1 /* 2 * arch/arm/probes/kprobes/checkers-common.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 enum probes_insn checker_stack_use_none(probes_opcode_t insn, 22 struct arch_probes_insn *asi, 23 const struct decode_header *h) 24 { 25 asi->stack_space = 0; 26 return INSN_GOOD_NO_SLOT; 27 } 28 29 enum probes_insn checker_stack_use_unknown(probes_opcode_t insn, 30 struct arch_probes_insn *asi, 31 const struct decode_header *h) 32 { 33 asi->stack_space = -1; 34 return INSN_GOOD_NO_SLOT; 35 } 36 37 #ifdef CONFIG_THUMB2_KERNEL 38 enum probes_insn checker_stack_use_imm_0xx(probes_opcode_t insn, 39 struct arch_probes_insn *asi, 40 const struct decode_header *h) 41 { 42 int imm = insn & 0xff; 43 asi->stack_space = imm; 44 return INSN_GOOD_NO_SLOT; 45 } 46 47 /* 48 * Different from other insn uses imm8, the real addressing offset of 49 * STRD in T32 encoding should be imm8 * 4. See ARMARM description. 50 */ 51 enum probes_insn checker_stack_use_t32strd(probes_opcode_t insn, 52 struct arch_probes_insn *asi, 53 const struct decode_header *h) 54 { 55 int imm = insn & 0xff; 56 asi->stack_space = imm << 2; 57 return INSN_GOOD_NO_SLOT; 58 } 59 #else 60 enum probes_insn checker_stack_use_imm_x0x(probes_opcode_t insn, 61 struct arch_probes_insn *asi, 62 const struct decode_header *h) 63 { 64 int imm = ((insn & 0xf00) >> 4) + (insn & 0xf); 65 asi->stack_space = imm; 66 return INSN_GOOD_NO_SLOT; 67 } 68 #endif 69 70 enum probes_insn checker_stack_use_imm_xxx(probes_opcode_t insn, 71 struct arch_probes_insn *asi, 72 const struct decode_header *h) 73 { 74 int imm = insn & 0xfff; 75 asi->stack_space = imm; 76 return INSN_GOOD_NO_SLOT; 77 } 78 79 enum probes_insn checker_stack_use_stmdx(probes_opcode_t insn, 80 struct arch_probes_insn *asi, 81 const struct decode_header *h) 82 { 83 unsigned int reglist = insn & 0xffff; 84 int pbit = insn & (1 << 24); 85 asi->stack_space = (hweight32(reglist) - (!pbit ? 1 : 0)) * 4; 86 87 return INSN_GOOD_NO_SLOT; 88 } 89 90 const union decode_action stack_check_actions[] = { 91 [STACK_USE_NONE] = {.decoder = checker_stack_use_none}, 92 [STACK_USE_UNKNOWN] = {.decoder = checker_stack_use_unknown}, 93 #ifdef CONFIG_THUMB2_KERNEL 94 [STACK_USE_FIXED_0XX] = {.decoder = checker_stack_use_imm_0xx}, 95 [STACK_USE_T32STRD] = {.decoder = checker_stack_use_t32strd}, 96 #else 97 [STACK_USE_FIXED_X0X] = {.decoder = checker_stack_use_imm_x0x}, 98 #endif 99 [STACK_USE_FIXED_XXX] = {.decoder = checker_stack_use_imm_xxx}, 100 [STACK_USE_STMDX] = {.decoder = checker_stack_use_stmdx}, 101 }; 102