ b/csu/libc-start.c
@@ -108,6 +108,8 @@ apply_irel (void)
 # define ARCH_INIT_CPU_FEATURES()
 #endif
 
+#include <libc-start.h>
+
 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
 					 MAIN_AUXVEC_DECL),
 			    int argc,
@@ -189,11 +191,16 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
   ARCH_INIT_CPU_FEATURES ();
 
   /* Perform IREL{,A} relocations.  */
-  apply_irel ();
+  ARCH_SETUP_IREL ();
 
   /* The stack guard goes into the TCB, so initialize it early.  */
   __libc_setup_tls ();
 
+  /* In some architectures, IREL{,A} relocations happen after TLS setup in
+     order to let IFUNC resolvers benefit from TCB information, e.g. powerpc's
+     hwcap and platform fields available in the TCB.  */
+  ARCH_APPLY_IREL ();
+
   /* Set up the stack checker's canary.  */
   uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
 # ifdef THREAD_SET_STACK_GUARD
@@ -224,7 +231,7 @@ LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
   __pointer_chk_guard_local = pointer_chk_guard;
 # endif
 
-#endif
+#endif /* !SHARED  */
 
   /* Register the destructor of the dynamic linker if there is any.  */
   if (__glibc_likely (rtld_fini != NULL))
-- 
cgit v1.2.3-65-gdbad