From: Mike Frysinger <vapier@gentoo.org>
Date: Sun, 1 Jan 2012 07:36:32 +0000 (-0500)
Subject: arm: handle unaligned ABS relocs
X-Git-Tag: glibc-2.17~716
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3447612d3ce9f6903c19526595c3acf0043daf80;p=thirdparty%2Fglibc.git

arm: handle unaligned ABS relocs

When relocating a misaligned R_ARM_ABS32, glibc currently crashes.

URL: https://bugs.gentoo.org/394237
URL: http://gcc.gnu.org/PR51456
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---

diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 34d606da462..6775af499e9 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,9 @@
+2012-08-12  Mike Frysinger  <vapier@gentoo.org>
+
+	* sysdeps/arm/dl-machine.h (elf_machine_rel) [R_ARM_ABS32]: Declare
+	a new unaligned struct.  Cast reloc_addr to that when updating the
+	value it points to.
+
 2012-08-09  Roland McGrath  <roland@hack.frob.com>
 
 	* sysdeps/arm/arm-features.h: Document ARM_ASSUME_NO_IWMMXT.
diff --git a/ports/sysdeps/arm/dl-machine.h b/ports/sysdeps/arm/dl-machine.h
index fe39a5e6823..ca66e83e0d1 100644
--- a/ports/sysdeps/arm/dl-machine.h
+++ b/ports/sysdeps/arm/dl-machine.h
@@ -413,6 +413,10 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
 	  break;
 	case R_ARM_ABS32:
 	  {
+	    struct unaligned
+	      {
+		Elf32_Addr x;
+	      } __attribute__((packed, may_alias));
 # ifndef RTLD_BOOTSTRAP
 	   /* This is defined in rtld.c, but nowhere in the static
 	      libc.a; make the reference weak so static programs can
@@ -431,7 +435,8 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
 		 used while loading those libraries.  */
 	      value -= map->l_addr + refsym->st_value;
 # endif
-	    *reloc_addr += value;
+	    /* Support relocations on mis-aligned offsets.  */
+	    ((struct unaligned *) reloc_addr)->x += value;
 	    break;
 	  }
 	case R_ARM_TLS_DESC: