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Re: fix ppc32 -msecure-plt TLS relaxation GD->LE
On Mar 14, 2006, Alan Modra <amodra@bigpond.net.au> wrote:
> On Fri, Mar 10, 2006 at 12:09:50AM -0300, Alexandre Oliva wrote:
>> Code compiled with -msecure-plt generates calls to __tls_get_addr with
>> a nonzero addend, that ends up making to the lower part of the TP
>> offset computed for the TL variable when Global Dynamic is relaxed to
>> Local Exec. This patch fixes it, by arranging for us to refer to the
>> same location in both relocations. We already did that for LD->LE,
>> but not GD->LE. [LG[D->IE cancels out the second relocation, so its
>> addend doesn't matter, so I left it along even though it's still
>> conceptually wrong.
>>
>> Tested on amd64-linux-gnu-x-ppc64-linux-gnu. Ok to install?
> OK, thanks! As you say, the GD->IE R_PPC_NONE addend doesn't matter,
> but I think it would be nicer to zero the addend. Please make that
> change too.
Done, here's what I'm checking in.
for binutils/ChangeLog
from Alexandre Oliva <aoliva@redhat.com>
* elf32-ppc.c (ppc_elf_relocate_section): Copy addend from
first relocation to the second when relaxing TLS GD to LE;
zero it out when relaxing to IE.
for ld/testsuite/ChangeLog
from Alexandre Oliva <aoliva@redhat.com>
* ld-powerpc/tls32.s: Verify that +32768 @plt addend is
discarded.
Index: bfd/elf32-ppc.c
===================================================================
--- bfd/elf32-ppc.c.orig 2006-03-17 03:32:48.000000000 -0300
+++ bfd/elf32-ppc.c 2006-03-17 03:36:48.000000000 -0300
@@ -5768,6 +5768,7 @@ ppc_elf_relocate_section (bfd *output_bf
insn1 |= 32 << 26; /* lwz */
insn2 = 0x7c631214; /* add 3,3,2 */
rel[1].r_info = ELF32_R_INFO (r_symndx2, R_PPC_NONE);
+ rel[1].r_addend = 0;
r_type = (((r_type - (R_PPC_GOT_TLSGD16 & 3)) & 3)
+ R_PPC_GOT_TPREL16);
rel->r_info = ELF32_R_INFO (r_symndx, r_type);
@@ -5782,13 +5783,13 @@ ppc_elf_relocate_section (bfd *output_bf
/* Was an LD reloc. */
r_symndx = 0;
rel->r_addend = htab->elf.tls_sec->vma + DTP_OFFSET;
- rel[1].r_addend = htab->elf.tls_sec->vma + DTP_OFFSET;
}
r_type = R_PPC_TPREL16_HA;
rel->r_info = ELF32_R_INFO (r_symndx, r_type);
rel[1].r_info = ELF32_R_INFO (r_symndx,
R_PPC_TPREL16_LO);
rel[1].r_offset += 2;
+ rel[1].r_addend = rel->r_addend;
}
bfd_put_32 (output_bfd, insn1, contents + rel->r_offset - 2);
bfd_put_32 (output_bfd, insn2, contents + offset);
Index: ld/testsuite/ld-powerpc/tls32.s
===================================================================
--- ld/testsuite/ld-powerpc/tls32.s.orig 2004-11-23 17:10:08.000000000 -0200
+++ ld/testsuite/ld-powerpc/tls32.s 2006-03-17 03:34:38.000000000 -0300
@@ -33,11 +33,11 @@ _start:
#global syms
#GD
addi 3,31,gd0@got@tlsgd #R_PPC_GOT_TLSGD16 gd0
- bl __tls_get_addr@plt #R_PPC_PLTREL24 __tls_get_addr
+ bl __tls_get_addr+0x8000@plt #R_PPC_PLTREL24 __tls_get_addr
#LD
addi 3,31,ld0@got@tlsld #R_PPC_GOT_TLSLD16 ld0
- bl __tls_get_addr@plt #R_PPC_PLTREL24 __tls_get_addr
+ bl __tls_get_addr+0x8000@plt #R_PPC_PLTREL24 __tls_get_addr
addi 9,3,ld0@dtprel #R_PPC_DTPREL16 ld0
--
Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/
Secretary for FSF Latin America http://www.fsfla.org/
Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org}