Fix 32-bit ARM builds in presence of new binutils.

glibc-fix-arm32.patch

@@ -0,0 +1,58 @@
+https://www.sourceware.org/ml/libc-alpha/2017-07/msg00518.html
+
+To: libc-alpha at sourceware dot org
+From: Jiong Wang <jiong dot wang at foss dot arm dot com>
+Subject: [ARM] Fix ld.so crash when built using Binutils 2.29
+
+Hi,
+
+   There is bug report that ld.so in GLIBC 2.24 built by Binutils 2.29 will crash
+on arm-linux-gnueabihf.  This is confirmed, and the details is at:
+
+    https://sourceware.org/bugzilla/show_bug.cgi?id=21725.
+
+   And I could also reproduce this crash using GLIBC master.
+
+   As analyzed in the PR, the old code was with the assumption that assembler
+won't set bit0 of thumb function address if it comes from PC-relative
+instructions and the calculation can be finished during assembling.  This
+assumption however does not hold after PR gas/21458.
+
+   I think ARM backend in GLIBC should be fix to be more portable so it could
+work with various combinations of GLIBC and Binutils.
+
+   OK for master and backport to all release branches?
+
+
+2017-07-12  Jiong Wang  <jiong.wang@arm.com>
+
+         * sysdeps/arm/dl-machine.h (elf_machine_load_address):  Also strip bit 0
+         of pcrel_address under Thumb mode.
+
+diff --git a/sysdeps/arm/dl-machine.h b/sysdeps/arm/dl-machine.h
+index 7053ead16ed0e7dac182660f7d88fa21f2b4799a..5b67e3d004818308d9bf93effb13d23a762e160f 100644
+--- a/sysdeps/arm/dl-machine.h
++++ b/sysdeps/arm/dl-machine.h
+@@ -56,11 +56,19 @@ elf_machine_load_address (void)
+   extern Elf32_Addr internal_function __dl_start (void *) asm ("_dl_start");
+   Elf32_Addr got_addr = (Elf32_Addr) &__dl_start;
+   Elf32_Addr pcrel_addr;
++  asm ("adr %0, _dl_start" : "=r" (pcrel_addr));
+ #ifdef __thumb__
+-  /* Clear the low bit of the funciton address.  */
++  /* Clear the low bit of the funciton address.
++
++     NOTE: got_addr is from GOT table whose lsb is always set by linker if it's
++     Thumb function address.  PCREL_ADDR comes from PC-relative calculation
++     which will finish during assembling.  GAS assembler before the fix for
++     PR gas/21458 was not setting the lsb but does after that.  Always do the
++     strip for both, so the code works with various combinations of glibc and
++     Binutils.  */
+   got_addr &= ~(Elf32_Addr) 1;
++  pcrel_addr &= ~(Elf32_Addr) 1;
+ #endif
+-  asm ("adr %0, _dl_start" : "=r" (pcrel_addr));
+   return pcrel_addr - got_addr;
+ }
+ 
+

glibc.spec

@@ -2286,6 +2286,7 @@ rm -f *.filelist*
 * Wed Jul 12 2017 Carlos O'Donell <carlos@redhat.com> - 2.25.90-24
 - Fix IFUNC crash in early startup for ppc64le static binaries (#1467518).
 - Enable building with BIND_NOW on ppc64le (#1467518).
+- Fix 32-bit ARM builds in presence of new binutils.
 
 * Wed Jul 12 2017 Florian Weimer <fweimer@redhat.com> - 2.25.90-23
 - malloc: Tell GCC optimizers about MAX_FAST_SIZE in _int_malloc (#1470060)