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
checker_stack_use_none(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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
checker_stack_use_unknown(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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
checker_stack_use_imm_0xx(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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 */
checker_stack_use_t32strd(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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
checker_stack_use_imm_x0x(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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
checker_stack_use_imm_xxx(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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
checker_stack_use_stmdx(probes_opcode_t insn,struct arch_probes_insn * asi,const struct decode_header * h)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