173 lines
3.6 KiB
C
173 lines
3.6 KiB
C
/*
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* Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (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, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#define unlikely(cond) (cond)
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#include "insn/insn.h"
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#include "insn/inat.c"
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#include "insn/insn.c"
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#include "../../elf.h"
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#include "../../arch.h"
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#include "../../warn.h"
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static int is_x86_64(struct elf *elf)
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{
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switch (elf->ehdr.e_machine) {
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case EM_X86_64:
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return 1;
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case EM_386:
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return 0;
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default:
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WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
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return -1;
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}
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}
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int arch_decode_instruction(struct elf *elf, struct section *sec,
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unsigned long offset, unsigned int maxlen,
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unsigned int *len, unsigned char *type,
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unsigned long *immediate)
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{
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struct insn insn;
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int x86_64;
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unsigned char op1, op2, ext;
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x86_64 = is_x86_64(elf);
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if (x86_64 == -1)
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return -1;
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insn_init(&insn, (void *)(sec->data + offset), maxlen, x86_64);
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insn_get_length(&insn);
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insn_get_opcode(&insn);
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insn_get_modrm(&insn);
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insn_get_immediate(&insn);
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if (!insn_complete(&insn)) {
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WARN_FUNC("can't decode instruction", sec, offset);
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return -1;
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}
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*len = insn.length;
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*type = INSN_OTHER;
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if (insn.vex_prefix.nbytes)
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return 0;
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op1 = insn.opcode.bytes[0];
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op2 = insn.opcode.bytes[1];
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switch (op1) {
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case 0x55:
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if (!insn.rex_prefix.nbytes)
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/* push rbp */
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*type = INSN_FP_SAVE;
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break;
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case 0x5d:
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if (!insn.rex_prefix.nbytes)
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/* pop rbp */
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*type = INSN_FP_RESTORE;
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break;
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case 0x70 ... 0x7f:
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*type = INSN_JUMP_CONDITIONAL;
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break;
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case 0x89:
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if (insn.rex_prefix.nbytes == 1 &&
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insn.rex_prefix.bytes[0] == 0x48 &&
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insn.modrm.nbytes && insn.modrm.bytes[0] == 0xe5)
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/* mov rsp, rbp */
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*type = INSN_FP_SETUP;
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break;
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case 0x90:
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*type = INSN_NOP;
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break;
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case 0x0f:
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if (op2 >= 0x80 && op2 <= 0x8f)
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*type = INSN_JUMP_CONDITIONAL;
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else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
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op2 == 0x35)
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/* sysenter, sysret */
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*type = INSN_CONTEXT_SWITCH;
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else if (op2 == 0x0b || op2 == 0xb9)
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/* ud2 */
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*type = INSN_BUG;
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else if (op2 == 0x0d || op2 == 0x1f)
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/* nopl/nopw */
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*type = INSN_NOP;
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else if (op2 == 0x01 && insn.modrm.nbytes &&
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(insn.modrm.bytes[0] == 0xc2 ||
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insn.modrm.bytes[0] == 0xd8))
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/* vmlaunch, vmrun */
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*type = INSN_CONTEXT_SWITCH;
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break;
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case 0xc9: /* leave */
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*type = INSN_FP_RESTORE;
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break;
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case 0xe3: /* jecxz/jrcxz */
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*type = INSN_JUMP_CONDITIONAL;
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break;
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case 0xe9:
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case 0xeb:
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*type = INSN_JUMP_UNCONDITIONAL;
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break;
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case 0xc2:
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case 0xc3:
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*type = INSN_RETURN;
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break;
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case 0xc5: /* iret */
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case 0xca: /* retf */
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case 0xcb: /* retf */
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*type = INSN_CONTEXT_SWITCH;
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break;
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case 0xe8:
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*type = INSN_CALL;
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break;
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case 0xff:
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ext = X86_MODRM_REG(insn.modrm.bytes[0]);
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if (ext == 2 || ext == 3)
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*type = INSN_CALL_DYNAMIC;
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else if (ext == 4)
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*type = INSN_JUMP_DYNAMIC;
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else if (ext == 5) /*jmpf */
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*type = INSN_CONTEXT_SWITCH;
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break;
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default:
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break;
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}
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*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;
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return 0;
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}
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