[PATCH] TLS i386/dl-machine.h changes
Jakub Jelinek
jakub@redhat.com
Thu Sep 12 09:32:00 GMT 2002
Hi!
IMHO R_386_TLS_DTPMOD32 should not use addend in REL version.
It is a counterpart of R_386_GLOB_DAT which doesn't use it either.
I believe the reason for R_386_GLOB_DAT is that if you reference
x, x + 8 and x + 16 in one library, you don't end up with 3 dynamic relocs
against x but just one.
ATM binutils will never create R_386_TLS_DTPMOD32 with addend != 0 (unlike
R_386_TLS_TPOFF32).
Not using the addend has a serious advantage for prelink - it can prelink
all DTPOFF32 relocs without the need for costly REL->RELA conversion.
Another thing is that sym != NULL implies sym_map != NULL (otherwise e.g.
Elf32_Addr value = sym == NULL ? 0 : sym_map->l_addr + sym->st_value;
would crash first).
Plus we need the TLS RELA support too...
2002-09-12 Jakub Jelinek <jakub@redhat.com>
* sysdeps/i386/dl-machine.h (elf_machine_rel) [R_386_TLS_DTPMOD32]:
Don't use addend.
[R_386_TLS_TPOFF32]: Remove redundant sym_map != NULL check.
(elf_machine_rela): Add support for TLS relocs.
--- libc/sysdeps/i386/dl-machine.h.jj 2002-08-31 09:40:43.000000000 +0200
+++ libc/sysdeps/i386/dl-machine.h 2002-09-12 18:19:22.000000000 +0200
@@ -410,8 +410,6 @@ elf_machine_rel (struct link_map *map, c
*reloc_addr = value;
break;
- /* XXX Remove TLS relocations which are not needed. */
-
#ifdef USE_TLS
case R_386_TLS_DTPMOD32:
# ifdef RTLD_BOOTSTRAP
@@ -432,7 +430,7 @@ elf_machine_rel (struct link_map *map, c
/* During relocation all TLS symbols are defined and used.
Therefore the offset is already correct. */
if (sym != NULL)
- *reloc_addr += sym->st_value;
+ *reloc_addr = sym->st_value;
# endif
break;
case R_386_TLS_TPOFF32:
@@ -444,7 +442,7 @@ elf_machine_rel (struct link_map *map, c
It is a positive value which will be subtracted from the
thread pointer. To get the variable position in the TLS
block we subtract the offset from that of the TLS block. */
- if (sym_map != NULL && sym != NULL)
+ if (sym != NULL)
*reloc_addr += sym_map->l_tls_offset - sym->st_value;
# endif
break;
@@ -516,7 +514,44 @@ elf_machine_rela (struct link_map *map,
case R_386_PC32:
*reloc_addr = (value + reloc->r_addend - (Elf32_Addr) reloc_addr);
break;
- /* XXX Do we have to handle the TLS relocation here? */
+
+#ifdef USE_TLS
+ case R_386_TLS_DTPMOD32:
+# ifdef RTLD_BOOTSTRAP
+ /* During startup the dynamic linker is always the module
+ with index 1.
+ XXX If this relocation is necessary move before RESOLVE
+ call. */
+ *reloc_addr = 1;
+# else
+ /* Get the information from the link map returned by the
+ resolv function. */
+ if (sym_map != NULL)
+ *reloc_addr = sym_map->l_tls_modid;
+# endif
+ break;
+ case R_386_TLS_DTPOFF32:
+# ifndef RTLD_BOOTSTRAP
+ /* During relocation all TLS symbols are defined and used.
+ Therefore the offset is already correct. */
+ *reloc_addr = (sym == NULL ? 0 : sym->st_value) + reloc->r_addend;
+# endif
+ break;
+ case R_386_TLS_TPOFF32:
+ /* The offset is positive, backward from the thread pointer. */
+# ifdef RTLD_BOOTSTRAP
+ *reloc_addr = map->l_tls_offset - sym->st_value + reloc->r_addend;
+# else
+ /* We know the offset of object the symbol is contained in.
+ It is a positive value which will be subtracted from the
+ thread pointer. To get the variable position in the TLS
+ block we subtract the offset from that of the TLS block. */
+ *reloc_addr
+ = (sym == NULL ? 0 : sym_map->l_tls_offset - sym->st_value)
+ + reloc->r_addend;
+# endif
+ break;
+#endif /* use TLS */
default:
/* We add these checks in the version to relocate ld.so only
if we are still debugging. */
Jakub
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