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; |
} |
} |
|
} |
|
/** @} |
*/ |