| 0,0 → 1,326 |
|---|
| /* |
| * 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 <elf_dyn.h> |
| #include <rtld.h> |
| #include <pcb.h> |
| |
| // for testing printf |
| #include <stdio.h> |
| |
| void __main(void); |
| void __io_init(void); |
| void __exit(void); |
| |
| static void kputint(unsigned i) |
| { |
| asm volatile ( |
| "mr %%r3, %0\n" |
| "li %%r9, 30\n" |
| "sc\n" |
| : |
| : "r" (i) |
| : "%r3","%r9" |
| ) ; |
| } |
| |
| #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; |
| } |
| |
| void test_func(void) |
| { |
| kputint(-1); |
| kputint(42); |
| kputint(-1); |
| } |
| |
| void __bootstrap(void); |
| |
| void __bootstrap(void) |
| { |
| unsigned bias; |
| uint32_t *plt; |
| elf_dyn_t *dynamic; |
| void *dptr; |
| unsigned dval; |
| int i; |
| |
| size_t rel_entries; |
| size_t r_offset; |
| elf_word r_info; |
| unsigned rel_type; |
| elf_word sym_idx; |
| uintptr_t sym_addr; |
| |
| elf_symbol_t *sym_table; |
| elf_rela_t *rel_table; |
| elf_rela_t *jmp_rel_table; |
| size_t jmp_rel_entries; |
| pcb_t *pcb; |
| uint32_t a, res; |
| uint32_t *r_ptr; |
| uint32_t *_plt_ent; |
| |
| kputint(42); |
| pcb = __pcb_get(); |
| |
| /* The program loader (iloader) kindly provided us with these */ |
| dynamic = pcb->rtld_dynamic; |
| bias = pcb->rtld_bias; |
| |
| kputint(bias); |
| kputint((unsigned)dynamic); |
| |
| /* parse DYNAMIC */ |
| plt = 0; |
| sym_table = 0; |
| rel_table = 0; |
| rel_entries = 0; |
| jmp_rel_table = 0; |
| jmp_rel_entries = 0; |
| |
| i = 0; |
| while (dynamic[i].d_tag != 0) { |
| // kputint((uintptr_t)&dynamic[i]); |
| // kputint((uintptr_t)&(dynamic[i].d_tag)); |
| // kputint(dynamic[i].d_tag); |
| |
| dptr = (void *)(dynamic[i].d_un.d_val + bias); |
| dval = dynamic[i].d_un.d_val; |
| |
| // kputint(0x10); |
| register unsigned tag = dynamic[i].d_tag; |
| |
| /* |
| * Note that switches only work because we are using |
| * -fno-jump-tables. |
| */ |
| switch (tag) { |
| case DT_PLTRELSZ: jmp_rel_entries = dval/8; break; |
| case DT_JMPREL: jmp_rel_table = dptr; break; |
| case DT_PLTGOT: |
| /* PLT address */ |
| plt = dptr; break; |
| case DT_SYMTAB: sym_table = dptr; break; |
| case DT_RELA: rel_table = dptr; break; |
| case DT_RELASZ: rel_entries = dval / 8; break; |
| default: break; |
| } |
| |
| // kputint(0x20); |
| |
| ++i; |
| } |
| |
| kputint(1); |
| kputint((unsigned)sym_table); |
| kputint((unsigned)rel_table); |
| kputint((unsigned)rel_entries); |
| |
| /* Now relocate all our dynsyms */ |
| kputint(-1); |
| |
| // 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 = jmp_rel_entries; |
| |
| 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; |
| |
| for (i=0; i<rel_entries; i++) { |
| // kputint(i); |
| r_offset = rel_table[i].r_offset; |
| r_info = rel_table[i].r_info; |
| r_ptr = (uint32_t *)(r_offset + bias); |
| a = rel_table[i].r_addend; |
| // kputint(-2); |
| // kputint(a); |
| // kputint(ELF32_R_TYPE(r_info)); |
| // kputint(ELF32_R_SYM(r_info)); |
| |
| rel_type = ELF32_R_TYPE(r_info); |
| |
| // kputint(rel_type); |
| // kputint(r_offset); |
| |
| switch (rel_type) { |
| case R_PPC_JMP_SLOT: |
| kputint(0xa); |
| sym_idx = ELF32_R_SYM(r_info); |
| |
| sym_addr = sym_table[sym_idx].st_value + bias; |
| kputint(sym_idx); |
| kputint(sym_addr); |
| |
| // r_ptr should point to a plt entry... |
| uint32_t pidx = (r_ptr - _plt_ent) / 2; |
| if (pidx >= plt_n) { |
| kputint(0xee00ee0ee00); |
| //while(1); |
| } |
| _plt_table[pidx] = sym_addr; |
| // kputint(pidx); |
| // plt[18] = _b(sym_addr, plt + 18); |
| // kputint(&plt[18]); |
| // kputint(plt[18]); |
| // while(1); |
| // while(1); |
| //*r_ptr = sym_addr; |
| break; |
| |
| case R_PPC_ADDR32: |
| kputint(0xb); |
| sym_idx = ELF32_R_SYM(r_info); |
| |
| sym_addr = sym_table[sym_idx].st_value + bias; |
| kputint(sym_idx); |
| kputint(sym_addr); |
| |
| *r_ptr = a + sym_addr; |
| break; |
| |
| case R_PPC_RELATIVE: |
| // kputint(0xc); |
| *r_ptr = a + bias; |
| break; |
| |
| case R_PPC_REL24: |
| kputint(0xd); |
| sym_idx = ELF32_R_SYM(r_info); |
| sym_addr = sym_table[sym_idx].st_value + bias; |
| kputint(sym_addr); |
| res = (sym_addr - (uint32_t)r_ptr + a) >> 2; |
| kputint(res); |
| if (res & 0xff000000) { |
| /* out of range?? */ |
| kputint(0xeeeeeeee); |
| //while(1); |
| } |
| *r_ptr = (*r_ptr & ~0x00ffffff) | (res & 0x00ffffff); |
| kputint(0x1d); |
| break; |
| } |
| } |
| |
| kputint(-3); |
| if (plt != 0) { |
| |
| /* .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 |
| } |
| |
| kputint(-5); |
| |
| /* This will come in handy */ |
| // runtime_env.rtld_dynamic = dynamic; |
| // runtime_env.rtld.bias = bias; |
| |
| kputint(_plt_table[0]); |
| } |
| // volatile int ff=1; |
| // while(ff); |
| test_func(); |
| kputint(0x42); |
| // while(1); |
| /* Init libc and run rtld main */ |
| kputint(0x22); |
| __main(); |
| |
| kputint(33); |
| __io_init(); |
| kputint(-1); |
| kputint(0x52); |
| printf("Hello, world! (from ppc rtld)\n"); |
| kputint(0x62); |
| while(1); |
| // kputint(34); |
| // _rtld_main(); |
| // kputint(35); |
| // __exit(); |
| |
| // kputint(36); |
| } |
| |
| /** @} |
| */ |