diff options
Diffstat (limited to 'arch/arm/probes/kprobes/checkers-thumb.c')
| -rw-r--r-- | arch/arm/probes/kprobes/checkers-thumb.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/arch/arm/probes/kprobes/checkers-thumb.c b/arch/arm/probes/kprobes/checkers-thumb.c new file mode 100644 index 00000000000..d608e3b9017 --- /dev/null +++ b/arch/arm/probes/kprobes/checkers-thumb.c @@ -0,0 +1,110 @@ +/* + * arch/arm/probes/kprobes/checkers-thumb.c + * + * Copyright (C) 2014 Huawei Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include <linux/kernel.h> +#include "../decode.h" +#include "../decode-thumb.h" +#include "checkers.h" + +static enum probes_insn __kprobes t32_check_stack(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + /* + * PROBES_T32_LDMSTM, PROBES_T32_LDRDSTRD and PROBES_T32_LDRSTR + * may get here. Simply mark all normal insns as STACK_USE_NONE. + */ + static const union decode_item table[] = { + + /* + * First, filter out all ldr insns to make our life easier. + * Following load insns may come here: + * LDM, LDRD, LDR. + * In T32 encoding, bit 20 is enough for distinguishing + * load and store. All load insns have this bit set, when + * all store insns have this bit clear. + */ + DECODE_CUSTOM (0x00100000, 0x00100000, STACK_USE_NONE), + + /* + * Mark all 'STR{,B,H}, Rt, [Rn, Rm]' as STACK_USE_UNKNOWN + * if Rn or Rm is SP. T32 doesn't encode STRD. + */ + /* xx | Rn | Rt | | Rm |*/ + /* STR (register) 1111 1000 0100 xxxx xxxx 0000 00xx xxxx */ + /* STRB (register) 1111 1000 0000 xxxx xxxx 0000 00xx xxxx */ + /* STRH (register) 1111 1000 0010 xxxx xxxx 0000 00xx xxxx */ + /* INVALID INSN 1111 1000 0110 xxxx xxxx 0000 00xx xxxx */ + /* By Introducing INVALID INSN, bit 21 and 22 can be ignored. */ + DECODE_OR (0xff9f0fc0, 0xf80d0000), + DECODE_CUSTOM (0xff900fcf, 0xf800000d, STACK_USE_UNKNOWN), + + + /* xx | Rn | Rt | PUW| imm8 |*/ + /* STR (imm 8) 1111 1000 0100 1101 xxxx 110x xxxx xxxx */ + /* STRB (imm 8) 1111 1000 0000 1101 xxxx 110x xxxx xxxx */ + /* STRH (imm 8) 1111 1000 0010 1101 xxxx 110x xxxx xxxx */ + /* INVALID INSN 1111 1000 0110 1101 xxxx 110x xxxx xxxx */ + /* Only consider U == 0 and P == 1: strx rx, [sp, #-<imm>] */ + DECODE_CUSTOM (0xff9f0e00, 0xf80d0c00, STACK_USE_FIXED_0XX), + + /* For STR{,B,H} (imm 12), offset is always positive, so ignore them. */ + + /* P U W | Rn | Rt | Rt2| imm8 |*/ + /* STRD (immediate) 1110 1001 01x0 1101 xxxx xxxx xxxx xxxx */ + /* + * Only consider U == 0 and P == 1. + * Also note that STRD in T32 encoding is special: + * imm = ZeroExtend(imm8:'00', 32) + */ + DECODE_CUSTOM (0xffdf0000, 0xe94d0000, STACK_USE_T32STRD), + + /* | Rn | */ + /* STMDB 1110 1001 00x0 1101 xxxx xxxx xxxx xxxx */ + DECODE_CUSTOM (0xffdf0000, 0xe90d0000, STACK_USE_STMDX), + + /* fall through */ + DECODE_CUSTOM (0, 0, STACK_USE_NONE), + DECODE_END + }; + + return probes_decode_insn(insn, asi, table, false, false, stack_check_actions, NULL); +} + +const struct decode_checker t32_stack_checker[NUM_PROBES_T32_ACTIONS] = { + [PROBES_T32_LDMSTM] = {.checker = t32_check_stack}, + [PROBES_T32_LDRDSTRD] = {.checker = t32_check_stack}, + [PROBES_T32_LDRSTR] = {.checker = t32_check_stack}, +}; + +/* + * See following comments. This insn must be 'push'. + */ +static enum probes_insn __kprobes t16_check_stack(probes_opcode_t insn, + struct arch_probes_insn *asi, + const struct decode_header *h) +{ + unsigned int reglist = insn & 0x1ff; + asi->stack_space = hweight32(reglist) * 4; + return INSN_GOOD; +} + +/* + * T16 encoding is simple: only the 'push' insn can need extra stack space. + * Other insns, like str, can only use r0-r7 as Rn. + */ +const struct decode_checker t16_stack_checker[NUM_PROBES_T16_ACTIONS] = { + [PROBES_T16_PUSH] = {.checker = t16_check_stack}, +}; |