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 #include "util/sample.h"
22 
23 #if INTEL_PT_INSN_BUF_SZ < MAX_INSN_SIZE || INTEL_PT_INSN_BUF_SZ > MAX_INSN
24 #error Instruction buffer size too small
25 #endif
26 
27 /* 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)28 static void intel_pt_insn_decoder(struct insn *insn,
29 				  struct intel_pt_insn *intel_pt_insn)
30 {
31 	enum intel_pt_insn_op op = INTEL_PT_OP_OTHER;
32 	enum intel_pt_insn_branch branch = INTEL_PT_BR_NO_BRANCH;
33 	int ext;
34 
35 	intel_pt_insn->rel = 0;
36 	intel_pt_insn->emulated_ptwrite = false;
37 
38 	if (insn_is_avx(insn)) {
39 		intel_pt_insn->op = INTEL_PT_OP_OTHER;
40 		intel_pt_insn->branch = INTEL_PT_BR_NO_BRANCH;
41 		intel_pt_insn->length = insn->length;
42 		return;
43 	}
44 
45 	switch (insn->opcode.bytes[0]) {
46 	case 0xf:
47 		switch (insn->opcode.bytes[1]) {
48 		case 0x01:
49 			switch (insn->modrm.bytes[0]) {
50 			case 0xc2: /* vmlaunch */
51 			case 0xc3: /* vmresume */
52 				op = INTEL_PT_OP_VMENTRY;
53 				branch = INTEL_PT_BR_INDIRECT;
54 				break;
55 			case 0xca:
56 				switch (insn->prefixes.bytes[3]) {
57 				case 0xf2: /* erets */
58 					op = INTEL_PT_OP_ERETS;
59 					branch = INTEL_PT_BR_INDIRECT;
60 					break;
61 				case 0xf3: /* eretu */
62 					op = INTEL_PT_OP_ERETU;
63 					branch = INTEL_PT_BR_INDIRECT;
64 					break;
65 				default:
66 					break;
67 				}
68 				break;
69 			default:
70 				break;
71 			}
72 			break;
73 		case 0x05: /* syscall */
74 		case 0x34: /* sysenter */
75 			op = INTEL_PT_OP_SYSCALL;
76 			branch = INTEL_PT_BR_INDIRECT;
77 			break;
78 		case 0x07: /* sysret */
79 		case 0x35: /* sysexit */
80 			op = INTEL_PT_OP_SYSRET;
81 			branch = INTEL_PT_BR_INDIRECT;
82 			break;
83 		case 0x80 ... 0x8f: /* jcc */
84 			op = INTEL_PT_OP_JCC;
85 			branch = INTEL_PT_BR_CONDITIONAL;
86 			break;
87 		default:
88 			break;
89 		}
90 		break;
91 	case 0x70 ... 0x7f: /* jcc */
92 		op = INTEL_PT_OP_JCC;
93 		branch = INTEL_PT_BR_CONDITIONAL;
94 		break;
95 	case 0xc2: /* near ret */
96 	case 0xc3: /* near ret */
97 	case 0xca: /* far ret */
98 	case 0xcb: /* far ret */
99 		op = INTEL_PT_OP_RET;
100 		branch = INTEL_PT_BR_INDIRECT;
101 		break;
102 	case 0xcf: /* iret */
103 		op = INTEL_PT_OP_IRET;
104 		branch = INTEL_PT_BR_INDIRECT;
105 		break;
106 	case 0xcc ... 0xce: /* int */
107 		op = INTEL_PT_OP_INT;
108 		branch = INTEL_PT_BR_INDIRECT;
109 		break;
110 	case 0xe8: /* call near rel */
111 		op = INTEL_PT_OP_CALL;
112 		branch = INTEL_PT_BR_UNCONDITIONAL;
113 		break;
114 	case 0x9a: /* call far absolute */
115 		op = INTEL_PT_OP_CALL;
116 		branch = INTEL_PT_BR_INDIRECT;
117 		break;
118 	case 0xe0 ... 0xe2: /* loop */
119 		op = INTEL_PT_OP_LOOP;
120 		branch = INTEL_PT_BR_CONDITIONAL;
121 		break;
122 	case 0xe3: /* jcc */
123 		op = INTEL_PT_OP_JCC;
124 		branch = INTEL_PT_BR_CONDITIONAL;
125 		break;
126 	case 0xe9: /* jmp */
127 	case 0xeb: /* jmp */
128 		op = INTEL_PT_OP_JMP;
129 		branch = INTEL_PT_BR_UNCONDITIONAL;
130 		break;
131 	case 0xea: /* far jmp */
132 		op = INTEL_PT_OP_JMP;
133 		branch = INTEL_PT_BR_INDIRECT;
134 		break;
135 	case 0xff: /* call near absolute, call far absolute ind */
136 		ext = (insn->modrm.bytes[0] >> 3) & 0x7;
137 		switch (ext) {
138 		case 2: /* near ind call */
139 		case 3: /* far ind call */
140 			op = INTEL_PT_OP_CALL;
141 			branch = INTEL_PT_BR_INDIRECT;
142 			break;
143 		case 4:
144 		case 5:
145 			op = INTEL_PT_OP_JMP;
146 			branch = INTEL_PT_BR_INDIRECT;
147 			break;
148 		default:
149 			break;
150 		}
151 		break;
152 	default:
153 		break;
154 	}
155 
156 	intel_pt_insn->op = op;
157 	intel_pt_insn->branch = branch;
158 	intel_pt_insn->length = insn->length;
159 
160 	if (branch == INTEL_PT_BR_CONDITIONAL ||
161 	    branch == INTEL_PT_BR_UNCONDITIONAL) {
162 #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
163 		switch (insn->immediate.nbytes) {
164 		case 1:
165 			intel_pt_insn->rel = insn->immediate.value;
166 			break;
167 		case 2:
168 			intel_pt_insn->rel =
169 					bswap_16((short)insn->immediate.value);
170 			break;
171 		case 4:
172 			intel_pt_insn->rel = bswap_32(insn->immediate.value);
173 			break;
174 		default:
175 			intel_pt_insn->rel = 0;
176 			break;
177 		}
178 #else
179 		intel_pt_insn->rel = insn->immediate.value;
180 #endif
181 	}
182 }
183 
intel_pt_get_insn(const unsigned char * buf,size_t len,int x86_64,struct intel_pt_insn * intel_pt_insn)184 int intel_pt_get_insn(const unsigned char *buf, size_t len, int x86_64,
185 		      struct intel_pt_insn *intel_pt_insn)
186 {
187 	struct insn insn;
188 	int ret;
189 
190 	ret = insn_decode(&insn, buf, len,
191 			  x86_64 ? INSN_MODE_64 : INSN_MODE_32);
192 	if (ret < 0 || insn.length > len)
193 		return -1;
194 
195 	intel_pt_insn_decoder(&insn, intel_pt_insn);
196 	if (insn.length < INTEL_PT_INSN_BUF_SZ)
197 		memcpy(intel_pt_insn->buf, buf, insn.length);
198 	else
199 		memcpy(intel_pt_insn->buf, buf, INTEL_PT_INSN_BUF_SZ);
200 	return 0;
201 }
202 
arch_is_branch(const unsigned char * buf,size_t len,int x86_64)203 int arch_is_branch(const unsigned char *buf, size_t len, int x86_64)
204 {
205 	struct intel_pt_insn in;
206 	if (intel_pt_get_insn(buf, len, x86_64, &in) < 0)
207 		return -1;
208 	return in.branch != INTEL_PT_BR_NO_BRANCH;
209 }
210 
dump_insn(struct perf_insn * x,uint64_t ip __maybe_unused,u8 * inbuf,int inlen,int * lenp)211 const char *dump_insn(struct perf_insn *x, uint64_t ip __maybe_unused,
212 		      u8 *inbuf, int inlen, int *lenp)
213 {
214 	struct insn insn;
215 	int n, i, ret;
216 	int left;
217 
218 	ret = insn_decode(&insn, inbuf, inlen,
219 			  x->is64bit ? INSN_MODE_64 : INSN_MODE_32);
220 
221 	if (ret < 0 || insn.length > inlen)
222 		return "<bad>";
223 	if (lenp)
224 		*lenp = insn.length;
225 	left = sizeof(x->out);
226 	n = snprintf(x->out, left, "insn: ");
227 	left -= n;
228 	for (i = 0; i < insn.length; i++) {
229 		n += snprintf(x->out + n, left, "%02x ", inbuf[i]);
230 		left -= n;
231 	}
232 	return x->out;
233 }
234 
235 const char *branch_name[] = {
236 	[INTEL_PT_OP_OTHER]	= "Other",
237 	[INTEL_PT_OP_CALL]	= "Call",
238 	[INTEL_PT_OP_RET]	= "Ret",
239 	[INTEL_PT_OP_JCC]	= "Jcc",
240 	[INTEL_PT_OP_JMP]	= "Jmp",
241 	[INTEL_PT_OP_LOOP]	= "Loop",
242 	[INTEL_PT_OP_IRET]	= "IRet",
243 	[INTEL_PT_OP_INT]	= "Int",
244 	[INTEL_PT_OP_SYSCALL]	= "Syscall",
245 	[INTEL_PT_OP_SYSRET]	= "Sysret",
246 	[INTEL_PT_OP_VMENTRY]	= "VMentry",
247 	[INTEL_PT_OP_ERETS]	= "Erets",
248 	[INTEL_PT_OP_ERETU]	= "Eretu",
249 };
250 
intel_pt_insn_name(enum intel_pt_insn_op op)251 const char *intel_pt_insn_name(enum intel_pt_insn_op op)
252 {
253 	return branch_name[op];
254 }
255 
intel_pt_insn_desc(const struct intel_pt_insn * intel_pt_insn,char * buf,size_t buf_len)256 int intel_pt_insn_desc(const struct intel_pt_insn *intel_pt_insn, char *buf,
257 		       size_t buf_len)
258 {
259 	switch (intel_pt_insn->branch) {
260 	case INTEL_PT_BR_CONDITIONAL:
261 	case INTEL_PT_BR_UNCONDITIONAL:
262 		return snprintf(buf, buf_len, "%s %s%d",
263 				intel_pt_insn_name(intel_pt_insn->op),
264 				intel_pt_insn->rel > 0 ? "+" : "",
265 				intel_pt_insn->rel);
266 	case INTEL_PT_BR_NO_BRANCH:
267 	case INTEL_PT_BR_INDIRECT:
268 		return snprintf(buf, buf_len, "%s",
269 				intel_pt_insn_name(intel_pt_insn->op));
270 	default:
271 		break;
272 	}
273 	return 0;
274 }
275 
intel_pt_insn_type(enum intel_pt_insn_op op)276 int intel_pt_insn_type(enum intel_pt_insn_op op)
277 {
278 	switch (op) {
279 	case INTEL_PT_OP_OTHER:
280 		return 0;
281 	case INTEL_PT_OP_CALL:
282 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL;
283 	case INTEL_PT_OP_RET:
284 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN;
285 	case INTEL_PT_OP_JCC:
286 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CONDITIONAL;
287 	case INTEL_PT_OP_JMP:
288 		return PERF_IP_FLAG_BRANCH;
289 	case INTEL_PT_OP_LOOP:
290 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CONDITIONAL;
291 	case INTEL_PT_OP_IRET:
292 	case INTEL_PT_OP_ERETS:
293 	case INTEL_PT_OP_ERETU:
294 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN |
295 		       PERF_IP_FLAG_INTERRUPT;
296 	case INTEL_PT_OP_INT:
297 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL |
298 		       PERF_IP_FLAG_INTERRUPT;
299 	case INTEL_PT_OP_SYSCALL:
300 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL |
301 		       PERF_IP_FLAG_SYSCALLRET;
302 	case INTEL_PT_OP_SYSRET:
303 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_RETURN |
304 		       PERF_IP_FLAG_SYSCALLRET;
305 	case INTEL_PT_OP_VMENTRY:
306 		return PERF_IP_FLAG_BRANCH | PERF_IP_FLAG_CALL |
307 		       PERF_IP_FLAG_VMENTRY;
308 	default:
309 		return 0;
310 	}
311 }
312