![Jonas Bonn](/assets/img/avatar_default.png)
This patch removes all the module loader hook implementations in the architecture specific code where the functionality is the same as that now provided by the recently added default hooks. Signed-off-by: Jonas Bonn <jonas@southpole.se> Acked-by: Mike Frysinger <vapier@gentoo.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
310 lines
8.7 KiB
C
310 lines
8.7 KiB
C
/* Kernel module help for PPC.
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Copyright (C) 2001 Rusty Russell.
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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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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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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 <linux/module.h>
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#include <linux/moduleloader.h>
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#include <linux/elf.h>
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#include <linux/vmalloc.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/ftrace.h>
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#include <linux/cache.h>
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#include <linux/bug.h>
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#include <linux/sort.h>
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#include "setup.h"
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#if 0
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#define DEBUGP printk
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#else
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#define DEBUGP(fmt , ...)
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#endif
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/* Count how many different relocations (different symbol, different
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addend) */
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static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num)
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{
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unsigned int i, r_info, r_addend, _count_relocs;
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_count_relocs = 0;
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r_info = 0;
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r_addend = 0;
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for (i = 0; i < num; i++)
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/* Only count 24-bit relocs, others don't need stubs */
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if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 &&
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(r_info != ELF32_R_SYM(rela[i].r_info) ||
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r_addend != rela[i].r_addend)) {
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_count_relocs++;
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r_info = ELF32_R_SYM(rela[i].r_info);
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r_addend = rela[i].r_addend;
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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_count_relocs++; /* add one for ftrace_caller */
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#endif
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return _count_relocs;
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}
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static int relacmp(const void *_x, const void *_y)
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{
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const Elf32_Rela *x, *y;
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y = (Elf32_Rela *)_x;
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x = (Elf32_Rela *)_y;
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/* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to
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* make the comparison cheaper/faster. It won't affect the sorting or
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* the counting algorithms' performance
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*/
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if (x->r_info < y->r_info)
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return -1;
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else if (x->r_info > y->r_info)
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return 1;
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else if (x->r_addend < y->r_addend)
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return -1;
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else if (x->r_addend > y->r_addend)
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return 1;
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else
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return 0;
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}
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static void relaswap(void *_x, void *_y, int size)
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{
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uint32_t *x, *y, tmp;
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int i;
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y = (uint32_t *)_x;
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x = (uint32_t *)_y;
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for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) {
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tmp = x[i];
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x[i] = y[i];
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y[i] = tmp;
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}
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}
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/* Get the potential trampolines size required of the init and
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non-init sections */
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static unsigned long get_plt_size(const Elf32_Ehdr *hdr,
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const Elf32_Shdr *sechdrs,
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const char *secstrings,
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int is_init)
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{
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unsigned long ret = 0;
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unsigned i;
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/* Everything marked ALLOC (this includes the exported
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symbols) */
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for (i = 1; i < hdr->e_shnum; i++) {
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/* If it's called *.init*, and we're not init, we're
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not interested */
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if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0)
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!= is_init)
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continue;
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/* We don't want to look at debug sections. */
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if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0)
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continue;
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if (sechdrs[i].sh_type == SHT_RELA) {
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DEBUGP("Found relocations in section %u\n", i);
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DEBUGP("Ptr: %p. Number: %u\n",
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(void *)hdr + sechdrs[i].sh_offset,
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sechdrs[i].sh_size / sizeof(Elf32_Rela));
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/* Sort the relocation information based on a symbol and
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* addend key. This is a stable O(n*log n) complexity
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* alogrithm but it will reduce the complexity of
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* count_relocs() to linear complexity O(n)
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*/
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sort((void *)hdr + sechdrs[i].sh_offset,
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sechdrs[i].sh_size / sizeof(Elf32_Rela),
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sizeof(Elf32_Rela), relacmp, relaswap);
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ret += count_relocs((void *)hdr
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+ sechdrs[i].sh_offset,
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sechdrs[i].sh_size
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/ sizeof(Elf32_Rela))
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* sizeof(struct ppc_plt_entry);
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}
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}
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return ret;
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}
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int module_frob_arch_sections(Elf32_Ehdr *hdr,
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Elf32_Shdr *sechdrs,
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char *secstrings,
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struct module *me)
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{
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unsigned int i;
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/* Find .plt and .init.plt sections */
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for (i = 0; i < hdr->e_shnum; i++) {
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if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0)
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me->arch.init_plt_section = i;
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else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0)
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me->arch.core_plt_section = i;
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}
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if (!me->arch.core_plt_section || !me->arch.init_plt_section) {
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printk("Module doesn't contain .plt or .init.plt sections.\n");
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return -ENOEXEC;
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}
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/* Override their sizes */
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sechdrs[me->arch.core_plt_section].sh_size
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= get_plt_size(hdr, sechdrs, secstrings, 0);
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sechdrs[me->arch.init_plt_section].sh_size
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= get_plt_size(hdr, sechdrs, secstrings, 1);
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return 0;
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}
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static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val)
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{
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if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16)
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&& entry->jump[1] == 0x396b0000 + (val & 0xffff))
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return 1;
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return 0;
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}
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/* Set up a trampoline in the PLT to bounce us to the distant function */
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static uint32_t do_plt_call(void *location,
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Elf32_Addr val,
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Elf32_Shdr *sechdrs,
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struct module *mod)
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{
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struct ppc_plt_entry *entry;
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DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location);
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/* Init, or core PLT? */
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if (location >= mod->module_core
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&& location < mod->module_core + mod->core_size)
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entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr;
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else
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entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr;
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/* Find this entry, or if that fails, the next avail. entry */
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while (entry->jump[0]) {
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if (entry_matches(entry, val)) return (uint32_t)entry;
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entry++;
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}
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/* Stolen from Paul Mackerras as well... */
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entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */
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entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/
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entry->jump[2] = 0x7d6903a6; /* mtctr r11 */
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entry->jump[3] = 0x4e800420; /* bctr */
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DEBUGP("Initialized plt for 0x%x at %p\n", val, entry);
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return (uint32_t)entry;
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}
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int apply_relocate_add(Elf32_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex,
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unsigned int relsec,
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struct module *module)
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{
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unsigned int i;
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Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
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Elf32_Sym *sym;
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uint32_t *location;
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uint32_t value;
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DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
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sechdrs[relsec].sh_info);
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for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
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/* This is where to make the change */
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location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
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+ rela[i].r_offset;
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/* This is the symbol it is referring to. Note that all
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undefined symbols have been resolved. */
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sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
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+ ELF32_R_SYM(rela[i].r_info);
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/* `Everything is relative'. */
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value = sym->st_value + rela[i].r_addend;
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switch (ELF32_R_TYPE(rela[i].r_info)) {
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case R_PPC_ADDR32:
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/* Simply set it */
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*(uint32_t *)location = value;
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break;
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case R_PPC_ADDR16_LO:
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/* Low half of the symbol */
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*(uint16_t *)location = value;
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break;
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case R_PPC_ADDR16_HI:
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/* Higher half of the symbol */
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*(uint16_t *)location = (value >> 16);
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break;
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case R_PPC_ADDR16_HA:
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/* Sign-adjusted lower 16 bits: PPC ELF ABI says:
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(((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF.
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This is the same, only sane.
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*/
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*(uint16_t *)location = (value + 0x8000) >> 16;
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break;
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case R_PPC_REL24:
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if ((int)(value - (uint32_t)location) < -0x02000000
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|| (int)(value - (uint32_t)location) >= 0x02000000)
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value = do_plt_call(location, value,
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sechdrs, module);
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/* Only replace bits 2 through 26 */
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DEBUGP("REL24 value = %08X. location = %08X\n",
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value, (uint32_t)location);
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DEBUGP("Location before: %08X.\n",
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*(uint32_t *)location);
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*(uint32_t *)location
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= (*(uint32_t *)location & ~0x03fffffc)
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| ((value - (uint32_t)location)
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& 0x03fffffc);
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DEBUGP("Location after: %08X.\n",
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*(uint32_t *)location);
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DEBUGP("ie. jump to %08X+%08X = %08X\n",
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*(uint32_t *)location & 0x03fffffc,
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(uint32_t)location,
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(*(uint32_t *)location & 0x03fffffc)
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+ (uint32_t)location);
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break;
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case R_PPC_REL32:
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/* 32-bit relative jump. */
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*(uint32_t *)location = value - (uint32_t)location;
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break;
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default:
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printk("%s: unknown ADD relocation: %u\n",
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module->name,
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ELF32_R_TYPE(rela[i].r_info));
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return -ENOEXEC;
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}
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}
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#ifdef CONFIG_DYNAMIC_FTRACE
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module->arch.tramp =
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do_plt_call(module->module_core,
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(unsigned long)ftrace_caller,
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sechdrs, module);
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#endif
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return 0;
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}
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