1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /*
3 * arch/arm/probes/kprobes/checkers-arm.c
4 *
5 * Copyright (C) 2014 Huawei Inc.
6 */
7
8 #include <linux/kernel.h>
9 #include "../decode.h"
10 #include "../decode-arm.h"
11 #include "checkers.h"
12
13 static enum probes_insn __kprobes arm_check_st
14 struct arch_probes_insn *asi,
15 const struct decode_header *h)
16 {
17 /*
18 * PROBES_LDRSTRD, PROBES_LDMSTM, PROB
19 * PROBES_STORE_EXTRA may get here. Si
20 * insns as STACK_USE_NONE.
21 */
22 static const union decode_item table[]
23 /*
24 * 'STR{,D,B,H}, Rt, [Rn, Rm]'
25 * if Rn or Rm is SP.
26 *
27 * STR (register) cccc 0
28 * STRB (register) cccc 0
29 */
30 DECODE_OR (0x0e10000f, 0
31 DECODE_OR (0x0e1f0000, 0
32
33 /*
34 *
35 * STRD (register) cccc 0
36 * STRH (register) cccc 0
37 */
38 DECODE_OR (0x0e5000bf, 0
39 DECODE_CUSTOM (0x0e5f00b0, 0
40
41 /*
42 * For PROBES_LDMSTM, only stm
43 *
44 * Bit B/A (bit 24) encodes ar
45 * before, 0 means after.
46 * Bit I/D (bit 23) encodes ar
47 * increment, 0 means decremen
48 *
49 * So:
50 *
51 *
52 *
53 * STMDX SP, [...] cccc 1
54 */
55 DECODE_CUSTOM (0x0edf0000, 0
56
57 /*
58 /* STR (immediate) cccc 0
59 /* STRB (immediate) cccc 0
60 /*
61 /* STRD (immediate) cccc 0
62 /* STRH (immediate) cccc 0
63 /*
64 * index = (P == '1'); add = (
65 * Above insns with:
66 * index == 0 (str{,d,h} rx
67 * add == 1 (str{,d,h} rx,
68 * should be STACK_USE_NONE.
69 * Only str{,b,d,h} rx,[sp,#-n
70 * required to be examined.
71 */
72 /* STR{,B} Rt,[SP,#-n] cccc 0
73 DECODE_CUSTOM (0x0f9f0000, 0
74
75 /* STR{D,H} Rt,[SP,#-n] cccc 0
76 DECODE_CUSTOM (0x0fdf00b0, 0
77
78 /* fall through */
79 DECODE_CUSTOM (0, 0, STACK_U
80 DECODE_END
81 };
82
83 return probes_decode_insn(insn, asi, t
84 }
85
86 const struct decode_checker arm_stack_checker[
87 [PROBES_LDRSTRD] = {.checker = arm_che
88 [PROBES_STORE_EXTRA] = {.checker = arm
89 [PROBES_STORE] = {.checker = arm_check
90 [PROBES_LDMSTM] = {.checker = arm_chec
91 };
92
93 static enum probes_insn __kprobes arm_check_re
94 struct arch_probes_insn *asi,
95 const struct decode_header *h)
96 {
97 asi->register_usage_flags = 0;
98 return INSN_GOOD;
99 }
100
101 static enum probes_insn arm_check_regs_normal(
102 struct arch_probes_insn *asi,
103 const struct decode_header *h)
104 {
105 u32 regs = h->type_regs.bits >> DECODE
106 int i;
107
108 asi->register_usage_flags = 0;
109 for (i = 0; i < 5; regs >>= 4, insn >>
110 if (regs & 0xf)
111 asi->register_usage_fl
112
113 return INSN_GOOD;
114 }
115
116
117 static enum probes_insn arm_check_regs_ldmstm(
118 struct arch_probes_insn *asi,
119 const struct decode_header *h)
120 {
121 unsigned int reglist = insn & 0xffff;
122 unsigned int rn = (insn >> 16) & 0xf;
123 asi->register_usage_flags = reglist |
124 return INSN_GOOD;
125 }
126
127 static enum probes_insn arm_check_regs_mov_ip_
128 struct arch_probes_insn *asi,
129 const struct decode_header *h)
130 {
131 /* Instruction is 'mov ip, sp' i.e. 'm
132 asi->register_usage_flags = (1 << 12)
133 return INSN_GOOD;
134 }
135
136 /*
137 * | Rn |Rt
138 * LDRD (register) cccc 000x x0x0 xxxx xx
139 * STRD (register) cccc 000x x0x0 xxxx xx
140 * | Rn |Rt
141 * LDRD (immediate) cccc 000x x1x0 xxxx xx
142 * STRD (immediate) cccc 000x x1x0 xxxx xx
143 *
144 * Such instructions access Rt/d and its next
145 * from others, a specific checker is required
146 * implicit register usage.
147 */
148 static enum probes_insn arm_check_regs_ldrdstr
149 struct arch_probes_insn *asi,
150 const struct decode_header *h)
151 {
152 int rdt = (insn >> 12) & 0xf;
153 arm_check_regs_normal(insn, asi, h);
154 asi->register_usage_flags |= 1 << (rdt
155 return INSN_GOOD;
156 }
157
158
159 const struct decode_checker arm_regs_checker[N
160 [PROBES_MRS] = {.checker = arm_check_r
161 [PROBES_SATURATING_ARITHMETIC] = {.che
162 [PROBES_MUL1] = {.checker = arm_check_
163 [PROBES_MUL2] = {.checker = arm_check_
164 [PROBES_MUL_ADD_LONG] = {.checker = ar
165 [PROBES_MUL_ADD] = {.checker = arm_che
166 [PROBES_LOAD] = {.checker = arm_check_
167 [PROBES_LOAD_EXTRA] = {.checker = arm_
168 [PROBES_STORE] = {.checker = arm_check
169 [PROBES_STORE_EXTRA] = {.checker = arm
170 [PROBES_DATA_PROCESSING_REG] = {.check
171 [PROBES_DATA_PROCESSING_IMM] = {.check
172 [PROBES_SEV] = {.checker = arm_check_r
173 [PROBES_WFE] = {.checker = arm_check_r
174 [PROBES_SATURATE] = {.checker = arm_ch
175 [PROBES_REV] = {.checker = arm_check_r
176 [PROBES_MMI] = {.checker = arm_check_r
177 [PROBES_PACK] = {.checker = arm_check_
178 [PROBES_EXTEND] = {.checker = arm_chec
179 [PROBES_EXTEND_ADD] = {.checker = arm_
180 [PROBES_BITFIELD] = {.checker = arm_ch
181 [PROBES_LDMSTM] = {.checker = arm_chec
182 [PROBES_MOV_IP_SP] = {.checker = arm_c
183 [PROBES_LDRSTRD] = {.checker = arm_che
184 };
185
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