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Linux/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

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  1 /*
  2  * intel_pt_decoder.c: Intel Processor Trace support
  3  * Copyright (c) 2013-2014, Intel Corporation.
  4  *
  5  * This program is free software; you can redistribute it and/or modify it
  6  * under the terms and conditions of the GNU General Public License,
  7  * version 2, as published by the Free Software Foundation.
  8  *
  9  * This program is distributed in the hope it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 12  * more details.
 13  *
 14  */
 15 
 16 #ifndef _GNU_SOURCE
 17 #define _GNU_SOURCE
 18 #endif
 19 #include <stdlib.h>
 20 #include <stdbool.h>
 21 #include <string.h>
 22 #include <errno.h>
 23 #include <stdint.h>
 24 #include <inttypes.h>
 25 #include <linux/compiler.h>
 26 
 27 #include "../cache.h"
 28 #include "../util.h"
 29 
 30 #include "intel-pt-insn-decoder.h"
 31 #include "intel-pt-pkt-decoder.h"
 32 #include "intel-pt-decoder.h"
 33 #include "intel-pt-log.h"
 34 
 35 #define INTEL_PT_BLK_SIZE 1024
 36 
 37 #define BIT63 (((uint64_t)1 << 63))
 38 
 39 #define INTEL_PT_RETURN 1
 40 
 41 /* Maximum number of loops with no packets consumed i.e. stuck in a loop */
 42 #define INTEL_PT_MAX_LOOPS 10000
 43 
 44 struct intel_pt_blk {
 45         struct intel_pt_blk *prev;
 46         uint64_t ip[INTEL_PT_BLK_SIZE];
 47 };
 48 
 49 struct intel_pt_stack {
 50         struct intel_pt_blk *blk;
 51         struct intel_pt_blk *spare;
 52         int pos;
 53 };
 54 
 55 enum intel_pt_pkt_state {
 56         INTEL_PT_STATE_NO_PSB,
 57         INTEL_PT_STATE_NO_IP,
 58         INTEL_PT_STATE_ERR_RESYNC,
 59         INTEL_PT_STATE_IN_SYNC,
 60         INTEL_PT_STATE_TNT,
 61         INTEL_PT_STATE_TIP,
 62         INTEL_PT_STATE_TIP_PGD,
 63         INTEL_PT_STATE_FUP,
 64         INTEL_PT_STATE_FUP_NO_TIP,
 65 };
 66 
 67 static inline bool intel_pt_sample_time(enum intel_pt_pkt_state pkt_state)
 68 {
 69         switch (pkt_state) {
 70         case INTEL_PT_STATE_NO_PSB:
 71         case INTEL_PT_STATE_NO_IP:
 72         case INTEL_PT_STATE_ERR_RESYNC:
 73         case INTEL_PT_STATE_IN_SYNC:
 74         case INTEL_PT_STATE_TNT:
 75                 return true;
 76         case INTEL_PT_STATE_TIP:
 77         case INTEL_PT_STATE_TIP_PGD:
 78         case INTEL_PT_STATE_FUP:
 79         case INTEL_PT_STATE_FUP_NO_TIP:
 80                 return false;
 81         default:
 82                 return true;
 83         };
 84 }
 85 
 86 #ifdef INTEL_PT_STRICT
 87 #define INTEL_PT_STATE_ERR1     INTEL_PT_STATE_NO_PSB
 88 #define INTEL_PT_STATE_ERR2     INTEL_PT_STATE_NO_PSB
 89 #define INTEL_PT_STATE_ERR3     INTEL_PT_STATE_NO_PSB
 90 #define INTEL_PT_STATE_ERR4     INTEL_PT_STATE_NO_PSB
 91 #else
 92 #define INTEL_PT_STATE_ERR1     (decoder->pkt_state)
 93 #define INTEL_PT_STATE_ERR2     INTEL_PT_STATE_NO_IP
 94 #define INTEL_PT_STATE_ERR3     INTEL_PT_STATE_ERR_RESYNC
 95 #define INTEL_PT_STATE_ERR4     INTEL_PT_STATE_IN_SYNC
 96 #endif
 97 
 98 struct intel_pt_decoder {
 99         int (*get_trace)(struct intel_pt_buffer *buffer, void *data);
100         int (*walk_insn)(struct intel_pt_insn *intel_pt_insn,
101                          uint64_t *insn_cnt_ptr, uint64_t *ip, uint64_t to_ip,
102                          uint64_t max_insn_cnt, void *data);
103         bool (*pgd_ip)(uint64_t ip, void *data);
104         void *data;
105         struct intel_pt_state state;
106         const unsigned char *buf;
107         size_t len;
108         bool return_compression;
109         bool branch_enable;
110         bool mtc_insn;
111         bool pge;
112         bool have_tma;
113         bool have_cyc;
114         bool fixup_last_mtc;
115         bool have_last_ip;
116         enum intel_pt_param_flags flags;
117         uint64_t pos;
118         uint64_t last_ip;
119         uint64_t ip;
120         uint64_t cr3;
121         uint64_t timestamp;
122         uint64_t tsc_timestamp;
123         uint64_t ref_timestamp;
124         uint64_t sample_timestamp;
125         uint64_t ret_addr;
126         uint64_t ctc_timestamp;
127         uint64_t ctc_delta;
128         uint64_t cycle_cnt;
129         uint64_t cyc_ref_timestamp;
130         uint32_t last_mtc;
131         uint32_t tsc_ctc_ratio_n;
132         uint32_t tsc_ctc_ratio_d;
133         uint32_t tsc_ctc_mult;
134         uint32_t tsc_slip;
135         uint32_t ctc_rem_mask;
136         int mtc_shift;
137         struct intel_pt_stack stack;
138         enum intel_pt_pkt_state pkt_state;
139         struct intel_pt_pkt packet;
140         struct intel_pt_pkt tnt;
141         int pkt_step;
142         int pkt_len;
143         int last_packet_type;
144         unsigned int cbr;
145         unsigned int cbr_seen;
146         unsigned int max_non_turbo_ratio;
147         double max_non_turbo_ratio_fp;
148         double cbr_cyc_to_tsc;
149         double calc_cyc_to_tsc;
150         bool have_calc_cyc_to_tsc;
151         int exec_mode;
152         unsigned int insn_bytes;
153         uint64_t period;
154         enum intel_pt_period_type period_type;
155         uint64_t tot_insn_cnt;
156         uint64_t period_insn_cnt;
157         uint64_t period_mask;
158         uint64_t period_ticks;
159         uint64_t last_masked_timestamp;
160         bool continuous_period;
161         bool overflow;
162         bool set_fup_tx_flags;
163         bool set_fup_ptw;
164         bool set_fup_mwait;
165         bool set_fup_pwre;
166         bool set_fup_exstop;
167         unsigned int fup_tx_flags;
168         unsigned int tx_flags;
169         uint64_t fup_ptw_payload;
170         uint64_t fup_mwait_payload;
171         uint64_t fup_pwre_payload;
172         uint64_t cbr_payload;
173         uint64_t timestamp_insn_cnt;
174         uint64_t sample_insn_cnt;
175         uint64_t stuck_ip;
176         int no_progress;
177         int stuck_ip_prd;
178         int stuck_ip_cnt;
179         const unsigned char *next_buf;
180         size_t next_len;
181         unsigned char temp_buf[INTEL_PT_PKT_MAX_SZ];
182 };
183 
184 static uint64_t intel_pt_lower_power_of_2(uint64_t x)
185 {
186         int i;
187 
188         for (i = 0; x != 1; i++)
189                 x >>= 1;
190 
191         return x << i;
192 }
193 
194 static void intel_pt_setup_period(struct intel_pt_decoder *decoder)
195 {
196         if (decoder->period_type == INTEL_PT_PERIOD_TICKS) {
197                 uint64_t period;
198 
199                 period = intel_pt_lower_power_of_2(decoder->period);
200                 decoder->period_mask  = ~(period - 1);
201                 decoder->period_ticks = period;
202         }
203 }
204 
205 static uint64_t multdiv(uint64_t t, uint32_t n, uint32_t d)
206 {
207         if (!d)
208                 return 0;
209         return (t / d) * n + ((t % d) * n) / d;
210 }
211 
212 struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
213 {
214         struct intel_pt_decoder *decoder;
215 
216         if (!params->get_trace || !params->walk_insn)
217                 return NULL;
218 
219         decoder = zalloc(sizeof(struct intel_pt_decoder));
220         if (!decoder)
221                 return NULL;
222 
223         decoder->get_trace          = params->get_trace;
224         decoder->walk_insn          = params->walk_insn;
225         decoder->pgd_ip             = params->pgd_ip;
226         decoder->data               = params->data;
227         decoder->return_compression = params->return_compression;
228         decoder->branch_enable      = params->branch_enable;
229 
230         decoder->flags              = params->flags;
231 
232         decoder->period             = params->period;
233         decoder->period_type        = params->period_type;
234 
235         decoder->max_non_turbo_ratio    = params->max_non_turbo_ratio;
236         decoder->max_non_turbo_ratio_fp = params->max_non_turbo_ratio;
237 
238         intel_pt_setup_period(decoder);
239 
240         decoder->mtc_shift = params->mtc_period;
241         decoder->ctc_rem_mask = (1 << decoder->mtc_shift) - 1;
242 
243         decoder->tsc_ctc_ratio_n = params->tsc_ctc_ratio_n;
244         decoder->tsc_ctc_ratio_d = params->tsc_ctc_ratio_d;
245 
246         if (!decoder->tsc_ctc_ratio_n)
247                 decoder->tsc_ctc_ratio_d = 0;
248 
249         if (decoder->tsc_ctc_ratio_d) {
250                 if (!(decoder->tsc_ctc_ratio_n % decoder->tsc_ctc_ratio_d))
251                         decoder->tsc_ctc_mult = decoder->tsc_ctc_ratio_n /
252                                                 decoder->tsc_ctc_ratio_d;
253 
254                 /*
255                  * Allow for timestamps appearing to backwards because a TSC
256                  * packet has slipped past a MTC packet, so allow 2 MTC ticks
257                  * or ...
258                  */
259                 decoder->tsc_slip = multdiv(2 << decoder->mtc_shift,
260                                         decoder->tsc_ctc_ratio_n,
261                                         decoder->tsc_ctc_ratio_d);
262         }
263         /* ... or 0x100 paranoia */
264         if (decoder->tsc_slip < 0x100)
265                 decoder->tsc_slip = 0x100;
266 
267         intel_pt_log("timestamp: mtc_shift %u\n", decoder->mtc_shift);
268         intel_pt_log("timestamp: tsc_ctc_ratio_n %u\n", decoder->tsc_ctc_ratio_n);
269         intel_pt_log("timestamp: tsc_ctc_ratio_d %u\n", decoder->tsc_ctc_ratio_d);
270         intel_pt_log("timestamp: tsc_ctc_mult %u\n", decoder->tsc_ctc_mult);
271         intel_pt_log("timestamp: tsc_slip %#x\n", decoder->tsc_slip);
272 
273         return decoder;
274 }
275 
276 static void intel_pt_pop_blk(struct intel_pt_stack *stack)
277 {
278         struct intel_pt_blk *blk = stack->blk;
279 
280         stack->blk = blk->prev;
281         if (!stack->spare)
282                 stack->spare = blk;
283         else
284                 free(blk);
285 }
286 
287 static uint64_t intel_pt_pop(struct intel_pt_stack *stack)
288 {
289         if (!stack->pos) {
290                 if (!stack->blk)
291                         return 0;
292                 intel_pt_pop_blk(stack);
293                 if (!stack->blk)
294                         return 0;
295                 stack->pos = INTEL_PT_BLK_SIZE;
296         }
297         return stack->blk->ip[--stack->pos];
298 }
299 
300 static int intel_pt_alloc_blk(struct intel_pt_stack *stack)
301 {
302         struct intel_pt_blk *blk;
303 
304         if (stack->spare) {
305                 blk = stack->spare;
306                 stack->spare = NULL;
307         } else {
308                 blk = malloc(sizeof(struct intel_pt_blk));
309                 if (!blk)
310                         return -ENOMEM;
311         }
312 
313         blk->prev = stack->blk;
314         stack->blk = blk;
315         stack->pos = 0;
316         return 0;
317 }
318 
319 static int intel_pt_push(struct intel_pt_stack *stack, uint64_t ip)
320 {
321         int err;
322 
323         if (!stack->blk || stack->pos == INTEL_PT_BLK_SIZE) {
324                 err = intel_pt_alloc_blk(stack);
325                 if (err)
326                         return err;
327         }
328 
329         stack->blk->ip[stack->pos++] = ip;
330         return 0;
331 }
332 
333 static void intel_pt_clear_stack(struct intel_pt_stack *stack)
334 {
335         while (stack->blk)
336                 intel_pt_pop_blk(stack);
337         stack->pos = 0;
338 }
339 
340 static void intel_pt_free_stack(struct intel_pt_stack *stack)
341 {
342         intel_pt_clear_stack(stack);
343         zfree(&stack->blk);
344         zfree(&stack->spare);
345 }
346 
347 void intel_pt_decoder_free(struct intel_pt_decoder *decoder)
348 {
349         intel_pt_free_stack(&decoder->stack);
350         free(decoder);
351 }
352 
353 static int intel_pt_ext_err(int code)
354 {
355         switch (code) {
356         case -ENOMEM:
357                 return INTEL_PT_ERR_NOMEM;
358         case -ENOSYS:
359                 return INTEL_PT_ERR_INTERN;
360         case -EBADMSG:
361                 return INTEL_PT_ERR_BADPKT;
362         case -ENODATA:
363                 return INTEL_PT_ERR_NODATA;
364         case -EILSEQ:
365                 return INTEL_PT_ERR_NOINSN;
366         case -ENOENT:
367                 return INTEL_PT_ERR_MISMAT;
368         case -EOVERFLOW:
369                 return INTEL_PT_ERR_OVR;
370         case -ENOSPC:
371                 return INTEL_PT_ERR_LOST;
372         case -ELOOP:
373                 return INTEL_PT_ERR_NELOOP;
374         default:
375                 return INTEL_PT_ERR_UNK;
376         }
377 }
378 
379 static const char *intel_pt_err_msgs[] = {
380         [INTEL_PT_ERR_NOMEM]  = "Memory allocation failed",
381         [INTEL_PT_ERR_INTERN] = "Internal error",
382         [INTEL_PT_ERR_BADPKT] = "Bad packet",
383         [INTEL_PT_ERR_NODATA] = "No more data",
384         [INTEL_PT_ERR_NOINSN] = "Failed to get instruction",
385         [INTEL_PT_ERR_MISMAT] = "Trace doesn't match instruction",
386         [INTEL_PT_ERR_OVR]    = "Overflow packet",
387         [INTEL_PT_ERR_LOST]   = "Lost trace data",
388         [INTEL_PT_ERR_UNK]    = "Unknown error!",
389         [INTEL_PT_ERR_NELOOP] = "Never-ending loop",
390 };
391 
392 int intel_pt__strerror(int code, char *buf, size_t buflen)
393 {
394         if (code < 1 || code >= INTEL_PT_ERR_MAX)
395                 code = INTEL_PT_ERR_UNK;
396         strlcpy(buf, intel_pt_err_msgs[code], buflen);
397         return 0;
398 }
399 
400 static uint64_t intel_pt_calc_ip(const struct intel_pt_pkt *packet,
401                                  uint64_t last_ip)
402 {
403         uint64_t ip;
404 
405         switch (packet->count) {
406         case 1:
407                 ip = (last_ip & (uint64_t)0xffffffffffff0000ULL) |
408                      packet->payload;
409                 break;
410         case 2:
411                 ip = (last_ip & (uint64_t)0xffffffff00000000ULL) |
412                      packet->payload;
413                 break;
414         case 3:
415                 ip = packet->payload;
416                 /* Sign-extend 6-byte ip */
417                 if (ip & (uint64_t)0x800000000000ULL)
418                         ip |= (uint64_t)0xffff000000000000ULL;
419                 break;
420         case 4:
421                 ip = (last_ip & (uint64_t)0xffff000000000000ULL) |
422                      packet->payload;
423                 break;
424         case 6:
425                 ip = packet->payload;
426                 break;
427         default:
428                 return 0;
429         }
430 
431         return ip;
432 }
433 
434 static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
435 {
436         decoder->last_ip = intel_pt_calc_ip(&decoder->packet, decoder->last_ip);
437         decoder->have_last_ip = true;
438 }
439 
440 static inline void intel_pt_set_ip(struct intel_pt_decoder *decoder)
441 {
442         intel_pt_set_last_ip(decoder);
443         decoder->ip = decoder->last_ip;
444 }
445 
446 static void intel_pt_decoder_log_packet(struct intel_pt_decoder *decoder)
447 {
448         intel_pt_log_packet(&decoder->packet, decoder->pkt_len, decoder->pos,
449                             decoder->buf);
450 }
451 
452 static int intel_pt_bug(struct intel_pt_decoder *decoder)
453 {
454         intel_pt_log("ERROR: Internal error\n");
455         decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
456         return -ENOSYS;
457 }
458 
459 static inline void intel_pt_clear_tx_flags(struct intel_pt_decoder *decoder)
460 {
461         decoder->tx_flags = 0;
462 }
463 
464 static inline void intel_pt_update_in_tx(struct intel_pt_decoder *decoder)
465 {
466         decoder->tx_flags = decoder->packet.payload & INTEL_PT_IN_TX;
467 }
468 
469 static int intel_pt_bad_packet(struct intel_pt_decoder *decoder)
470 {
471         intel_pt_clear_tx_flags(decoder);
472         decoder->have_tma = false;
473         decoder->pkt_len = 1;
474         decoder->pkt_step = 1;
475         intel_pt_decoder_log_packet(decoder);
476         if (decoder->pkt_state != INTEL_PT_STATE_NO_PSB) {
477                 intel_pt_log("ERROR: Bad packet\n");
478                 decoder->pkt_state = INTEL_PT_STATE_ERR1;
479         }
480         return -EBADMSG;
481 }
482 
483 static int intel_pt_get_data(struct intel_pt_decoder *decoder)
484 {
485         struct intel_pt_buffer buffer = { .buf = 0, };
486         int ret;
487 
488         decoder->pkt_step = 0;
489 
490         intel_pt_log("Getting more data\n");
491         ret = decoder->get_trace(&buffer, decoder->data);
492         if (ret)
493                 return ret;
494         decoder->buf = buffer.buf;
495         decoder->len = buffer.len;
496         if (!decoder->len) {
497                 intel_pt_log("No more data\n");
498                 return -ENODATA;
499         }
500         if (!buffer.consecutive) {
501                 decoder->ip = 0;
502                 decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
503                 decoder->ref_timestamp = buffer.ref_timestamp;
504                 decoder->timestamp = 0;
505                 decoder->have_tma = false;
506                 decoder->state.trace_nr = buffer.trace_nr;
507                 intel_pt_log("Reference timestamp 0x%" PRIx64 "\n",
508                              decoder->ref_timestamp);
509                 return -ENOLINK;
510         }
511 
512         return 0;
513 }
514 
515 static int intel_pt_get_next_data(struct intel_pt_decoder *decoder)
516 {
517         if (!decoder->next_buf)
518                 return intel_pt_get_data(decoder);
519 
520         decoder->buf = decoder->next_buf;
521         decoder->len = decoder->next_len;
522         decoder->next_buf = 0;
523         decoder->next_len = 0;
524         return 0;
525 }
526 
527 static int intel_pt_get_split_packet(struct intel_pt_decoder *decoder)
528 {
529         unsigned char *buf = decoder->temp_buf;
530         size_t old_len, len, n;
531         int ret;
532 
533         old_len = decoder->len;
534         len = decoder->len;
535         memcpy(buf, decoder->buf, len);
536 
537         ret = intel_pt_get_data(decoder);
538         if (ret) {
539                 decoder->pos += old_len;
540                 return ret < 0 ? ret : -EINVAL;
541         }
542 
543         n = INTEL_PT_PKT_MAX_SZ - len;
544         if (n > decoder->len)
545                 n = decoder->len;
546         memcpy(buf + len, decoder->buf, n);
547         len += n;
548 
549         ret = intel_pt_get_packet(buf, len, &decoder->packet);
550         if (ret < (int)old_len) {
551                 decoder->next_buf = decoder->buf;
552                 decoder->next_len = decoder->len;
553                 decoder->buf = buf;
554                 decoder->len = old_len;
555                 return intel_pt_bad_packet(decoder);
556         }
557 
558         decoder->next_buf = decoder->buf + (ret - old_len);
559         decoder->next_len = decoder->len - (ret - old_len);
560 
561         decoder->buf = buf;
562         decoder->len = ret;
563 
564         return ret;
565 }
566 
567 struct intel_pt_pkt_info {
568         struct intel_pt_decoder   *decoder;
569         struct intel_pt_pkt       packet;
570         uint64_t                  pos;
571         int                       pkt_len;
572         int                       last_packet_type;
573         void                      *data;
574 };
575 
576 typedef int (*intel_pt_pkt_cb_t)(struct intel_pt_pkt_info *pkt_info);
577 
578 /* Lookahead packets in current buffer */
579 static int intel_pt_pkt_lookahead(struct intel_pt_decoder *decoder,
580                                   intel_pt_pkt_cb_t cb, void *data)
581 {
582         struct intel_pt_pkt_info pkt_info;
583         const unsigned char *buf = decoder->buf;
584         size_t len = decoder->len;
585         int ret;
586 
587         pkt_info.decoder          = decoder;
588         pkt_info.pos              = decoder->pos;
589         pkt_info.pkt_len          = decoder->pkt_step;
590         pkt_info.last_packet_type = decoder->last_packet_type;
591         pkt_info.data             = data;
592 
593         while (1) {
594                 do {
595                         pkt_info.pos += pkt_info.pkt_len;
596                         buf          += pkt_info.pkt_len;
597                         len          -= pkt_info.pkt_len;
598 
599                         if (!len)
600                                 return INTEL_PT_NEED_MORE_BYTES;
601 
602                         ret = intel_pt_get_packet(buf, len, &pkt_info.packet);
603                         if (!ret)
604                                 return INTEL_PT_NEED_MORE_BYTES;
605                         if (ret < 0)
606                                 return ret;
607 
608                         pkt_info.pkt_len = ret;
609                 } while (pkt_info.packet.type == INTEL_PT_PAD);
610 
611                 ret = cb(&pkt_info);
612                 if (ret)
613                         return 0;
614 
615                 pkt_info.last_packet_type = pkt_info.packet.type;
616         }
617 }
618 
619 struct intel_pt_calc_cyc_to_tsc_info {
620         uint64_t        cycle_cnt;
621         unsigned int    cbr;
622         uint32_t        last_mtc;
623         uint64_t        ctc_timestamp;
624         uint64_t        ctc_delta;
625         uint64_t        tsc_timestamp;
626         uint64_t        timestamp;
627         bool            have_tma;
628         bool            fixup_last_mtc;
629         bool            from_mtc;
630         double          cbr_cyc_to_tsc;
631 };
632 
633 /*
634  * MTC provides a 8-bit slice of CTC but the TMA packet only provides the lower
635  * 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC
636  * provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
637  * packet by copying the missing bits from the current MTC assuming the least
638  * difference between the two, and that the current MTC comes after last_mtc.
639  */
640 static void intel_pt_fixup_last_mtc(uint32_t mtc, int mtc_shift,
641                                     uint32_t *last_mtc)
642 {
643         uint32_t first_missing_bit = 1U << (16 - mtc_shift);
644         uint32_t mask = ~(first_missing_bit - 1);
645 
646         *last_mtc |= mtc & mask;
647         if (*last_mtc >= mtc) {
648                 *last_mtc -= first_missing_bit;
649                 *last_mtc &= 0xff;
650         }
651 }
652 
653 static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
654 {
655         struct intel_pt_decoder *decoder = pkt_info->decoder;
656         struct intel_pt_calc_cyc_to_tsc_info *data = pkt_info->data;
657         uint64_t timestamp;
658         double cyc_to_tsc;
659         unsigned int cbr;
660         uint32_t mtc, mtc_delta, ctc, fc, ctc_rem;
661 
662         switch (pkt_info->packet.type) {
663         case INTEL_PT_TNT:
664         case INTEL_PT_TIP_PGE:
665         case INTEL_PT_TIP:
666         case INTEL_PT_FUP:
667         case INTEL_PT_PSB:
668         case INTEL_PT_PIP:
669         case INTEL_PT_MODE_EXEC:
670         case INTEL_PT_MODE_TSX:
671         case INTEL_PT_PSBEND:
672         case INTEL_PT_PAD:
673         case INTEL_PT_VMCS:
674         case INTEL_PT_MNT:
675         case INTEL_PT_PTWRITE:
676         case INTEL_PT_PTWRITE_IP:
677                 return 0;
678 
679         case INTEL_PT_MTC:
680                 if (!data->have_tma)
681                         return 0;
682 
683                 mtc = pkt_info->packet.payload;
684                 if (decoder->mtc_shift > 8 && data->fixup_last_mtc) {
685                         data->fixup_last_mtc = false;
686                         intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
687                                                 &data->last_mtc);
688                 }
689                 if (mtc > data->last_mtc)
690                         mtc_delta = mtc - data->last_mtc;
691                 else
692                         mtc_delta = mtc + 256 - data->last_mtc;
693                 data->ctc_delta += mtc_delta << decoder->mtc_shift;
694                 data->last_mtc = mtc;
695 
696                 if (decoder->tsc_ctc_mult) {
697                         timestamp = data->ctc_timestamp +
698                                 data->ctc_delta * decoder->tsc_ctc_mult;
699                 } else {
700                         timestamp = data->ctc_timestamp +
701                                 multdiv(data->ctc_delta,
702                                         decoder->tsc_ctc_ratio_n,
703                                         decoder->tsc_ctc_ratio_d);
704                 }
705 
706                 if (timestamp < data->timestamp)
707                         return 1;
708 
709                 if (pkt_info->last_packet_type != INTEL_PT_CYC) {
710                         data->timestamp = timestamp;
711                         return 0;
712                 }
713 
714                 break;
715 
716         case INTEL_PT_TSC:
717                 /*
718                  * For now, do not support using TSC packets - refer
719                  * intel_pt_calc_cyc_to_tsc().
720                  */
721                 if (data->from_mtc)
722                         return 1;
723                 timestamp = pkt_info->packet.payload |
724                             (data->timestamp & (0xffULL << 56));
725                 if (data->from_mtc && timestamp < data->timestamp &&
726                     data->timestamp - timestamp < decoder->tsc_slip)
727                         return 1;
728                 if (timestamp < data->timestamp)
729                         timestamp += (1ULL << 56);
730                 if (pkt_info->last_packet_type != INTEL_PT_CYC) {
731                         if (data->from_mtc)
732                                 return 1;
733                         data->tsc_timestamp = timestamp;
734                         data->timestamp = timestamp;
735                         return 0;
736                 }
737                 break;
738 
739         case INTEL_PT_TMA:
740                 if (data->from_mtc)
741                         return 1;
742 
743                 if (!decoder->tsc_ctc_ratio_d)
744                         return 0;
745 
746                 ctc = pkt_info->packet.payload;
747                 fc = pkt_info->packet.count;
748                 ctc_rem = ctc & decoder->ctc_rem_mask;
749 
750                 data->last_mtc = (ctc >> decoder->mtc_shift) & 0xff;
751 
752                 data->ctc_timestamp = data->tsc_timestamp - fc;
753                 if (decoder->tsc_ctc_mult) {
754                         data->ctc_timestamp -= ctc_rem * decoder->tsc_ctc_mult;
755                 } else {
756                         data->ctc_timestamp -=
757                                 multdiv(ctc_rem, decoder->tsc_ctc_ratio_n,
758                                         decoder->tsc_ctc_ratio_d);
759                 }
760 
761                 data->ctc_delta = 0;
762                 data->have_tma = true;
763                 data->fixup_last_mtc = true;
764 
765                 return 0;
766 
767         case INTEL_PT_CYC:
768                 data->cycle_cnt += pkt_info->packet.payload;
769                 return 0;
770 
771         case INTEL_PT_CBR:
772                 cbr = pkt_info->packet.payload;
773                 if (data->cbr && data->cbr != cbr)
774                         return 1;
775                 data->cbr = cbr;
776                 data->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
777                 return 0;
778 
779         case INTEL_PT_TIP_PGD:
780         case INTEL_PT_TRACESTOP:
781         case INTEL_PT_EXSTOP:
782         case INTEL_PT_EXSTOP_IP:
783         case INTEL_PT_MWAIT:
784         case INTEL_PT_PWRE:
785         case INTEL_PT_PWRX:
786         case INTEL_PT_OVF:
787         case INTEL_PT_BAD: /* Does not happen */
788         default:
789                 return 1;
790         }
791 
792         if (!data->cbr && decoder->cbr) {
793                 data->cbr = decoder->cbr;
794                 data->cbr_cyc_to_tsc = decoder->cbr_cyc_to_tsc;
795         }
796 
797         if (!data->cycle_cnt)
798                 return 1;
799 
800         cyc_to_tsc = (double)(timestamp - decoder->timestamp) / data->cycle_cnt;
801 
802         if (data->cbr && cyc_to_tsc > data->cbr_cyc_to_tsc &&
803             cyc_to_tsc / data->cbr_cyc_to_tsc > 1.25) {
804                 intel_pt_log("Timestamp: calculated %g TSC ticks per cycle too big (c.f. CBR-based value %g), pos " x64_fmt "\n",
805                              cyc_to_tsc, data->cbr_cyc_to_tsc, pkt_info->pos);
806                 return 1;
807         }
808 
809         decoder->calc_cyc_to_tsc = cyc_to_tsc;
810         decoder->have_calc_cyc_to_tsc = true;
811 
812         if (data->cbr) {
813                 intel_pt_log("Timestamp: calculated %g TSC ticks per cycle c.f. CBR-based value %g, pos " x64_fmt "\n",
814                              cyc_to_tsc, data->cbr_cyc_to_tsc, pkt_info->pos);
815         } else {
816                 intel_pt_log("Timestamp: calculated %g TSC ticks per cycle c.f. unknown CBR-based value, pos " x64_fmt "\n",
817                              cyc_to_tsc, pkt_info->pos);
818         }
819 
820         return 1;
821 }
822 
823 static void intel_pt_calc_cyc_to_tsc(struct intel_pt_decoder *decoder,
824                                      bool from_mtc)
825 {
826         struct intel_pt_calc_cyc_to_tsc_info data = {
827                 .cycle_cnt      = 0,
828                 .cbr            = 0,
829                 .last_mtc       = decoder->last_mtc,
830                 .ctc_timestamp  = decoder->ctc_timestamp,
831                 .ctc_delta      = decoder->ctc_delta,
832                 .tsc_timestamp  = decoder->tsc_timestamp,
833                 .timestamp      = decoder->timestamp,
834                 .have_tma       = decoder->have_tma,
835                 .fixup_last_mtc = decoder->fixup_last_mtc,
836                 .from_mtc       = from_mtc,
837                 .cbr_cyc_to_tsc = 0,
838         };
839 
840         /*
841          * For now, do not support using TSC packets for at least the reasons:
842          * 1) timing might have stopped
843          * 2) TSC packets within PSB+ can slip against CYC packets
844          */
845         if (!from_mtc)
846                 return;
847 
848         intel_pt_pkt_lookahead(decoder, intel_pt_calc_cyc_cb, &data);
849 }
850 
851 static int intel_pt_get_next_packet(struct intel_pt_decoder *decoder)
852 {
853         int ret;
854 
855         decoder->last_packet_type = decoder->packet.type;
856 
857         do {
858                 decoder->pos += decoder->pkt_step;
859                 decoder->buf += decoder->pkt_step;
860                 decoder->len -= decoder->pkt_step;
861 
862                 if (!decoder->len) {
863                         ret = intel_pt_get_next_data(decoder);
864                         if (ret)
865                                 return ret;
866                 }
867 
868                 ret = intel_pt_get_packet(decoder->buf, decoder->len,
869                                           &decoder->packet);
870                 if (ret == INTEL_PT_NEED_MORE_BYTES &&
871                     decoder->len < INTEL_PT_PKT_MAX_SZ && !decoder->next_buf) {
872                         ret = intel_pt_get_split_packet(decoder);
873                         if (ret < 0)
874                                 return ret;
875                 }
876                 if (ret <= 0)
877                         return intel_pt_bad_packet(decoder);
878 
879                 decoder->pkt_len = ret;
880                 decoder->pkt_step = ret;
881                 intel_pt_decoder_log_packet(decoder);
882         } while (decoder->packet.type == INTEL_PT_PAD);
883 
884         return 0;
885 }
886 
887 static uint64_t intel_pt_next_period(struct intel_pt_decoder *decoder)
888 {
889         uint64_t timestamp, masked_timestamp;
890 
891         timestamp = decoder->timestamp + decoder->timestamp_insn_cnt;
892         masked_timestamp = timestamp & decoder->period_mask;
893         if (decoder->continuous_period) {
894                 if (masked_timestamp != decoder->last_masked_timestamp)
895                         return 1;
896         } else {
897                 timestamp += 1;
898                 masked_timestamp = timestamp & decoder->period_mask;
899                 if (masked_timestamp != decoder->last_masked_timestamp) {
900                         decoder->last_masked_timestamp = masked_timestamp;
901                         decoder->continuous_period = true;
902                 }
903         }
904         return decoder->period_ticks - (timestamp - masked_timestamp);
905 }
906 
907 static uint64_t intel_pt_next_sample(struct intel_pt_decoder *decoder)
908 {
909         switch (decoder->period_type) {
910         case INTEL_PT_PERIOD_INSTRUCTIONS:
911                 return decoder->period - decoder->period_insn_cnt;
912         case INTEL_PT_PERIOD_TICKS:
913                 return intel_pt_next_period(decoder);
914         case INTEL_PT_PERIOD_NONE:
915         case INTEL_PT_PERIOD_MTC:
916         default:
917                 return 0;
918         }
919 }
920 
921 static void intel_pt_sample_insn(struct intel_pt_decoder *decoder)
922 {
923         uint64_t timestamp, masked_timestamp;
924 
925         switch (decoder->period_type) {
926         case INTEL_PT_PERIOD_INSTRUCTIONS:
927                 decoder->period_insn_cnt = 0;
928                 break;
929         case INTEL_PT_PERIOD_TICKS:
930                 timestamp = decoder->timestamp + decoder->timestamp_insn_cnt;
931                 masked_timestamp = timestamp & decoder->period_mask;
932                 decoder->last_masked_timestamp = masked_timestamp;
933                 break;
934         case INTEL_PT_PERIOD_NONE:
935         case INTEL_PT_PERIOD_MTC:
936         default:
937                 break;
938         }
939 
940         decoder->state.type |= INTEL_PT_INSTRUCTION;
941 }
942 
943 static int intel_pt_walk_insn(struct intel_pt_decoder *decoder,
944                               struct intel_pt_insn *intel_pt_insn, uint64_t ip)
945 {
946         uint64_t max_insn_cnt, insn_cnt = 0;
947         int err;
948 
949         if (!decoder->mtc_insn)
950                 decoder->mtc_insn = true;
951 
952         max_insn_cnt = intel_pt_next_sample(decoder);
953 
954         err = decoder->walk_insn(intel_pt_insn, &insn_cnt, &decoder->ip, ip,
955                                  max_insn_cnt, decoder->data);
956 
957         decoder->tot_insn_cnt += insn_cnt;
958         decoder->timestamp_insn_cnt += insn_cnt;
959         decoder->sample_insn_cnt += insn_cnt;
960         decoder->period_insn_cnt += insn_cnt;
961 
962         if (err) {
963                 decoder->no_progress = 0;
964                 decoder->pkt_state = INTEL_PT_STATE_ERR2;
965                 intel_pt_log_at("ERROR: Failed to get instruction",
966                                 decoder->ip);
967                 if (err == -ENOENT)
968                         return -ENOLINK;
969                 return -EILSEQ;
970         }
971 
972         if (ip && decoder->ip == ip) {
973                 err = -EAGAIN;
974                 goto out;
975         }
976 
977         if (max_insn_cnt && insn_cnt >= max_insn_cnt)
978                 intel_pt_sample_insn(decoder);
979 
980         if (intel_pt_insn->branch == INTEL_PT_BR_NO_BRANCH) {
981                 decoder->state.type = INTEL_PT_INSTRUCTION;
982                 decoder->state.from_ip = decoder->ip;
983                 decoder->state.to_ip = 0;
984                 decoder->ip += intel_pt_insn->length;
985                 err = INTEL_PT_RETURN;
986                 goto out;
987         }
988 
989         if (intel_pt_insn->op == INTEL_PT_OP_CALL) {
990                 /* Zero-length calls are excluded */
991                 if (intel_pt_insn->branch != INTEL_PT_BR_UNCONDITIONAL ||
992                     intel_pt_insn->rel) {
993                         err = intel_pt_push(&decoder->stack, decoder->ip +
994                                             intel_pt_insn->length);
995                         if (err)
996                                 goto out;
997                 }
998         } else if (intel_pt_insn->op == INTEL_PT_OP_RET) {
999                 decoder->ret_addr = intel_pt_pop(&decoder->stack);
1000         }
1001 
1002         if (intel_pt_insn->branch == INTEL_PT_BR_UNCONDITIONAL) {
1003                 int cnt = decoder->no_progress++;
1004 
1005                 decoder->state.from_ip = decoder->ip;
1006                 decoder->ip += intel_pt_insn->length +
1007                                 intel_pt_insn->rel;
1008                 decoder->state.to_ip = decoder->ip;
1009                 err = INTEL_PT_RETURN;
1010 
1011                 /*
1012                  * Check for being stuck in a loop.  This can happen if a
1013                  * decoder error results in the decoder erroneously setting the
1014                  * ip to an address that is itself in an infinite loop that
1015                  * consumes no packets.  When that happens, there must be an
1016                  * unconditional branch.
1017                  */
1018                 if (cnt) {
1019                         if (cnt == 1) {
1020                                 decoder->stuck_ip = decoder->state.to_ip;
1021                                 decoder->stuck_ip_prd = 1;
1022                                 decoder->stuck_ip_cnt = 1;
1023                         } else if (cnt > INTEL_PT_MAX_LOOPS ||
1024                                    decoder->state.to_ip == decoder->stuck_ip) {
1025                                 intel_pt_log_at("ERROR: Never-ending loop",
1026                                                 decoder->state.to_ip);
1027                                 decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
1028                                 err = -ELOOP;
1029                                 goto out;
1030                         } else if (!--decoder->stuck_ip_cnt) {
1031                                 decoder->stuck_ip_prd += 1;
1032                                 decoder->stuck_ip_cnt = decoder->stuck_ip_prd;
1033                                 decoder->stuck_ip = decoder->state.to_ip;
1034                         }
1035                 }
1036                 goto out_no_progress;
1037         }
1038 out:
1039         decoder->no_progress = 0;
1040 out_no_progress:
1041         decoder->state.insn_op = intel_pt_insn->op;
1042         decoder->state.insn_len = intel_pt_insn->length;
1043         memcpy(decoder->state.insn, intel_pt_insn->buf,
1044                INTEL_PT_INSN_BUF_SZ);
1045 
1046         if (decoder->tx_flags & INTEL_PT_IN_TX)
1047                 decoder->state.flags |= INTEL_PT_IN_TX;
1048 
1049         return err;
1050 }
1051 
1052 static bool intel_pt_fup_event(struct intel_pt_decoder *decoder)
1053 {
1054         bool ret = false;
1055 
1056         if (decoder->set_fup_tx_flags) {
1057                 decoder->set_fup_tx_flags = false;
1058                 decoder->tx_flags = decoder->fup_tx_flags;
1059                 decoder->state.type = INTEL_PT_TRANSACTION;
1060                 decoder->state.from_ip = decoder->ip;
1061                 decoder->state.to_ip = 0;
1062                 decoder->state.flags = decoder->fup_tx_flags;
1063                 return true;
1064         }
1065         if (decoder->set_fup_ptw) {
1066                 decoder->set_fup_ptw = false;
1067                 decoder->state.type = INTEL_PT_PTW;
1068                 decoder->state.flags |= INTEL_PT_FUP_IP;
1069                 decoder->state.from_ip = decoder->ip;
1070                 decoder->state.to_ip = 0;
1071                 decoder->state.ptw_payload = decoder->fup_ptw_payload;
1072                 return true;
1073         }
1074         if (decoder->set_fup_mwait) {
1075                 decoder->set_fup_mwait = false;
1076                 decoder->state.type = INTEL_PT_MWAIT_OP;
1077                 decoder->state.from_ip = decoder->ip;
1078                 decoder->state.to_ip = 0;
1079                 decoder->state.mwait_payload = decoder->fup_mwait_payload;
1080                 ret = true;
1081         }
1082         if (decoder->set_fup_pwre) {
1083                 decoder->set_fup_pwre = false;
1084                 decoder->state.type |= INTEL_PT_PWR_ENTRY;
1085                 decoder->state.type &= ~INTEL_PT_BRANCH;
1086                 decoder->state.from_ip = decoder->ip;
1087                 decoder->state.to_ip = 0;
1088                 decoder->state.pwre_payload = decoder->fup_pwre_payload;
1089                 ret = true;
1090         }
1091         if (decoder->set_fup_exstop) {
1092                 decoder->set_fup_exstop = false;
1093                 decoder->state.type |= INTEL_PT_EX_STOP;
1094                 decoder->state.type &= ~INTEL_PT_BRANCH;
1095                 decoder->state.flags |= INTEL_PT_FUP_IP;
1096                 decoder->state.from_ip = decoder->ip;
1097                 decoder->state.to_ip = 0;
1098                 ret = true;
1099         }
1100         return ret;
1101 }
1102 
1103 static inline bool intel_pt_fup_with_nlip(struct intel_pt_decoder *decoder,
1104                                           struct intel_pt_insn *intel_pt_insn,
1105                                           uint64_t ip, int err)
1106 {
1107         return decoder->flags & INTEL_PT_FUP_WITH_NLIP && !err &&
1108                intel_pt_insn->branch == INTEL_PT_BR_INDIRECT &&
1109                ip == decoder->ip + intel_pt_insn->length;
1110 }
1111 
1112 static int intel_pt_walk_fup(struct intel_pt_decoder *decoder)
1113 {
1114         struct intel_pt_insn intel_pt_insn;
1115         uint64_t ip;
1116         int err;
1117 
1118         ip = decoder->last_ip;
1119 
1120         while (1) {
1121                 err = intel_pt_walk_insn(decoder, &intel_pt_insn, ip);
1122                 if (err == INTEL_PT_RETURN)
1123                         return 0;
1124                 if (err == -EAGAIN ||
1125                     intel_pt_fup_with_nlip(decoder, &intel_pt_insn, ip, err)) {
1126                         if (intel_pt_fup_event(decoder))
1127                                 return 0;
1128                         return -EAGAIN;
1129                 }
1130                 decoder->set_fup_tx_flags = false;
1131                 if (err)
1132                         return err;
1133 
1134                 if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
1135                         intel_pt_log_at("ERROR: Unexpected indirect branch",
1136                                         decoder->ip);
1137                         decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
1138                         return -ENOENT;
1139                 }
1140 
1141                 if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
1142                         intel_pt_log_at("ERROR: Unexpected conditional branch",
1143                                         decoder->ip);
1144                         decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
1145                         return -ENOENT;
1146                 }
1147 
1148                 intel_pt_bug(decoder);
1149         }
1150 }
1151 
1152 static int intel_pt_walk_tip(struct intel_pt_decoder *decoder)
1153 {
1154         struct intel_pt_insn intel_pt_insn;
1155         int err;
1156 
1157         err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
1158         if (err == INTEL_PT_RETURN &&
1159             decoder->pgd_ip &&
1160             decoder->pkt_state == INTEL_PT_STATE_TIP_PGD &&
1161             (decoder->state.type & INTEL_PT_BRANCH) &&
1162             decoder->pgd_ip(decoder->state.to_ip, decoder->data)) {
1163                 /* Unconditional branch leaving filter region */
1164                 decoder->no_progress = 0;
1165                 decoder->pge = false;
1166                 decoder->continuous_period = false;
1167                 decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1168                 decoder->state.type |= INTEL_PT_TRACE_END;
1169                 return 0;
1170         }
1171         if (err == INTEL_PT_RETURN)
1172                 return 0;
1173         if (err)
1174                 return err;
1175 
1176         if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
1177                 if (decoder->pkt_state == INTEL_PT_STATE_TIP_PGD) {
1178                         decoder->pge = false;
1179                         decoder->continuous_period = false;
1180                         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1181                         decoder->state.from_ip = decoder->ip;
1182                         if (decoder->packet.count == 0) {
1183                                 decoder->state.to_ip = 0;
1184                         } else {
1185                                 decoder->state.to_ip = decoder->last_ip;
1186                                 decoder->ip = decoder->last_ip;
1187                         }
1188                         decoder->state.type |= INTEL_PT_TRACE_END;
1189                 } else {
1190                         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1191                         decoder->state.from_ip = decoder->ip;
1192                         if (decoder->packet.count == 0) {
1193                                 decoder->state.to_ip = 0;
1194                         } else {
1195                                 decoder->state.to_ip = decoder->last_ip;
1196                                 decoder->ip = decoder->last_ip;
1197                         }
1198                 }
1199                 return 0;
1200         }
1201 
1202         if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
1203                 uint64_t to_ip = decoder->ip + intel_pt_insn.length +
1204                                  intel_pt_insn.rel;
1205 
1206                 if (decoder->pgd_ip &&
1207                     decoder->pkt_state == INTEL_PT_STATE_TIP_PGD &&
1208                     decoder->pgd_ip(to_ip, decoder->data)) {
1209                         /* Conditional branch leaving filter region */
1210                         decoder->pge = false;
1211                         decoder->continuous_period = false;
1212                         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1213                         decoder->ip = to_ip;
1214                         decoder->state.from_ip = decoder->ip;
1215                         decoder->state.to_ip = to_ip;
1216                         decoder->state.type |= INTEL_PT_TRACE_END;
1217                         return 0;
1218                 }
1219                 intel_pt_log_at("ERROR: Conditional branch when expecting indirect branch",
1220                                 decoder->ip);
1221                 decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
1222                 return -ENOENT;
1223         }
1224 
1225         return intel_pt_bug(decoder);
1226 }
1227 
1228 static int intel_pt_walk_tnt(struct intel_pt_decoder *decoder)
1229 {
1230         struct intel_pt_insn intel_pt_insn;
1231         int err;
1232 
1233         while (1) {
1234                 err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
1235                 if (err == INTEL_PT_RETURN)
1236                         return 0;
1237                 if (err)
1238                         return err;
1239 
1240                 if (intel_pt_insn.op == INTEL_PT_OP_RET) {
1241                         if (!decoder->return_compression) {
1242                                 intel_pt_log_at("ERROR: RET when expecting conditional branch",
1243                                                 decoder->ip);
1244                                 decoder->pkt_state = INTEL_PT_STATE_ERR3;
1245                                 return -ENOENT;
1246                         }
1247                         if (!decoder->ret_addr) {
1248                                 intel_pt_log_at("ERROR: Bad RET compression (stack empty)",
1249                                                 decoder->ip);
1250                                 decoder->pkt_state = INTEL_PT_STATE_ERR3;
1251                                 return -ENOENT;
1252                         }
1253                         if (!(decoder->tnt.payload & BIT63)) {
1254                                 intel_pt_log_at("ERROR: Bad RET compression (TNT=N)",
1255                                                 decoder->ip);
1256                                 decoder->pkt_state = INTEL_PT_STATE_ERR3;
1257                                 return -ENOENT;
1258                         }
1259                         decoder->tnt.count -= 1;
1260                         if (!decoder->tnt.count)
1261                                 decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1262                         decoder->tnt.payload <<= 1;
1263                         decoder->state.from_ip = decoder->ip;
1264                         decoder->ip = decoder->ret_addr;
1265                         decoder->state.to_ip = decoder->ip;
1266                         return 0;
1267                 }
1268 
1269                 if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
1270                         /* Handle deferred TIPs */
1271                         err = intel_pt_get_next_packet(decoder);
1272                         if (err)
1273                                 return err;
1274                         if (decoder->packet.type != INTEL_PT_TIP ||
1275                             decoder->packet.count == 0) {
1276                                 intel_pt_log_at("ERROR: Missing deferred TIP for indirect branch",
1277                                                 decoder->ip);
1278                                 decoder->pkt_state = INTEL_PT_STATE_ERR3;
1279                                 decoder->pkt_step = 0;
1280                                 return -ENOENT;
1281                         }
1282                         intel_pt_set_last_ip(decoder);
1283                         decoder->state.from_ip = decoder->ip;
1284                         decoder->state.to_ip = decoder->last_ip;
1285                         decoder->ip = decoder->last_ip;
1286                         return 0;
1287                 }
1288 
1289                 if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
1290                         decoder->tnt.count -= 1;
1291                         if (!decoder->tnt.count)
1292                                 decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
1293                         if (decoder->tnt.payload & BIT63) {
1294                                 decoder->tnt.payload <<= 1;
1295                                 decoder->state.from_ip = decoder->ip;
1296                                 decoder->ip += intel_pt_insn.length +
1297                                                intel_pt_insn.rel;
1298                                 decoder->state.to_ip = decoder->ip;
1299                                 return 0;
1300                         }
1301                         /* Instruction sample for a non-taken branch */
1302                         if (decoder->state.type & INTEL_PT_INSTRUCTION) {
1303                                 decoder->tnt.payload <<= 1;
1304                                 decoder->state.type = INTEL_PT_INSTRUCTION;
1305                                 decoder->state.from_ip = decoder->ip;
1306                                 decoder->state.to_ip = 0;
1307                                 decoder->ip += intel_pt_insn.length;
1308                                 return 0;
1309                         }
1310                         decoder->ip += intel_pt_insn.length;
1311                         if (!decoder->tnt.count)
1312                                 return -EAGAIN;
1313                         decoder->tnt.payload <<= 1;
1314                         continue;
1315                 }
1316 
1317                 return intel_pt_bug(decoder);
1318         }
1319 }
1320 
1321 static int intel_pt_mode_tsx(struct intel_pt_decoder *decoder, bool *no_tip)
1322 {
1323         unsigned int fup_tx_flags;
1324         int err;
1325 
1326         fup_tx_flags = decoder->packet.payload &
1327                        (INTEL_PT_IN_TX | INTEL_PT_ABORT_TX);
1328         err = intel_pt_get_next_packet(decoder);
1329         if (err)
1330                 return err;
1331         if (decoder->packet.type == INTEL_PT_FUP) {
1332                 decoder->fup_tx_flags = fup_tx_flags;
1333                 decoder->set_fup_tx_flags = true;
1334                 if (!(decoder->fup_tx_flags & INTEL_PT_ABORT_TX))
1335                         *no_tip = true;
1336         } else {
1337                 intel_pt_log_at("ERROR: Missing FUP after MODE.TSX",
1338                                 decoder->pos);
1339                 intel_pt_update_in_tx(decoder);
1340         }
1341         return 0;
1342 }
1343 
1344 static void intel_pt_calc_tsc_timestamp(struct intel_pt_decoder *decoder)
1345 {
1346         uint64_t timestamp;
1347 
1348         decoder->have_tma = false;
1349 
1350         if (decoder->ref_timestamp) {
1351                 timestamp = decoder->packet.payload |
1352                             (decoder->ref_timestamp & (0xffULL << 56));
1353                 if (timestamp < decoder->ref_timestamp) {
1354                         if (decoder->ref_timestamp - timestamp > (1ULL << 55))
1355                                 timestamp += (1ULL << 56);
1356                 } else {
1357                         if (timestamp - decoder->ref_timestamp > (1ULL << 55))
1358                                 timestamp -= (1ULL << 56);
1359                 }
1360                 decoder->tsc_timestamp = timestamp;
1361                 decoder->timestamp = timestamp;
1362                 decoder->ref_timestamp = 0;
1363                 decoder->timestamp_insn_cnt = 0;
1364         } else if (decoder->timestamp) {
1365                 timestamp = decoder->packet.payload |
1366                             (decoder->timestamp & (0xffULL << 56));
1367                 decoder->tsc_timestamp = timestamp;
1368                 if (timestamp < decoder->timestamp &&
1369                     decoder->timestamp - timestamp < decoder->tsc_slip) {
1370                         intel_pt_log_to("Suppressing backwards timestamp",
1371                                         timestamp);
1372                         timestamp = decoder->timestamp;
1373                 }
1374                 if (timestamp < decoder->timestamp) {
1375                         intel_pt_log_to("Wraparound timestamp", timestamp);
1376                         timestamp += (1ULL << 56);
1377                         decoder->tsc_timestamp = timestamp;
1378                 }
1379                 decoder->timestamp = timestamp;
1380                 decoder->timestamp_insn_cnt = 0;
1381         }
1382 
1383         if (decoder->last_packet_type == INTEL_PT_CYC) {
1384                 decoder->cyc_ref_timestamp = decoder->timestamp;
1385                 decoder->cycle_cnt = 0;
1386                 decoder->have_calc_cyc_to_tsc = false;
1387                 intel_pt_calc_cyc_to_tsc(decoder, false);
1388         }
1389 
1390         intel_pt_log_to("Setting timestamp", decoder->timestamp);
1391 }
1392 
1393 static int intel_pt_overflow(struct intel_pt_decoder *decoder)
1394 {
1395         intel_pt_log("ERROR: Buffer overflow\n");
1396         intel_pt_clear_tx_flags(decoder);
1397         decoder->cbr = 0;
1398         decoder->timestamp_insn_cnt = 0;
1399         decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
1400         decoder->overflow = true;
1401         return -EOVERFLOW;
1402 }
1403 
1404 static void intel_pt_calc_tma(struct intel_pt_decoder *decoder)
1405 {
1406         uint32_t ctc = decoder->packet.payload;
1407         uint32_t fc = decoder->packet.count;
1408         uint32_t ctc_rem = ctc & decoder->ctc_rem_mask;
1409 
1410         if (!decoder->tsc_ctc_ratio_d)
1411                 return;
1412 
1413         decoder->last_mtc = (ctc >> decoder->mtc_shift) & 0xff;
1414         decoder->ctc_timestamp = decoder->tsc_timestamp - fc;
1415         if (decoder->tsc_ctc_mult) {
1416                 decoder->ctc_timestamp -= ctc_rem * decoder->tsc_ctc_mult;
1417         } else {
1418                 decoder->ctc_timestamp -= multdiv(ctc_rem,
1419                                                   decoder->tsc_ctc_ratio_n,
1420                                                   decoder->tsc_ctc_ratio_d);
1421         }
1422         decoder->ctc_delta = 0;
1423         decoder->have_tma = true;
1424         decoder->fixup_last_mtc = true;
1425         intel_pt_log("CTC timestamp " x64_fmt " last MTC %#x  CTC rem %#x\n",
1426                      decoder->ctc_timestamp, decoder->last_mtc, ctc_rem);
1427 }
1428 
1429 static void intel_pt_calc_mtc_timestamp(struct intel_pt_decoder *decoder)
1430 {
1431         uint64_t timestamp;
1432         uint32_t mtc, mtc_delta;
1433 
1434         if (!decoder->have_tma)
1435                 return;
1436 
1437         mtc = decoder->packet.payload;
1438 
1439         if (decoder->mtc_shift > 8 && decoder->fixup_last_mtc) {
1440                 decoder->fixup_last_mtc = false;
1441                 intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
1442                                         &decoder->last_mtc);
1443         }
1444 
1445         if (mtc > decoder->last_mtc)
1446                 mtc_delta = mtc - decoder->last_mtc;
1447         else
1448                 mtc_delta = mtc + 256 - decoder->last_mtc;
1449 
1450         decoder->ctc_delta += mtc_delta << decoder->mtc_shift;
1451 
1452         if (decoder->tsc_ctc_mult) {
1453                 timestamp = decoder->ctc_timestamp +
1454                             decoder->ctc_delta * decoder->tsc_ctc_mult;
1455         } else {
1456                 timestamp = decoder->ctc_timestamp +
1457                             multdiv(decoder->ctc_delta,
1458                                     decoder->tsc_ctc_ratio_n,
1459                                     decoder->tsc_ctc_ratio_d);
1460         }
1461 
1462         if (timestamp < decoder->timestamp)
1463                 intel_pt_log("Suppressing MTC timestamp " x64_fmt " less than current timestamp " x64_fmt "\n",
1464                              timestamp, decoder->timestamp);
1465         else
1466                 decoder->timestamp = timestamp;
1467 
1468         decoder->timestamp_insn_cnt = 0;
1469         decoder->last_mtc = mtc;
1470 
1471         if (decoder->last_packet_type == INTEL_PT_CYC) {
1472                 decoder->cyc_ref_timestamp = decoder->timestamp;
1473                 decoder->cycle_cnt = 0;
1474                 decoder->have_calc_cyc_to_tsc = false;
1475                 intel_pt_calc_cyc_to_tsc(decoder, true);
1476         }
1477 
1478         intel_pt_log_to("Setting timestamp", decoder->timestamp);
1479 }
1480 
1481 static void intel_pt_calc_cbr(struct intel_pt_decoder *decoder)
1482 {
1483         unsigned int cbr = decoder->packet.payload & 0xff;
1484 
1485         decoder->cbr_payload = decoder->packet.payload;
1486 
1487         if (decoder->cbr == cbr)
1488                 return;
1489 
1490         decoder->cbr = cbr;
1491         decoder->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
1492 }
1493 
1494 static void intel_pt_calc_cyc_timestamp(struct intel_pt_decoder *decoder)
1495 {
1496         uint64_t timestamp = decoder->cyc_ref_timestamp;
1497 
1498         decoder->have_cyc = true;
1499 
1500         decoder->cycle_cnt += decoder->packet.payload;
1501 
1502         if (!decoder->cyc_ref_timestamp)
1503                 return;
1504 
1505         if (decoder->have_calc_cyc_to_tsc)
1506                 timestamp += decoder->cycle_cnt * decoder->calc_cyc_to_tsc;
1507         else if (decoder->cbr)
1508                 timestamp += decoder->cycle_cnt * decoder->cbr_cyc_to_tsc;
1509         else
1510                 return;
1511 
1512         if (timestamp < decoder->timestamp)
1513                 intel_pt_log("Suppressing CYC timestamp " x64_fmt " less than current timestamp " x64_fmt "\n",
1514                              timestamp, decoder->timestamp);
1515         else
1516                 decoder->timestamp = timestamp;
1517 
1518         decoder->timestamp_insn_cnt = 0;
1519 
1520         intel_pt_log_to("Setting timestamp", decoder->timestamp);
1521 }
1522 
1523 /* Walk PSB+ packets when already in sync. */
1524 static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder)
1525 {
1526         int err;
1527 
1528         while (1) {
1529                 err = intel_pt_get_next_packet(decoder);
1530                 if (err)
1531                         return err;
1532 
1533                 switch (decoder->packet.type) {
1534                 case INTEL_PT_PSBEND:
1535                         return 0;
1536 
1537                 case INTEL_PT_TIP_PGD:
1538                 case INTEL_PT_TIP_PGE:
1539                 case INTEL_PT_TIP:
1540                 case INTEL_PT_TNT:
1541                 case INTEL_PT_TRACESTOP:
1542                 case INTEL_PT_BAD:
1543                 case INTEL_PT_PSB:
1544                 case INTEL_PT_PTWRITE:
1545                 case INTEL_PT_PTWRITE_IP:
1546                 case INTEL_PT_EXSTOP:
1547                 case INTEL_PT_EXSTOP_IP:
1548                 case INTEL_PT_MWAIT:
1549                 case INTEL_PT_PWRE:
1550                 case INTEL_PT_PWRX:
1551                         decoder->have_tma = false;
1552                         intel_pt_log("ERROR: Unexpected packet\n");
1553                         return -EAGAIN;
1554 
1555                 case INTEL_PT_OVF:
1556                         return intel_pt_overflow(decoder);
1557 
1558                 case INTEL_PT_TSC:
1559                         intel_pt_calc_tsc_timestamp(decoder);
1560                         break;
1561 
1562                 case INTEL_PT_TMA:
1563                         intel_pt_calc_tma(decoder);
1564                         break;
1565 
1566                 case INTEL_PT_CBR:
1567                         intel_pt_calc_cbr(decoder);
1568                         break;
1569 
1570                 case INTEL_PT_MODE_EXEC:
1571                         decoder->exec_mode = decoder->packet.payload;
1572                         break;
1573 
1574                 case INTEL_PT_PIP:
1575                         decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
1576                         break;
1577 
1578                 case INTEL_PT_FUP:
1579                         decoder->pge = true;
1580                         if (decoder->packet.count)
1581                                 intel_pt_set_last_ip(decoder);
1582                         break;
1583 
1584                 case INTEL_PT_MODE_TSX:
1585                         intel_pt_update_in_tx(decoder);
1586                         break;
1587 
1588                 case INTEL_PT_MTC:
1589                         intel_pt_calc_mtc_timestamp(decoder);
1590                         if (decoder->period_type == INTEL_PT_PERIOD_MTC)
1591                                 decoder->state.type |= INTEL_PT_INSTRUCTION;
1592                         break;
1593 
1594                 case INTEL_PT_CYC:
1595                 case INTEL_PT_VMCS:
1596                 case INTEL_PT_MNT:
1597                 case INTEL_PT_PAD:
1598                 default:
1599                         break;
1600                 }
1601         }
1602 }
1603 
1604 static int intel_pt_walk_fup_tip(struct intel_pt_decoder *decoder)
1605 {
1606         int err;
1607 
1608         if (decoder->tx_flags & INTEL_PT_ABORT_TX) {
1609                 decoder->tx_flags = 0;
1610                 decoder->state.flags &= ~INTEL_PT_IN_TX;
1611                 decoder->state.flags |= INTEL_PT_ABORT_TX;
1612         } else {
1613                 decoder->state.flags |= INTEL_PT_ASYNC;
1614         }
1615 
1616         while (1) {
1617                 err = intel_pt_get_next_packet(decoder);
1618                 if (err)
1619                         return err;
1620 
1621                 switch (decoder->packet.type) {
1622                 case INTEL_PT_TNT:
1623                 case INTEL_PT_FUP:
1624                 case INTEL_PT_TRACESTOP:
1625                 case INTEL_PT_PSB:
1626                 case INTEL_PT_TSC:
1627                 case INTEL_PT_TMA:
1628                 case INTEL_PT_MODE_TSX:
1629                 case INTEL_PT_BAD:
1630                 case INTEL_PT_PSBEND:
1631                 case INTEL_PT_PTWRITE:
1632                 case INTEL_PT_PTWRITE_IP:
1633                 case INTEL_PT_EXSTOP:
1634                 case INTEL_PT_EXSTOP_IP:
1635                 case INTEL_PT_MWAIT:
1636                 case INTEL_PT_PWRE:
1637                 case INTEL_PT_PWRX:
1638                         intel_pt_log("ERROR: Missing TIP after FUP\n");
1639                         decoder->pkt_state = INTEL_PT_STATE_ERR3;
1640                         decoder->pkt_step = 0;
1641                         return -ENOENT;
1642 
1643                 case INTEL_PT_CBR:
1644                         intel_pt_calc_cbr(decoder);
1645                         break;
1646 
1647                 case INTEL_PT_OVF:
1648                         return intel_pt_overflow(decoder);
1649 
1650                 case INTEL_PT_TIP_PGD:
1651                         decoder->state.from_ip = decoder->ip;
1652                         if (decoder->packet.count == 0) {
1653                                 decoder->state.to_ip = 0;
1654                         } else {
1655                                 intel_pt_set_ip(decoder);
1656                                 decoder->state.to_ip = decoder->ip;
1657                         }
1658                         decoder->pge = false;
1659                         decoder->continuous_period = false;
1660                         decoder->state.type |= INTEL_PT_TRACE_END;
1661                         return 0;
1662 
1663                 case INTEL_PT_TIP_PGE:
1664                         decoder->pge = true;
1665                         intel_pt_log("Omitting PGE ip " x64_fmt "\n",
1666                                      decoder->ip);
1667                         decoder->state.from_ip = 0;
1668                         if (decoder->packet.count == 0) {
1669                                 decoder->state.to_ip = 0;
1670                         } else {
1671                                 intel_pt_set_ip(decoder);
1672                                 decoder->state.to_ip = decoder->ip;
1673                         }
1674                         decoder->state.type |= INTEL_PT_TRACE_BEGIN;
1675                         return 0;
1676 
1677                 case INTEL_PT_TIP:
1678                         decoder->state.from_ip = decoder->ip;
1679                         if (decoder->packet.count == 0) {
1680                                 decoder->state.to_ip = 0;
1681                         } else {
1682                                 intel_pt_set_ip(decoder);
1683                                 decoder->state.to_ip = decoder->ip;
1684                         }
1685                         return 0;
1686 
1687                 case INTEL_PT_PIP:
1688                         decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
1689                         break;
1690 
1691                 case INTEL_PT_MTC:
1692                         intel_pt_calc_mtc_timestamp(decoder);
1693                         if (decoder->period_type == INTEL_PT_PERIOD_MTC)
1694                                 decoder->state.type |= INTEL_PT_INSTRUCTION;
1695                         break;
1696 
1697                 case INTEL_PT_CYC:
1698                         intel_pt_calc_cyc_timestamp(decoder);
1699                         break;
1700 
1701                 case INTEL_PT_MODE_EXEC:
1702                         decoder->exec_mode = decoder->packet.payload;
1703                         break;
1704 
1705                 case INTEL_PT_VMCS:
1706                 case INTEL_PT_MNT:
1707                 case INTEL_PT_PAD:
1708                         break;
1709 
1710                 default:
1711                         return intel_pt_bug(decoder);
1712                 }
1713         }
1714 }
1715 
1716 static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
1717 {
1718         bool no_tip = false;
1719         int err;
1720 
1721         while (1) {
1722                 err = intel_pt_get_next_packet(decoder);
1723                 if (err)
1724                         return err;
1725 next:
1726                 switch (decoder->packet.type) {
1727                 case INTEL_PT_TNT:
1728                         if (!decoder->packet.count)
1729                                 break;
1730                         decoder->tnt = decoder->packet;
1731                         decoder->pkt_state = INTEL_PT_STATE_TNT;
1732                         err = intel_pt_walk_tnt(decoder);
1733                         if (err == -EAGAIN)
1734                                 break;
1735                         return err;
1736 
1737                 case INTEL_PT_TIP_PGD:
1738                         if (decoder->packet.count != 0)
1739                                 intel_pt_set_last_ip(decoder);
1740                         decoder->pkt_state = INTEL_PT_STATE_TIP_PGD;
1741                         return intel_pt_walk_tip(decoder);
1742 
1743                 case INTEL_PT_TIP_PGE: {
1744                         decoder->pge = true;
1745                         if (decoder->packet.count == 0) {
1746                                 intel_pt_log_at("Skipping zero TIP.PGE",
1747                                                 decoder->pos);
1748                                 break;
1749                         }
1750                         intel_pt_set_ip(decoder);
1751                         decoder->state.from_ip = 0;
1752                         decoder->state.to_ip = decoder->ip;
1753                         decoder->state.type |= INTEL_PT_TRACE_BEGIN;
1754                         return 0;
1755                 }
1756 
1757                 case INTEL_PT_OVF:
1758                         return intel_pt_overflow(decoder);
1759 
1760                 case INTEL_PT_TIP:
1761                         if (decoder->packet.count != 0)
1762                                 intel_pt_set_last_ip(decoder);
1763                         decoder->pkt_state = INTEL_PT_STATE_TIP;
1764                         return intel_pt_walk_tip(decoder);
1765 
1766                 case INTEL_PT_FUP:
1767                         if (decoder->packet.count == 0) {
1768                                 intel_pt_log_at("Skipping zero FUP",
1769                                                 decoder->pos);
1770                                 no_tip = false;
1771                                 break;
1772                         }
1773                         intel_pt_set_last_ip(decoder);
1774                         if (!decoder->branch_enable) {
1775                                 decoder->ip = decoder->last_ip;
1776                                 if (intel_pt_fup_event(decoder))
1777                                         return 0;
1778                                 no_tip = false;
1779                                 break;
1780                         }
1781                         if (decoder->set_fup_mwait)
1782                                 no_tip = true;
1783                         err = intel_pt_walk_fup(decoder);
1784                         if (err != -EAGAIN) {
1785                                 if (err)
1786                                         return err;
1787                                 if (no_tip)
1788                                         decoder->pkt_state =
1789                                                 INTEL_PT_STATE_FUP_NO_TIP;
1790                                 else
1791                                         decoder->pkt_state = INTEL_PT_STATE_FUP;
1792                                 return 0;
1793                         }
1794                         if (no_tip) {
1795                                 no_tip = false;
1796                                 break;
1797                         }
1798                         return intel_pt_walk_fup_tip(decoder);
1799 
1800                 case INTEL_PT_TRACESTOP:
1801                         decoder->pge = false;
1802                         decoder->continuous_period = false;
1803                         intel_pt_clear_tx_flags(decoder);
1804                         decoder->have_tma = false;
1805                         break;
1806 
1807                 case INTEL_PT_PSB:
1808                         decoder->last_ip = 0;
1809                         decoder->have_last_ip = true;
1810                         intel_pt_clear_stack(&decoder->stack);
1811                         err = intel_pt_walk_psbend(decoder);
1812                         if (err == -EAGAIN)
1813                                 goto next;
1814                         if (err)
1815                                 return err;
1816                         break;
1817 
1818                 case INTEL_PT_PIP:
1819                         decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
1820                         break;
1821 
1822                 case INTEL_PT_MTC:
1823                         intel_pt_calc_mtc_timestamp(decoder);
1824                         if (decoder->period_type != INTEL_PT_PERIOD_MTC)
1825                                 break;
1826                         /*
1827                          * Ensure that there has been an instruction since the
1828                          * last MTC.
1829                          */
1830                         if (!decoder->mtc_insn)
1831                                 break;
1832                         decoder->mtc_insn = false;
1833                         /* Ensure that there is a timestamp */
1834                         if (!decoder->timestamp)
1835                                 break;
1836                         decoder->state.type = INTEL_PT_INSTRUCTION;
1837                         decoder->state.from_ip = decoder->ip;
1838                         decoder->state.to_ip = 0;
1839                         decoder->mtc_insn = false;
1840                         return 0;
1841 
1842                 case INTEL_PT_TSC:
1843                         intel_pt_calc_tsc_timestamp(decoder);
1844                         break;
1845 
1846                 case INTEL_PT_TMA:
1847                         intel_pt_calc_tma(decoder);
1848                         break;
1849 
1850                 case INTEL_PT_CYC:
1851                         intel_pt_calc_cyc_timestamp(decoder);
1852                         break;
1853 
1854                 case INTEL_PT_CBR:
1855                         intel_pt_calc_cbr(decoder);
1856                         if (!decoder->branch_enable &&
1857                             decoder->cbr != decoder->cbr_seen) {
1858                                 decoder->cbr_seen = decoder->cbr;
1859                                 decoder->state.type = INTEL_PT_CBR_CHG;
1860                                 decoder->state.from_ip = decoder->ip;
1861                                 decoder->state.to_ip = 0;
1862                                 decoder->state.cbr_payload =
1863                                                         decoder->packet.payload;
1864                                 return 0;
1865                         }
1866                         break;
1867 
1868                 case INTEL_PT_MODE_EXEC:
1869                         decoder->exec_mode = decoder->packet.payload;
1870                         break;
1871 
1872                 case INTEL_PT_MODE_TSX:
1873                         /* MODE_TSX need not be followed by FUP */
1874                         if (!decoder->pge) {
1875                                 intel_pt_update_in_tx(decoder);
1876                                 break;
1877                         }
1878                         err = intel_pt_mode_tsx(decoder, &no_tip);
1879                         if (err)
1880                                 return err;
1881                         goto next;
1882 
1883                 case INTEL_PT_BAD: /* Does not happen */
1884                         return intel_pt_bug(decoder);
1885 
1886                 case INTEL_PT_PSBEND:
1887                 case INTEL_PT_VMCS:
1888                 case INTEL_PT_MNT:
1889                 case INTEL_PT_PAD:
1890                         break;
1891 
1892                 case INTEL_PT_PTWRITE_IP:
1893                         decoder->fup_ptw_payload = decoder->packet.payload;
1894                         err = intel_pt_get_next_packet(decoder);
1895                         if (err)
1896                                 return err;
1897                         if (decoder->packet.type == INTEL_PT_FUP) {
1898                                 decoder->set_fup_ptw = true;
1899                                 no_tip = true;
1900                         } else {
1901                                 intel_pt_log_at("ERROR: Missing FUP after PTWRITE",
1902                                                 decoder->pos);
1903                         }
1904                         goto next;
1905 
1906                 case INTEL_PT_PTWRITE:
1907                         decoder->state.type = INTEL_PT_PTW;
1908                         decoder->state.from_ip = decoder->ip;
1909                         decoder->state.to_ip = 0;
1910                         decoder->state.ptw_payload = decoder->packet.payload;
1911                         return 0;
1912 
1913                 case INTEL_PT_MWAIT:
1914                         decoder->fup_mwait_payload = decoder->packet.payload;
1915                         decoder->set_fup_mwait = true;
1916                         break;
1917 
1918                 case INTEL_PT_PWRE:
1919                         if (decoder->set_fup_mwait) {
1920                                 decoder->fup_pwre_payload =
1921                                                         decoder->packet.payload;
1922                                 decoder->set_fup_pwre = true;
1923                                 break;
1924                         }
1925                         decoder->state.type = INTEL_PT_PWR_ENTRY;
1926                         decoder->state.from_ip = decoder->ip;
1927                         decoder->state.to_ip = 0;
1928                         decoder->state.pwrx_payload = decoder->packet.payload;
1929                         return 0;
1930 
1931                 case INTEL_PT_EXSTOP_IP:
1932                         err = intel_pt_get_next_packet(decoder);
1933                         if (err)
1934                                 return err;
1935                         if (decoder->packet.type == INTEL_PT_FUP) {
1936                                 decoder->set_fup_exstop = true;
1937                                 no_tip = true;
1938                         } else {
1939                                 intel_pt_log_at("ERROR: Missing FUP after EXSTOP",
1940                                                 decoder->pos);
1941                         }
1942                         goto next;
1943 
1944                 case INTEL_PT_EXSTOP:
1945                         decoder->state.type = INTEL_PT_EX_STOP;
1946                         decoder->state.from_ip = decoder->ip;
1947                         decoder->state.to_ip = 0;
1948                         return 0;
1949 
1950                 case INTEL_PT_PWRX:
1951                         decoder->state.type = INTEL_PT_PWR_EXIT;
1952                         decoder->state.from_ip = decoder->ip;
1953                         decoder->state.to_ip = 0;
1954                         decoder->state.pwrx_payload = decoder->packet.payload;
1955                         return 0;
1956 
1957                 default:
1958                         return intel_pt_bug(decoder);
1959                 }
1960         }
1961 }
1962 
1963 static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)
1964 {
1965         return decoder->packet.count &&
1966                (decoder->have_last_ip || decoder->packet.count == 3 ||
1967                 decoder->packet.count == 6);
1968 }
1969 
1970 /* Walk PSB+ packets to get in sync. */
1971 static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)
1972 {
1973         int err;
1974 
1975         while (1) {
1976                 err = intel_pt_get_next_packet(decoder);
1977                 if (err)
1978                         return err;
1979 
1980                 switch (decoder->packet.type) {
1981                 case INTEL_PT_TIP_PGD:
1982                         decoder->continuous_period = false;
1983                         __fallthrough;
1984                 case INTEL_PT_TIP_PGE:
1985                 case INTEL_PT_TIP:
1986                 case INTEL_PT_PTWRITE:
1987                 case INTEL_PT_PTWRITE_IP:
1988                 case INTEL_PT_EXSTOP:
1989                 case INTEL_PT_EXSTOP_IP:
1990                 case INTEL_PT_MWAIT:
1991                 case INTEL_PT_PWRE:
1992                 case INTEL_PT_PWRX:
1993                         intel_pt_log("ERROR: Unexpected packet\n");
1994                         return -ENOENT;
1995 
1996                 case INTEL_PT_FUP:
1997                         decoder->pge = true;
1998                         if (intel_pt_have_ip(decoder)) {
1999                                 uint64_t current_ip = decoder->ip;
2000 
2001                                 intel_pt_set_ip(decoder);
2002                                 if (current_ip)
2003                                         intel_pt_log_to("Setting IP",
2004                                                         decoder->ip);
2005                         }
2006                         break;
2007 
2008                 case INTEL_PT_MTC:
2009                         intel_pt_calc_mtc_timestamp(decoder);
2010                         break;
2011 
2012                 case INTEL_PT_TSC:
2013                         intel_pt_calc_tsc_timestamp(decoder);
2014                         break;
2015 
2016                 case INTEL_PT_TMA:
2017                         intel_pt_calc_tma(decoder);
2018                         break;
2019 
2020                 case INTEL_PT_CYC:
2021                         intel_pt_calc_cyc_timestamp(decoder);
2022                         break;
2023 
2024                 case INTEL_PT_CBR:
2025                         intel_pt_calc_cbr(decoder);
2026                         break;
2027 
2028                 case INTEL_PT_PIP:
2029                         decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
2030                         break;
2031 
2032                 case INTEL_PT_MODE_EXEC:
2033                         decoder->exec_mode = decoder->packet.payload;
2034                         break;
2035 
2036                 case INTEL_PT_MODE_TSX:
2037                         intel_pt_update_in_tx(decoder);
2038                         break;
2039 
2040                 case INTEL_PT_TRACESTOP:
2041                         decoder->pge = false;
2042                         decoder->continuous_period = false;
2043                         intel_pt_clear_tx_flags(decoder);
2044                         __fallthrough;
2045 
2046                 case INTEL_PT_TNT:
2047                         decoder->have_tma = false;
2048                         intel_pt_log("ERROR: Unexpected packet\n");
2049                         if (decoder->ip)
2050                                 decoder->pkt_state = INTEL_PT_STATE_ERR4;
2051                         else
2052                                 decoder->pkt_state = INTEL_PT_STATE_ERR3;
2053                         return -ENOENT;
2054 
2055                 case INTEL_PT_BAD: /* Does not happen */
2056                         return intel_pt_bug(decoder);
2057 
2058                 case INTEL_PT_OVF:
2059                         return intel_pt_overflow(decoder);
2060 
2061                 case INTEL_PT_PSBEND:
2062                         return 0;
2063 
2064                 case INTEL_PT_PSB:
2065                 case INTEL_PT_VMCS:
2066                 case INTEL_PT_MNT:
2067                 case INTEL_PT_PAD:
2068                 default:
2069                         break;
2070                 }
2071         }
2072 }
2073 
2074 static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
2075 {
2076         int err;
2077 
2078         while (1) {
2079                 err = intel_pt_get_next_packet(decoder);
2080                 if (err)
2081                         return err;
2082 
2083                 switch (decoder->packet.type) {
2084                 case INTEL_PT_TIP_PGD:
2085                         decoder->continuous_period = false;
2086                         __fallthrough;
2087                 case INTEL_PT_TIP_PGE:
2088                 case INTEL_PT_TIP:
2089                         decoder->pge = decoder->packet.type != INTEL_PT_TIP_PGD;
2090                         if (intel_pt_have_ip(decoder))
2091                                 intel_pt_set_ip(decoder);
2092                         if (!decoder->ip)
2093                                 break;
2094                         if (decoder->packet.type == INTEL_PT_TIP_PGE)
2095                                 decoder->state.type |= INTEL_PT_TRACE_BEGIN;
2096                         if (decoder->packet.type == INTEL_PT_TIP_PGD)
2097                                 decoder->state.type |= INTEL_PT_TRACE_END;
2098                         return 0;
2099 
2100                 case INTEL_PT_FUP:
2101                         if (intel_pt_have_ip(decoder))
2102                                 intel_pt_set_ip(decoder);
2103                         if (decoder->ip)
2104                                 return 0;
2105                         break;
2106 
2107                 case INTEL_PT_MTC:
2108                         intel_pt_calc_mtc_timestamp(decoder);
2109                         break;
2110 
2111                 case INTEL_PT_TSC:
2112                         intel_pt_calc_tsc_timestamp(decoder);
2113                         break;
2114 
2115                 case INTEL_PT_TMA:
2116                         intel_pt_calc_tma(decoder);
2117                         break;
2118 
2119                 case INTEL_PT_CYC:
2120                         intel_pt_calc_cyc_timestamp(decoder);
2121                         break;
2122 
2123                 case INTEL_PT_CBR:
2124                         intel_pt_calc_cbr(decoder);
2125                         break;
2126 
2127                 case INTEL_PT_PIP:
2128                         decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
2129                         break;
2130 
2131                 case INTEL_PT_MODE_EXEC:
2132                         decoder->exec_mode = decoder->packet.payload;
2133                         break;
2134 
2135                 case INTEL_PT_MODE_TSX:
2136                         intel_pt_update_in_tx(decoder);
2137                         break;
2138 
2139                 case INTEL_PT_OVF:
2140                         return intel_pt_overflow(decoder);
2141 
2142                 case INTEL_PT_BAD: /* Does not happen */
2143                         return intel_pt_bug(decoder);
2144 
2145                 case INTEL_PT_TRACESTOP:
2146                         decoder->pge = false;
2147                         decoder->continuous_period = false;
2148                         intel_pt_clear_tx_flags(decoder);
2149                         decoder->have_tma = false;
2150                         break;
2151 
2152                 case INTEL_PT_PSB:
2153                         decoder->last_ip = 0;
2154                         decoder->have_last_ip = true;
2155                         intel_pt_clear_stack(&decoder->stack);
2156                         err = intel_pt_walk_psb(decoder);
2157                         if (err)
2158                                 return err;
2159                         if (decoder->ip) {
2160                                 /* Do not have a sample */
2161                                 decoder->state.type = 0;
2162                                 return 0;
2163                         }
2164                         break;
2165 
2166                 case INTEL_PT_TNT:
2167                 case INTEL_PT_PSBEND:
2168                 case INTEL_PT_VMCS:
2169                 case INTEL_PT_MNT:
2170                 case INTEL_PT_PAD:
2171                 case INTEL_PT_PTWRITE:
2172                 case INTEL_PT_PTWRITE_IP:
2173                 case INTEL_PT_EXSTOP:
2174                 case INTEL_PT_EXSTOP_IP:
2175                 case INTEL_PT_MWAIT:
2176                 case INTEL_PT_PWRE:
2177                 case INTEL_PT_PWRX:
2178                 default:
2179                         break;
2180                 }
2181         }
2182 }
2183 
2184 static int intel_pt_sync_ip(struct intel_pt_decoder *decoder)
2185 {
2186         int err;
2187 
2188         decoder->set_fup_tx_flags = false;
2189         decoder->set_fup_ptw = false;
2190         decoder->set_fup_mwait = false;
2191         decoder->set_fup_pwre = false;
2192         decoder->set_fup_exstop = false;
2193 
2194         if (!decoder->branch_enable) {
2195                 decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
2196                 decoder->overflow = false;
2197                 decoder->state.type = 0; /* Do not have a sample */
2198                 return 0;
2199         }
2200 
2201         intel_pt_log("Scanning for full IP\n");
2202         err = intel_pt_walk_to_ip(decoder);
2203         if (err)
2204                 return err;
2205 
2206         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
2207         decoder->overflow = false;
2208 
2209         decoder->state.from_ip = 0;
2210         decoder->state.to_ip = decoder->ip;
2211         intel_pt_log_to("Setting IP", decoder->ip);
2212 
2213         return 0;
2214 }
2215 
2216 static int intel_pt_part_psb(struct intel_pt_decoder *decoder)
2217 {
2218         const unsigned char *end = decoder->buf + decoder->len;
2219         size_t i;
2220 
2221         for (i = INTEL_PT_PSB_LEN - 1; i; i--) {
2222                 if (i > decoder->len)
2223                         continue;
2224                 if (!memcmp(end - i, INTEL_PT_PSB_STR, i))
2225                         return i;
2226         }
2227         return 0;
2228 }
2229 
2230 static int intel_pt_rest_psb(struct intel_pt_decoder *decoder, int part_psb)
2231 {
2232         size_t rest_psb = INTEL_PT_PSB_LEN - part_psb;
2233         const char *psb = INTEL_PT_PSB_STR;
2234 
2235         if (rest_psb > decoder->len ||
2236             memcmp(decoder->buf, psb + part_psb, rest_psb))
2237                 return 0;
2238 
2239         return rest_psb;
2240 }
2241 
2242 static int intel_pt_get_split_psb(struct intel_pt_decoder *decoder,
2243                                   int part_psb)
2244 {
2245         int rest_psb, ret;
2246 
2247         decoder->pos += decoder->len;
2248         decoder->len = 0;
2249 
2250         ret = intel_pt_get_next_data(decoder);
2251         if (ret)
2252                 return ret;
2253 
2254         rest_psb = intel_pt_rest_psb(decoder, part_psb);
2255         if (!rest_psb)
2256                 return 0;
2257 
2258         decoder->pos -= part_psb;
2259         decoder->next_buf = decoder->buf + rest_psb;
2260         decoder->next_len = decoder->len - rest_psb;
2261         memcpy(decoder->temp_buf, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
2262         decoder->buf = decoder->temp_buf;
2263         decoder->len = INTEL_PT_PSB_LEN;
2264 
2265         return 0;
2266 }
2267 
2268 static int intel_pt_scan_for_psb(struct intel_pt_decoder *decoder)
2269 {
2270         unsigned char *next;
2271         int ret;
2272 
2273         intel_pt_log("Scanning for PSB\n");
2274         while (1) {
2275                 if (!decoder->len) {
2276                         ret = intel_pt_get_next_data(decoder);
2277                         if (ret)
2278                                 return ret;
2279                 }
2280 
2281                 next = memmem(decoder->buf, decoder->len, INTEL_PT_PSB_STR,
2282                               INTEL_PT_PSB_LEN);
2283                 if (!next) {
2284                         int part_psb;
2285 
2286                         part_psb = intel_pt_part_psb(decoder);
2287                         if (part_psb) {
2288                                 ret = intel_pt_get_split_psb(decoder, part_psb);
2289                                 if (ret)
2290                                         return ret;
2291                         } else {
2292                                 decoder->pos += decoder->len;
2293                                 decoder->len = 0;
2294                         }
2295                         continue;
2296                 }
2297 
2298                 decoder->pkt_step = next - decoder->buf;
2299                 return intel_pt_get_next_packet(decoder);
2300         }
2301 }
2302 
2303 static int intel_pt_sync(struct intel_pt_decoder *decoder)
2304 {
2305         int err;
2306 
2307         decoder->pge = false;
2308         decoder->continuous_period = false;
2309         decoder->have_last_ip = false;
2310         decoder->last_ip = 0;
2311         decoder->ip = 0;
2312         intel_pt_clear_stack(&decoder->stack);
2313 
2314         err = intel_pt_scan_for_psb(decoder);
2315         if (err)
2316                 return err;
2317 
2318         decoder->have_last_ip = true;
2319         decoder->pkt_state = INTEL_PT_STATE_NO_IP;
2320 
2321         err = intel_pt_walk_psb(decoder);
2322         if (err)
2323                 return err;
2324 
2325         if (decoder->ip) {
2326                 decoder->state.type = 0; /* Do not have a sample */
2327                 decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
2328         } else {
2329                 return intel_pt_sync_ip(decoder);
2330         }
2331 
2332         return 0;
2333 }
2334 
2335 static uint64_t intel_pt_est_timestamp(struct intel_pt_decoder *decoder)
2336 {
2337         uint64_t est = decoder->sample_insn_cnt << 1;
2338 
2339         if (!decoder->cbr || !decoder->max_non_turbo_ratio)
2340                 goto out;
2341 
2342         est *= decoder->max_non_turbo_ratio;
2343         est /= decoder->cbr;
2344 out:
2345         return decoder->sample_timestamp + est;
2346 }
2347 
2348 const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
2349 {
2350         int err;
2351 
2352         do {
2353                 decoder->state.type = INTEL_PT_BRANCH;
2354                 decoder->state.flags = 0;
2355 
2356                 switch (decoder->pkt_state) {
2357                 case INTEL_PT_STATE_NO_PSB:
2358                         err = intel_pt_sync(decoder);
2359                         break;
2360                 case INTEL_PT_STATE_NO_IP:
2361                         decoder->have_last_ip = false;
2362                         decoder->last_ip = 0;
2363                         decoder->ip = 0;
2364                         __fallthrough;
2365                 case INTEL_PT_STATE_ERR_RESYNC:
2366                         err = intel_pt_sync_ip(decoder);
2367                         break;
2368                 case INTEL_PT_STATE_IN_SYNC:
2369                         err = intel_pt_walk_trace(decoder);
2370                         break;
2371                 case INTEL_PT_STATE_TNT:
2372                         err = intel_pt_walk_tnt(decoder);
2373                         if (err == -EAGAIN)
2374                                 err = intel_pt_walk_trace(decoder);
2375                         break;
2376                 case INTEL_PT_STATE_TIP:
2377                 case INTEL_PT_STATE_TIP_PGD:
2378                         err = intel_pt_walk_tip(decoder);
2379                         break;
2380                 case INTEL_PT_STATE_FUP:
2381                         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
2382                         err = intel_pt_walk_fup(decoder);
2383                         if (err == -EAGAIN)
2384                                 err = intel_pt_walk_fup_tip(decoder);
2385                         else if (!err)
2386                                 decoder->pkt_state = INTEL_PT_STATE_FUP;
2387                         break;
2388                 case INTEL_PT_STATE_FUP_NO_TIP:
2389                         decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
2390                         err = intel_pt_walk_fup(decoder);
2391                         if (err == -EAGAIN)
2392                                 err = intel_pt_walk_trace(decoder);
2393                         break;
2394                 default:
2395                         err = intel_pt_bug(decoder);
2396                         break;
2397                 }
2398         } while (err == -ENOLINK);
2399 
2400         if (err) {
2401                 decoder->state.err = intel_pt_ext_err(err);
2402                 decoder->state.from_ip = decoder->ip;
2403                 decoder->sample_timestamp = decoder->timestamp;
2404                 decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
2405         } else {
2406                 decoder->state.err = 0;
2407                 if (decoder->cbr != decoder->cbr_seen && decoder->state.type) {
2408                         decoder->cbr_seen = decoder->cbr;
2409                         decoder->state.type |= INTEL_PT_CBR_CHG;
2410                         decoder->state.cbr_payload = decoder->cbr_payload;
2411                 }
2412                 if (intel_pt_sample_time(decoder->pkt_state)) {
2413                         decoder->sample_timestamp = decoder->timestamp;
2414                         decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
2415                 }
2416         }
2417 
2418         decoder->state.timestamp = decoder->sample_timestamp;
2419         decoder->state.est_timestamp = intel_pt_est_timestamp(decoder);
2420         decoder->state.cr3 = decoder->cr3;
2421         decoder->state.tot_insn_cnt = decoder->tot_insn_cnt;
2422 
2423         return &decoder->state;
2424 }
2425 
2426 /**
2427  * intel_pt_next_psb - move buffer pointer to the start of the next PSB packet.
2428  * @buf: pointer to buffer pointer
2429  * @len: size of buffer
2430  *
2431  * Updates the buffer pointer to point to the start of the next PSB packet if
2432  * there is one, otherwise the buffer pointer is unchanged.  If @buf is updated,
2433  * @len is adjusted accordingly.
2434  *
2435  * Return: %true if a PSB packet is found, %false otherwise.
2436  */
2437 static bool intel_pt_next_psb(unsigned char **buf, size_t *len)
2438 {
2439         unsigned char *next;
2440 
2441         next = memmem(*buf, *len, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
2442         if (next) {
2443                 *len -= next - *buf;
2444                 *buf = next;
2445                 return true;
2446         }
2447         return false;
2448 }
2449 
2450 /**
2451  * intel_pt_step_psb - move buffer pointer to the start of the following PSB
2452  *                     packet.
2453  * @buf: pointer to buffer pointer
2454  * @len: size of buffer
2455  *
2456  * Updates the buffer pointer to point to the start of the following PSB packet
2457  * (skipping the PSB at @buf itself) if there is one, otherwise the buffer
2458  * pointer is unchanged.  If @buf is updated, @len is adjusted accordingly.
2459  *
2460  * Return: %true if a PSB packet is found, %false otherwise.
2461  */
2462 static bool intel_pt_step_psb(unsigned char **buf, size_t *len)
2463 {
2464         unsigned char *next;
2465 
2466         if (!*len)
2467                 return false;
2468 
2469         next = memmem(*buf + 1, *len - 1, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
2470         if (next) {
2471                 *len -= next - *buf;
2472                 *buf = next;
2473                 return true;
2474         }
2475         return false;
2476 }
2477 
2478 /**
2479  * intel_pt_last_psb - find the last PSB packet in a buffer.
2480  * @buf: buffer
2481  * @len: size of buffer
2482  *
2483  * This function finds the last PSB in a buffer.
2484  *
2485  * Return: A pointer to the last PSB in @buf if found, %NULL otherwise.
2486  */
2487 static unsigned char *intel_pt_last_psb(unsigned char *buf, size_t len)
2488 {
2489         const char *n = INTEL_PT_PSB_STR;
2490         unsigned char *p;
2491         size_t k;
2492 
2493         if (len < INTEL_PT_PSB_LEN)
2494                 return NULL;
2495 
2496         k = len - INTEL_PT_PSB_LEN + 1;
2497         while (1) {
2498                 p = memrchr(buf, n[0], k);
2499                 if (!p)
2500                         return NULL;
2501                 if (!memcmp(p + 1, n + 1, INTEL_PT_PSB_LEN - 1))
2502                         return p;
2503                 k = p - buf;
2504                 if (!k)
2505                         return NULL;
2506         }
2507 }
2508 
2509 /**
2510  * intel_pt_next_tsc - find and return next TSC.
2511  * @buf: buffer
2512  * @len: size of buffer
2513  * @tsc: TSC value returned
2514  * @rem: returns remaining size when TSC is found
2515  *
2516  * Find a TSC packet in @buf and return the TSC value.  This function assumes
2517  * that @buf starts at a PSB and that PSB+ will contain TSC and so stops if a
2518  * PSBEND packet is found.
2519  *
2520  * Return: %true if TSC is found, false otherwise.
2521  */
2522 static bool intel_pt_next_tsc(unsigned char *buf, size_t len, uint64_t *tsc,
2523                               size_t *rem)
2524 {
2525         struct intel_pt_pkt packet;
2526         int ret;
2527 
2528         while (len) {
2529                 ret = intel_pt_get_packet(buf, len, &packet);
2530                 if (ret <= 0)
2531                         return false;
2532                 if (packet.type == INTEL_PT_TSC) {
2533                         *tsc = packet.payload;
2534                         *rem = len;
2535                         return true;
2536                 }
2537                 if (packet.type == INTEL_PT_PSBEND)
2538                         return false;
2539                 buf += ret;
2540                 len -= ret;
2541         }
2542         return false;
2543 }
2544 
2545 /**
2546  * intel_pt_tsc_cmp - compare 7-byte TSCs.
2547  * @tsc1: first TSC to compare
2548  * @tsc2: second TSC to compare
2549  *
2550  * This function compares 7-byte TSC values allowing for the possibility that
2551  * TSC wrapped around.  Generally it is not possible to know if TSC has wrapped
2552  * around so for that purpose this function assumes the absolute difference is
2553  * less than half the maximum difference.
2554  *
2555  * Return: %-1 if @tsc1 is before @tsc2, %0 if @tsc1 == @tsc2, %1 if @tsc1 is
2556  * after @tsc2.
2557  */
2558 static int intel_pt_tsc_cmp(uint64_t tsc1, uint64_t tsc2)
2559 {
2560         const uint64_t halfway = (1ULL << 55);
2561 
2562         if (tsc1 == tsc2)
2563                 return 0;
2564 
2565         if (tsc1 < tsc2) {
2566                 if (tsc2 - tsc1 < halfway)
2567                         return -1;
2568                 else
2569                         return 1;
2570         } else {
2571                 if (tsc1 - tsc2 < halfway)
2572                         return 1;
2573                 else
2574                         return -1;
2575         }
2576 }
2577 
2578 /**
2579  * intel_pt_find_overlap_tsc - determine start of non-overlapped trace data
2580  *                             using TSC.
2581  * @buf_a: first buffer
2582  * @len_a: size of first buffer
2583  * @buf_b: second buffer
2584  * @len_b: size of second buffer
2585  * @consecutive: returns true if there is data in buf_b that is consecutive
2586  *               to buf_a
2587  *
2588  * If the trace contains TSC we can look at the last TSC of @buf_a and the
2589  * first TSC of @buf_b in order to determine if the buffers overlap, and then
2590  * walk forward in @buf_b until a later TSC is found.  A precondition is that
2591  * @buf_a and @buf_b are positioned at a PSB.
2592  *
2593  * Return: A pointer into @buf_b from where non-overlapped data starts, or
2594  * @buf_b + @len_b if there is no non-overlapped data.
2595  */
2596 static unsigned char *intel_pt_find_overlap_tsc(unsigned char *buf_a,
2597                                                 size_t len_a,
2598                                                 unsigned char *buf_b,
2599                                                 size_t len_b, bool *consecutive)
2600 {
2601         uint64_t tsc_a, tsc_b;
2602         unsigned char *p;
2603         size_t len, rem_a, rem_b;
2604 
2605         p = intel_pt_last_psb(buf_a, len_a);
2606         if (!p)
2607                 return buf_b; /* No PSB in buf_a => no overlap */
2608 
2609         len = len_a - (p - buf_a);
2610         if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a)) {
2611                 /* The last PSB+ in buf_a is incomplete, so go back one more */
2612                 len_a -= len;
2613                 p = intel_pt_last_psb(buf_a, len_a);
2614                 if (!p)
2615                         return buf_b; /* No full PSB+ => assume no overlap */
2616                 len = len_a - (p - buf_a);
2617                 if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a))
2618                         return buf_b; /* No TSC in buf_a => assume no overlap */
2619         }
2620 
2621         while (1) {
2622                 /* Ignore PSB+ with no TSC */
2623                 if (intel_pt_next_tsc(buf_b, len_b, &tsc_b, &rem_b)) {
2624                         int cmp = intel_pt_tsc_cmp(tsc_a, tsc_b);
2625 
2626                         /* Same TSC, so buffers are consecutive */
2627                         if (!cmp && rem_b >= rem_a) {
2628                                 *consecutive = true;
2629                                 return buf_b + len_b - (rem_b - rem_a);
2630                         }
2631                         if (cmp < 0)
2632                                 return buf_b; /* tsc_a < tsc_b => no overlap */
2633                 }
2634 
2635                 if (!intel_pt_step_psb(&buf_b, &len_b))
2636                         return buf_b + len_b; /* No PSB in buf_b => no data */
2637         }
2638 }
2639 
2640 /**
2641  * intel_pt_find_overlap - determine start of non-overlapped trace data.
2642  * @buf_a: first buffer
2643  * @len_a: size of first buffer
2644  * @buf_b: second buffer
2645  * @len_b: size of second buffer
2646  * @have_tsc: can use TSC packets to detect overlap
2647  * @consecutive: returns true if there is data in buf_b that is consecutive
2648  *               to buf_a
2649  *
2650  * When trace samples or snapshots are recorded there is the possibility that
2651  * the data overlaps.  Note that, for the purposes of decoding, data is only
2652  * useful if it begins with a PSB packet.
2653  *
2654  * Return: A pointer into @buf_b from where non-overlapped data starts, or
2655  * @buf_b + @len_b if there is no non-overlapped data.
2656  */
2657 unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a,
2658                                      unsigned char *buf_b, size_t len_b,
2659                                      bool have_tsc, bool *consecutive)
2660 {
2661         unsigned char *found;
2662 
2663         /* Buffer 'b' must start at PSB so throw away everything before that */
2664         if (!intel_pt_next_psb(&buf_b, &len_b))
2665                 return buf_b + len_b; /* No PSB */
2666 
2667         if (!intel_pt_next_psb(&buf_a, &len_a))
2668                 return buf_b; /* No overlap */
2669 
2670         if (have_tsc) {
2671                 found = intel_pt_find_overlap_tsc(buf_a, len_a, buf_b, len_b,
2672                                                   consecutive);
2673                 if (found)
2674                         return found;
2675         }
2676 
2677         /*
2678          * Buffer 'b' cannot end within buffer 'a' so, for comparison purposes,
2679          * we can ignore the first part of buffer 'a'.
2680          */
2681         while (len_b < len_a) {
2682                 if (!intel_pt_step_psb(&buf_a, &len_a))
2683                         return buf_b; /* No overlap */
2684         }
2685 
2686         /* Now len_b >= len_a */
2687         while (1) {
2688                 /* Potential overlap so check the bytes */
2689                 found = memmem(buf_a, len_a, buf_b, len_a);
2690                 if (found) {
2691                         *consecutive = true;
2692                         return buf_b + len_a;
2693                 }
2694 
2695                 /* Try again at next PSB in buffer 'a' */
2696                 if (!intel_pt_step_psb(&buf_a, &len_a))
2697                         return buf_b; /* No overlap */
2698         }
2699 }
2700 

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