0ed964589c
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
325 lines
8.7 KiB
C
325 lines
8.7 KiB
C
/*
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* Copyright (C) 2002 Richard Henderson
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* Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <common.h>
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#include <errno.h>
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#include <module.h>
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#include <elf.h>
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#include <malloc.h>
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#include <xfuncs.h>
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#include <command.h>
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#include <fs.h>
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#include <kallsyms.h>
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#include <linux/list.h>
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static unsigned int find_sec(Elf_Ehdr *hdr,
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Elf_Shdr *sechdrs,
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const char *secstrings,
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const char *name)
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{
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unsigned int i;
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for (i = 1; i < hdr->e_shnum; i++) {
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debug("find_sec: %s %s\n", name, secstrings+sechdrs[i].sh_name);
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/* Alloc bit cleared means "ignore it." */
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if ((sechdrs[i].sh_flags & SHF_ALLOC) &&
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!strcmp(secstrings+sechdrs[i].sh_name, name))
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return i;
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}
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return 0;
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}
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/* Provided by the linker */
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extern const struct kernel_symbol __usymtab_start[];
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extern const struct kernel_symbol __usymtab_end[];
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/* lookup symbol in given range of kernel_symbols */
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static const struct kernel_symbol *lookup_symbol(const char *name,
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const struct kernel_symbol *start,
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const struct kernel_symbol *stop)
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{
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const struct kernel_symbol *ks = start;
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for (; ks < stop; ks++) {
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if (strcmp(ks->name, name) == 0)
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return ks;
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}
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return NULL;
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}
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static unsigned long resolve_symbol(Elf32_Shdr *sechdrs,
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const char *name)
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{
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const struct kernel_symbol *ks;
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debug("%s: %s\n", __FUNCTION__, name);
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ks = lookup_symbol(name, __usymtab_start,
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__usymtab_end);
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if (ks)
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return ks->value;
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return 0;
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}
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/* Change all symbols so that sh_value encodes the pointer directly. */
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static int simplify_symbols(Elf32_Shdr *sechdrs,
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unsigned int symindex,
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const char *strtab)
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{
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Elf32_Sym *sym = (void *)sechdrs[symindex].sh_addr;
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unsigned long secbase;
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unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf32_Sym);
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int ret = 0;
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for (i = 1; i < n; i++) {
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switch (sym[i].st_shndx) {
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case SHN_COMMON:
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/* We compiled with -fno-common. These are not
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supposed to happen. */
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printf("Common symbol: %s\n", strtab + sym[i].st_name);
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printf("please compile with -fno-common\n");
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ret = -1;
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break;
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case SHN_ABS:
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/* Don't need to do anything */
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debug("Absolute symbol: 0x%08lx\n",
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(long)sym[i].st_value);
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break;
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case SHN_UNDEF:
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sym[i].st_value
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= resolve_symbol(sechdrs,
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strtab + sym[i].st_name);
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debug("undef : %20s 0x%08x 0x%08lx\n", strtab + sym[i].st_name, sym[i].st_value);
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/* Ok if resolved. */
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if (sym[i].st_value != 0)
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break;
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/* Ok if weak. */
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if (ELF32_ST_BIND(sym[i].st_info) == STB_WEAK)
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break;
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printf("Unknown symbol %s\n",
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strtab + sym[i].st_name);
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ret = -1;
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break;
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default:
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secbase = sechdrs[sym[i].st_shndx].sh_addr;
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debug("default: %20s 0x%08x 0x%08lx\n", strtab + sym[i].st_name, sym[i].st_value, secbase);
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sym[i].st_value += secbase;
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break;
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}
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}
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return ret;
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}
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#define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
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#define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
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/* Update size with this section: return offset. */
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static long get_offset(unsigned long *size, Elf32_Shdr *sechdr)
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{
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long ret;
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ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
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*size = ret + sechdr->sh_size;
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return ret;
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}
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static void layout_sections( struct module *mod,
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const Elf32_Ehdr *hdr,
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Elf32_Shdr *sechdrs,
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const char *secstrings)
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{
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static unsigned long const masks[][2] = {
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/* NOTE: all executable code must be the first section
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* in this array; otherwise modify the text_size
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* finder in the two loops below */
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{ SHF_EXECINSTR | SHF_ALLOC },
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{ SHF_ALLOC, SHF_WRITE },
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{ SHF_WRITE | SHF_ALLOC },
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{ SHF_ALLOC, 0 }
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};
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unsigned int m, i;
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for (i = 0; i < hdr->e_shnum; i++)
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sechdrs[i].sh_entsize = ~0UL;
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debug("Core section allocation order:\n");
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for (m = 0; m < ARRAY_SIZE(masks); ++m) {
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for (i = 0; i < hdr->e_shnum; ++i) {
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Elf32_Shdr *s = &sechdrs[i];
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if ((s->sh_flags & masks[m][0]) != masks[m][0]
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|| (s->sh_flags & masks[m][1])
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|| s->sh_entsize != ~0UL
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|| strncmp(secstrings + s->sh_name,
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".init", 5) == 0)
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continue;
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s->sh_entsize = get_offset(&mod->core_size, s);
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debug("\t%s 0x%08x\n", secstrings + s->sh_name, s->sh_entsize);
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}
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}
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debug("core_size: %ld\n", mod->core_size);
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}
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LIST_HEAD(module_list);
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struct module * load_module(void *mod_image, unsigned long len)
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{
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struct module *module = NULL;
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Elf32_Ehdr *ehdr; /* Elf header structure pointer */
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Elf32_Shdr *sechdrs; /* Section header structure pointer */
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Elf32_Sym *sym;
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unsigned int numsyms;
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char *strtab = 0; /* String table pointer */
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int i; /* Loop counter */
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unsigned int strindex = 0;
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unsigned int symindex = 0;
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unsigned int modindex;
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char *secstrings;
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void *ptr = NULL;
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int err;
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int cmdindex;
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if (len < sizeof(*ehdr))
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return NULL;
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ehdr = (Elf32_Ehdr *)mod_image;
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if (len < ehdr->e_shoff + ehdr->e_shnum * sizeof(Elf_Shdr))
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return NULL;
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/* Find the section header string table for output info */
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sechdrs = (Elf32_Shdr *) (mod_image + ehdr->e_shoff +
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(ehdr->e_shstrndx * sizeof (Elf32_Shdr)));
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if (sechdrs->sh_type == SHT_SYMTAB)
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strtab = (char *) (mod_image + sechdrs->sh_offset);
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/* Convenience variables */
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sechdrs = (void *)ehdr + ehdr->e_shoff;
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secstrings = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
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sechdrs[0].sh_addr = 0;
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for (i = 0; i < ehdr->e_shnum; i++) {
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debug("%d addr: 0x%08x size: 0x%08x ofs: 0x%08x\n",
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i, sechdrs[i].sh_addr, sechdrs[i].sh_size, sechdrs[i].sh_offset);
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/* Mark all sections sh_addr with their address in the
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temporary image. */
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sechdrs[i].sh_addr = (size_t)ehdr + sechdrs[i].sh_offset;
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if (sechdrs[i].sh_type == SHT_SYMTAB) {
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symindex = i;
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strindex = sechdrs[i].sh_link;
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strtab = mod_image + sechdrs[strindex].sh_offset;
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}
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}
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modindex = find_sec(ehdr, sechdrs, secstrings,
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".gnu.linkonce.this_module");
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if (!modindex) {
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printf("No module found in object\n");
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err = -ENOEXEC;
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goto cleanup;
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}
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module = (void *)sechdrs[modindex].sh_addr;
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if (symindex == 0) {
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printf("module has no symbols (stripped?)\n");
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err = -ENOEXEC;
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goto cleanup;
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}
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/* Determine total sizes, and put offsets in sh_entsize. For now
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this is done generically; there doesn't appear to be any
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special cases for the architectures. */
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layout_sections(module, ehdr, sechdrs, secstrings);
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ptr = xzalloc(module->core_size);
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module->module_core = ptr;
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/* Transfer each section which specifies SHF_ALLOC */
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debug("final section addresses:\n");
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for (i = 0; i < ehdr->e_shnum; i++) {
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void *dest;
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if (!(sechdrs[i].sh_flags & SHF_ALLOC))
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continue;
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dest = module->module_core + sechdrs[i].sh_entsize;
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debug("0x%08x dest 0x%p\n", sechdrs[i].sh_addr, dest);
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if (sechdrs[i].sh_type != SHT_NOBITS)
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memcpy(dest, (void *)sechdrs[i].sh_addr,
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sechdrs[i].sh_size);
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/* Update sh_addr to point to copy in image. */
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sechdrs[i].sh_addr = (unsigned long)dest;
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}
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/* Fix up syms, so that st_value is a pointer to location. */
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err = simplify_symbols(sechdrs, symindex, strtab);
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if (err < 0)
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goto cleanup;
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for (i = 0; i < ehdr->e_shnum; i++) {
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if (sechdrs[i].sh_type == SHT_REL) {
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apply_relocate(sechdrs, strtab, symindex, i, module);
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}
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if (sechdrs[i].sh_type == SHT_RELA)
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apply_relocate_add(sechdrs, strtab, symindex, i, module);
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}
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numsyms = sechdrs[symindex].sh_size / sizeof(Elf32_Sym);
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sym = (void *)sechdrs[symindex].sh_addr;
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cmdindex = find_sec(ehdr, sechdrs, secstrings, ".barebox_cmd");
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if (cmdindex) {
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struct command *cmd =(struct command *)sechdrs[cmdindex].sh_addr;
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for (i = 0; i < sechdrs[cmdindex].sh_size / sizeof(struct command); i++) {
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register_command(cmd);
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cmd++;
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}
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}
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for (i = 0; i < numsyms; i++) {
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if (!strcmp(strtab + sym[i].st_name, MODULE_SYMBOL_PREFIX "init_module")) {
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printf("found init_module() at 0x%08x\n", sym[i].st_value);
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module->init = (void *)sym[i].st_value;
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}
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}
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list_add_tail(&module->list, &module_list);
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return module;
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cleanup:
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if (ptr)
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free(ptr);
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if (module)
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free(module);
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return NULL;
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}
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