Wang Nan | 6624cf6 | 2015-01-05 19:29:21 +0800 | [diff] [blame] | 1 | /* |
| 2 | * arch/arm/probes/kprobes/checkers-arm.c |
| 3 | * |
| 4 | * Copyright (C) 2014 Huawei Inc. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
| 17 | #include "../decode.h" |
| 18 | #include "../decode-arm.h" |
| 19 | #include "checkers.h" |
| 20 | |
| 21 | static enum probes_insn __kprobes arm_check_stack(probes_opcode_t insn, |
| 22 | struct arch_probes_insn *asi, |
| 23 | const struct decode_header *h) |
| 24 | { |
| 25 | /* |
| 26 | * PROBES_LDRSTRD, PROBES_LDMSTM, PROBES_STORE, |
| 27 | * PROBES_STORE_EXTRA may get here. Simply mark all normal |
| 28 | * insns as STACK_USE_NONE. |
| 29 | */ |
| 30 | static const union decode_item table[] = { |
| 31 | /* |
| 32 | * 'STR{,D,B,H}, Rt, [Rn, Rm]' should be marked as UNKNOWN |
| 33 | * if Rn or Rm is SP. |
| 34 | * x |
| 35 | * STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx |
| 36 | * STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx |
| 37 | */ |
| 38 | DECODE_OR (0x0e10000f, 0x0600000d), |
| 39 | DECODE_OR (0x0e1f0000, 0x060d0000), |
| 40 | |
| 41 | /* |
| 42 | * x |
| 43 | * STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx |
| 44 | * STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx |
| 45 | */ |
| 46 | DECODE_OR (0x0e5000bf, 0x000000bd), |
| 47 | DECODE_CUSTOM (0x0e5f00b0, 0x000d00b0, STACK_USE_UNKNOWN), |
| 48 | |
| 49 | /* |
| 50 | * For PROBES_LDMSTM, only stmdx sp, [...] need to examine |
| 51 | * |
| 52 | * Bit B/A (bit 24) encodes arithmetic operation order. 1 means |
| 53 | * before, 0 means after. |
| 54 | * Bit I/D (bit 23) encodes arithmetic operation. 1 means |
| 55 | * increment, 0 means decrement. |
| 56 | * |
| 57 | * So: |
| 58 | * B I |
| 59 | * / / |
| 60 | * A D | Rn | |
| 61 | * STMDX SP, [...] cccc 100x 00x0 xxxx xxxx xxxx xxxx xxxx |
| 62 | */ |
| 63 | DECODE_CUSTOM (0x0edf0000, 0x080d0000, STACK_USE_STMDX), |
| 64 | |
| 65 | /* P U W | Rn | Rt | imm12 |*/ |
| 66 | /* STR (immediate) cccc 010x x0x0 1101 xxxx xxxx xxxx xxxx */ |
| 67 | /* STRB (immediate) cccc 010x x1x0 1101 xxxx xxxx xxxx xxxx */ |
| 68 | /* P U W | Rn | Rt |imm4| |imm4|*/ |
| 69 | /* STRD (immediate) cccc 000x x1x0 1101 xxxx xxxx 1111 xxxx */ |
| 70 | /* STRH (immediate) cccc 000x x1x0 1101 xxxx xxxx 1011 xxxx */ |
| 71 | /* |
| 72 | * index = (P == '1'); add = (U == '1'). |
| 73 | * Above insns with: |
| 74 | * index == 0 (str{,d,h} rx, [sp], #+/-imm) or |
| 75 | * add == 1 (str{,d,h} rx, [sp, #+<imm>]) |
| 76 | * should be STACK_USE_NONE. |
| 77 | * Only str{,b,d,h} rx,[sp,#-n] (P == 1 and U == 0) are |
| 78 | * required to be examined. |
| 79 | */ |
| 80 | /* STR{,B} Rt,[SP,#-n] cccc 0101 0xx0 1101 xxxx xxxx xxxx xxxx */ |
| 81 | DECODE_CUSTOM (0x0f9f0000, 0x050d0000, STACK_USE_FIXED_XXX), |
| 82 | |
| 83 | /* STR{D,H} Rt,[SP,#-n] cccc 0001 01x0 1101 xxxx xxxx 1x11 xxxx */ |
| 84 | DECODE_CUSTOM (0x0fdf00b0, 0x014d00b0, STACK_USE_FIXED_X0X), |
| 85 | |
| 86 | /* fall through */ |
| 87 | DECODE_CUSTOM (0, 0, STACK_USE_NONE), |
| 88 | DECODE_END |
| 89 | }; |
| 90 | |
| 91 | return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL); |
| 92 | } |
| 93 | |
| 94 | const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = { |
| 95 | [PROBES_LDRSTRD] = {.checker = arm_check_stack}, |
| 96 | [PROBES_STORE_EXTRA] = {.checker = arm_check_stack}, |
| 97 | [PROBES_STORE] = {.checker = arm_check_stack}, |
| 98 | [PROBES_LDMSTM] = {.checker = arm_check_stack}, |
| 99 | }; |
Wang Nan | 28a1899 | 2015-01-05 19:29:44 +0800 | [diff] [blame] | 100 | |
| 101 | static enum probes_insn __kprobes arm_check_regs_nouse(probes_opcode_t insn, |
| 102 | struct arch_probes_insn *asi, |
| 103 | const struct decode_header *h) |
| 104 | { |
| 105 | asi->register_usage_flags = 0; |
| 106 | return INSN_GOOD; |
| 107 | } |
| 108 | |
| 109 | static enum probes_insn arm_check_regs_normal(probes_opcode_t insn, |
| 110 | struct arch_probes_insn *asi, |
| 111 | const struct decode_header *h) |
| 112 | { |
| 113 | u32 regs = h->type_regs.bits >> DECODE_TYPE_BITS; |
| 114 | int i; |
| 115 | |
| 116 | asi->register_usage_flags = 0; |
| 117 | for (i = 0; i < 5; regs >>= 4, insn >>= 4, i++) |
| 118 | if (regs & 0xf) |
| 119 | asi->register_usage_flags |= 1 << (insn & 0xf); |
| 120 | |
| 121 | return INSN_GOOD; |
| 122 | } |
| 123 | |
| 124 | |
| 125 | static enum probes_insn arm_check_regs_ldmstm(probes_opcode_t insn, |
| 126 | struct arch_probes_insn *asi, |
| 127 | const struct decode_header *h) |
| 128 | { |
| 129 | unsigned int reglist = insn & 0xffff; |
| 130 | unsigned int rn = (insn >> 16) & 0xf; |
| 131 | asi->register_usage_flags = reglist | (1 << rn); |
| 132 | return INSN_GOOD; |
| 133 | } |
| 134 | |
| 135 | static enum probes_insn arm_check_regs_mov_ip_sp(probes_opcode_t insn, |
| 136 | struct arch_probes_insn *asi, |
| 137 | const struct decode_header *h) |
| 138 | { |
| 139 | /* Instruction is 'mov ip, sp' i.e. 'mov r12, r13' */ |
| 140 | asi->register_usage_flags = (1 << 12) | (1<< 13); |
| 141 | return INSN_GOOD; |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * | Rn |Rt/d| | Rm | |
| 146 | * LDRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1101 xxxx |
| 147 | * STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx |
| 148 | * | Rn |Rt/d| |imm4L| |
| 149 | * LDRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1101 xxxx |
| 150 | * STRD (immediate) cccc 000x x1x0 xxxx xxxx xxxx 1111 xxxx |
| 151 | * |
| 152 | * Such instructions access Rt/d and its next register, so different |
| 153 | * from others, a specific checker is required to handle this extra |
| 154 | * implicit register usage. |
| 155 | */ |
| 156 | static enum probes_insn arm_check_regs_ldrdstrd(probes_opcode_t insn, |
| 157 | struct arch_probes_insn *asi, |
| 158 | const struct decode_header *h) |
| 159 | { |
| 160 | int rdt = (insn >> 12) & 0xf; |
| 161 | arm_check_regs_normal(insn, asi, h); |
| 162 | asi->register_usage_flags |= 1 << (rdt + 1); |
| 163 | return INSN_GOOD; |
| 164 | } |
| 165 | |
| 166 | |
| 167 | const struct decode_checker arm_regs_checker[NUM_PROBES_ARM_ACTIONS] = { |
| 168 | [PROBES_MRS] = {.checker = arm_check_regs_normal}, |
| 169 | [PROBES_SATURATING_ARITHMETIC] = {.checker = arm_check_regs_normal}, |
| 170 | [PROBES_MUL1] = {.checker = arm_check_regs_normal}, |
| 171 | [PROBES_MUL2] = {.checker = arm_check_regs_normal}, |
| 172 | [PROBES_MUL_ADD_LONG] = {.checker = arm_check_regs_normal}, |
| 173 | [PROBES_MUL_ADD] = {.checker = arm_check_regs_normal}, |
| 174 | [PROBES_LOAD] = {.checker = arm_check_regs_normal}, |
| 175 | [PROBES_LOAD_EXTRA] = {.checker = arm_check_regs_normal}, |
| 176 | [PROBES_STORE] = {.checker = arm_check_regs_normal}, |
| 177 | [PROBES_STORE_EXTRA] = {.checker = arm_check_regs_normal}, |
| 178 | [PROBES_DATA_PROCESSING_REG] = {.checker = arm_check_regs_normal}, |
| 179 | [PROBES_DATA_PROCESSING_IMM] = {.checker = arm_check_regs_normal}, |
| 180 | [PROBES_SEV] = {.checker = arm_check_regs_nouse}, |
| 181 | [PROBES_WFE] = {.checker = arm_check_regs_nouse}, |
| 182 | [PROBES_SATURATE] = {.checker = arm_check_regs_normal}, |
| 183 | [PROBES_REV] = {.checker = arm_check_regs_normal}, |
| 184 | [PROBES_MMI] = {.checker = arm_check_regs_normal}, |
| 185 | [PROBES_PACK] = {.checker = arm_check_regs_normal}, |
| 186 | [PROBES_EXTEND] = {.checker = arm_check_regs_normal}, |
| 187 | [PROBES_EXTEND_ADD] = {.checker = arm_check_regs_normal}, |
| 188 | [PROBES_BITFIELD] = {.checker = arm_check_regs_normal}, |
| 189 | [PROBES_LDMSTM] = {.checker = arm_check_regs_ldmstm}, |
| 190 | [PROBES_MOV_IP_SP] = {.checker = arm_check_regs_mov_ip_sp}, |
| 191 | [PROBES_LDRSTRD] = {.checker = arm_check_regs_ldrdstrd}, |
| 192 | }; |