| 0,0 → 1,238 |
|---|
| /* |
| * Copyright (c) 2008 Jiri Svoboda |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup rtld rtld |
| * @brief |
| * @{ |
| */ |
| /** |
| * @file |
| */ |
| |
| #include <stdio.h> |
| |
| #include <arch.h> |
| #include <elf_dyn.h> |
| #include <symbol.h> |
| #include <rtld.h> |
| |
| #define __L(ptr) ((uint32_t)(ptr) & 0x0000ffff) |
| #define __HA(ptr) ((uint32_t)(ptr) >> 16) |
| |
| // ldis r11, .PLTtable@ha |
| static inline uint32_t _ldis(unsigned rD, uint16_t imm16) |
| { |
| /* Special case of addis: ldis rD,SIMM == addis rD,0,SIMM */ |
| return 0x3C000000 | (rD << 21) | imm16; |
| } |
| |
| static inline uint32_t _lwz(unsigned rD, uint16_t disp16, unsigned rA) |
| { |
| return 0x80000000 | (rD << 21) | (rA << 16) | disp16; |
| } |
| |
| static inline uint32_t _mtctr(unsigned rS) |
| { |
| /* mtctr rD == mtspr 9, rD */ |
| return 0x7c0003a6 | (rS << 21) | (9/*CTR*/ << 16); |
| } |
| |
| static inline uint32_t _bctr() |
| { |
| /* bcctr 0x1f, 0 */ |
| return 0x4c000420 | (0x1f/*always*/ << 21); |
| } |
| |
| /* branch */ |
| static inline uint32_t _b(uint32_t *addr, uint32_t *location) |
| { |
| uint32_t raddr = ((uint32_t)addr - (uint32_t)location) & 0x03fffffc; |
| return 0x48000000 | raddr; |
| } |
| |
| |
| /* |
| * Fill in PLT |
| */ |
| void module_process_pre_arch(module_t *m) |
| { |
| uint32_t *plt; |
| uint32_t *_plt_ent; |
| int i; |
| |
| plt = m->dyn.plt_got; |
| if (!plt) { |
| /* Module has no PLT */ |
| return; |
| } |
| |
| // PLT entries start here. However, each occupies 2 words |
| _plt_ent = plt + 18; |
| |
| // By definition of the ppc ABI, there's 1:1 correspondence |
| // between JMPREL entries and PLT entries |
| unsigned plt_n = m->dyn.plt_rel_sz / sizeof(elf_rela_t); |
| |
| uint32_t *_plt_table; |
| uint32_t *_plt_call; |
| uint32_t *_plt_resolve; |
| |
| _plt_resolve = plt; |
| _plt_call = plt + 6; |
| _plt_table = plt + 18 + plt_n; |
| |
| /* .PLTcall: */ |
| plt[6] = _ldis(11, __HA(_plt_table)); // ldis r11, .PLTtable@ha |
| plt[7] = _lwz(11, __L(_plt_table), 11); // lwz r11, .PLTtable@l(r11) |
| plt[8] = _mtctr(11); // mtctr r11 |
| plt[9] = _bctr(); |
| |
| /* .PLTi, i = 0..N-1 */ |
| // kputint(-4); |
| for (i = 0; i < plt_n; ++i) { |
| //_plt_table[i] == function address; |
| plt[18+i] = _b(_plt_call, &plt[18+i]); // b .PLTcall |
| } |
| } |
| |
| void rel_table_process(module_t *m, elf_rel_t *rt, size_t rt_size) |
| { |
| /* Unused */ |
| (void)m; (void)rt; (void)rt_size; |
| } |
| |
| /** |
| * Process (fixup) all relocations in a relocation table. |
| */ |
| void rela_table_process(module_t *m, elf_rela_t *rt, size_t rt_size) |
| { |
| int i; |
| |
| size_t rt_entries; |
| size_t r_offset; |
| elf_word r_info; |
| unsigned rel_type; |
| elf_word sym_idx; |
| uintptr_t sym_addr; |
| uintptr_t r_addend; |
| |
| elf_symbol_t *sym_table; |
| elf_symbol_t *sym; |
| uint32_t *r_ptr; |
| char *str_tab; |
| |
| elf_symbol_t *sym_def; |
| module_t *dest; |
| |
| uint32_t *plt; |
| uint32_t *_plt_table; |
| uint32_t *_plt_ent; |
| uint32_t plt_n; |
| uint32_t pidx; |
| |
| plt = m->dyn.plt_got; |
| plt_n = m->dyn.plt_rel_sz / sizeof(elf_rela_t); |
| _plt_ent = plt+ 18; |
| _plt_table = plt + 18 + plt_n; |
| |
| printf("parse relocation table\n"); |
| |
| sym_table = m->dyn.sym_tab; |
| rt_entries = rt_size / sizeof(elf_rela_t); |
| str_tab = m->dyn.str_tab; |
| |
| printf("address: 0x%x, entries: %d\n", (uintptr_t)rt, rt_entries); |
| |
| for (i = 0; i < rt_entries; ++i) { |
| printf("symbol %d: ", i); |
| r_offset = rt[i].r_offset; |
| r_info = rt[i].r_info; |
| r_addend = rt[i].r_addend; |
| |
| sym_idx = ELF32_R_SYM(r_info); |
| sym = &sym_table[sym_idx]; |
| |
| printf("name '%s', value 0x%x, size 0x%x\n", |
| str_tab + sym->st_name, |
| sym->st_value, |
| sym->st_size); |
| |
| rel_type = ELF32_R_TYPE(r_info); |
| r_ptr = (uint32_t *)(r_offset + m->bias); |
| |
| if (sym->st_name != 0) { |
| printf("rel_type: %x, rel_offset: 0x%x\n", rel_type, r_offset); |
| sym_def = symbol_def_find(str_tab + sym->st_name, &dest); |
| printf("dest name: '%s'\n", dest->dyn.soname); |
| printf("dest bias: 0x%x\n", dest->bias); |
| if (sym_def) { |
| if (sym_def->st_shndx == SHN_ABS) { |
| /* Do not add bias to absolute symbols */ |
| sym_addr = sym_def->st_value; |
| } else { |
| sym_addr = sym_def->st_value + dest->bias; |
| } |
| printf("symbol definition found, addr=0x%x\n", sym_addr); |
| } else { |
| printf("symbol definition not found\n"); |
| continue; |
| } |
| } |
| |
| switch (rel_type) { |
| case R_PPC_JMP_SLOT: |
| printf("fixup R_PPC_JMP_SLOT (b+v)\n"); |
| pidx = (r_ptr - _plt_ent) / 2; |
| if (pidx >= plt_n) { |
| printf("error: proc index out of range\n"); |
| //kputint(0xee00ee0ee00); |
| while(1); |
| } |
| _plt_table[pidx] = sym_addr; |
| break; |
| |
| case R_PPC_ADDR32: |
| printf("fixup R_PPC_ADDR32 (b+v+a)\n"); |
| *r_ptr = r_addend + sym_addr; |
| break; |
| |
| case R_PPC_RELATIVE: |
| printf("fixup R_PPC_RELATIVE (b+a)\n"); |
| *r_ptr = r_addend + m->bias; |
| break; |
| case R_PPC_REL24: |
| printf("ignore R_PPC_RELATIVE\n"); |
| /*TODO*/ |
| break; |
| } |
| } |
| |
| } |
| |
| /** @} |
| */ |