1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * intel_pt_insn_decoder.c: Intel Processor Trace support
4 * Copyright (c) 2013-2014, Intel Corporation.
5 */
6
7 #include <linux/kernel.h>
8 #include <stdio.h>
9 #include <string.h>
10 #include <endian.h>
11 #include <byteswap.h>
12 #include "../../../arch/x86/include/asm/insn.h"
13
14 #include "../../../arch/x86/lib/inat.c"
15 #include "../../../arch/x86/lib/insn.c"
16
17 #include "event.h"
18
19 #include "intel-pt-insn-decoder.h"
20 #include "dump-insn.h"
21
22 #if INTEL_PT_INSN_BUF_SZ < MAX_INSN_SIZE || INTEL_PT_INSN_BUF_SZ > MAX_INSN
23 #error Instruction buffer size too small
24 #endif
25
26 /* Based on branch_type() from arch/x86/events/intel/lbr.c */
intel_pt_insn_decoder(struct insn * insn,struct intel_pt_insn * intel_pt_insn)27 static void intel_pt_insn_decoder(struct insn *insn,
28 struct intel_pt_insn *intel_pt_insn)
29 {
30 enum intel_pt_insn_op op = INTEL_PT_OP_OTHER;
31 enum intel_pt_insn_branch branch = INTEL_PT_BR_NO_BRANCH;
32 int ext;
33
34 intel_pt_insn->rel = 0;
35
36 if (insn_is_avx(insn)) {
37 intel_pt_insn->op = INTEL_PT_OP_OTHER;
38 intel_pt_insn->branch = INTEL_PT_BR_NO_BRANCH;
39 intel_pt_insn->length = insn->length;
40 return;
41 }
42
43 switch (insn->opcode.bytes[0]) {
44 case 0xf:
45 switch (insn->opcode.bytes[1]) {
46 case 0x05: /* syscall */
47 case 0x34: /* sysenter */
48 op = INTEL_PT_OP_SYSCALL;
49 branch = INTEL_PT_BR_INDIRECT;
50 break;
51 case 0x07: /* sysret */
52 case 0x35: /* sysexit */
53 op = INTEL_PT_OP_SYSRET;
54 branch = INTEL_PT_BR_INDIRECT;
55 break;
56 case 0x80 ... 0x8f: /* jcc */
57 op = INTEL_PT_OP_JCC;
58 branch = INTEL_PT_BR_CONDITIONAL;
59 break;
60 default:
61 break;
62 }
63 break;
64 case 0x70 ... 0x7f: /* jcc */
65 op = INTEL_PT_OP_JCC;
66 branch = INTEL_PT_BR_CONDITIONAL;
67 break;
68 case 0xc2: /* near ret */
69 case 0xc3: /* near ret */
70 case 0xca: /* far ret */
71 case 0xcb: /* far ret */
72 op = INTEL_PT_OP_RET;
73 branch = INTEL_PT_BR_INDIRECT;
74 break;
75 case 0xcf: /* iret */
76 op = INTEL_PT_OP_IRET;
77 branch = INTEL_PT_BR_INDIRECT;
78 break;
79 case 0xcc ... 0xce: /* int */
80 op = INTEL_PT_OP_INT;
81 branch = INTEL_PT_BR_INDIRECT;
82 break;
83 case 0xe8: /* call near rel */
84 op = INTEL_PT_OP_CALL;
85 branch = INTEL_PT_BR_UNCONDITIONAL;
86 break;
87 case 0x9a: /* call far absolute */
88 op = INTEL_PT_OP_CALL;
89 branch = INTEL_PT_BR_INDIRECT;
90 break;
91 case 0xe0 ... 0xe2: /* loop */
92 op = INTEL_PT_OP_LOOP;
93 branch = INTEL_PT_BR_CONDITIONAL;
94 break;
95 case 0xe3: /* jcc */
96 op = INTEL_PT_OP_JCC;
97 branch = INTEL_PT_BR_CONDITIONAL;
98 break;
99 case 0xe9: /* jmp */
100 case 0xeb: /* jmp */
101 op = INTEL_PT_OP_JMP;
102 branch = INTEL_PT_BR_UNCONDITIONAL;
103 break;
104 case 0xea: /* far jmp */
105 op = INTEL_PT_OP_JMP;
106 branch = INTEL_PT_BR_INDIRECT;
107 break;
108 case 0xff: /* call near absolute, call far absolute ind */
109 ext = (insn->modrm.bytes[0] >> 3) & 0x7;
110 switch (ext) {
111 case 2: /* near ind call */
112 case 3: /* far ind call */
113 op = INTEL_PT_OP_CALL;
114 branch = INTEL_PT_BR_INDIRECT;
115 break;
116 case 4:
117 case 5:
118 op = INTEL_PT_OP_JMP;
119 branch = INTEL_PT_BR_INDIRECT;
120 break;
121 default:
122 break;
123 }
124 break;
125 default:
126 break;
127 }
128
129 intel_pt_insn->op = op;
130 intel_pt_insn->branch = branch;
131 intel_pt_insn->length = insn->length;
132
133 if (branch == INTEL_PT_BR_CONDITIONAL ||
134 branch == INTEL_PT_BR_UNCONDITIONAL) {
135 #if __BYTE_ORDER == __BIG_ENDIAN
136 switch (insn->immediate.nbytes) {
137 case 1:
138 intel_pt_insn->rel = insn->immediate.value;
139 break;
140 case 2:
141 intel_pt_insn->rel =
142 bswap_16((short)insn->immediate.value);
143 break;
144 case 4:
145 intel_pt_insn->rel = bswap_32(insn->immediate.value);
146 break;
147 default:
148 intel_pt_insn->rel = 0;
149 break;
150 }
151 #else
152 intel_pt_insn->rel = insn->immediate.value;
153 #endif
154 }
155 }
156
intel_pt_get_insn(const unsigned char * buf,size_t len,int x86_64,struct intel_pt_insn * intel_pt_insn)157 int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64,
158 struct intel_pt_insn *intel_pt_insn)
159 {
160 struct insn insn;
161
162 insn_init(&insn, buf, len, x86_64);
163 insn_get_length(&insn);
164 if (!insn_complete(&insn) || insn.length > len)
165 return -1;
166 intel_pt_insn_decoder(&insn, intel_pt_insn);
167 if (insn.length < INTEL_PT_INSN_BUF_SZ)
168 memcpy(intel_pt_insn->buf, buf, insn.length);
169 else
170 memcpy(intel_pt_insn->buf, buf, INTEL_PT_INSN_BUF_SZ);
171 return 0;
172 }
173
arch_is_branch(const unsigned char * buf,size_t len,int x86_64)174 int arch_is_branch(const unsigned char *buf, size_t len, int x86_64)
175 {
176 struct intel_pt_insn in;
177 if (intel_pt_get_insn(buf, len, x86_64, &in) < 0)
178 return -1;
179 return in.branch != INTEL_PT_BR_NO_BRANCH;
180 }
181
dump_insn(struct perf_insn * x,uint64_t ip __maybe_unused,u8 * inbuf,int inlen,int * lenp)182 const char *dump_insn(struct perf_insn *x, uint64_t ip __maybe_unused,
183 u8 *inbuf, int inlen, int *lenp)
184 {
185 struct insn insn;
186 int n, i;
187 int left;
188
189 insn_init(&insn, inbuf, inlen, x->is64bit);
190 insn_get_length(&insn);
191 if (!insn_complete(&insn) || insn.length > inlen)
192 return "<bad>";
193 if (lenp)
194 *lenp = insn.length;
195 left = sizeof(x->out);
196 n = snprintf(x->out, left, "insn: ");
197 left -= n;
198 for (i = 0; i < insn.length; i++) {
199 n += snprintf(x->out + n, left, "%02x ", inbuf[i]);
200 left -= n;
201 }
202 return x->out;
203 }
204
205 const char *branch_name[] = {
206 [INTEL_PT_OP_OTHER] = "Other",
207 [INTEL_PT_OP_CALL] = "Call",
208 [INTEL_PT_OP_RET] = "Ret",
209 [INTEL_PT_OP_JCC] = "Jcc",
210 [INTEL_PT_OP_JMP] = "Jmp",
211 [INTEL_PT_OP_LOOP] = "Loop",
212 [INTEL_PT_OP_IRET] = "IRet",
213 [INTEL_PT_OP_INT] = "Int",
214 [INTEL_PT_OP_SYSCALL] = "Syscall",
215 [INTEL_PT_OP_SYSRET] = "Sysret",
216 };
217
intel_pt_insn_name(enum intel_pt_insn_op op)218 const char *intel_pt_insn_name(enum intel_pt_insn_op op)
219 {
220 return branch_name[op];
221 }
222
intel_pt_insn_desc(const struct intel_pt_insn * intel_pt_insn,char * buf,size_t buf_len)223 int intel_pt_insn_desc(const struct intel_pt_insn *intel_pt_insn, char *buf,
224 size_t buf_len)
225 {
226 switch (intel_pt_insn->branch) {
227 case INTEL_PT_BR_CONDITIONAL:
228 case INTEL_PT_BR_UNCONDITIONAL:
229 return snprintf(buf, buf_len, "%s %s%d",
230 intel_pt_insn_name(intel_pt_insn->op),
231 intel_pt_insn->rel > 0 ? "+" : "",
232 intel_pt_insn->rel);
233 case INTEL_PT_BR_NO_BRANCH:
234 case INTEL_PT_BR_INDIRECT:
235 return snprintf(buf, buf_len, "%s",
236 intel_pt_insn_name(intel_pt_insn->op));
237 default:
238 break;
239 }
240 return 0;
241 }
242
intel_pt_insn_type(enum intel_pt_insn_op op)243 int intel_pt_insn_type(enum intel_pt_insn_op op)
244 {
245 switch (op) {
246 case INTEL_PT_OP_OTHER:
247 return 0;
248 case INTEL_PT_OP_CALL:
249 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL;
250 case INTEL_PT_OP_RET:
251 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN;
252 case INTEL_PT_OP_JCC:
253 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CONDITIONAL;
254 case INTEL_PT_OP_JMP:
255 return PERF_IP_FLAG_BRANCH;
256 case INTEL_PT_OP_LOOP:
257 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CONDITIONAL;
258 case INTEL_PT_OP_IRET:
259 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN |
260 PERF_IP_FLAG_INTERRUPT;
261 case INTEL_PT_OP_INT:
262 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL |
263 PERF_IP_FLAG_INTERRUPT;
264 case INTEL_PT_OP_SYSCALL:
265 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL |
266 PERF_IP_FLAG_SYSCALLRET;
267 case INTEL_PT_OP_SYSRET:
268 return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN |
269 PERF_IP_FLAG_SYSCALLRET;
270 default:
271 return 0;
272 }
273 }
274
