1 // SPDX-License-Identifier: GPL-2.0-only 1
2 /*
3 * arch/arm/probes/kprobes/checkers-thumb.c
4 *
5 * Copyright (C) 2014 Huawei Inc.
6 */
7
8 #include <linux/kernel.h>
9 #include "../decode.h"
10 #include "../decode-thumb.h"
11 #include "checkers.h"
12
13 static enum probes_insn __kprobes t32_check_st
14 struct arch_probes_insn *asi,
15 const struct decode_header *h)
16 {
17 /*
18 * PROBES_T32_LDMSTM, PROBES_T32_LDRDS
19 * may get here. Simply mark all norma
20 */
21 static const union decode_item table[]
22
23 /*
24 * First, filter out all ldr i
25 * Following load insns may co
26 * LDM, LDRD, LDR.
27 * In T32 encoding, bit 20 is
28 * load and store. All load in
29 * all store insns have this b
30 */
31 DECODE_CUSTOM (0x00100000, 0
32
33 /*
34 * Mark all 'STR{,B,H}, Rt, [R
35 * if Rn or Rm is SP. T32 does
36 */
37 /*
38 /* STR (register) 1111 1
39 /* STRB (register) 1111 1
40 /* STRH (register) 1111 1
41 /* INVALID INSN 1111 1
42 /* By Introducing INVALID INSN
43 DECODE_OR (0xff9f0fc0, 0
44 DECODE_CUSTOM (0xff900fcf, 0
45
46
47 /*
48 /* STR (imm 8) 1111 1
49 /* STRB (imm 8) 1111 1
50 /* STRH (imm 8) 1111 1
51 /* INVALID INSN 1111 1
52 /* Only consider U == 0 and P
53 DECODE_CUSTOM (0xff9f0e00, 0
54
55 /* For STR{,B,H} (imm 12), off
56
57 /*
58 /* STRD (immediate) 1110 1
59 /*
60 * Only consider U == 0 and P
61 * Also note that STRD in T32
62 * imm = ZeroExtend(imm8:'00',
63 */
64 DECODE_CUSTOM (0xffdf0000, 0
65
66 /*
67 /* STMDB 1110 1
68 DECODE_CUSTOM (0xffdf0000, 0
69
70 /* fall through */
71 DECODE_CUSTOM (0, 0, STACK_U
72 DECODE_END
73 };
74
75 return probes_decode_insn(insn, asi, t
76 }
77
78 const struct decode_checker t32_stack_checker[
79 [PROBES_T32_LDMSTM] = {.checker = t32_
80 [PROBES_T32_LDRDSTRD] = {.checker = t3
81 [PROBES_T32_LDRSTR] = {.checker = t32_
82 };
83
84 /*
85 * See following comments. This insn must be '
86 */
87 static enum probes_insn __kprobes t16_check_st
88 struct arch_probes_insn *asi,
89 const struct decode_header *h)
90 {
91 unsigned int reglist = insn & 0x1ff;
92 asi->stack_space = hweight32(reglist)
93 return INSN_GOOD;
94 }
95
96 /*
97 * T16 encoding is simple: only the 'push' ins
98 * Other insns, like str, can only use r0-r7 a
99 */
100 const struct decode_checker t16_stack_checker[
101 [PROBES_T16_PUSH] = {.checker = t16_ch
102 };
103
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