16624cf65SWang Nan /* 26624cf65SWang Nan * arch/arm/probes/kprobes/checkers-arm.c 36624cf65SWang Nan * 46624cf65SWang Nan * Copyright (C) 2014 Huawei Inc. 56624cf65SWang Nan * 66624cf65SWang Nan * This program is free software; you can redistribute it and/or modify 76624cf65SWang Nan * it under the terms of the GNU General Public License version 2 as 86624cf65SWang Nan * published by the Free Software Foundation. 96624cf65SWang Nan * 106624cf65SWang Nan * This program is distributed in the hope that it will be useful, 116624cf65SWang Nan * but WITHOUT ANY WARRANTY; without even the implied warranty of 126624cf65SWang Nan * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 136624cf65SWang Nan * General Public License for more details. 146624cf65SWang Nan */ 156624cf65SWang Nan 166624cf65SWang Nan #include <linux/kernel.h> 176624cf65SWang Nan #include "../decode.h" 186624cf65SWang Nan #include "../decode-arm.h" 196624cf65SWang Nan #include "checkers.h" 206624cf65SWang Nan 216624cf65SWang Nan static enum probes_insn __kprobes arm_check_stack(probes_opcode_t insn, 226624cf65SWang Nan struct arch_probes_insn *asi, 236624cf65SWang Nan const struct decode_header *h) 246624cf65SWang Nan { 256624cf65SWang Nan /* 266624cf65SWang Nan * PROBES_LDRSTRD, PROBES_LDMSTM, PROBES_STORE, 276624cf65SWang Nan * PROBES_STORE_EXTRA may get here. Simply mark all normal 286624cf65SWang Nan * insns as STACK_USE_NONE. 296624cf65SWang Nan */ 306624cf65SWang Nan static const union decode_item table[] = { 316624cf65SWang Nan /* 326624cf65SWang Nan * 'STR{,D,B,H}, Rt, [Rn, Rm]' should be marked as UNKNOWN 336624cf65SWang Nan * if Rn or Rm is SP. 346624cf65SWang Nan * x 356624cf65SWang Nan * STR (register) cccc 011x x0x0 xxxx xxxx xxxx xxxx xxxx 366624cf65SWang Nan * STRB (register) cccc 011x x1x0 xxxx xxxx xxxx xxxx xxxx 376624cf65SWang Nan */ 386624cf65SWang Nan DECODE_OR (0x0e10000f, 0x0600000d), 396624cf65SWang Nan DECODE_OR (0x0e1f0000, 0x060d0000), 406624cf65SWang Nan 416624cf65SWang Nan /* 426624cf65SWang Nan * x 436624cf65SWang Nan * STRD (register) cccc 000x x0x0 xxxx xxxx xxxx 1111 xxxx 446624cf65SWang Nan * STRH (register) cccc 000x x0x0 xxxx xxxx xxxx 1011 xxxx 456624cf65SWang Nan */ 466624cf65SWang Nan DECODE_OR (0x0e5000bf, 0x000000bd), 476624cf65SWang Nan DECODE_CUSTOM (0x0e5f00b0, 0x000d00b0, STACK_USE_UNKNOWN), 486624cf65SWang Nan 496624cf65SWang Nan /* 506624cf65SWang Nan * For PROBES_LDMSTM, only stmdx sp, [...] need to examine 516624cf65SWang Nan * 526624cf65SWang Nan * Bit B/A (bit 24) encodes arithmetic operation order. 1 means 536624cf65SWang Nan * before, 0 means after. 546624cf65SWang Nan * Bit I/D (bit 23) encodes arithmetic operation. 1 means 556624cf65SWang Nan * increment, 0 means decrement. 566624cf65SWang Nan * 576624cf65SWang Nan * So: 586624cf65SWang Nan * B I 596624cf65SWang Nan * / / 606624cf65SWang Nan * A D | Rn | 616624cf65SWang Nan * STMDX SP, [...] cccc 100x 00x0 xxxx xxxx xxxx xxxx xxxx 626624cf65SWang Nan */ 636624cf65SWang Nan DECODE_CUSTOM (0x0edf0000, 0x080d0000, STACK_USE_STMDX), 646624cf65SWang Nan 656624cf65SWang Nan /* P U W | Rn | Rt | imm12 |*/ 666624cf65SWang Nan /* STR (immediate) cccc 010x x0x0 1101 xxxx xxxx xxxx xxxx */ 676624cf65SWang Nan /* STRB (immediate) cccc 010x x1x0 1101 xxxx xxxx xxxx xxxx */ 686624cf65SWang Nan /* P U W | Rn | Rt |imm4| |imm4|*/ 696624cf65SWang Nan /* STRD (immediate) cccc 000x x1x0 1101 xxxx xxxx 1111 xxxx */ 706624cf65SWang Nan /* STRH (immediate) cccc 000x x1x0 1101 xxxx xxxx 1011 xxxx */ 716624cf65SWang Nan /* 726624cf65SWang Nan * index = (P == '1'); add = (U == '1'). 736624cf65SWang Nan * Above insns with: 746624cf65SWang Nan * index == 0 (str{,d,h} rx, [sp], #+/-imm) or 756624cf65SWang Nan * add == 1 (str{,d,h} rx, [sp, #+<imm>]) 766624cf65SWang Nan * should be STACK_USE_NONE. 776624cf65SWang Nan * Only str{,b,d,h} rx,[sp,#-n] (P == 1 and U == 0) are 786624cf65SWang Nan * required to be examined. 796624cf65SWang Nan */ 806624cf65SWang Nan /* STR{,B} Rt,[SP,#-n] cccc 0101 0xx0 1101 xxxx xxxx xxxx xxxx */ 816624cf65SWang Nan DECODE_CUSTOM (0x0f9f0000, 0x050d0000, STACK_USE_FIXED_XXX), 826624cf65SWang Nan 836624cf65SWang Nan /* STR{D,H} Rt,[SP,#-n] cccc 0001 01x0 1101 xxxx xxxx 1x11 xxxx */ 846624cf65SWang Nan DECODE_CUSTOM (0x0fdf00b0, 0x014d00b0, STACK_USE_FIXED_X0X), 856624cf65SWang Nan 866624cf65SWang Nan /* fall through */ 876624cf65SWang Nan DECODE_CUSTOM (0, 0, STACK_USE_NONE), 886624cf65SWang Nan DECODE_END 896624cf65SWang Nan }; 906624cf65SWang Nan 916624cf65SWang Nan return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL); 926624cf65SWang Nan } 936624cf65SWang Nan 946624cf65SWang Nan const struct decode_checker arm_stack_checker[NUM_PROBES_ARM_ACTIONS] = { 956624cf65SWang Nan [PROBES_LDRSTRD] = {.checker = arm_check_stack}, 966624cf65SWang Nan [PROBES_STORE_EXTRA] = {.checker = arm_check_stack}, 976624cf65SWang Nan [PROBES_STORE] = {.checker = arm_check_stack}, 986624cf65SWang Nan [PROBES_LDMSTM] = {.checker = arm_check_stack}, 996624cf65SWang Nan }; 100