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tegrakernel/kernel/kernel-4.9/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c

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/*
* intel_pt_decoder.c: Intel Processor Trace support
* Copyright (c) 2013-2014, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
#include <inttypes.h>
#include <linux/compiler.h>
#include "../cache.h"
#include "../util.h"
#include "../auxtrace.h"
#include "intel-pt-insn-decoder.h"
#include "intel-pt-pkt-decoder.h"
#include "intel-pt-decoder.h"
#include "intel-pt-log.h"
#define INTEL_PT_BLK_SIZE 1024
#define BIT63 (((uint64_t)1 << 63))
#define INTEL_PT_RETURN 1
/* Maximum number of loops with no packets consumed i.e. stuck in a loop */
#define INTEL_PT_MAX_LOOPS 10000
struct intel_pt_blk {
struct intel_pt_blk *prev;
uint64_t ip[INTEL_PT_BLK_SIZE];
};
struct intel_pt_stack {
struct intel_pt_blk *blk;
struct intel_pt_blk *spare;
int pos;
};
enum intel_pt_pkt_state {
INTEL_PT_STATE_NO_PSB,
INTEL_PT_STATE_NO_IP,
INTEL_PT_STATE_ERR_RESYNC,
INTEL_PT_STATE_IN_SYNC,
INTEL_PT_STATE_TNT_CONT,
INTEL_PT_STATE_TNT,
INTEL_PT_STATE_TIP,
INTEL_PT_STATE_TIP_PGD,
INTEL_PT_STATE_FUP,
INTEL_PT_STATE_FUP_NO_TIP,
};
static inline bool intel_pt_sample_time(enum intel_pt_pkt_state pkt_state)
{
switch (pkt_state) {
case INTEL_PT_STATE_NO_PSB:
case INTEL_PT_STATE_NO_IP:
case INTEL_PT_STATE_ERR_RESYNC:
case INTEL_PT_STATE_IN_SYNC:
case INTEL_PT_STATE_TNT_CONT:
return true;
case INTEL_PT_STATE_TNT:
case INTEL_PT_STATE_TIP:
case INTEL_PT_STATE_TIP_PGD:
case INTEL_PT_STATE_FUP:
case INTEL_PT_STATE_FUP_NO_TIP:
return false;
default:
return true;
};
}
#ifdef INTEL_PT_STRICT
#define INTEL_PT_STATE_ERR1 INTEL_PT_STATE_NO_PSB
#define INTEL_PT_STATE_ERR2 INTEL_PT_STATE_NO_PSB
#define INTEL_PT_STATE_ERR3 INTEL_PT_STATE_NO_PSB
#define INTEL_PT_STATE_ERR4 INTEL_PT_STATE_NO_PSB
#else
#define INTEL_PT_STATE_ERR1 (decoder->pkt_state)
#define INTEL_PT_STATE_ERR2 INTEL_PT_STATE_NO_IP
#define INTEL_PT_STATE_ERR3 INTEL_PT_STATE_ERR_RESYNC
#define INTEL_PT_STATE_ERR4 INTEL_PT_STATE_IN_SYNC
#endif
struct intel_pt_decoder {
int (*get_trace)(struct intel_pt_buffer *buffer, void *data);
int (*walk_insn)(struct intel_pt_insn *intel_pt_insn,
uint64_t *insn_cnt_ptr, uint64_t *ip, uint64_t to_ip,
uint64_t max_insn_cnt, void *data);
bool (*pgd_ip)(uint64_t ip, void *data);
void *data;
struct intel_pt_state state;
const unsigned char *buf;
size_t len;
bool return_compression;
bool mtc_insn;
bool pge;
bool have_tma;
bool have_cyc;
bool fixup_last_mtc;
bool have_last_ip;
enum intel_pt_param_flags flags;
uint64_t pos;
uint64_t last_ip;
uint64_t ip;
uint64_t cr3;
uint64_t timestamp;
uint64_t tsc_timestamp;
uint64_t ref_timestamp;
uint64_t sample_timestamp;
uint64_t ret_addr;
uint64_t ctc_timestamp;
uint64_t ctc_delta;
uint64_t cycle_cnt;
uint64_t cyc_ref_timestamp;
uint32_t last_mtc;
uint32_t tsc_ctc_ratio_n;
uint32_t tsc_ctc_ratio_d;
uint32_t tsc_ctc_mult;
uint32_t tsc_slip;
uint32_t ctc_rem_mask;
int mtc_shift;
struct intel_pt_stack stack;
enum intel_pt_pkt_state pkt_state;
struct intel_pt_pkt packet;
struct intel_pt_pkt tnt;
int pkt_step;
int pkt_len;
int last_packet_type;
unsigned int cbr;
unsigned int max_non_turbo_ratio;
double max_non_turbo_ratio_fp;
double cbr_cyc_to_tsc;
double calc_cyc_to_tsc;
bool have_calc_cyc_to_tsc;
int exec_mode;
unsigned int insn_bytes;
uint64_t period;
enum intel_pt_period_type period_type;
uint64_t tot_insn_cnt;
uint64_t period_insn_cnt;
uint64_t period_mask;
uint64_t period_ticks;
uint64_t last_masked_timestamp;
bool continuous_period;
bool overflow;
bool set_fup_tx_flags;
unsigned int fup_tx_flags;
unsigned int tx_flags;
uint64_t timestamp_insn_cnt;
uint64_t sample_insn_cnt;
uint64_t stuck_ip;
int no_progress;
int stuck_ip_prd;
int stuck_ip_cnt;
const unsigned char *next_buf;
size_t next_len;
unsigned char temp_buf[INTEL_PT_PKT_MAX_SZ];
};
static uint64_t intel_pt_lower_power_of_2(uint64_t x)
{
int i;
for (i = 0; x != 1; i++)
x >>= 1;
return x << i;
}
static void intel_pt_setup_period(struct intel_pt_decoder *decoder)
{
if (decoder->period_type == INTEL_PT_PERIOD_TICKS) {
uint64_t period;
period = intel_pt_lower_power_of_2(decoder->period);
decoder->period_mask = ~(period - 1);
decoder->period_ticks = period;
}
}
static uint64_t multdiv(uint64_t t, uint32_t n, uint32_t d)
{
if (!d)
return 0;
return (t / d) * n + ((t % d) * n) / d;
}
struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
{
struct intel_pt_decoder *decoder;
if (!params->get_trace || !params->walk_insn)
return NULL;
decoder = zalloc(sizeof(struct intel_pt_decoder));
if (!decoder)
return NULL;
decoder->get_trace = params->get_trace;
decoder->walk_insn = params->walk_insn;
decoder->pgd_ip = params->pgd_ip;
decoder->data = params->data;
decoder->return_compression = params->return_compression;
decoder->flags = params->flags;
decoder->period = params->period;
decoder->period_type = params->period_type;
decoder->max_non_turbo_ratio = params->max_non_turbo_ratio;
decoder->max_non_turbo_ratio_fp = params->max_non_turbo_ratio;
intel_pt_setup_period(decoder);
decoder->mtc_shift = params->mtc_period;
decoder->ctc_rem_mask = (1 << decoder->mtc_shift) - 1;
decoder->tsc_ctc_ratio_n = params->tsc_ctc_ratio_n;
decoder->tsc_ctc_ratio_d = params->tsc_ctc_ratio_d;
if (!decoder->tsc_ctc_ratio_n)
decoder->tsc_ctc_ratio_d = 0;
if (decoder->tsc_ctc_ratio_d) {
if (!(decoder->tsc_ctc_ratio_n % decoder->tsc_ctc_ratio_d))
decoder->tsc_ctc_mult = decoder->tsc_ctc_ratio_n /
decoder->tsc_ctc_ratio_d;
}
/*
* A TSC packet can slip past MTC packets so that the timestamp appears
* to go backwards. One estimate is that can be up to about 40 CPU
* cycles, which is certainly less than 0x1000 TSC ticks, but accept
* slippage an order of magnitude more to be on the safe side.
*/
decoder->tsc_slip = 0x10000;
intel_pt_log("timestamp: mtc_shift %u\n", decoder->mtc_shift);
intel_pt_log("timestamp: tsc_ctc_ratio_n %u\n", decoder->tsc_ctc_ratio_n);
intel_pt_log("timestamp: tsc_ctc_ratio_d %u\n", decoder->tsc_ctc_ratio_d);
intel_pt_log("timestamp: tsc_ctc_mult %u\n", decoder->tsc_ctc_mult);
intel_pt_log("timestamp: tsc_slip %#x\n", decoder->tsc_slip);
return decoder;
}
static void intel_pt_pop_blk(struct intel_pt_stack *stack)
{
struct intel_pt_blk *blk = stack->blk;
stack->blk = blk->prev;
if (!stack->spare)
stack->spare = blk;
else
free(blk);
}
static uint64_t intel_pt_pop(struct intel_pt_stack *stack)
{
if (!stack->pos) {
if (!stack->blk)
return 0;
intel_pt_pop_blk(stack);
if (!stack->blk)
return 0;
stack->pos = INTEL_PT_BLK_SIZE;
}
return stack->blk->ip[--stack->pos];
}
static int intel_pt_alloc_blk(struct intel_pt_stack *stack)
{
struct intel_pt_blk *blk;
if (stack->spare) {
blk = stack->spare;
stack->spare = NULL;
} else {
blk = malloc(sizeof(struct intel_pt_blk));
if (!blk)
return -ENOMEM;
}
blk->prev = stack->blk;
stack->blk = blk;
stack->pos = 0;
return 0;
}
static int intel_pt_push(struct intel_pt_stack *stack, uint64_t ip)
{
int err;
if (!stack->blk || stack->pos == INTEL_PT_BLK_SIZE) {
err = intel_pt_alloc_blk(stack);
if (err)
return err;
}
stack->blk->ip[stack->pos++] = ip;
return 0;
}
static void intel_pt_clear_stack(struct intel_pt_stack *stack)
{
while (stack->blk)
intel_pt_pop_blk(stack);
stack->pos = 0;
}
static void intel_pt_free_stack(struct intel_pt_stack *stack)
{
intel_pt_clear_stack(stack);
zfree(&stack->blk);
zfree(&stack->spare);
}
void intel_pt_decoder_free(struct intel_pt_decoder *decoder)
{
intel_pt_free_stack(&decoder->stack);
free(decoder);
}
static int intel_pt_ext_err(int code)
{
switch (code) {
case -ENOMEM:
return INTEL_PT_ERR_NOMEM;
case -ENOSYS:
return INTEL_PT_ERR_INTERN;
case -EBADMSG:
return INTEL_PT_ERR_BADPKT;
case -ENODATA:
return INTEL_PT_ERR_NODATA;
case -EILSEQ:
return INTEL_PT_ERR_NOINSN;
case -ENOENT:
return INTEL_PT_ERR_MISMAT;
case -EOVERFLOW:
return INTEL_PT_ERR_OVR;
case -ENOSPC:
return INTEL_PT_ERR_LOST;
case -ELOOP:
return INTEL_PT_ERR_NELOOP;
default:
return INTEL_PT_ERR_UNK;
}
}
static const char *intel_pt_err_msgs[] = {
[INTEL_PT_ERR_NOMEM] = "Memory allocation failed",
[INTEL_PT_ERR_INTERN] = "Internal error",
[INTEL_PT_ERR_BADPKT] = "Bad packet",
[INTEL_PT_ERR_NODATA] = "No more data",
[INTEL_PT_ERR_NOINSN] = "Failed to get instruction",
[INTEL_PT_ERR_MISMAT] = "Trace doesn't match instruction",
[INTEL_PT_ERR_OVR] = "Overflow packet",
[INTEL_PT_ERR_LOST] = "Lost trace data",
[INTEL_PT_ERR_UNK] = "Unknown error!",
[INTEL_PT_ERR_NELOOP] = "Never-ending loop",
};
int intel_pt__strerror(int code, char *buf, size_t buflen)
{
if (code < 1 || code >= INTEL_PT_ERR_MAX)
code = INTEL_PT_ERR_UNK;
strlcpy(buf, intel_pt_err_msgs[code], buflen);
return 0;
}
static uint64_t intel_pt_calc_ip(const struct intel_pt_pkt *packet,
uint64_t last_ip)
{
uint64_t ip;
switch (packet->count) {
case 1:
ip = (last_ip & (uint64_t)0xffffffffffff0000ULL) |
packet->payload;
break;
case 2:
ip = (last_ip & (uint64_t)0xffffffff00000000ULL) |
packet->payload;
break;
case 3:
ip = packet->payload;
/* Sign-extend 6-byte ip */
if (ip & (uint64_t)0x800000000000ULL)
ip |= (uint64_t)0xffff000000000000ULL;
break;
case 4:
ip = (last_ip & (uint64_t)0xffff000000000000ULL) |
packet->payload;
break;
case 6:
ip = packet->payload;
break;
default:
return 0;
}
return ip;
}
static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
{
decoder->last_ip = intel_pt_calc_ip(&decoder->packet, decoder->last_ip);
decoder->have_last_ip = true;
}
static inline void intel_pt_set_ip(struct intel_pt_decoder *decoder)
{
intel_pt_set_last_ip(decoder);
decoder->ip = decoder->last_ip;
}
static void intel_pt_decoder_log_packet(struct intel_pt_decoder *decoder)
{
intel_pt_log_packet(&decoder->packet, decoder->pkt_len, decoder->pos,
decoder->buf);
}
static int intel_pt_bug(struct intel_pt_decoder *decoder)
{
intel_pt_log("ERROR: Internal error\n");
decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
return -ENOSYS;
}
static inline void intel_pt_clear_tx_flags(struct intel_pt_decoder *decoder)
{
decoder->tx_flags = 0;
}
static inline void intel_pt_update_in_tx(struct intel_pt_decoder *decoder)
{
decoder->tx_flags = decoder->packet.payload & INTEL_PT_IN_TX;
}
static int intel_pt_bad_packet(struct intel_pt_decoder *decoder)
{
intel_pt_clear_tx_flags(decoder);
decoder->have_tma = false;
decoder->pkt_len = 1;
decoder->pkt_step = 1;
intel_pt_decoder_log_packet(decoder);
if (decoder->pkt_state != INTEL_PT_STATE_NO_PSB) {
intel_pt_log("ERROR: Bad packet\n");
decoder->pkt_state = INTEL_PT_STATE_ERR1;
}
return -EBADMSG;
}
static int intel_pt_get_data(struct intel_pt_decoder *decoder)
{
struct intel_pt_buffer buffer = { .buf = 0, };
int ret;
decoder->pkt_step = 0;
intel_pt_log("Getting more data\n");
ret = decoder->get_trace(&buffer, decoder->data);
if (ret)
return ret;
decoder->buf = buffer.buf;
decoder->len = buffer.len;
if (!decoder->len) {
intel_pt_log("No more data\n");
return -ENODATA;
}
if (!buffer.consecutive) {
decoder->ip = 0;
decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
decoder->ref_timestamp = buffer.ref_timestamp;
decoder->timestamp = 0;
decoder->have_tma = false;
decoder->state.trace_nr = buffer.trace_nr;
intel_pt_log("Reference timestamp 0x%" PRIx64 "\n",
decoder->ref_timestamp);
return -ENOLINK;
}
return 0;
}
static int intel_pt_get_next_data(struct intel_pt_decoder *decoder)
{
if (!decoder->next_buf)
return intel_pt_get_data(decoder);
decoder->buf = decoder->next_buf;
decoder->len = decoder->next_len;
decoder->next_buf = 0;
decoder->next_len = 0;
return 0;
}
static int intel_pt_get_split_packet(struct intel_pt_decoder *decoder)
{
unsigned char *buf = decoder->temp_buf;
size_t old_len, len, n;
int ret;
old_len = decoder->len;
len = decoder->len;
memcpy(buf, decoder->buf, len);
ret = intel_pt_get_data(decoder);
if (ret) {
decoder->pos += old_len;
return ret < 0 ? ret : -EINVAL;
}
n = INTEL_PT_PKT_MAX_SZ - len;
if (n > decoder->len)
n = decoder->len;
memcpy(buf + len, decoder->buf, n);
len += n;
ret = intel_pt_get_packet(buf, len, &decoder->packet);
if (ret < (int)old_len) {
decoder->next_buf = decoder->buf;
decoder->next_len = decoder->len;
decoder->buf = buf;
decoder->len = old_len;
return intel_pt_bad_packet(decoder);
}
decoder->next_buf = decoder->buf + (ret - old_len);
decoder->next_len = decoder->len - (ret - old_len);
decoder->buf = buf;
decoder->len = ret;
return ret;
}
struct intel_pt_pkt_info {
struct intel_pt_decoder *decoder;
struct intel_pt_pkt packet;
uint64_t pos;
int pkt_len;
int last_packet_type;
void *data;
};
typedef int (*intel_pt_pkt_cb_t)(struct intel_pt_pkt_info *pkt_info);
/* Lookahead packets in current buffer */
static int intel_pt_pkt_lookahead(struct intel_pt_decoder *decoder,
intel_pt_pkt_cb_t cb, void *data)
{
struct intel_pt_pkt_info pkt_info;
const unsigned char *buf = decoder->buf;
size_t len = decoder->len;
int ret;
pkt_info.decoder = decoder;
pkt_info.pos = decoder->pos;
pkt_info.pkt_len = decoder->pkt_step;
pkt_info.last_packet_type = decoder->last_packet_type;
pkt_info.data = data;
while (1) {
do {
pkt_info.pos += pkt_info.pkt_len;
buf += pkt_info.pkt_len;
len -= pkt_info.pkt_len;
if (!len)
return INTEL_PT_NEED_MORE_BYTES;
ret = intel_pt_get_packet(buf, len, &pkt_info.packet);
if (!ret)
return INTEL_PT_NEED_MORE_BYTES;
if (ret < 0)
return ret;
pkt_info.pkt_len = ret;
} while (pkt_info.packet.type == INTEL_PT_PAD);
ret = cb(&pkt_info);
if (ret)
return 0;
pkt_info.last_packet_type = pkt_info.packet.type;
}
}
struct intel_pt_calc_cyc_to_tsc_info {
uint64_t cycle_cnt;
unsigned int cbr;
uint32_t last_mtc;
uint64_t ctc_timestamp;
uint64_t ctc_delta;
uint64_t tsc_timestamp;
uint64_t timestamp;
bool have_tma;
bool fixup_last_mtc;
bool from_mtc;
double cbr_cyc_to_tsc;
};
/*
* MTC provides a 8-bit slice of CTC but the TMA packet only provides the lower
* 16 bits of CTC. If mtc_shift > 8 then some of the MTC bits are not in the CTC
* provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
* packet by copying the missing bits from the current MTC assuming the least
* difference between the two, and that the current MTC comes after last_mtc.
*/
static void intel_pt_fixup_last_mtc(uint32_t mtc, int mtc_shift,
uint32_t *last_mtc)
{
uint32_t first_missing_bit = 1U << (16 - mtc_shift);
uint32_t mask = ~(first_missing_bit - 1);
*last_mtc |= mtc & mask;
if (*last_mtc >= mtc) {
*last_mtc -= first_missing_bit;
*last_mtc &= 0xff;
}
}
static int intel_pt_calc_cyc_cb(struct intel_pt_pkt_info *pkt_info)
{
struct intel_pt_decoder *decoder = pkt_info->decoder;
struct intel_pt_calc_cyc_to_tsc_info *data = pkt_info->data;
uint64_t timestamp;
double cyc_to_tsc;
unsigned int cbr;
uint32_t mtc, mtc_delta, ctc, fc, ctc_rem;
switch (pkt_info->packet.type) {
case INTEL_PT_TNT:
case INTEL_PT_TIP_PGE:
case INTEL_PT_TIP:
case INTEL_PT_FUP:
case INTEL_PT_PSB:
case INTEL_PT_PIP:
case INTEL_PT_MODE_EXEC:
case INTEL_PT_MODE_TSX:
case INTEL_PT_PSBEND:
case INTEL_PT_PAD:
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
return 0;
case INTEL_PT_MTC:
if (!data->have_tma)
return 0;
mtc = pkt_info->packet.payload;
if (decoder->mtc_shift > 8 && data->fixup_last_mtc) {
data->fixup_last_mtc = false;
intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
&data->last_mtc);
}
if (mtc > data->last_mtc)
mtc_delta = mtc - data->last_mtc;
else
mtc_delta = mtc + 256 - data->last_mtc;
data->ctc_delta += mtc_delta << decoder->mtc_shift;
data->last_mtc = mtc;
if (decoder->tsc_ctc_mult) {
timestamp = data->ctc_timestamp +
data->ctc_delta * decoder->tsc_ctc_mult;
} else {
timestamp = data->ctc_timestamp +
multdiv(data->ctc_delta,
decoder->tsc_ctc_ratio_n,
decoder->tsc_ctc_ratio_d);
}
if (timestamp < data->timestamp)
return 1;
if (pkt_info->last_packet_type != INTEL_PT_CYC) {
data->timestamp = timestamp;
return 0;
}
break;
case INTEL_PT_TSC:
timestamp = pkt_info->packet.payload |
(data->timestamp & (0xffULL << 56));
if (data->from_mtc && timestamp < data->timestamp &&
data->timestamp - timestamp < decoder->tsc_slip)
return 1;
if (timestamp < data->timestamp)
timestamp += (1ULL << 56);
if (pkt_info->last_packet_type != INTEL_PT_CYC) {
if (data->from_mtc)
return 1;
data->tsc_timestamp = timestamp;
data->timestamp = timestamp;
return 0;
}
break;
case INTEL_PT_TMA:
if (data->from_mtc)
return 1;
if (!decoder->tsc_ctc_ratio_d)
return 0;
ctc = pkt_info->packet.payload;
fc = pkt_info->packet.count;
ctc_rem = ctc & decoder->ctc_rem_mask;
data->last_mtc = (ctc >> decoder->mtc_shift) & 0xff;
data->ctc_timestamp = data->tsc_timestamp - fc;
if (decoder->tsc_ctc_mult) {
data->ctc_timestamp -= ctc_rem * decoder->tsc_ctc_mult;
} else {
data->ctc_timestamp -=
multdiv(ctc_rem, decoder->tsc_ctc_ratio_n,
decoder->tsc_ctc_ratio_d);
}
data->ctc_delta = 0;
data->have_tma = true;
data->fixup_last_mtc = true;
return 0;
case INTEL_PT_CYC:
data->cycle_cnt += pkt_info->packet.payload;
return 0;
case INTEL_PT_CBR:
cbr = pkt_info->packet.payload;
if (data->cbr && data->cbr != cbr)
return 1;
data->cbr = cbr;
data->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
return 0;
case INTEL_PT_TIP_PGD:
case INTEL_PT_TRACESTOP:
case INTEL_PT_OVF:
case INTEL_PT_BAD: /* Does not happen */
default:
return 1;
}
if (!data->cbr && decoder->cbr) {
data->cbr = decoder->cbr;
data->cbr_cyc_to_tsc = decoder->cbr_cyc_to_tsc;
}
if (!data->cycle_cnt)
return 1;
cyc_to_tsc = (double)(timestamp - decoder->timestamp) / data->cycle_cnt;
if (data->cbr && cyc_to_tsc > data->cbr_cyc_to_tsc &&
cyc_to_tsc / data->cbr_cyc_to_tsc > 1.25) {
intel_pt_log("Timestamp: calculated %g TSC ticks per cycle too big (c.f. CBR-based value %g), pos " x64_fmt "\n",
cyc_to_tsc, data->cbr_cyc_to_tsc, pkt_info->pos);
return 1;
}
decoder->calc_cyc_to_tsc = cyc_to_tsc;
decoder->have_calc_cyc_to_tsc = true;
if (data->cbr) {
intel_pt_log("Timestamp: calculated %g TSC ticks per cycle c.f. CBR-based value %g, pos " x64_fmt "\n",
cyc_to_tsc, data->cbr_cyc_to_tsc, pkt_info->pos);
} else {
intel_pt_log("Timestamp: calculated %g TSC ticks per cycle c.f. unknown CBR-based value, pos " x64_fmt "\n",
cyc_to_tsc, pkt_info->pos);
}
return 1;
}
static void intel_pt_calc_cyc_to_tsc(struct intel_pt_decoder *decoder,
bool from_mtc)
{
struct intel_pt_calc_cyc_to_tsc_info data = {
.cycle_cnt = 0,
.cbr = 0,
.last_mtc = decoder->last_mtc,
.ctc_timestamp = decoder->ctc_timestamp,
.ctc_delta = decoder->ctc_delta,
.tsc_timestamp = decoder->tsc_timestamp,
.timestamp = decoder->timestamp,
.have_tma = decoder->have_tma,
.fixup_last_mtc = decoder->fixup_last_mtc,
.from_mtc = from_mtc,
.cbr_cyc_to_tsc = 0,
};
intel_pt_pkt_lookahead(decoder, intel_pt_calc_cyc_cb, &data);
}
static int intel_pt_get_next_packet(struct intel_pt_decoder *decoder)
{
int ret;
decoder->last_packet_type = decoder->packet.type;
do {
decoder->pos += decoder->pkt_step;
decoder->buf += decoder->pkt_step;
decoder->len -= decoder->pkt_step;
if (!decoder->len) {
ret = intel_pt_get_next_data(decoder);
if (ret)
return ret;
}
ret = intel_pt_get_packet(decoder->buf, decoder->len,
&decoder->packet);
if (ret == INTEL_PT_NEED_MORE_BYTES &&
decoder->len < INTEL_PT_PKT_MAX_SZ && !decoder->next_buf) {
ret = intel_pt_get_split_packet(decoder);
if (ret < 0)
return ret;
}
if (ret <= 0)
return intel_pt_bad_packet(decoder);
decoder->pkt_len = ret;
decoder->pkt_step = ret;
intel_pt_decoder_log_packet(decoder);
} while (decoder->packet.type == INTEL_PT_PAD);
return 0;
}
static uint64_t intel_pt_next_period(struct intel_pt_decoder *decoder)
{
uint64_t timestamp, masked_timestamp;
timestamp = decoder->timestamp + decoder->timestamp_insn_cnt;
masked_timestamp = timestamp & decoder->period_mask;
if (decoder->continuous_period) {
if (masked_timestamp > decoder->last_masked_timestamp)
return 1;
} else {
timestamp += 1;
masked_timestamp = timestamp & decoder->period_mask;
if (masked_timestamp > decoder->last_masked_timestamp) {
decoder->last_masked_timestamp = masked_timestamp;
decoder->continuous_period = true;
}
}
if (masked_timestamp < decoder->last_masked_timestamp)
return decoder->period_ticks;
return decoder->period_ticks - (timestamp - masked_timestamp);
}
static uint64_t intel_pt_next_sample(struct intel_pt_decoder *decoder)
{
switch (decoder->period_type) {
case INTEL_PT_PERIOD_INSTRUCTIONS:
return decoder->period - decoder->period_insn_cnt;
case INTEL_PT_PERIOD_TICKS:
return intel_pt_next_period(decoder);
case INTEL_PT_PERIOD_NONE:
case INTEL_PT_PERIOD_MTC:
default:
return 0;
}
}
static void intel_pt_sample_insn(struct intel_pt_decoder *decoder)
{
uint64_t timestamp, masked_timestamp;
switch (decoder->period_type) {
case INTEL_PT_PERIOD_INSTRUCTIONS:
decoder->period_insn_cnt = 0;
break;
case INTEL_PT_PERIOD_TICKS:
timestamp = decoder->timestamp + decoder->timestamp_insn_cnt;
masked_timestamp = timestamp & decoder->period_mask;
if (masked_timestamp > decoder->last_masked_timestamp)
decoder->last_masked_timestamp = masked_timestamp;
else
decoder->last_masked_timestamp += decoder->period_ticks;
break;
case INTEL_PT_PERIOD_NONE:
case INTEL_PT_PERIOD_MTC:
default:
break;
}
decoder->state.type |= INTEL_PT_INSTRUCTION;
}
static int intel_pt_walk_insn(struct intel_pt_decoder *decoder,
struct intel_pt_insn *intel_pt_insn, uint64_t ip)
{
uint64_t max_insn_cnt, insn_cnt = 0;
int err;
if (!decoder->mtc_insn)
decoder->mtc_insn = true;
max_insn_cnt = intel_pt_next_sample(decoder);
err = decoder->walk_insn(intel_pt_insn, &insn_cnt, &decoder->ip, ip,
max_insn_cnt, decoder->data);
decoder->tot_insn_cnt += insn_cnt;
decoder->timestamp_insn_cnt += insn_cnt;
decoder->sample_insn_cnt += insn_cnt;
decoder->period_insn_cnt += insn_cnt;
if (err) {
decoder->no_progress = 0;
decoder->pkt_state = INTEL_PT_STATE_ERR2;
intel_pt_log_at("ERROR: Failed to get instruction",
decoder->ip);
if (err == -ENOENT)
return -ENOLINK;
return -EILSEQ;
}
if (ip && decoder->ip == ip) {
err = -EAGAIN;
goto out;
}
if (max_insn_cnt && insn_cnt >= max_insn_cnt)
intel_pt_sample_insn(decoder);
if (intel_pt_insn->branch == INTEL_PT_BR_NO_BRANCH) {
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
decoder->ip += intel_pt_insn->length;
err = INTEL_PT_RETURN;
goto out;
}
if (intel_pt_insn->op == INTEL_PT_OP_CALL) {
/* Zero-length calls are excluded */
if (intel_pt_insn->branch != INTEL_PT_BR_UNCONDITIONAL ||
intel_pt_insn->rel) {
err = intel_pt_push(&decoder->stack, decoder->ip +
intel_pt_insn->length);
if (err)
goto out;
}
} else if (intel_pt_insn->op == INTEL_PT_OP_RET) {
decoder->ret_addr = intel_pt_pop(&decoder->stack);
}
if (intel_pt_insn->branch == INTEL_PT_BR_UNCONDITIONAL) {
int cnt = decoder->no_progress++;
decoder->state.from_ip = decoder->ip;
decoder->ip += intel_pt_insn->length +
intel_pt_insn->rel;
decoder->state.to_ip = decoder->ip;
err = INTEL_PT_RETURN;
/*
* Check for being stuck in a loop. This can happen if a
* decoder error results in the decoder erroneously setting the
* ip to an address that is itself in an infinite loop that
* consumes no packets. When that happens, there must be an
* unconditional branch.
*/
if (cnt) {
if (cnt == 1) {
decoder->stuck_ip = decoder->state.to_ip;
decoder->stuck_ip_prd = 1;
decoder->stuck_ip_cnt = 1;
} else if (cnt > INTEL_PT_MAX_LOOPS ||
decoder->state.to_ip == decoder->stuck_ip) {
intel_pt_log_at("ERROR: Never-ending loop",
decoder->state.to_ip);
decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
err = -ELOOP;
goto out;
} else if (!--decoder->stuck_ip_cnt) {
decoder->stuck_ip_prd += 1;
decoder->stuck_ip_cnt = decoder->stuck_ip_prd;
decoder->stuck_ip = decoder->state.to_ip;
}
}
goto out_no_progress;
}
out:
decoder->no_progress = 0;
out_no_progress:
decoder->state.insn_op = intel_pt_insn->op;
decoder->state.insn_len = intel_pt_insn->length;
if (decoder->tx_flags & INTEL_PT_IN_TX)
decoder->state.flags |= INTEL_PT_IN_TX;
return err;
}
static inline bool intel_pt_fup_with_nlip(struct intel_pt_decoder *decoder,
struct intel_pt_insn *intel_pt_insn,
uint64_t ip, int err)
{
return decoder->flags & INTEL_PT_FUP_WITH_NLIP && !err &&
intel_pt_insn->branch == INTEL_PT_BR_INDIRECT &&
ip == decoder->ip + intel_pt_insn->length;
}
static int intel_pt_walk_fup(struct intel_pt_decoder *decoder)
{
struct intel_pt_insn intel_pt_insn;
uint64_t ip;
int err;
ip = decoder->last_ip;
while (1) {
err = intel_pt_walk_insn(decoder, &intel_pt_insn, ip);
if (err == INTEL_PT_RETURN)
return 0;
if (err == -EAGAIN ||
intel_pt_fup_with_nlip(decoder, &intel_pt_insn, ip, err)) {
if (decoder->set_fup_tx_flags) {
decoder->set_fup_tx_flags = false;
decoder->tx_flags = decoder->fup_tx_flags;
decoder->state.type = INTEL_PT_TRANSACTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
decoder->state.flags = decoder->fup_tx_flags;
return 0;
}
return -EAGAIN;
}
decoder->set_fup_tx_flags = false;
if (err)
return err;
if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
intel_pt_log_at("ERROR: Unexpected indirect branch",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
return -ENOENT;
}
if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
intel_pt_log_at("ERROR: Unexpected conditional branch",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
return -ENOENT;
}
intel_pt_bug(decoder);
}
}
static int intel_pt_walk_tip(struct intel_pt_decoder *decoder)
{
struct intel_pt_insn intel_pt_insn;
int err;
err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
if (err == INTEL_PT_RETURN &&
decoder->pgd_ip &&
decoder->pkt_state == INTEL_PT_STATE_TIP_PGD &&
(decoder->state.type & INTEL_PT_BRANCH) &&
decoder->pgd_ip(decoder->state.to_ip, decoder->data)) {
/* Unconditional branch leaving filter region */
decoder->no_progress = 0;
decoder->pge = false;
decoder->continuous_period = false;
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->state.to_ip = 0;
return 0;
}
if (err == INTEL_PT_RETURN)
return 0;
if (err)
return err;
if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
if (decoder->pkt_state == INTEL_PT_STATE_TIP_PGD) {
decoder->pge = false;
decoder->continuous_period = false;
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
if (decoder->packet.count != 0)
decoder->ip = decoder->last_ip;
} else {
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->state.from_ip = decoder->ip;
if (decoder->packet.count == 0) {
decoder->state.to_ip = 0;
} else {
decoder->state.to_ip = decoder->last_ip;
decoder->ip = decoder->last_ip;
}
}
return 0;
}
if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
uint64_t to_ip = decoder->ip + intel_pt_insn.length +
intel_pt_insn.rel;
if (decoder->pgd_ip &&
decoder->pkt_state == INTEL_PT_STATE_TIP_PGD &&
decoder->pgd_ip(to_ip, decoder->data)) {
/* Conditional branch leaving filter region */
decoder->pge = false;
decoder->continuous_period = false;
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->ip = to_ip;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
return 0;
}
intel_pt_log_at("ERROR: Conditional branch when expecting indirect branch",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
return -ENOENT;
}
return intel_pt_bug(decoder);
}
static int intel_pt_walk_tnt(struct intel_pt_decoder *decoder)
{
struct intel_pt_insn intel_pt_insn;
int err;
while (1) {
err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
if (err == INTEL_PT_RETURN)
return 0;
if (err)
return err;
if (intel_pt_insn.op == INTEL_PT_OP_RET) {
if (!decoder->return_compression) {
intel_pt_log_at("ERROR: RET when expecting conditional branch",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR3;
return -ENOENT;
}
if (!decoder->ret_addr) {
intel_pt_log_at("ERROR: Bad RET compression (stack empty)",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR3;
return -ENOENT;
}
if (!(decoder->tnt.payload & BIT63)) {
intel_pt_log_at("ERROR: Bad RET compression (TNT=N)",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR3;
return -ENOENT;
}
decoder->tnt.count -= 1;
if (decoder->tnt.count)
decoder->pkt_state = INTEL_PT_STATE_TNT_CONT;
else
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->tnt.payload <<= 1;
decoder->state.from_ip = decoder->ip;
decoder->ip = decoder->ret_addr;
decoder->state.to_ip = decoder->ip;
return 0;
}
if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
/* Handle deferred TIPs */
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
if (decoder->packet.type != INTEL_PT_TIP ||
decoder->packet.count == 0) {
intel_pt_log_at("ERROR: Missing deferred TIP for indirect branch",
decoder->ip);
decoder->pkt_state = INTEL_PT_STATE_ERR3;
decoder->pkt_step = 0;
return -ENOENT;
}
intel_pt_set_last_ip(decoder);
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = decoder->last_ip;
decoder->ip = decoder->last_ip;
return 0;
}
if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
decoder->tnt.count -= 1;
if (decoder->tnt.count)
decoder->pkt_state = INTEL_PT_STATE_TNT_CONT;
else
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
if (decoder->tnt.payload & BIT63) {
decoder->tnt.payload <<= 1;
decoder->state.from_ip = decoder->ip;
decoder->ip += intel_pt_insn.length +
intel_pt_insn.rel;
decoder->state.to_ip = decoder->ip;
return 0;
}
/* Instruction sample for a non-taken branch */
if (decoder->state.type & INTEL_PT_INSTRUCTION) {
decoder->tnt.payload <<= 1;
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
decoder->ip += intel_pt_insn.length;
return 0;
}
decoder->ip += intel_pt_insn.length;
if (!decoder->tnt.count) {
decoder->sample_timestamp = decoder->timestamp;
decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
return -EAGAIN;
}
decoder->tnt.payload <<= 1;
continue;
}
return intel_pt_bug(decoder);
}
}
static int intel_pt_mode_tsx(struct intel_pt_decoder *decoder, bool *no_tip)
{
unsigned int fup_tx_flags;
int err;
fup_tx_flags = decoder->packet.payload &
(INTEL_PT_IN_TX | INTEL_PT_ABORT_TX);
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
if (decoder->packet.type == INTEL_PT_FUP) {
decoder->fup_tx_flags = fup_tx_flags;
decoder->set_fup_tx_flags = true;
if (!(decoder->fup_tx_flags & INTEL_PT_ABORT_TX))
*no_tip = true;
} else {
intel_pt_log_at("ERROR: Missing FUP after MODE.TSX",
decoder->pos);
intel_pt_update_in_tx(decoder);
}
return 0;
}
static void intel_pt_calc_tsc_timestamp(struct intel_pt_decoder *decoder)
{
uint64_t timestamp;
decoder->have_tma = false;
if (decoder->ref_timestamp) {
timestamp = decoder->packet.payload |
(decoder->ref_timestamp & (0xffULL << 56));
if (timestamp < decoder->ref_timestamp) {
if (decoder->ref_timestamp - timestamp > (1ULL << 55))
timestamp += (1ULL << 56);
} else {
if (timestamp - decoder->ref_timestamp > (1ULL << 55))
timestamp -= (1ULL << 56);
}
decoder->tsc_timestamp = timestamp;
decoder->timestamp = timestamp;
decoder->ref_timestamp = 0;
decoder->timestamp_insn_cnt = 0;
} else if (decoder->timestamp) {
timestamp = decoder->packet.payload |
(decoder->timestamp & (0xffULL << 56));
decoder->tsc_timestamp = timestamp;
if (timestamp < decoder->timestamp &&
decoder->timestamp - timestamp < decoder->tsc_slip) {
intel_pt_log_to("Suppressing backwards timestamp",
timestamp);
timestamp = decoder->timestamp;
}
if (timestamp < decoder->timestamp) {
intel_pt_log_to("Wraparound timestamp", timestamp);
timestamp += (1ULL << 56);
decoder->tsc_timestamp = timestamp;
}
decoder->timestamp = timestamp;
decoder->timestamp_insn_cnt = 0;
}
if (decoder->last_packet_type == INTEL_PT_CYC) {
decoder->cyc_ref_timestamp = decoder->timestamp;
decoder->cycle_cnt = 0;
decoder->have_calc_cyc_to_tsc = false;
intel_pt_calc_cyc_to_tsc(decoder, false);
}
intel_pt_log_to("Setting timestamp", decoder->timestamp);
}
static int intel_pt_overflow(struct intel_pt_decoder *decoder)
{
intel_pt_log("ERROR: Buffer overflow\n");
intel_pt_clear_tx_flags(decoder);
decoder->timestamp_insn_cnt = 0;
decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
decoder->overflow = true;
return -EOVERFLOW;
}
static void intel_pt_calc_tma(struct intel_pt_decoder *decoder)
{
uint32_t ctc = decoder->packet.payload;
uint32_t fc = decoder->packet.count;
uint32_t ctc_rem = ctc & decoder->ctc_rem_mask;
if (!decoder->tsc_ctc_ratio_d)
return;
decoder->last_mtc = (ctc >> decoder->mtc_shift) & 0xff;
decoder->ctc_timestamp = decoder->tsc_timestamp - fc;
if (decoder->tsc_ctc_mult) {
decoder->ctc_timestamp -= ctc_rem * decoder->tsc_ctc_mult;
} else {
decoder->ctc_timestamp -= multdiv(ctc_rem,
decoder->tsc_ctc_ratio_n,
decoder->tsc_ctc_ratio_d);
}
decoder->ctc_delta = 0;
decoder->have_tma = true;
decoder->fixup_last_mtc = true;
intel_pt_log("CTC timestamp " x64_fmt " last MTC %#x CTC rem %#x\n",
decoder->ctc_timestamp, decoder->last_mtc, ctc_rem);
}
static void intel_pt_calc_mtc_timestamp(struct intel_pt_decoder *decoder)
{
uint64_t timestamp;
uint32_t mtc, mtc_delta;
if (!decoder->have_tma)
return;
mtc = decoder->packet.payload;
if (decoder->mtc_shift > 8 && decoder->fixup_last_mtc) {
decoder->fixup_last_mtc = false;
intel_pt_fixup_last_mtc(mtc, decoder->mtc_shift,
&decoder->last_mtc);
}
if (mtc > decoder->last_mtc)
mtc_delta = mtc - decoder->last_mtc;
else
mtc_delta = mtc + 256 - decoder->last_mtc;
decoder->ctc_delta += mtc_delta << decoder->mtc_shift;
if (decoder->tsc_ctc_mult) {
timestamp = decoder->ctc_timestamp +
decoder->ctc_delta * decoder->tsc_ctc_mult;
} else {
timestamp = decoder->ctc_timestamp +
multdiv(decoder->ctc_delta,
decoder->tsc_ctc_ratio_n,
decoder->tsc_ctc_ratio_d);
}
if (timestamp < decoder->timestamp)
intel_pt_log("Suppressing MTC timestamp " x64_fmt " less than current timestamp " x64_fmt "\n",
timestamp, decoder->timestamp);
else
decoder->timestamp = timestamp;
decoder->timestamp_insn_cnt = 0;
decoder->last_mtc = mtc;
if (decoder->last_packet_type == INTEL_PT_CYC) {
decoder->cyc_ref_timestamp = decoder->timestamp;
decoder->cycle_cnt = 0;
decoder->have_calc_cyc_to_tsc = false;
intel_pt_calc_cyc_to_tsc(decoder, true);
}
}
static void intel_pt_calc_cbr(struct intel_pt_decoder *decoder)
{
unsigned int cbr = decoder->packet.payload;
if (decoder->cbr == cbr)
return;
decoder->cbr = cbr;
decoder->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
}
static void intel_pt_calc_cyc_timestamp(struct intel_pt_decoder *decoder)
{
uint64_t timestamp = decoder->cyc_ref_timestamp;
decoder->have_cyc = true;
decoder->cycle_cnt += decoder->packet.payload;
if (!decoder->cyc_ref_timestamp)
return;
if (decoder->have_calc_cyc_to_tsc)
timestamp += decoder->cycle_cnt * decoder->calc_cyc_to_tsc;
else if (decoder->cbr)
timestamp += decoder->cycle_cnt * decoder->cbr_cyc_to_tsc;
else
return;
if (timestamp < decoder->timestamp)
intel_pt_log("Suppressing CYC timestamp " x64_fmt " less than current timestamp " x64_fmt "\n",
timestamp, decoder->timestamp);
else
decoder->timestamp = timestamp;
decoder->timestamp_insn_cnt = 0;
}
/* Walk PSB+ packets when already in sync. */
static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder)
{
int err;
while (1) {
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
switch (decoder->packet.type) {
case INTEL_PT_PSBEND:
return 0;
case INTEL_PT_TIP_PGD:
case INTEL_PT_TIP_PGE:
case INTEL_PT_TIP:
case INTEL_PT_TNT:
case INTEL_PT_TRACESTOP:
case INTEL_PT_BAD:
case INTEL_PT_PSB:
decoder->have_tma = false;
intel_pt_log("ERROR: Unexpected packet\n");
return -EAGAIN;
case INTEL_PT_OVF:
return intel_pt_overflow(decoder);
case INTEL_PT_TSC:
intel_pt_calc_tsc_timestamp(decoder);
break;
case INTEL_PT_TMA:
intel_pt_calc_tma(decoder);
break;
case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
break;
case INTEL_PT_MODE_EXEC:
decoder->exec_mode = decoder->packet.payload;
break;
case INTEL_PT_PIP:
decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
break;
case INTEL_PT_FUP:
decoder->pge = true;
if (decoder->packet.count)
intel_pt_set_last_ip(decoder);
break;
case INTEL_PT_MODE_TSX:
intel_pt_update_in_tx(decoder);
break;
case INTEL_PT_MTC:
intel_pt_calc_mtc_timestamp(decoder);
if (decoder->period_type == INTEL_PT_PERIOD_MTC)
decoder->state.type |= INTEL_PT_INSTRUCTION;
break;
case INTEL_PT_CYC:
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
case INTEL_PT_PAD:
default:
break;
}
}
}
static int intel_pt_walk_fup_tip(struct intel_pt_decoder *decoder)
{
int err;
if (decoder->tx_flags & INTEL_PT_ABORT_TX) {
decoder->tx_flags = 0;
decoder->state.flags &= ~INTEL_PT_IN_TX;
decoder->state.flags |= INTEL_PT_ABORT_TX;
} else {
decoder->state.flags |= INTEL_PT_ASYNC;
}
while (1) {
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
switch (decoder->packet.type) {
case INTEL_PT_TNT:
case INTEL_PT_FUP:
case INTEL_PT_TRACESTOP:
case INTEL_PT_PSB:
case INTEL_PT_TSC:
case INTEL_PT_TMA:
case INTEL_PT_MODE_TSX:
case INTEL_PT_BAD:
case INTEL_PT_PSBEND:
intel_pt_log("ERROR: Missing TIP after FUP\n");
decoder->pkt_state = INTEL_PT_STATE_ERR3;
decoder->pkt_step = 0;
return -ENOENT;
case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
break;
case INTEL_PT_OVF:
return intel_pt_overflow(decoder);
case INTEL_PT_TIP_PGD:
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
if (decoder->packet.count != 0) {
intel_pt_set_ip(decoder);
intel_pt_log("Omitting PGD ip " x64_fmt "\n",
decoder->ip);
}
decoder->pge = false;
decoder->continuous_period = false;
return 0;
case INTEL_PT_TIP_PGE:
decoder->pge = true;
intel_pt_log("Omitting PGE ip " x64_fmt "\n",
decoder->ip);
decoder->state.from_ip = 0;
if (decoder->packet.count == 0) {
decoder->state.to_ip = 0;
} else {
intel_pt_set_ip(decoder);
decoder->state.to_ip = decoder->ip;
}
return 0;
case INTEL_PT_TIP:
decoder->state.from_ip = decoder->ip;
if (decoder->packet.count == 0) {
decoder->state.to_ip = 0;
} else {
intel_pt_set_ip(decoder);
decoder->state.to_ip = decoder->ip;
}
return 0;
case INTEL_PT_PIP:
decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
break;
case INTEL_PT_MTC:
intel_pt_calc_mtc_timestamp(decoder);
if (decoder->period_type == INTEL_PT_PERIOD_MTC)
decoder->state.type |= INTEL_PT_INSTRUCTION;
break;
case INTEL_PT_CYC:
intel_pt_calc_cyc_timestamp(decoder);
break;
case INTEL_PT_MODE_EXEC:
decoder->exec_mode = decoder->packet.payload;
break;
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
case INTEL_PT_PAD:
break;
default:
return intel_pt_bug(decoder);
}
}
}
static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
{
bool no_tip = false;
int err;
while (1) {
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
next:
switch (decoder->packet.type) {
case INTEL_PT_TNT:
if (!decoder->packet.count)
break;
decoder->tnt = decoder->packet;
decoder->pkt_state = INTEL_PT_STATE_TNT;
err = intel_pt_walk_tnt(decoder);
if (err == -EAGAIN)
break;
return err;
case INTEL_PT_TIP_PGD:
if (decoder->packet.count != 0)
intel_pt_set_last_ip(decoder);
decoder->pkt_state = INTEL_PT_STATE_TIP_PGD;
return intel_pt_walk_tip(decoder);
case INTEL_PT_TIP_PGE: {
decoder->pge = true;
if (decoder->packet.count == 0) {
intel_pt_log_at("Skipping zero TIP.PGE",
decoder->pos);
break;
}
intel_pt_set_ip(decoder);
decoder->state.from_ip = 0;
decoder->state.to_ip = decoder->ip;
return 0;
}
case INTEL_PT_OVF:
return intel_pt_overflow(decoder);
case INTEL_PT_TIP:
if (decoder->packet.count != 0)
intel_pt_set_last_ip(decoder);
decoder->pkt_state = INTEL_PT_STATE_TIP;
return intel_pt_walk_tip(decoder);
case INTEL_PT_FUP:
if (decoder->packet.count == 0) {
intel_pt_log_at("Skipping zero FUP",
decoder->pos);
no_tip = false;
break;
}
intel_pt_set_last_ip(decoder);
err = intel_pt_walk_fup(decoder);
if (err != -EAGAIN) {
if (err)
return err;
if (no_tip)
decoder->pkt_state =
INTEL_PT_STATE_FUP_NO_TIP;
else
decoder->pkt_state = INTEL_PT_STATE_FUP;
return 0;
}
if (no_tip) {
no_tip = false;
break;
}
return intel_pt_walk_fup_tip(decoder);
case INTEL_PT_TRACESTOP:
decoder->pge = false;
decoder->continuous_period = false;
intel_pt_clear_tx_flags(decoder);
decoder->have_tma = false;
break;
case INTEL_PT_PSB:
decoder->last_ip = 0;
decoder->have_last_ip = true;
intel_pt_clear_stack(&decoder->stack);
err = intel_pt_walk_psbend(decoder);
if (err == -EAGAIN)
goto next;
if (err)
return err;
break;
case INTEL_PT_PIP:
decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
break;
case INTEL_PT_MTC:
intel_pt_calc_mtc_timestamp(decoder);
if (decoder->period_type != INTEL_PT_PERIOD_MTC)
break;
/*
* Ensure that there has been an instruction since the
* last MTC.
*/
if (!decoder->mtc_insn)
break;
decoder->mtc_insn = false;
/* Ensure that there is a timestamp */
if (!decoder->timestamp)
break;
decoder->state.type = INTEL_PT_INSTRUCTION;
decoder->state.from_ip = decoder->ip;
decoder->state.to_ip = 0;
decoder->mtc_insn = false;
return 0;
case INTEL_PT_TSC:
intel_pt_calc_tsc_timestamp(decoder);
break;
case INTEL_PT_TMA:
intel_pt_calc_tma(decoder);
break;
case INTEL_PT_CYC:
intel_pt_calc_cyc_timestamp(decoder);
break;
case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
break;
case INTEL_PT_MODE_EXEC:
decoder->exec_mode = decoder->packet.payload;
break;
case INTEL_PT_MODE_TSX:
/* MODE_TSX need not be followed by FUP */
if (!decoder->pge) {
intel_pt_update_in_tx(decoder);
break;
}
err = intel_pt_mode_tsx(decoder, &no_tip);
if (err)
return err;
goto next;
case INTEL_PT_BAD: /* Does not happen */
return intel_pt_bug(decoder);
case INTEL_PT_PSBEND:
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
case INTEL_PT_PAD:
break;
default:
return intel_pt_bug(decoder);
}
}
}
static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)
{
return decoder->packet.count &&
(decoder->have_last_ip || decoder->packet.count == 3 ||
decoder->packet.count == 6);
}
/* Walk PSB+ packets to get in sync. */
static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)
{
int err;
while (1) {
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
switch (decoder->packet.type) {
case INTEL_PT_TIP_PGD:
decoder->continuous_period = false;
__fallthrough;
case INTEL_PT_TIP_PGE:
case INTEL_PT_TIP:
intel_pt_log("ERROR: Unexpected packet\n");
return -ENOENT;
case INTEL_PT_FUP:
decoder->pge = true;
if (intel_pt_have_ip(decoder)) {
uint64_t current_ip = decoder->ip;
intel_pt_set_ip(decoder);
if (current_ip)
intel_pt_log_to("Setting IP",
decoder->ip);
}
break;
case INTEL_PT_MTC:
intel_pt_calc_mtc_timestamp(decoder);
break;
case INTEL_PT_TSC:
intel_pt_calc_tsc_timestamp(decoder);
break;
case INTEL_PT_TMA:
intel_pt_calc_tma(decoder);
break;
case INTEL_PT_CYC:
intel_pt_calc_cyc_timestamp(decoder);
break;
case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
break;
case INTEL_PT_PIP:
decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
break;
case INTEL_PT_MODE_EXEC:
decoder->exec_mode = decoder->packet.payload;
break;
case INTEL_PT_MODE_TSX:
intel_pt_update_in_tx(decoder);
break;
case INTEL_PT_TRACESTOP:
decoder->pge = false;
decoder->continuous_period = false;
intel_pt_clear_tx_flags(decoder);
__fallthrough;
case INTEL_PT_TNT:
decoder->have_tma = false;
intel_pt_log("ERROR: Unexpected packet\n");
if (decoder->ip)
decoder->pkt_state = INTEL_PT_STATE_ERR4;
else
decoder->pkt_state = INTEL_PT_STATE_ERR3;
return -ENOENT;
case INTEL_PT_BAD: /* Does not happen */
return intel_pt_bug(decoder);
case INTEL_PT_OVF:
return intel_pt_overflow(decoder);
case INTEL_PT_PSBEND:
return 0;
case INTEL_PT_PSB:
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
case INTEL_PT_PAD:
default:
break;
}
}
}
static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
{
int err;
while (1) {
err = intel_pt_get_next_packet(decoder);
if (err)
return err;
switch (decoder->packet.type) {
case INTEL_PT_TIP_PGD:
decoder->continuous_period = false;
__fallthrough;
case INTEL_PT_TIP_PGE:
case INTEL_PT_TIP:
decoder->pge = decoder->packet.type != INTEL_PT_TIP_PGD;
if (intel_pt_have_ip(decoder))
intel_pt_set_ip(decoder);
if (decoder->ip)
return 0;
break;
case INTEL_PT_FUP:
if (intel_pt_have_ip(decoder))
intel_pt_set_ip(decoder);
if (decoder->ip)
return 0;
break;
case INTEL_PT_MTC:
intel_pt_calc_mtc_timestamp(decoder);
break;
case INTEL_PT_TSC:
intel_pt_calc_tsc_timestamp(decoder);
break;
case INTEL_PT_TMA:
intel_pt_calc_tma(decoder);
break;
case INTEL_PT_CYC:
intel_pt_calc_cyc_timestamp(decoder);
break;
case INTEL_PT_CBR:
intel_pt_calc_cbr(decoder);
break;
case INTEL_PT_PIP:
decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
break;
case INTEL_PT_MODE_EXEC:
decoder->exec_mode = decoder->packet.payload;
break;
case INTEL_PT_MODE_TSX:
intel_pt_update_in_tx(decoder);
break;
case INTEL_PT_OVF:
return intel_pt_overflow(decoder);
case INTEL_PT_BAD: /* Does not happen */
return intel_pt_bug(decoder);
case INTEL_PT_TRACESTOP:
decoder->pge = false;
decoder->continuous_period = false;
intel_pt_clear_tx_flags(decoder);
decoder->have_tma = false;
break;
case INTEL_PT_PSB:
decoder->last_ip = 0;
decoder->have_last_ip = true;
intel_pt_clear_stack(&decoder->stack);
err = intel_pt_walk_psb(decoder);
if (err)
return err;
if (decoder->ip) {
/* Do not have a sample */
decoder->state.type = 0;
return 0;
}
break;
case INTEL_PT_TNT:
case INTEL_PT_PSBEND:
case INTEL_PT_VMCS:
case INTEL_PT_MNT:
case INTEL_PT_PAD:
default:
break;
}
}
}
static int intel_pt_sync_ip(struct intel_pt_decoder *decoder)
{
int err;
decoder->set_fup_tx_flags = false;
intel_pt_log("Scanning for full IP\n");
err = intel_pt_walk_to_ip(decoder);
if (err)
return err;
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
decoder->overflow = false;
decoder->state.from_ip = 0;
decoder->state.to_ip = decoder->ip;
intel_pt_log_to("Setting IP", decoder->ip);
return 0;
}
static int intel_pt_part_psb(struct intel_pt_decoder *decoder)
{
const unsigned char *end = decoder->buf + decoder->len;
size_t i;
for (i = INTEL_PT_PSB_LEN - 1; i; i--) {
if (i > decoder->len)
continue;
if (!memcmp(end - i, INTEL_PT_PSB_STR, i))
return i;
}
return 0;
}
static int intel_pt_rest_psb(struct intel_pt_decoder *decoder, int part_psb)
{
size_t rest_psb = INTEL_PT_PSB_LEN - part_psb;
const char *psb = INTEL_PT_PSB_STR;
if (rest_psb > decoder->len ||
memcmp(decoder->buf, psb + part_psb, rest_psb))
return 0;
return rest_psb;
}
static int intel_pt_get_split_psb(struct intel_pt_decoder *decoder,
int part_psb)
{
int rest_psb, ret;
decoder->pos += decoder->len;
decoder->len = 0;
ret = intel_pt_get_next_data(decoder);
if (ret)
return ret;
rest_psb = intel_pt_rest_psb(decoder, part_psb);
if (!rest_psb)
return 0;
decoder->pos -= part_psb;
decoder->next_buf = decoder->buf + rest_psb;
decoder->next_len = decoder->len - rest_psb;
memcpy(decoder->temp_buf, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
decoder->buf = decoder->temp_buf;
decoder->len = INTEL_PT_PSB_LEN;
return 0;
}
static int intel_pt_scan_for_psb(struct intel_pt_decoder *decoder)
{
unsigned char *next;
int ret;
intel_pt_log("Scanning for PSB\n");
while (1) {
if (!decoder->len) {
ret = intel_pt_get_next_data(decoder);
if (ret)
return ret;
}
next = memmem(decoder->buf, decoder->len, INTEL_PT_PSB_STR,
INTEL_PT_PSB_LEN);
if (!next) {
int part_psb;
part_psb = intel_pt_part_psb(decoder);
if (part_psb) {
ret = intel_pt_get_split_psb(decoder, part_psb);
if (ret)
return ret;
} else {
decoder->pos += decoder->len;
decoder->len = 0;
}
continue;
}
decoder->pkt_step = next - decoder->buf;
return intel_pt_get_next_packet(decoder);
}
}
static int intel_pt_sync(struct intel_pt_decoder *decoder)
{
int err;
decoder->pge = false;
decoder->continuous_period = false;
decoder->have_last_ip = false;
decoder->last_ip = 0;
decoder->ip = 0;
intel_pt_clear_stack(&decoder->stack);
err = intel_pt_scan_for_psb(decoder);
if (err)
return err;
decoder->have_last_ip = true;
decoder->pkt_state = INTEL_PT_STATE_NO_IP;
err = intel_pt_walk_psb(decoder);
if (err)
return err;
if (decoder->ip) {
decoder->state.type = 0; /* Do not have a sample */
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
} else {
return intel_pt_sync_ip(decoder);
}
return 0;
}
static uint64_t intel_pt_est_timestamp(struct intel_pt_decoder *decoder)
{
uint64_t est = decoder->sample_insn_cnt << 1;
if (!decoder->cbr || !decoder->max_non_turbo_ratio)
goto out;
est *= decoder->max_non_turbo_ratio;
est /= decoder->cbr;
out:
return decoder->sample_timestamp + est;
}
const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
{
int err;
do {
decoder->state.type = INTEL_PT_BRANCH;
decoder->state.flags = 0;
switch (decoder->pkt_state) {
case INTEL_PT_STATE_NO_PSB:
err = intel_pt_sync(decoder);
break;
case INTEL_PT_STATE_NO_IP:
decoder->have_last_ip = false;
decoder->last_ip = 0;
decoder->ip = 0;
/* Fall through */
case INTEL_PT_STATE_ERR_RESYNC:
err = intel_pt_sync_ip(decoder);
break;
case INTEL_PT_STATE_IN_SYNC:
err = intel_pt_walk_trace(decoder);
break;
case INTEL_PT_STATE_TNT:
case INTEL_PT_STATE_TNT_CONT:
err = intel_pt_walk_tnt(decoder);
if (err == -EAGAIN)
err = intel_pt_walk_trace(decoder);
break;
case INTEL_PT_STATE_TIP:
case INTEL_PT_STATE_TIP_PGD:
err = intel_pt_walk_tip(decoder);
break;
case INTEL_PT_STATE_FUP:
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
err = intel_pt_walk_fup(decoder);
if (err == -EAGAIN)
err = intel_pt_walk_fup_tip(decoder);
else if (!err)
decoder->pkt_state = INTEL_PT_STATE_FUP;
break;
case INTEL_PT_STATE_FUP_NO_TIP:
decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
err = intel_pt_walk_fup(decoder);
if (err == -EAGAIN)
err = intel_pt_walk_trace(decoder);
break;
default:
err = intel_pt_bug(decoder);
break;
}
} while (err == -ENOLINK);
if (err) {
decoder->state.err = intel_pt_ext_err(err);
decoder->state.from_ip = decoder->ip;
decoder->sample_timestamp = decoder->timestamp;
decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
} else {
decoder->state.err = 0;
if (intel_pt_sample_time(decoder->pkt_state)) {
decoder->sample_timestamp = decoder->timestamp;
decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
}
}
decoder->state.timestamp = decoder->sample_timestamp;
decoder->state.est_timestamp = intel_pt_est_timestamp(decoder);
decoder->state.cr3 = decoder->cr3;
decoder->state.tot_insn_cnt = decoder->tot_insn_cnt;
return &decoder->state;
}
/**
* intel_pt_next_psb - move buffer pointer to the start of the next PSB packet.
* @buf: pointer to buffer pointer
* @len: size of buffer
*
* Updates the buffer pointer to point to the start of the next PSB packet if
* there is one, otherwise the buffer pointer is unchanged. If @buf is updated,
* @len is adjusted accordingly.
*
* Return: %true if a PSB packet is found, %false otherwise.
*/
static bool intel_pt_next_psb(unsigned char **buf, size_t *len)
{
unsigned char *next;
next = memmem(*buf, *len, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
if (next) {
*len -= next - *buf;
*buf = next;
return true;
}
return false;
}
/**
* intel_pt_step_psb - move buffer pointer to the start of the following PSB
* packet.
* @buf: pointer to buffer pointer
* @len: size of buffer
*
* Updates the buffer pointer to point to the start of the following PSB packet
* (skipping the PSB at @buf itself) if there is one, otherwise the buffer
* pointer is unchanged. If @buf is updated, @len is adjusted accordingly.
*
* Return: %true if a PSB packet is found, %false otherwise.
*/
static bool intel_pt_step_psb(unsigned char **buf, size_t *len)
{
unsigned char *next;
if (!*len)
return false;
next = memmem(*buf + 1, *len - 1, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
if (next) {
*len -= next - *buf;
*buf = next;
return true;
}
return false;
}
/**
* intel_pt_last_psb - find the last PSB packet in a buffer.
* @buf: buffer
* @len: size of buffer
*
* This function finds the last PSB in a buffer.
*
* Return: A pointer to the last PSB in @buf if found, %NULL otherwise.
*/
static unsigned char *intel_pt_last_psb(unsigned char *buf, size_t len)
{
const char *n = INTEL_PT_PSB_STR;
unsigned char *p;
size_t k;
if (len < INTEL_PT_PSB_LEN)
return NULL;
k = len - INTEL_PT_PSB_LEN + 1;
while (1) {
p = memrchr(buf, n[0], k);
if (!p)
return NULL;
if (!memcmp(p + 1, n + 1, INTEL_PT_PSB_LEN - 1))
return p;
k = p - buf;
if (!k)
return NULL;
}
}
/**
* intel_pt_next_tsc - find and return next TSC.
* @buf: buffer
* @len: size of buffer
* @tsc: TSC value returned
* @rem: returns remaining size when TSC is found
*
* Find a TSC packet in @buf and return the TSC value. This function assumes
* that @buf starts at a PSB and that PSB+ will contain TSC and so stops if a
* PSBEND packet is found.
*
* Return: %true if TSC is found, false otherwise.
*/
static bool intel_pt_next_tsc(unsigned char *buf, size_t len, uint64_t *tsc,
size_t *rem)
{
struct intel_pt_pkt packet;
int ret;
while (len) {
ret = intel_pt_get_packet(buf, len, &packet);
if (ret <= 0)
return false;
if (packet.type == INTEL_PT_TSC) {
*tsc = packet.payload;
*rem = len;
return true;
}
if (packet.type == INTEL_PT_PSBEND)
return false;
buf += ret;
len -= ret;
}
return false;
}
/**
* intel_pt_tsc_cmp - compare 7-byte TSCs.
* @tsc1: first TSC to compare
* @tsc2: second TSC to compare
*
* This function compares 7-byte TSC values allowing for the possibility that
* TSC wrapped around. Generally it is not possible to know if TSC has wrapped
* around so for that purpose this function assumes the absolute difference is
* less than half the maximum difference.
*
* Return: %-1 if @tsc1 is before @tsc2, %0 if @tsc1 == @tsc2, %1 if @tsc1 is
* after @tsc2.
*/
static int intel_pt_tsc_cmp(uint64_t tsc1, uint64_t tsc2)
{
const uint64_t halfway = (1ULL << 55);
if (tsc1 == tsc2)
return 0;
if (tsc1 < tsc2) {
if (tsc2 - tsc1 < halfway)
return -1;
else
return 1;
} else {
if (tsc1 - tsc2 < halfway)
return 1;
else
return -1;
}
}
#define MAX_PADDING (PERF_AUXTRACE_RECORD_ALIGNMENT - 1)
/**
* adj_for_padding - adjust overlap to account for padding.
* @buf_b: second buffer
* @buf_a: first buffer
* @len_a: size of first buffer
*
* @buf_a might have up to 7 bytes of padding appended. Adjust the overlap
* accordingly.
*
* Return: A pointer into @buf_b from where non-overlapped data starts
*/
static unsigned char *adj_for_padding(unsigned char *buf_b,
unsigned char *buf_a, size_t len_a)
{
unsigned char *p = buf_b - MAX_PADDING;
unsigned char *q = buf_a + len_a - MAX_PADDING;
int i;
for (i = MAX_PADDING; i; i--, p++, q++) {
if (*p != *q)
break;
}
return p;
}
/**
* intel_pt_find_overlap_tsc - determine start of non-overlapped trace data
* using TSC.
* @buf_a: first buffer
* @len_a: size of first buffer
* @buf_b: second buffer
* @len_b: size of second buffer
* @consecutive: returns true if there is data in buf_b that is consecutive
* to buf_a
*
* If the trace contains TSC we can look at the last TSC of @buf_a and the
* first TSC of @buf_b in order to determine if the buffers overlap, and then
* walk forward in @buf_b until a later TSC is found. A precondition is that
* @buf_a and @buf_b are positioned at a PSB.
*
* Return: A pointer into @buf_b from where non-overlapped data starts, or
* @buf_b + @len_b if there is no non-overlapped data.
*/
static unsigned char *intel_pt_find_overlap_tsc(unsigned char *buf_a,
size_t len_a,
unsigned char *buf_b,
size_t len_b, bool *consecutive)
{
uint64_t tsc_a, tsc_b;
unsigned char *p;
size_t len, rem_a, rem_b;
p = intel_pt_last_psb(buf_a, len_a);
if (!p)
return buf_b; /* No PSB in buf_a => no overlap */
len = len_a - (p - buf_a);
if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a)) {
/* The last PSB+ in buf_a is incomplete, so go back one more */
len_a -= len;
p = intel_pt_last_psb(buf_a, len_a);
if (!p)
return buf_b; /* No full PSB+ => assume no overlap */
len = len_a - (p - buf_a);
if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a))
return buf_b; /* No TSC in buf_a => assume no overlap */
}
while (1) {
/* Ignore PSB+ with no TSC */
if (intel_pt_next_tsc(buf_b, len_b, &tsc_b, &rem_b)) {
int cmp = intel_pt_tsc_cmp(tsc_a, tsc_b);
/* Same TSC, so buffers are consecutive */
if (!cmp && rem_b >= rem_a) {
unsigned char *start;
*consecutive = true;
start = buf_b + len_b - (rem_b - rem_a);
return adj_for_padding(start, buf_a, len_a);
}
if (cmp < 0)
return buf_b; /* tsc_a < tsc_b => no overlap */
}
if (!intel_pt_step_psb(&buf_b, &len_b))
return buf_b + len_b; /* No PSB in buf_b => no data */
}
}
/**
* intel_pt_find_overlap - determine start of non-overlapped trace data.
* @buf_a: first buffer
* @len_a: size of first buffer
* @buf_b: second buffer
* @len_b: size of second buffer
* @have_tsc: can use TSC packets to detect overlap
* @consecutive: returns true if there is data in buf_b that is consecutive
* to buf_a
*
* When trace samples or snapshots are recorded there is the possibility that
* the data overlaps. Note that, for the purposes of decoding, data is only
* useful if it begins with a PSB packet.
*
* Return: A pointer into @buf_b from where non-overlapped data starts, or
* @buf_b + @len_b if there is no non-overlapped data.
*/
unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a,
unsigned char *buf_b, size_t len_b,
bool have_tsc, bool *consecutive)
{
unsigned char *found;
/* Buffer 'b' must start at PSB so throw away everything before that */
if (!intel_pt_next_psb(&buf_b, &len_b))
return buf_b + len_b; /* No PSB */
if (!intel_pt_next_psb(&buf_a, &len_a))
return buf_b; /* No overlap */
if (have_tsc) {
found = intel_pt_find_overlap_tsc(buf_a, len_a, buf_b, len_b,
consecutive);
if (found)
return found;
}
/*
* Buffer 'b' cannot end within buffer 'a' so, for comparison purposes,
* we can ignore the first part of buffer 'a'.
*/
while (len_b < len_a) {
if (!intel_pt_step_psb(&buf_a, &len_a))
return buf_b; /* No overlap */
}
/* Now len_b >= len_a */
while (1) {
/* Potential overlap so check the bytes */
found = memmem(buf_a, len_a, buf_b, len_a);
if (found) {
*consecutive = true;
return adj_for_padding(buf_b + len_a, buf_a, len_a);
}
/* Try again at next PSB in buffer 'a' */
if (!intel_pt_step_psb(&buf_a, &len_a))
return buf_b; /* No overlap */
}
}
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