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

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