xref: /linux/tools/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.c (revision 55d0969c451159cff86949b38c39171cab962069)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * intel_pt_pkt_decoder.c: Intel Processor Trace support
4  * Copyright (c) 2013-2014, Intel Corporation.
5  */
6 
7 #include <stdio.h>
8 #include <string.h>
9 #include <endian.h>
10 #include <byteswap.h>
11 #include <linux/kernel.h>
12 #include <linux/compiler.h>
13 #include <linux/unaligned.h>
14 
15 #include "intel-pt-pkt-decoder.h"
16 
17 #define BIT(n)		(1 << (n))
18 
19 #define BIT63		((uint64_t)1 << 63)
20 
21 #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
22 #define memcpy_le64(d, s, n) do { \
23 	memcpy((d), (s), (n));    \
24 	*(d) = le64_to_cpu(*(d)); \
25 } while (0)
26 #else
27 #define memcpy_le64 memcpy
28 #endif
29 
30 static const char * const packet_name[] = {
31 	[INTEL_PT_BAD]		= "Bad Packet!",
32 	[INTEL_PT_PAD]		= "PAD",
33 	[INTEL_PT_TNT]		= "TNT",
34 	[INTEL_PT_TIP_PGD]	= "TIP.PGD",
35 	[INTEL_PT_TIP_PGE]	= "TIP.PGE",
36 	[INTEL_PT_TSC]		= "TSC",
37 	[INTEL_PT_TMA]		= "TMA",
38 	[INTEL_PT_MODE_EXEC]	= "MODE.Exec",
39 	[INTEL_PT_MODE_TSX]	= "MODE.TSX",
40 	[INTEL_PT_MTC]		= "MTC",
41 	[INTEL_PT_TIP]		= "TIP",
42 	[INTEL_PT_FUP]		= "FUP",
43 	[INTEL_PT_CYC]		= "CYC",
44 	[INTEL_PT_VMCS]		= "VMCS",
45 	[INTEL_PT_PSB]		= "PSB",
46 	[INTEL_PT_PSBEND]	= "PSBEND",
47 	[INTEL_PT_CBR]		= "CBR",
48 	[INTEL_PT_TRACESTOP]	= "TraceSTOP",
49 	[INTEL_PT_PIP]		= "PIP",
50 	[INTEL_PT_OVF]		= "OVF",
51 	[INTEL_PT_MNT]		= "MNT",
52 	[INTEL_PT_PTWRITE]	= "PTWRITE",
53 	[INTEL_PT_PTWRITE_IP]	= "PTWRITE",
54 	[INTEL_PT_EXSTOP]	= "EXSTOP",
55 	[INTEL_PT_EXSTOP_IP]	= "EXSTOP",
56 	[INTEL_PT_MWAIT]	= "MWAIT",
57 	[INTEL_PT_PWRE]		= "PWRE",
58 	[INTEL_PT_PWRX]		= "PWRX",
59 	[INTEL_PT_BBP]		= "BBP",
60 	[INTEL_PT_BIP]		= "BIP",
61 	[INTEL_PT_BEP]		= "BEP",
62 	[INTEL_PT_BEP_IP]	= "BEP",
63 	[INTEL_PT_CFE]		= "CFE",
64 	[INTEL_PT_CFE_IP]	= "CFE",
65 	[INTEL_PT_EVD]		= "EVD",
66 };
67 
68 const char *intel_pt_pkt_name(enum intel_pt_pkt_type type)
69 {
70 	return packet_name[type];
71 }
72 
73 static int intel_pt_get_long_tnt(const unsigned char *buf, size_t len,
74 				 struct intel_pt_pkt *packet)
75 {
76 	uint64_t payload;
77 	int count;
78 
79 	if (len < 8)
80 		return INTEL_PT_NEED_MORE_BYTES;
81 
82 	payload = get_unaligned_le64(buf);
83 
84 	for (count = 47; count; count--) {
85 		if (payload & BIT63)
86 			break;
87 		payload <<= 1;
88 	}
89 
90 	packet->type = INTEL_PT_TNT;
91 	packet->count = count;
92 	packet->payload = payload << 1;
93 	return 8;
94 }
95 
96 static int intel_pt_get_pip(const unsigned char *buf, size_t len,
97 			    struct intel_pt_pkt *packet)
98 {
99 	uint64_t payload = 0;
100 
101 	if (len < 8)
102 		return INTEL_PT_NEED_MORE_BYTES;
103 
104 	packet->type = INTEL_PT_PIP;
105 	memcpy_le64(&payload, buf + 2, 6);
106 	packet->payload = payload;
107 
108 	return 8;
109 }
110 
111 static int intel_pt_get_tracestop(struct intel_pt_pkt *packet)
112 {
113 	packet->type = INTEL_PT_TRACESTOP;
114 	return 2;
115 }
116 
117 static int intel_pt_get_cbr(const unsigned char *buf, size_t len,
118 			    struct intel_pt_pkt *packet)
119 {
120 	if (len < 4)
121 		return INTEL_PT_NEED_MORE_BYTES;
122 	packet->type = INTEL_PT_CBR;
123 	packet->payload = get_unaligned_le16(buf + 2);
124 	return 4;
125 }
126 
127 static int intel_pt_get_vmcs(const unsigned char *buf, size_t len,
128 			     struct intel_pt_pkt *packet)
129 {
130 	if (len < 7)
131 		return INTEL_PT_NEED_MORE_BYTES;
132 
133 	packet->type = INTEL_PT_VMCS;
134 	packet->count = 5;
135 	memcpy_le64(&packet->payload, buf + 2, 5);
136 
137 	return 7;
138 }
139 
140 static int intel_pt_get_ovf(struct intel_pt_pkt *packet)
141 {
142 	packet->type = INTEL_PT_OVF;
143 	return 2;
144 }
145 
146 static int intel_pt_get_psb(const unsigned char *buf, size_t len,
147 			    struct intel_pt_pkt *packet)
148 {
149 	int i;
150 
151 	if (len < 16)
152 		return INTEL_PT_NEED_MORE_BYTES;
153 
154 	for (i = 2; i < 16; i += 2) {
155 		if (buf[i] != 2 || buf[i + 1] != 0x82)
156 			return INTEL_PT_BAD_PACKET;
157 	}
158 
159 	packet->type = INTEL_PT_PSB;
160 	return 16;
161 }
162 
163 static int intel_pt_get_psbend(struct intel_pt_pkt *packet)
164 {
165 	packet->type = INTEL_PT_PSBEND;
166 	return 2;
167 }
168 
169 static int intel_pt_get_tma(const unsigned char *buf, size_t len,
170 			    struct intel_pt_pkt *packet)
171 {
172 	if (len < 7)
173 		return INTEL_PT_NEED_MORE_BYTES;
174 
175 	packet->type = INTEL_PT_TMA;
176 	packet->payload = buf[2] | (buf[3] << 8);
177 	packet->count = buf[5] | ((buf[6] & BIT(0)) << 8);
178 	return 7;
179 }
180 
181 static int intel_pt_get_pad(struct intel_pt_pkt *packet)
182 {
183 	packet->type = INTEL_PT_PAD;
184 	return 1;
185 }
186 
187 static int intel_pt_get_mnt(const unsigned char *buf, size_t len,
188 			    struct intel_pt_pkt *packet)
189 {
190 	if (len < 11)
191 		return INTEL_PT_NEED_MORE_BYTES;
192 	packet->type = INTEL_PT_MNT;
193 	packet->payload = get_unaligned_le64(buf + 3);
194 	return 11;
195 }
196 
197 static int intel_pt_get_3byte(const unsigned char *buf, size_t len,
198 			      struct intel_pt_pkt *packet)
199 {
200 	if (len < 3)
201 		return INTEL_PT_NEED_MORE_BYTES;
202 
203 	switch (buf[2]) {
204 	case 0x88: /* MNT */
205 		return intel_pt_get_mnt(buf, len, packet);
206 	default:
207 		return INTEL_PT_BAD_PACKET;
208 	}
209 }
210 
211 static int intel_pt_get_ptwrite(const unsigned char *buf, size_t len,
212 				struct intel_pt_pkt *packet)
213 {
214 	packet->count = (buf[1] >> 5) & 0x3;
215 	packet->type = buf[1] & BIT(7) ? INTEL_PT_PTWRITE_IP :
216 					 INTEL_PT_PTWRITE;
217 
218 	switch (packet->count) {
219 	case 0:
220 		if (len < 6)
221 			return INTEL_PT_NEED_MORE_BYTES;
222 		packet->payload = get_unaligned_le32(buf + 2);
223 		return 6;
224 	case 1:
225 		if (len < 10)
226 			return INTEL_PT_NEED_MORE_BYTES;
227 		packet->payload = get_unaligned_le64(buf + 2);
228 		return 10;
229 	default:
230 		return INTEL_PT_BAD_PACKET;
231 	}
232 }
233 
234 static int intel_pt_get_exstop(struct intel_pt_pkt *packet)
235 {
236 	packet->type = INTEL_PT_EXSTOP;
237 	return 2;
238 }
239 
240 static int intel_pt_get_exstop_ip(struct intel_pt_pkt *packet)
241 {
242 	packet->type = INTEL_PT_EXSTOP_IP;
243 	return 2;
244 }
245 
246 static int intel_pt_get_mwait(const unsigned char *buf, size_t len,
247 			      struct intel_pt_pkt *packet)
248 {
249 	if (len < 10)
250 		return INTEL_PT_NEED_MORE_BYTES;
251 	packet->type = INTEL_PT_MWAIT;
252 	packet->payload = get_unaligned_le64(buf + 2);
253 	return 10;
254 }
255 
256 static int intel_pt_get_pwre(const unsigned char *buf, size_t len,
257 			     struct intel_pt_pkt *packet)
258 {
259 	if (len < 4)
260 		return INTEL_PT_NEED_MORE_BYTES;
261 	packet->type = INTEL_PT_PWRE;
262 	memcpy_le64(&packet->payload, buf + 2, 2);
263 	return 4;
264 }
265 
266 static int intel_pt_get_pwrx(const unsigned char *buf, size_t len,
267 			     struct intel_pt_pkt *packet)
268 {
269 	if (len < 7)
270 		return INTEL_PT_NEED_MORE_BYTES;
271 	packet->type = INTEL_PT_PWRX;
272 	memcpy_le64(&packet->payload, buf + 2, 5);
273 	return 7;
274 }
275 
276 static int intel_pt_get_bbp(const unsigned char *buf, size_t len,
277 			    struct intel_pt_pkt *packet)
278 {
279 	if (len < 3)
280 		return INTEL_PT_NEED_MORE_BYTES;
281 	packet->type = INTEL_PT_BBP;
282 	packet->count = buf[2] >> 7;
283 	packet->payload = buf[2] & 0x1f;
284 	return 3;
285 }
286 
287 static int intel_pt_get_bip_4(const unsigned char *buf, size_t len,
288 			      struct intel_pt_pkt *packet)
289 {
290 	if (len < 5)
291 		return INTEL_PT_NEED_MORE_BYTES;
292 	packet->type = INTEL_PT_BIP;
293 	packet->count = buf[0] >> 3;
294 	memcpy_le64(&packet->payload, buf + 1, 4);
295 	return 5;
296 }
297 
298 static int intel_pt_get_bip_8(const unsigned char *buf, size_t len,
299 			      struct intel_pt_pkt *packet)
300 {
301 	if (len < 9)
302 		return INTEL_PT_NEED_MORE_BYTES;
303 	packet->type = INTEL_PT_BIP;
304 	packet->count = buf[0] >> 3;
305 	packet->payload = get_unaligned_le64(buf + 1);
306 	return 9;
307 }
308 
309 static int intel_pt_get_bep(size_t len, struct intel_pt_pkt *packet)
310 {
311 	if (len < 2)
312 		return INTEL_PT_NEED_MORE_BYTES;
313 	packet->type = INTEL_PT_BEP;
314 	return 2;
315 }
316 
317 static int intel_pt_get_bep_ip(size_t len, struct intel_pt_pkt *packet)
318 {
319 	if (len < 2)
320 		return INTEL_PT_NEED_MORE_BYTES;
321 	packet->type = INTEL_PT_BEP_IP;
322 	return 2;
323 }
324 
325 static int intel_pt_get_cfe(const unsigned char *buf, size_t len,
326 			    struct intel_pt_pkt *packet)
327 {
328 	if (len < 4)
329 		return INTEL_PT_NEED_MORE_BYTES;
330 	packet->type = buf[2] & 0x80 ? INTEL_PT_CFE_IP : INTEL_PT_CFE;
331 	packet->count = buf[2] & 0x1f;
332 	packet->payload = buf[3];
333 	return 4;
334 }
335 
336 static int intel_pt_get_evd(const unsigned char *buf, size_t len,
337 			    struct intel_pt_pkt *packet)
338 {
339 	if (len < 11)
340 		return INTEL_PT_NEED_MORE_BYTES;
341 	packet->type = INTEL_PT_EVD;
342 	packet->count = buf[2] & 0x3f;
343 	packet->payload = buf[3];
344 	packet->payload = get_unaligned_le64(buf + 3);
345 	return 11;
346 }
347 
348 static int intel_pt_get_ext(const unsigned char *buf, size_t len,
349 			    struct intel_pt_pkt *packet)
350 {
351 	if (len < 2)
352 		return INTEL_PT_NEED_MORE_BYTES;
353 
354 	if ((buf[1] & 0x1f) == 0x12)
355 		return intel_pt_get_ptwrite(buf, len, packet);
356 
357 	switch (buf[1]) {
358 	case 0xa3: /* Long TNT */
359 		return intel_pt_get_long_tnt(buf, len, packet);
360 	case 0x43: /* PIP */
361 		return intel_pt_get_pip(buf, len, packet);
362 	case 0x83: /* TraceStop */
363 		return intel_pt_get_tracestop(packet);
364 	case 0x03: /* CBR */
365 		return intel_pt_get_cbr(buf, len, packet);
366 	case 0xc8: /* VMCS */
367 		return intel_pt_get_vmcs(buf, len, packet);
368 	case 0xf3: /* OVF */
369 		return intel_pt_get_ovf(packet);
370 	case 0x82: /* PSB */
371 		return intel_pt_get_psb(buf, len, packet);
372 	case 0x23: /* PSBEND */
373 		return intel_pt_get_psbend(packet);
374 	case 0x73: /* TMA */
375 		return intel_pt_get_tma(buf, len, packet);
376 	case 0xC3: /* 3-byte header */
377 		return intel_pt_get_3byte(buf, len, packet);
378 	case 0x62: /* EXSTOP no IP */
379 		return intel_pt_get_exstop(packet);
380 	case 0xE2: /* EXSTOP with IP */
381 		return intel_pt_get_exstop_ip(packet);
382 	case 0xC2: /* MWAIT */
383 		return intel_pt_get_mwait(buf, len, packet);
384 	case 0x22: /* PWRE */
385 		return intel_pt_get_pwre(buf, len, packet);
386 	case 0xA2: /* PWRX */
387 		return intel_pt_get_pwrx(buf, len, packet);
388 	case 0x63: /* BBP */
389 		return intel_pt_get_bbp(buf, len, packet);
390 	case 0x33: /* BEP no IP */
391 		return intel_pt_get_bep(len, packet);
392 	case 0xb3: /* BEP with IP */
393 		return intel_pt_get_bep_ip(len, packet);
394 	case 0x13: /* CFE */
395 		return intel_pt_get_cfe(buf, len, packet);
396 	case 0x53: /* EVD */
397 		return intel_pt_get_evd(buf, len, packet);
398 	default:
399 		return INTEL_PT_BAD_PACKET;
400 	}
401 }
402 
403 static int intel_pt_get_short_tnt(unsigned int byte,
404 				  struct intel_pt_pkt *packet)
405 {
406 	int count;
407 
408 	for (count = 6; count; count--) {
409 		if (byte & BIT(7))
410 			break;
411 		byte <<= 1;
412 	}
413 
414 	packet->type = INTEL_PT_TNT;
415 	packet->count = count;
416 	packet->payload = (uint64_t)byte << 57;
417 
418 	return 1;
419 }
420 
421 static int intel_pt_get_cyc(unsigned int byte, const unsigned char *buf,
422 			    size_t len, struct intel_pt_pkt *packet)
423 {
424 	unsigned int offs = 1, shift;
425 	uint64_t payload = byte >> 3;
426 
427 	byte >>= 2;
428 	len -= 1;
429 	for (shift = 5; byte & 1; shift += 7) {
430 		if (offs > 9)
431 			return INTEL_PT_BAD_PACKET;
432 		if (len < offs)
433 			return INTEL_PT_NEED_MORE_BYTES;
434 		byte = buf[offs++];
435 		payload |= ((uint64_t)byte >> 1) << shift;
436 	}
437 
438 	packet->type = INTEL_PT_CYC;
439 	packet->payload = payload;
440 	return offs;
441 }
442 
443 static int intel_pt_get_ip(enum intel_pt_pkt_type type, unsigned int byte,
444 			   const unsigned char *buf, size_t len,
445 			   struct intel_pt_pkt *packet)
446 {
447 	int ip_len;
448 
449 	packet->count = byte >> 5;
450 
451 	switch (packet->count) {
452 	case 0:
453 		ip_len = 0;
454 		break;
455 	case 1:
456 		if (len < 3)
457 			return INTEL_PT_NEED_MORE_BYTES;
458 		ip_len = 2;
459 		packet->payload = get_unaligned_le16(buf + 1);
460 		break;
461 	case 2:
462 		if (len < 5)
463 			return INTEL_PT_NEED_MORE_BYTES;
464 		ip_len = 4;
465 		packet->payload = get_unaligned_le32(buf + 1);
466 		break;
467 	case 3:
468 	case 4:
469 		if (len < 7)
470 			return INTEL_PT_NEED_MORE_BYTES;
471 		ip_len = 6;
472 		memcpy_le64(&packet->payload, buf + 1, 6);
473 		break;
474 	case 6:
475 		if (len < 9)
476 			return INTEL_PT_NEED_MORE_BYTES;
477 		ip_len = 8;
478 		packet->payload = get_unaligned_le64(buf + 1);
479 		break;
480 	default:
481 		return INTEL_PT_BAD_PACKET;
482 	}
483 
484 	packet->type = type;
485 
486 	return ip_len + 1;
487 }
488 
489 static int intel_pt_get_mode(const unsigned char *buf, size_t len,
490 			     struct intel_pt_pkt *packet)
491 {
492 	if (len < 2)
493 		return INTEL_PT_NEED_MORE_BYTES;
494 
495 	switch (buf[1] >> 5) {
496 	case 0:
497 		packet->type = INTEL_PT_MODE_EXEC;
498 		packet->count = buf[1];
499 		switch (buf[1] & 3) {
500 		case 0:
501 			packet->payload = 16;
502 			break;
503 		case 1:
504 			packet->payload = 64;
505 			break;
506 		case 2:
507 			packet->payload = 32;
508 			break;
509 		default:
510 			return INTEL_PT_BAD_PACKET;
511 		}
512 		break;
513 	case 1:
514 		packet->type = INTEL_PT_MODE_TSX;
515 		if ((buf[1] & 3) == 3)
516 			return INTEL_PT_BAD_PACKET;
517 		packet->payload = buf[1] & 3;
518 		break;
519 	default:
520 		return INTEL_PT_BAD_PACKET;
521 	}
522 
523 	return 2;
524 }
525 
526 static int intel_pt_get_tsc(const unsigned char *buf, size_t len,
527 			    struct intel_pt_pkt *packet)
528 {
529 	if (len < 8)
530 		return INTEL_PT_NEED_MORE_BYTES;
531 	packet->type = INTEL_PT_TSC;
532 	memcpy_le64(&packet->payload, buf + 1, 7);
533 	return 8;
534 }
535 
536 static int intel_pt_get_mtc(const unsigned char *buf, size_t len,
537 			    struct intel_pt_pkt *packet)
538 {
539 	if (len < 2)
540 		return INTEL_PT_NEED_MORE_BYTES;
541 	packet->type = INTEL_PT_MTC;
542 	packet->payload = buf[1];
543 	return 2;
544 }
545 
546 static int intel_pt_do_get_packet(const unsigned char *buf, size_t len,
547 				  struct intel_pt_pkt *packet,
548 				  enum intel_pt_pkt_ctx ctx)
549 {
550 	unsigned int byte;
551 
552 	memset(packet, 0, sizeof(struct intel_pt_pkt));
553 
554 	if (!len)
555 		return INTEL_PT_NEED_MORE_BYTES;
556 
557 	byte = buf[0];
558 
559 	switch (ctx) {
560 	case INTEL_PT_NO_CTX:
561 		break;
562 	case INTEL_PT_BLK_4_CTX:
563 		if ((byte & 0x7) == 4)
564 			return intel_pt_get_bip_4(buf, len, packet);
565 		break;
566 	case INTEL_PT_BLK_8_CTX:
567 		if ((byte & 0x7) == 4)
568 			return intel_pt_get_bip_8(buf, len, packet);
569 		break;
570 	default:
571 		break;
572 	}
573 
574 	if (!(byte & BIT(0))) {
575 		if (byte == 0)
576 			return intel_pt_get_pad(packet);
577 		if (byte == 2)
578 			return intel_pt_get_ext(buf, len, packet);
579 		return intel_pt_get_short_tnt(byte, packet);
580 	}
581 
582 	if ((byte & 2))
583 		return intel_pt_get_cyc(byte, buf, len, packet);
584 
585 	switch (byte & 0x1f) {
586 	case 0x0D:
587 		return intel_pt_get_ip(INTEL_PT_TIP, byte, buf, len, packet);
588 	case 0x11:
589 		return intel_pt_get_ip(INTEL_PT_TIP_PGE, byte, buf, len,
590 				       packet);
591 	case 0x01:
592 		return intel_pt_get_ip(INTEL_PT_TIP_PGD, byte, buf, len,
593 				       packet);
594 	case 0x1D:
595 		return intel_pt_get_ip(INTEL_PT_FUP, byte, buf, len, packet);
596 	case 0x19:
597 		switch (byte) {
598 		case 0x99:
599 			return intel_pt_get_mode(buf, len, packet);
600 		case 0x19:
601 			return intel_pt_get_tsc(buf, len, packet);
602 		case 0x59:
603 			return intel_pt_get_mtc(buf, len, packet);
604 		default:
605 			return INTEL_PT_BAD_PACKET;
606 		}
607 	default:
608 		return INTEL_PT_BAD_PACKET;
609 	}
610 }
611 
612 void intel_pt_upd_pkt_ctx(const struct intel_pt_pkt *packet,
613 			  enum intel_pt_pkt_ctx *ctx)
614 {
615 	switch (packet->type) {
616 	case INTEL_PT_BAD:
617 	case INTEL_PT_PAD:
618 	case INTEL_PT_TSC:
619 	case INTEL_PT_TMA:
620 	case INTEL_PT_MTC:
621 	case INTEL_PT_FUP:
622 	case INTEL_PT_CYC:
623 	case INTEL_PT_CBR:
624 	case INTEL_PT_MNT:
625 	case INTEL_PT_EXSTOP:
626 	case INTEL_PT_EXSTOP_IP:
627 	case INTEL_PT_PWRE:
628 	case INTEL_PT_PWRX:
629 	case INTEL_PT_BIP:
630 		break;
631 	case INTEL_PT_TNT:
632 	case INTEL_PT_TIP:
633 	case INTEL_PT_TIP_PGD:
634 	case INTEL_PT_TIP_PGE:
635 	case INTEL_PT_MODE_EXEC:
636 	case INTEL_PT_MODE_TSX:
637 	case INTEL_PT_PIP:
638 	case INTEL_PT_OVF:
639 	case INTEL_PT_VMCS:
640 	case INTEL_PT_TRACESTOP:
641 	case INTEL_PT_PSB:
642 	case INTEL_PT_PSBEND:
643 	case INTEL_PT_PTWRITE:
644 	case INTEL_PT_PTWRITE_IP:
645 	case INTEL_PT_MWAIT:
646 	case INTEL_PT_BEP:
647 	case INTEL_PT_BEP_IP:
648 	case INTEL_PT_CFE:
649 	case INTEL_PT_CFE_IP:
650 	case INTEL_PT_EVD:
651 		*ctx = INTEL_PT_NO_CTX;
652 		break;
653 	case INTEL_PT_BBP:
654 		if (packet->count)
655 			*ctx = INTEL_PT_BLK_4_CTX;
656 		else
657 			*ctx = INTEL_PT_BLK_8_CTX;
658 		break;
659 	default:
660 		break;
661 	}
662 }
663 
664 int intel_pt_get_packet(const unsigned char *buf, size_t len,
665 			struct intel_pt_pkt *packet, enum intel_pt_pkt_ctx *ctx)
666 {
667 	int ret;
668 
669 	ret = intel_pt_do_get_packet(buf, len, packet, *ctx);
670 	if (ret > 0) {
671 		while (ret < 8 && len > (size_t)ret && !buf[ret])
672 			ret += 1;
673 		intel_pt_upd_pkt_ctx(packet, ctx);
674 	}
675 	return ret;
676 }
677 
678 int intel_pt_pkt_desc(const struct intel_pt_pkt *packet, char *buf,
679 		      size_t buf_len)
680 {
681 	int ret, i, nr;
682 	unsigned long long payload = packet->payload;
683 	const char *name = intel_pt_pkt_name(packet->type);
684 
685 	switch (packet->type) {
686 	case INTEL_PT_BAD:
687 	case INTEL_PT_PAD:
688 	case INTEL_PT_PSB:
689 	case INTEL_PT_PSBEND:
690 	case INTEL_PT_TRACESTOP:
691 	case INTEL_PT_OVF:
692 		return snprintf(buf, buf_len, "%s", name);
693 	case INTEL_PT_TNT: {
694 		size_t blen = buf_len;
695 
696 		ret = snprintf(buf, blen, "%s ", name);
697 		if (ret < 0)
698 			return ret;
699 		buf += ret;
700 		blen -= ret;
701 		for (i = 0; i < packet->count; i++) {
702 			if (payload & BIT63)
703 				ret = snprintf(buf, blen, "T");
704 			else
705 				ret = snprintf(buf, blen, "N");
706 			if (ret < 0)
707 				return ret;
708 			buf += ret;
709 			blen -= ret;
710 			payload <<= 1;
711 		}
712 		ret = snprintf(buf, blen, " (%d)", packet->count);
713 		if (ret < 0)
714 			return ret;
715 		blen -= ret;
716 		return buf_len - blen;
717 	}
718 	case INTEL_PT_TIP_PGD:
719 	case INTEL_PT_TIP_PGE:
720 	case INTEL_PT_TIP:
721 	case INTEL_PT_FUP:
722 		if (!(packet->count))
723 			return snprintf(buf, buf_len, "%s no ip", name);
724 		fallthrough;
725 	case INTEL_PT_CYC:
726 	case INTEL_PT_VMCS:
727 	case INTEL_PT_MTC:
728 	case INTEL_PT_MNT:
729 	case INTEL_PT_CBR:
730 	case INTEL_PT_TSC:
731 		return snprintf(buf, buf_len, "%s 0x%llx", name, payload);
732 	case INTEL_PT_TMA:
733 		return snprintf(buf, buf_len, "%s CTC 0x%x FC 0x%x", name,
734 				(unsigned)payload, packet->count);
735 	case INTEL_PT_MODE_EXEC:
736 		return snprintf(buf, buf_len, "%s IF:%d %lld",
737 				name, !!(packet->count & 4), payload);
738 	case INTEL_PT_MODE_TSX:
739 		return snprintf(buf, buf_len, "%s TXAbort:%u InTX:%u",
740 				name, (unsigned)(payload >> 1) & 1,
741 				(unsigned)payload & 1);
742 	case INTEL_PT_PIP:
743 		nr = packet->payload & INTEL_PT_VMX_NR_FLAG ? 1 : 0;
744 		payload &= ~INTEL_PT_VMX_NR_FLAG;
745 		ret = snprintf(buf, buf_len, "%s 0x%llx (NR=%d)",
746 			       name, payload >> 1, nr);
747 		return ret;
748 	case INTEL_PT_PTWRITE:
749 		return snprintf(buf, buf_len, "%s 0x%llx IP:0", name, payload);
750 	case INTEL_PT_PTWRITE_IP:
751 		return snprintf(buf, buf_len, "%s 0x%llx IP:1", name, payload);
752 	case INTEL_PT_BEP:
753 	case INTEL_PT_EXSTOP:
754 		return snprintf(buf, buf_len, "%s IP:0", name);
755 	case INTEL_PT_BEP_IP:
756 	case INTEL_PT_EXSTOP_IP:
757 		return snprintf(buf, buf_len, "%s IP:1", name);
758 	case INTEL_PT_MWAIT:
759 		return snprintf(buf, buf_len, "%s 0x%llx Hints 0x%x Extensions 0x%x",
760 				name, payload, (unsigned int)(payload & 0xff),
761 				(unsigned int)((payload >> 32) & 0x3));
762 	case INTEL_PT_PWRE:
763 		return snprintf(buf, buf_len, "%s 0x%llx HW:%u CState:%u Sub-CState:%u",
764 				name, payload, !!(payload & 0x80),
765 				(unsigned int)((payload >> 12) & 0xf),
766 				(unsigned int)((payload >> 8) & 0xf));
767 	case INTEL_PT_PWRX:
768 		return snprintf(buf, buf_len, "%s 0x%llx Last CState:%u Deepest CState:%u Wake Reason 0x%x",
769 				name, payload,
770 				(unsigned int)((payload >> 4) & 0xf),
771 				(unsigned int)(payload & 0xf),
772 				(unsigned int)((payload >> 8) & 0xf));
773 	case INTEL_PT_BBP:
774 		return snprintf(buf, buf_len, "%s SZ %s-byte Type 0x%llx",
775 				name, packet->count ? "4" : "8", payload);
776 	case INTEL_PT_BIP:
777 		return snprintf(buf, buf_len, "%s ID 0x%02x Value 0x%llx",
778 				name, packet->count, payload);
779 	case INTEL_PT_CFE:
780 	case INTEL_PT_CFE_IP:
781 		return snprintf(buf, buf_len, "%s IP:%d Type 0x%02x Vector 0x%llx",
782 				name, packet->type == INTEL_PT_CFE_IP, packet->count, payload);
783 	case INTEL_PT_EVD:
784 		return snprintf(buf, buf_len, "%s Type 0x%02x Payload 0x%llx",
785 				name, packet->count, payload);
786 	default:
787 		break;
788 	}
789 	return snprintf(buf, buf_len, "%s 0x%llx (%d)",
790 			name, payload, packet->count);
791 }
792