1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Common helper functions for kprobes and uprobes |
4 | * |
5 | * Copyright IBM Corp. 2014 |
6 | */ |
7 | |
8 | #include <linux/errno.h> |
9 | #include <asm/kprobes.h> |
10 | #include <asm/dis.h> |
11 | |
12 | int probe_is_prohibited_opcode(u16 *insn) |
13 | { |
14 | if (!is_known_insn((unsigned char *)insn)) |
15 | return -EINVAL; |
16 | switch (insn[0] >> 8) { |
17 | case 0x0c: /* bassm */ |
18 | case 0x0b: /* bsm */ |
19 | case 0x83: /* diag */ |
20 | case 0x44: /* ex */ |
21 | case 0xac: /* stnsm */ |
22 | case 0xad: /* stosm */ |
23 | return -EINVAL; |
24 | case 0xc6: |
25 | switch (insn[0] & 0x0f) { |
26 | case 0x00: /* exrl */ |
27 | return -EINVAL; |
28 | } |
29 | } |
30 | switch (insn[0]) { |
31 | case 0x0101: /* pr */ |
32 | case 0xb25a: /* bsa */ |
33 | case 0xb240: /* bakr */ |
34 | case 0xb258: /* bsg */ |
35 | case 0xb218: /* pc */ |
36 | case 0xb228: /* pt */ |
37 | case 0xb98d: /* epsw */ |
38 | case 0xe560: /* tbegin */ |
39 | case 0xe561: /* tbeginc */ |
40 | case 0xb2f8: /* tend */ |
41 | return -EINVAL; |
42 | } |
43 | return 0; |
44 | } |
45 | |
46 | int probe_get_fixup_type(u16 *insn) |
47 | { |
48 | /* default fixup method */ |
49 | int fixup = FIXUP_PSW_NORMAL; |
50 | |
51 | switch (insn[0] >> 8) { |
52 | case 0x05: /* balr */ |
53 | case 0x0d: /* basr */ |
54 | fixup = FIXUP_RETURN_REGISTER; |
55 | /* if r2 = 0, no branch will be taken */ |
56 | if ((insn[0] & 0x0f) == 0) |
57 | fixup |= FIXUP_BRANCH_NOT_TAKEN; |
58 | break; |
59 | case 0x06: /* bctr */ |
60 | case 0x07: /* bcr */ |
61 | fixup = FIXUP_BRANCH_NOT_TAKEN; |
62 | break; |
63 | case 0x45: /* bal */ |
64 | case 0x4d: /* bas */ |
65 | fixup = FIXUP_RETURN_REGISTER; |
66 | break; |
67 | case 0x47: /* bc */ |
68 | case 0x46: /* bct */ |
69 | case 0x86: /* bxh */ |
70 | case 0x87: /* bxle */ |
71 | fixup = FIXUP_BRANCH_NOT_TAKEN; |
72 | break; |
73 | case 0x82: /* lpsw */ |
74 | fixup = FIXUP_NOT_REQUIRED; |
75 | break; |
76 | case 0xb2: /* lpswe */ |
77 | if ((insn[0] & 0xff) == 0xb2) |
78 | fixup = FIXUP_NOT_REQUIRED; |
79 | break; |
80 | case 0xa7: /* bras */ |
81 | if ((insn[0] & 0x0f) == 0x05) |
82 | fixup |= FIXUP_RETURN_REGISTER; |
83 | break; |
84 | case 0xc0: |
85 | if ((insn[0] & 0x0f) == 0x05) /* brasl */ |
86 | fixup |= FIXUP_RETURN_REGISTER; |
87 | break; |
88 | case 0xeb: |
89 | switch (insn[2] & 0xff) { |
90 | case 0x44: /* bxhg */ |
91 | case 0x45: /* bxleg */ |
92 | fixup = FIXUP_BRANCH_NOT_TAKEN; |
93 | break; |
94 | } |
95 | break; |
96 | case 0xe3: /* bctg */ |
97 | if ((insn[2] & 0xff) == 0x46) |
98 | fixup = FIXUP_BRANCH_NOT_TAKEN; |
99 | break; |
100 | case 0xec: |
101 | switch (insn[2] & 0xff) { |
102 | case 0xe5: /* clgrb */ |
103 | case 0xe6: /* cgrb */ |
104 | case 0xf6: /* crb */ |
105 | case 0xf7: /* clrb */ |
106 | case 0xfc: /* cgib */ |
107 | case 0xfd: /* cglib */ |
108 | case 0xfe: /* cib */ |
109 | case 0xff: /* clib */ |
110 | fixup = FIXUP_BRANCH_NOT_TAKEN; |
111 | break; |
112 | } |
113 | break; |
114 | } |
115 | return fixup; |
116 | } |
117 | |
118 | int probe_is_insn_relative_long(u16 *insn) |
119 | { |
120 | /* Check if we have a RIL-b or RIL-c format instruction which |
121 | * we need to modify in order to avoid instruction emulation. */ |
122 | switch (insn[0] >> 8) { |
123 | case 0xc0: |
124 | if ((insn[0] & 0x0f) == 0x00) /* larl */ |
125 | return true; |
126 | break; |
127 | case 0xc4: |
128 | switch (insn[0] & 0x0f) { |
129 | case 0x02: /* llhrl */ |
130 | case 0x04: /* lghrl */ |
131 | case 0x05: /* lhrl */ |
132 | case 0x06: /* llghrl */ |
133 | case 0x07: /* sthrl */ |
134 | case 0x08: /* lgrl */ |
135 | case 0x0b: /* stgrl */ |
136 | case 0x0c: /* lgfrl */ |
137 | case 0x0d: /* lrl */ |
138 | case 0x0e: /* llgfrl */ |
139 | case 0x0f: /* strl */ |
140 | return true; |
141 | } |
142 | break; |
143 | case 0xc6: |
144 | switch (insn[0] & 0x0f) { |
145 | case 0x02: /* pfdrl */ |
146 | case 0x04: /* cghrl */ |
147 | case 0x05: /* chrl */ |
148 | case 0x06: /* clghrl */ |
149 | case 0x07: /* clhrl */ |
150 | case 0x08: /* cgrl */ |
151 | case 0x0a: /* clgrl */ |
152 | case 0x0c: /* cgfrl */ |
153 | case 0x0d: /* crl */ |
154 | case 0x0e: /* clgfrl */ |
155 | case 0x0f: /* clrl */ |
156 | return true; |
157 | } |
158 | break; |
159 | } |
160 | return false; |
161 | } |
162 | |