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elf: Move _dl_setup_hash to its own file 

And compile it with the early CFLAGS.  _dl_setup_hash is called
very early for the ld.so link map, so it should be compiled
differently.

Reviewed-by: Stefan Liebler <stli@linux.ibm.com>
Tested-by: Stefan Liebler <stli@linux.ibm.com>
This commit is contained in:
Florian Weimer 2022-01-18 13:53:11 +01:00
parent f8b765bec4
commit c90363403b
3 changed files with 65 additions and 45 deletions
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2
elf/Makefile
View File

@ -74,6 +74,7 @@ dl-routines = \
dl-reloc \
dl-runtime \
dl-scope \
dl-setup_hash \
dl-sort-maps \
dl-thread_gscope_wait \
dl-tls \
@ -169,6 +170,7 @@ CFLAGS-.os += $(call elide-stack-protector,.os,$(all-rtld-routines))
# Add the requested compiler flags to the early startup code.
CFLAGS-dl-printf.os += $(rtld-early-cflags)
CFLAGS-dl-setup_hash.os += $(rtld-early-cflags)
CFLAGS-dl-sysdep.os += $(rtld-early-cflags)
CFLAGS-dl-tunables.os += $(rtld-early-cflags)
CFLAGS-dl-write.os += $(rtld-early-cflags)

45
elf/dl-lookup.c
View File

@ -953,51 +953,6 @@ _dl_lookup_symbol_x (const char *undef_name, struct link_map *undef_map,
}
/* Cache the location of MAP's hash table. */
void
_dl_setup_hash (struct link_map *map)
{
Elf_Symndx *hash;
if (__glibc_likely (map->l_info[ELF_MACHINE_GNU_HASH_ADDRIDX] != NULL))
{
Elf32_Word *hash32
= (void *) D_PTR (map, l_info[ELF_MACHINE_GNU_HASH_ADDRIDX]);
map->l_nbuckets = *hash32++;
Elf32_Word symbias = *hash32++;
Elf32_Word bitmask_nwords = *hash32++;
/* Must be a power of two. */
assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
map->l_gnu_shift = *hash32++;
map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
map->l_gnu_buckets = hash32;
hash32 += map->l_nbuckets;
map->l_gnu_chain_zero = hash32 - symbias;
/* Initialize MIPS xhash translation table. */
ELF_MACHINE_XHASH_SETUP (hash32, symbias, map);
return;
}
if (!map->l_info[DT_HASH])
return;
hash = (void *) D_PTR (map, l_info[DT_HASH]);
map->l_nbuckets = *hash++;
/* Skip nchain. */
hash++;
map->l_buckets = hash;
hash += map->l_nbuckets;
map->l_chain = hash;
}
static void
_dl_debug_bindings (const char *undef_name, struct link_map *undef_map,
const ElfW(Sym) **ref, struct sym_val *value,

63
elf/dl-setup_hash.c Normal file
View File

@ -0,0 +1,63 @@
/* Cache the location of a link map hash table.
Copyright (C) 1995-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <assert.h>
#include <link.h>
#include <ldsodefs.h>
void
_dl_setup_hash (struct link_map *map)
{
Elf_Symndx *hash;
if (__glibc_likely (map->l_info[ELF_MACHINE_GNU_HASH_ADDRIDX] != NULL))
{
Elf32_Word *hash32
= (void *) D_PTR (map, l_info[ELF_MACHINE_GNU_HASH_ADDRIDX]);
map->l_nbuckets = *hash32++;
Elf32_Word symbias = *hash32++;
Elf32_Word bitmask_nwords = *hash32++;
/* Must be a power of two. */
assert ((bitmask_nwords & (bitmask_nwords - 1)) == 0);
map->l_gnu_bitmask_idxbits = bitmask_nwords - 1;
map->l_gnu_shift = *hash32++;
map->l_gnu_bitmask = (ElfW(Addr) *) hash32;
hash32 += __ELF_NATIVE_CLASS / 32 * bitmask_nwords;
map->l_gnu_buckets = hash32;
hash32 += map->l_nbuckets;
map->l_gnu_chain_zero = hash32 - symbias;
/* Initialize MIPS xhash translation table. */
ELF_MACHINE_XHASH_SETUP (hash32, symbias, map);
return;
}
if (!map->l_info[DT_HASH])
return;
hash = (void *) D_PTR (map, l_info[DT_HASH]);
map->l_nbuckets = *hash++;
/* Skip nchain. */
hash++;
map->l_buckets = hash;
hash += map->l_nbuckets;
map->l_chain = hash;
}