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authorAnders Kaseorg2011-05-19 16:55:27 -0600
committerRusty Russell2011-05-19 16:55:28 +0930
commit6845756b29e4c4e7db41e2d75cafa9d091bc1c07 (patch)
treecceb66e295b238d2ab62a9ca77c9b6adce867935
parent9d63487f86115b1d3ef69670043bcf2b83c4d227 (diff)
modpost: Update 64k section support for binutils 2.18.50
Binutils 2.18.50 made a backwards-incompatible change in the way it writes ELF objects with over 65280 sections, to improve conformance with the ELF specification and interoperability with other ELF tools. Specifically, it no longer adds 256 to section indices SHN_LORESERVE and higher to skip over the reserved range SHN_LORESERVE through SHN_HIRESERVE; those values are only considered special in the st_shndx field, and not in other places where section indices are stored. See: http://sourceware.org/bugzilla/show_bug.cgi?id=5900 http://groups.google.com/group/generic-abi/browse_thread/thread/e8bb63714b072e67/6c63738f12cc8a17 Signed-off-by: Anders Kaseorg <andersk@ksplice.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--scripts/mod/modpost.c16
-rw-r--r--scripts/mod/modpost.h27
2 files changed, 14 insertions, 29 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index cd104afcc5f2..413c53693e62 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -420,11 +420,10 @@ static int parse_elf(struct elf_info *info, const char *filename)
return 0;
}
- if (hdr->e_shnum == 0) {
+ if (hdr->e_shnum == SHN_UNDEF) {
/*
* There are more than 64k sections,
* read count from .sh_size.
- * note: it doesn't need shndx2secindex()
*/
info->num_sections = TO_NATIVE(sechdrs[0].sh_size);
}
@@ -432,8 +431,7 @@ static int parse_elf(struct elf_info *info, const char *filename)
info->num_sections = hdr->e_shnum;
}
if (hdr->e_shstrndx == SHN_XINDEX) {
- info->secindex_strings =
- shndx2secindex(TO_NATIVE(sechdrs[0].sh_link));
+ info->secindex_strings = TO_NATIVE(sechdrs[0].sh_link);
}
else {
info->secindex_strings = hdr->e_shstrndx;
@@ -489,7 +487,7 @@ static int parse_elf(struct elf_info *info, const char *filename)
sechdrs[i].sh_offset;
info->symtab_stop = (void *)hdr +
sechdrs[i].sh_offset + sechdrs[i].sh_size;
- sh_link_idx = shndx2secindex(sechdrs[i].sh_link);
+ sh_link_idx = sechdrs[i].sh_link;
info->strtab = (void *)hdr +
sechdrs[sh_link_idx].sh_offset;
}
@@ -516,11 +514,9 @@ static int parse_elf(struct elf_info *info, const char *filename)
if (symtab_shndx_idx != ~0U) {
Elf32_Word *p;
- if (symtab_idx !=
- shndx2secindex(sechdrs[symtab_shndx_idx].sh_link))
+ if (symtab_idx != sechdrs[symtab_shndx_idx].sh_link)
fatal("%s: SYMTAB_SHNDX has bad sh_link: %u!=%u\n",
- filename,
- shndx2secindex(sechdrs[symtab_shndx_idx].sh_link),
+ filename, sechdrs[symtab_shndx_idx].sh_link,
symtab_idx);
/* Fix endianness */
for (p = info->symtab_shndx_start; p < info->symtab_shndx_stop;
@@ -1446,7 +1442,7 @@ static unsigned int *reloc_location(struct elf_info *elf,
Elf_Shdr *sechdr, Elf_Rela *r)
{
Elf_Shdr *sechdrs = elf->sechdrs;
- int section = shndx2secindex(sechdr->sh_info);
+ int section = sechdr->sh_info;
return (void *)elf->hdr + sechdrs[section].sh_offset +
r->r_offset;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 0388cfccac8d..2031119080dc 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -145,33 +145,22 @@ static inline int is_shndx_special(unsigned int i)
return i != SHN_XINDEX && i >= SHN_LORESERVE && i <= SHN_HIRESERVE;
}
-/* shndx is in [0..SHN_LORESERVE) U (SHN_HIRESERVE, 0xfffffff], thus:
- * shndx == 0 <=> sechdrs[0]
- * ......
- * shndx == SHN_LORESERVE-1 <=> sechdrs[SHN_LORESERVE-1]
- * shndx == SHN_HIRESERVE+1 <=> sechdrs[SHN_LORESERVE]
- * shndx == SHN_HIRESERVE+2 <=> sechdrs[SHN_LORESERVE+1]
- * ......
- * fyi: sym->st_shndx is uint16, SHN_LORESERVE = ff00, SHN_HIRESERVE = ffff,
- * so basically we map 0000..feff -> 0000..feff
- * ff00..ffff -> (you are a bad boy, dont do it)
- * 10000..xxxx -> ff00..(xxxx-0x100)
+/*
+ * Move reserved section indices SHN_LORESERVE..SHN_HIRESERVE out of
+ * the way to -256..-1, to avoid conflicting with real section
+ * indices.
*/
-static inline unsigned int shndx2secindex(unsigned int i)
-{
- if (i <= SHN_HIRESERVE)
- return i;
- return i - (SHN_HIRESERVE + 1 - SHN_LORESERVE);
-}
+#define SPECIAL(i) ((i) - (SHN_HIRESERVE + 1))
/* Accessor for sym->st_shndx, hides ugliness of "64k sections" */
static inline unsigned int get_secindex(const struct elf_info *info,
const Elf_Sym *sym)
{
+ if (is_shndx_special(sym->st_shndx))
+ return SPECIAL(sym->st_shndx);
if (sym->st_shndx != SHN_XINDEX)
return sym->st_shndx;
- return shndx2secindex(info->symtab_shndx_start[sym -
- info->symtab_start]);
+ return info->symtab_shndx_start[sym - info->symtab_start];
}
/* file2alias.c */