intel-pt-decoder.c 75.4 KB
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// SPDX-License-Identifier: GPL-2.0-only
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/*
 * intel_pt_decoder.c: Intel Processor Trace support
 * Copyright (c) 2013-2014, Intel Corporation.
 */

#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>
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#include <linux/compiler.h>
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#include "../cache.h"
#include "../util.h"
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#include "../auxtrace.h"
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#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,
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	INTEL_PT_STATE_TNT_CONT,
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	INTEL_PT_STATE_TNT,
	INTEL_PT_STATE_TIP,
	INTEL_PT_STATE_TIP_PGD,
	INTEL_PT_STATE_FUP,
	INTEL_PT_STATE_FUP_NO_TIP,
};

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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:
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	case INTEL_PT_STATE_TNT_CONT:
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		return true;
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	case INTEL_PT_STATE_TNT:
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	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;
	};
}

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#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);
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	bool (*pgd_ip)(uint64_t ip, void *data);
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	int (*lookahead)(void *data, intel_pt_lookahead_cb_t cb, void *cb_data);
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	void *data;
	struct intel_pt_state state;
	const unsigned char *buf;
	size_t len;
	bool return_compression;
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	bool branch_enable;
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	bool mtc_insn;
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	bool pge;
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	bool have_tma;
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	bool have_cyc;
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	bool fixup_last_mtc;
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	bool have_last_ip;
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	bool in_psb;
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	enum intel_pt_param_flags flags;
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	uint64_t pos;
	uint64_t last_ip;
	uint64_t ip;
	uint64_t cr3;
	uint64_t timestamp;
	uint64_t tsc_timestamp;
	uint64_t ref_timestamp;
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	uint64_t buf_timestamp;
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	uint64_t sample_timestamp;
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	uint64_t ret_addr;
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	uint64_t ctc_timestamp;
	uint64_t ctc_delta;
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	uint64_t cycle_cnt;
	uint64_t cyc_ref_timestamp;
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	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;
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	struct intel_pt_stack stack;
	enum intel_pt_pkt_state pkt_state;
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	enum intel_pt_pkt_ctx pkt_ctx;
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	enum intel_pt_pkt_ctx prev_pkt_ctx;
	enum intel_pt_blk_type blk_type;
	int blk_type_pos;
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	struct intel_pt_pkt packet;
	struct intel_pt_pkt tnt;
	int pkt_step;
	int pkt_len;
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	int last_packet_type;
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	unsigned int cbr;
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	unsigned int cbr_seen;
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	unsigned int max_non_turbo_ratio;
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	double max_non_turbo_ratio_fp;
	double cbr_cyc_to_tsc;
	double calc_cyc_to_tsc;
	bool have_calc_cyc_to_tsc;
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	int exec_mode;
	unsigned int insn_bytes;
	uint64_t period;
	enum intel_pt_period_type period_type;
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	uint64_t tot_insn_cnt;
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	uint64_t period_insn_cnt;
	uint64_t period_mask;
	uint64_t period_ticks;
	uint64_t last_masked_timestamp;
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	uint64_t tot_cyc_cnt;
	uint64_t sample_tot_cyc_cnt;
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	uint64_t base_cyc_cnt;
	uint64_t cyc_cnt_timestamp;
	double tsc_to_cyc;
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	bool continuous_period;
	bool overflow;
	bool set_fup_tx_flags;
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	bool set_fup_ptw;
	bool set_fup_mwait;
	bool set_fup_pwre;
	bool set_fup_exstop;
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	bool set_fup_bep;
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	bool sample_cyc;
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	unsigned int fup_tx_flags;
	unsigned int tx_flags;
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	uint64_t fup_ptw_payload;
	uint64_t fup_mwait_payload;
	uint64_t fup_pwre_payload;
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	uint64_t cbr_payload;
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	uint64_t timestamp_insn_cnt;
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	uint64_t sample_insn_cnt;
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	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;
	}
}

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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;
}

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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;
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	decoder->pgd_ip             = params->pgd_ip;
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	decoder->lookahead          = params->lookahead;
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	decoder->data               = params->data;
	decoder->return_compression = params->return_compression;
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	decoder->branch_enable      = params->branch_enable;
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	decoder->flags              = params->flags;

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	decoder->period             = params->period;
	decoder->period_type        = params->period_type;

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	decoder->max_non_turbo_ratio    = params->max_non_turbo_ratio;
	decoder->max_non_turbo_ratio_fp = params->max_non_turbo_ratio;
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	intel_pt_setup_period(decoder);

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	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;
	}
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	/*
	 * 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;
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	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);

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	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)
{
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	if (code < 1 || code >= INTEL_PT_ERR_MAX)
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		code = INTEL_PT_ERR_UNK;
	strlcpy(buf, intel_pt_err_msgs[code], buflen);
	return 0;
}

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static uint64_t intel_pt_calc_ip(const struct intel_pt_pkt *packet,
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				 uint64_t last_ip)
{
	uint64_t ip;

	switch (packet->count) {
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	case 1:
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		ip = (last_ip & (uint64_t)0xffffffffffff0000ULL) |
		     packet->payload;
		break;
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	case 2:
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		ip = (last_ip & (uint64_t)0xffffffff00000000ULL) |
		     packet->payload;
		break;
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	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;
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	case 6:
		ip = packet->payload;
		break;
	default:
		return 0;
	}

	return ip;
}

static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
{
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	decoder->last_ip = intel_pt_calc_ip(&decoder->packet, decoder->last_ip);
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	decoder->have_last_ip = true;
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}

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);
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	decoder->have_tma = false;
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	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;
}

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static inline void intel_pt_update_sample_time(struct intel_pt_decoder *decoder)
{
	decoder->sample_timestamp = decoder->timestamp;
	decoder->sample_insn_cnt = decoder->timestamp_insn_cnt;
}

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static void intel_pt_reposition(struct intel_pt_decoder *decoder)
{
	decoder->ip = 0;
	decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
	decoder->timestamp = 0;
	decoder->have_tma = false;
}

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static int intel_pt_get_data(struct intel_pt_decoder *decoder, bool reposition)
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{
	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;
	}
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	decoder->buf_timestamp = buffer.ref_timestamp;
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	if (!buffer.consecutive || reposition) {
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		intel_pt_reposition(decoder);
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		decoder->ref_timestamp = buffer.ref_timestamp;
		decoder->state.trace_nr = buffer.trace_nr;
		intel_pt_log("Reference timestamp 0x%" PRIx64 "\n",
			     decoder->ref_timestamp);
		return -ENOLINK;
	}

	return 0;
}

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static int intel_pt_get_next_data(struct intel_pt_decoder *decoder,
				  bool reposition)
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{
	if (!decoder->next_buf)
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		return intel_pt_get_data(decoder, reposition);
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	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);

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	ret = intel_pt_get_data(decoder, false);
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	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;

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	decoder->prev_pkt_ctx = decoder->pkt_ctx;
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	ret = intel_pt_get_packet(buf, len, &decoder->packet, &decoder->pkt_ctx);
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	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;
}

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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;
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	enum intel_pt_pkt_ctx pkt_ctx = decoder->pkt_ctx;
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	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;

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			ret = intel_pt_get_packet(buf, len, &pkt_info.packet,
						  &pkt_ctx);
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			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;
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	bool            fixup_last_mtc;
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	bool            from_mtc;
	double          cbr_cyc_to_tsc;
};

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/*
 * 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;
	}
}

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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:
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	case INTEL_PT_PTWRITE:
	case INTEL_PT_PTWRITE_IP:
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	case INTEL_PT_BBP:
	case INTEL_PT_BIP:
	case INTEL_PT_BEP:
	case INTEL_PT_BEP_IP:
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		return 0;

	case INTEL_PT_MTC:
		if (!data->have_tma)
			return 0;

		mtc = pkt_info->packet.payload;
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		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);
		}
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		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:
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		/*
		 * For now, do not support using TSC packets - refer
		 * intel_pt_calc_cyc_to_tsc().
		 */
		if (data->from_mtc)
			return 1;
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		timestamp = pkt_info->packet.payload |
			    (data->timestamp & (0xffULL << 56));
		if (data->from_mtc && timestamp < data->timestamp &&
		    data->timestamp - timestamp < decoder->tsc_slip)
			return 1;
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		if (timestamp < data->timestamp)
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			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;
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		data->fixup_last_mtc = true;
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		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:
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	case INTEL_PT_EXSTOP:
	case INTEL_PT_EXSTOP_IP:
	case INTEL_PT_MWAIT:
	case INTEL_PT_PWRE:
	case INTEL_PT_PWRX:
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	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,
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		.fixup_last_mtc = decoder->fixup_last_mtc,
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		.from_mtc       = from_mtc,
		.cbr_cyc_to_tsc = 0,
	};

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	/*
	 * For now, do not support using TSC packets for at least the reasons:
	 * 1) timing might have stopped
	 * 2) TSC packets within PSB+ can slip against CYC packets
	 */
	if (!from_mtc)
		return;

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	intel_pt_pkt_lookahead(decoder, intel_pt_calc_cyc_cb, &data);
}

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static int intel_pt_get_next_packet(struct intel_pt_decoder *decoder)
{
	int ret;

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	decoder->last_packet_type = decoder->packet.type;

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	do {
		decoder->pos += decoder->pkt_step;
		decoder->buf += decoder->pkt_step;
		decoder->len -= decoder->pkt_step;

		if (!decoder->len) {
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			ret = intel_pt_get_next_data(decoder, false);
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			if (ret)
				return ret;
		}

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		decoder->prev_pkt_ctx = decoder->pkt_ctx;
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		ret = intel_pt_get_packet(decoder->buf, decoder->len,
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					  &decoder->packet, &decoder->pkt_ctx);
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		if (ret == INTEL_PT_NEED_MORE_BYTES && BITS_PER_LONG == 32 &&
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		    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) {
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		if (masked_timestamp > decoder->last_masked_timestamp)
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			return 1;
	} else {
		timestamp += 1;
		masked_timestamp = timestamp & decoder->period_mask;
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		if (masked_timestamp > decoder->last_masked_timestamp) {
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			decoder->last_masked_timestamp = masked_timestamp;
			decoder->continuous_period = true;
		}
	}
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	if (masked_timestamp < decoder->last_masked_timestamp)
		return decoder->period_ticks;

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	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:
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	case INTEL_PT_PERIOD_MTC:
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	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;
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		if (masked_timestamp > decoder->last_masked_timestamp)
			decoder->last_masked_timestamp = masked_timestamp;
		else
			decoder->last_masked_timestamp += decoder->period_ticks;
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		break;
	case INTEL_PT_PERIOD_NONE:
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	case INTEL_PT_PERIOD_MTC:
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	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;

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	if (!decoder->mtc_insn)
		decoder->mtc_insn = true;

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	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);

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	decoder->tot_insn_cnt += insn_cnt;
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	decoder->timestamp_insn_cnt += insn_cnt;
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	decoder->sample_insn_cnt += insn_cnt;
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	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;
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	memcpy(decoder->state.insn, intel_pt_insn->buf,
	       INTEL_PT_INSN_BUF_SZ);
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	if (decoder->tx_flags & INTEL_PT_IN_TX)
		decoder->state.flags |= INTEL_PT_IN_TX;

	return err;
}

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static bool intel_pt_fup_event(struct intel_pt_decoder *decoder)
{
	bool ret = false;

	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 true;
	}
	if (decoder->set_fup_ptw) {
		decoder->set_fup_ptw = false;
		decoder->state.type = INTEL_PT_PTW;
		decoder->state.flags |= INTEL_PT_FUP_IP;
		decoder->state.from_ip = decoder->ip;
		decoder->state.to_ip = 0;
		decoder->state.ptw_payload = decoder->fup_ptw_payload;
		return true;
	}
	if (decoder->set_fup_mwait) {
		decoder->set_fup_mwait = false;
		decoder->state.type = INTEL_PT_MWAIT_OP;
		decoder->state.from_ip = decoder->ip;
		decoder->state.to_ip = 0;
		decoder->state.mwait_payload = decoder->fup_mwait_payload;
		ret = true;
	}
	if (decoder->set_fup_pwre) {
		decoder->set_fup_pwre = false;
		decoder->state.type |= INTEL_PT_PWR_ENTRY;
		decoder->state.type &= ~INTEL_PT_BRANCH;
		decoder->state.from_ip = decoder->ip;
		decoder->state.to_ip = 0;
		decoder->state.pwre_payload = decoder->fup_pwre_payload;
		ret = true;
	}
	if (decoder->set_fup_exstop) {
		decoder->set_fup_exstop = false;
		decoder->state.type |= INTEL_PT_EX_STOP;
		decoder->state.type &= ~INTEL_PT_BRANCH;
		decoder->state.flags |= INTEL_PT_FUP_IP;
		decoder->state.from_ip = decoder->ip;
		decoder->state.to_ip = 0;
		ret = true;
	}
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	if (decoder->set_fup_bep) {
		decoder->set_fup_bep = false;
		decoder->state.type |= INTEL_PT_BLK_ITEMS;
		decoder->state.type &= ~INTEL_PT_BRANCH;
		decoder->state.from_ip = decoder->ip;
		decoder->state.to_ip = 0;
		ret = true;
	}
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	return ret;
}

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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;
}

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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;
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		if (err == -EAGAIN ||
		    intel_pt_fup_with_nlip(decoder, &intel_pt_insn, ip, err)) {
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			if (intel_pt_fup_event(decoder))
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				return 0;
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			return -EAGAIN;
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		}
		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);
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	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;
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		decoder->state.type |= INTEL_PT_TRACE_END;
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		return 0;
	}
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	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;
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			if (decoder->packet.count == 0) {
				decoder->state.to_ip = 0;
			} else {
				decoder->state.to_ip = decoder->last_ip;
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				decoder->ip = decoder->last_ip;
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			}
			decoder->state.type |= INTEL_PT_TRACE_END;
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		} 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) {
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		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;
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			decoder->state.to_ip = to_ip;
			decoder->state.type |= INTEL_PT_TRACE_END;
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			return 0;
		}
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		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;
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			if (decoder->tnt.count)
				decoder->pkt_state = INTEL_PT_STATE_TNT_CONT;
			else
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				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;
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			if (decoder->tnt.count)
				decoder->pkt_state = INTEL_PT_STATE_TNT_CONT;
			else
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				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;
			}
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			decoder->sample_cyc = false;
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			decoder->ip += intel_pt_insn.length;
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			if (!decoder->tnt.count) {
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				intel_pt_update_sample_time(decoder);
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				return -EAGAIN;
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			}
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			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;
}

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static uint64_t intel_pt_8b_tsc(uint64_t timestamp, uint64_t ref_timestamp)
{
	timestamp |= (ref_timestamp & (0xffULL << 56));

	if (timestamp < ref_timestamp) {
		if (ref_timestamp - timestamp > (1ULL << 55))
			timestamp += (1ULL << 56);
	} else {
		if (timestamp - ref_timestamp > (1ULL << 55))
			timestamp -= (1ULL << 56);
	}

	return timestamp;
}

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static void intel_pt_calc_tsc_timestamp(struct intel_pt_decoder *decoder)
{
	uint64_t timestamp;

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	decoder->have_tma = false;

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	if (decoder->ref_timestamp) {
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		timestamp = intel_pt_8b_tsc(decoder->packet.payload,
					    decoder->ref_timestamp);
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		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));
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		decoder->tsc_timestamp = timestamp;
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		if (timestamp < decoder->timestamp &&
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		    decoder->timestamp - timestamp < decoder->tsc_slip) {
			intel_pt_log_to("Suppressing backwards timestamp",
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					timestamp);
			timestamp = decoder->timestamp;
		}
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		if (timestamp < decoder->timestamp) {
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			intel_pt_log_to("Wraparound timestamp", timestamp);
			timestamp += (1ULL << 56);
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			decoder->tsc_timestamp = timestamp;
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		}
		decoder->timestamp = timestamp;
		decoder->timestamp_insn_cnt = 0;
	}

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	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);
	}

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	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);
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	decoder->timestamp_insn_cnt = 0;
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	decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
	decoder->overflow = true;
	return -EOVERFLOW;
}

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static inline void intel_pt_mtc_cyc_cnt_pge(struct intel_pt_decoder *decoder)
{
	if (decoder->have_cyc)
		return;

	decoder->cyc_cnt_timestamp = decoder->timestamp;
	decoder->base_cyc_cnt = decoder->tot_cyc_cnt;
}

static inline void intel_pt_mtc_cyc_cnt_cbr(struct intel_pt_decoder *decoder)
{
	decoder->tsc_to_cyc = decoder->cbr / decoder->max_non_turbo_ratio_fp;

	if (decoder->pge)
		intel_pt_mtc_cyc_cnt_pge(decoder);
}

static inline void intel_pt_mtc_cyc_cnt_upd(struct intel_pt_decoder *decoder)
{
	uint64_t tot_cyc_cnt, tsc_delta;

	if (decoder->have_cyc)
		return;

	decoder->sample_cyc = true;

	if (!decoder->pge || decoder->timestamp <= decoder->cyc_cnt_timestamp)
		return;

	tsc_delta = decoder->timestamp - decoder->cyc_cnt_timestamp;
	tot_cyc_cnt = tsc_delta * decoder->tsc_to_cyc + decoder->base_cyc_cnt;

	if (tot_cyc_cnt > decoder->tot_cyc_cnt)
		decoder->tot_cyc_cnt = tot_cyc_cnt;
}

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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;

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	if (decoder->pge && !decoder->in_psb)
		intel_pt_mtc_cyc_cnt_pge(decoder);
	else
		intel_pt_mtc_cyc_cnt_upd(decoder);

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	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;
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	decoder->fixup_last_mtc = true;
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	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;

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	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);
	}

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	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;

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	intel_pt_mtc_cyc_cnt_upd(decoder);

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	decoder->timestamp_insn_cnt = 0;
	decoder->last_mtc = mtc;
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	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);
	}
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	intel_pt_log_to("Setting timestamp", decoder->timestamp);
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}

static void intel_pt_calc_cbr(struct intel_pt_decoder *decoder)
{
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	unsigned int cbr = decoder->packet.payload & 0xff;
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	decoder->cbr_payload = decoder->packet.payload;

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	if (decoder->cbr == cbr)
		return;

	decoder->cbr = cbr;
	decoder->cbr_cyc_to_tsc = decoder->max_non_turbo_ratio_fp / cbr;
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	intel_pt_mtc_cyc_cnt_cbr(decoder);
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}

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;
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	if (decoder->pge)
		decoder->tot_cyc_cnt += decoder->packet.payload;
	decoder->sample_cyc = true;
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	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;
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	decoder->timestamp_insn_cnt = 0;
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	intel_pt_log_to("Setting timestamp", decoder->timestamp);
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}

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static void intel_pt_bbp(struct intel_pt_decoder *decoder)
{
	if (decoder->prev_pkt_ctx == INTEL_PT_NO_CTX) {
		memset(decoder->state.items.mask, 0, sizeof(decoder->state.items.mask));
		decoder->state.items.is_32_bit = false;
	}
	decoder->blk_type = decoder->packet.payload;
	decoder->blk_type_pos = intel_pt_blk_type_pos(decoder->blk_type);
	if (decoder->blk_type == INTEL_PT_GP_REGS)
		decoder->state.items.is_32_bit = decoder->packet.count;
	if (decoder->blk_type_pos < 0) {
		intel_pt_log("WARNING: Unknown block type %u\n",
			     decoder->blk_type);
	} else if (decoder->state.items.mask[decoder->blk_type_pos]) {
		intel_pt_log("WARNING: Duplicate block type %u\n",
			     decoder->blk_type);
	}
}

static void intel_pt_bip(struct intel_pt_decoder *decoder)
{
	uint32_t id = decoder->packet.count;
	uint32_t bit = 1 << id;
	int pos = decoder->blk_type_pos;

	if (pos < 0 || id >= INTEL_PT_BLK_ITEM_ID_CNT) {
		intel_pt_log("WARNING: Unknown block item %u type %d\n",
			     id, decoder->blk_type);
		return;
	}

	if (decoder->state.items.mask[pos] & bit) {
		intel_pt_log("WARNING: Duplicate block item %u type %d\n",
			     id, decoder->blk_type);
	}

	decoder->state.items.mask[pos] |= bit;
	decoder->state.items.val[pos][id] = decoder->packet.payload;
}

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/* Walk PSB+ packets when already in sync. */
static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder)
{
	int err;

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	decoder->in_psb = true;

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	while (1) {
		err = intel_pt_get_next_packet(decoder);
		if (err)
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			goto out;
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		switch (decoder->packet.type) {
		case INTEL_PT_PSBEND:
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			err = 0;
			goto out;
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		case INTEL_PT_TIP_PGD:
		case INTEL_PT_TIP_PGE:
		case INTEL_PT_TIP:
		case INTEL_PT_TNT:
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		case INTEL_PT_TRACESTOP:
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		case INTEL_PT_BAD:
		case INTEL_PT_PSB:
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		case INTEL_PT_PTWRITE:
		case INTEL_PT_PTWRITE_IP:
		case INTEL_PT_EXSTOP:
		case INTEL_PT_EXSTOP_IP:
		case INTEL_PT_MWAIT:
		case INTEL_PT_PWRE:
		case INTEL_PT_PWRX:
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		case INTEL_PT_BBP:
		case INTEL_PT_BIP:
		case INTEL_PT_BEP:
		case INTEL_PT_BEP_IP:
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			decoder->have_tma = false;
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			intel_pt_log("ERROR: Unexpected packet\n");
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			err = -EAGAIN;
			goto out;
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		case INTEL_PT_OVF:
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			err = intel_pt_overflow(decoder);
			goto out;
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		case INTEL_PT_TSC:
			intel_pt_calc_tsc_timestamp(decoder);
			break;

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		case INTEL_PT_TMA:
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			intel_pt_calc_tma(decoder);
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			break;

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		case INTEL_PT_CBR:
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			intel_pt_calc_cbr(decoder);
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			break;

		case INTEL_PT_MODE_EXEC:
			decoder->exec_mode = decoder->packet.payload;
			break;

		case INTEL_PT_PIP:
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			decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
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			break;

		case INTEL_PT_FUP:
			decoder->pge = true;
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			if (decoder->packet.count)
				intel_pt_set_last_ip(decoder);
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			break;

		case INTEL_PT_MODE_TSX:
			intel_pt_update_in_tx(decoder);
			break;

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		case INTEL_PT_MTC:
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			intel_pt_calc_mtc_timestamp(decoder);
			if (decoder->period_type == INTEL_PT_PERIOD_MTC)
				decoder->state.type |= INTEL_PT_INSTRUCTION;
1744 1745 1746 1747 1748
			break;

		case INTEL_PT_CYC:
		case INTEL_PT_VMCS:
		case INTEL_PT_MNT:
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		case INTEL_PT_PAD:
		default:
			break;
		}
	}
1754 1755 1756 1757
out:
	decoder->in_psb = false;

	return err;
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}

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:
1780
		case INTEL_PT_TRACESTOP:
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		case INTEL_PT_PSB:
		case INTEL_PT_TSC:
1783
		case INTEL_PT_TMA:
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		case INTEL_PT_MODE_TSX:
		case INTEL_PT_BAD:
		case INTEL_PT_PSBEND:
1787 1788 1789 1790 1791 1792 1793
		case INTEL_PT_PTWRITE:
		case INTEL_PT_PTWRITE_IP:
		case INTEL_PT_EXSTOP:
		case INTEL_PT_EXSTOP_IP:
		case INTEL_PT_MWAIT:
		case INTEL_PT_PWRE:
		case INTEL_PT_PWRX:
1794 1795 1796 1797
		case INTEL_PT_BBP:
		case INTEL_PT_BIP:
		case INTEL_PT_BEP:
		case INTEL_PT_BEP_IP:
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			intel_pt_log("ERROR: Missing TIP after FUP\n");
			decoder->pkt_state = INTEL_PT_STATE_ERR3;
1800
			decoder->pkt_step = 0;
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			return -ENOENT;

1803 1804 1805 1806
		case INTEL_PT_CBR:
			intel_pt_calc_cbr(decoder);
			break;

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		case INTEL_PT_OVF:
			return intel_pt_overflow(decoder);

		case INTEL_PT_TIP_PGD:
			decoder->state.from_ip = decoder->ip;
1812 1813 1814
			if (decoder->packet.count == 0) {
				decoder->state.to_ip = 0;
			} else {
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				intel_pt_set_ip(decoder);
1816
				decoder->state.to_ip = decoder->ip;
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			}
			decoder->pge = false;
			decoder->continuous_period = false;
1820
			decoder->state.type |= INTEL_PT_TRACE_END;
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			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;
			}
1834
			decoder->state.type |= INTEL_PT_TRACE_BEGIN;
1835
			intel_pt_mtc_cyc_cnt_pge(decoder);
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			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:
1849 1850 1851 1852
			decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
			break;

		case INTEL_PT_MTC:
1853 1854 1855
			intel_pt_calc_mtc_timestamp(decoder);
			if (decoder->period_type == INTEL_PT_PERIOD_MTC)
				decoder->state.type |= INTEL_PT_INSTRUCTION;
1856 1857 1858
			break;

		case INTEL_PT_CYC:
1859
			intel_pt_calc_cyc_timestamp(decoder);
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			break;

		case INTEL_PT_MODE_EXEC:
			decoder->exec_mode = decoder->packet.payload;
			break;

1866 1867
		case INTEL_PT_VMCS:
		case INTEL_PT_MNT:
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		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;
1906
			intel_pt_mtc_cyc_cnt_pge(decoder);
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			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;
1915
			decoder->state.type |= INTEL_PT_TRACE_BEGIN;
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			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);
1936 1937
			if (!decoder->branch_enable) {
				decoder->ip = decoder->last_ip;
1938 1939 1940
				if (intel_pt_fup_event(decoder))
					return 0;
				no_tip = false;
1941 1942
				break;
			}
1943 1944
			if (decoder->set_fup_mwait)
				no_tip = true;
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			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);

1962
		case INTEL_PT_TRACESTOP:
1963 1964 1965 1966
			decoder->pge = false;
			decoder->continuous_period = false;
			intel_pt_clear_tx_flags(decoder);
			decoder->have_tma = false;
1967 1968
			break;

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		case INTEL_PT_PSB:
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			decoder->last_ip = 0;
			decoder->have_last_ip = true;
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			intel_pt_clear_stack(&decoder->stack);
			err = intel_pt_walk_psbend(decoder);
			if (err == -EAGAIN)
				goto next;
			if (err)
				return err;
1978 1979 1980 1981 1982 1983 1984
			/*
			 * PSB+ CBR will not have changed but cater for the
			 * possibility of another CBR change that gets caught up
			 * in the PSB+.
			 */
			if (decoder->cbr != decoder->cbr_seen)
				return 0;
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			break;

		case INTEL_PT_PIP:
1988 1989 1990 1991
			decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
			break;

		case INTEL_PT_MTC:
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
			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;
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		case INTEL_PT_TSC:
			intel_pt_calc_tsc_timestamp(decoder);
			break;

2015
		case INTEL_PT_TMA:
2016
			intel_pt_calc_tma(decoder);
2017 2018 2019
			break;

		case INTEL_PT_CYC:
2020
			intel_pt_calc_cyc_timestamp(decoder);
2021 2022
			break;

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		case INTEL_PT_CBR:
2024
			intel_pt_calc_cbr(decoder);
2025
			if (decoder->cbr != decoder->cbr_seen)
2026
				return 0;
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			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:
2048 2049
		case INTEL_PT_VMCS:
		case INTEL_PT_MNT:
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		case INTEL_PT_PAD:
			break;

2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117
		case INTEL_PT_PTWRITE_IP:
			decoder->fup_ptw_payload = decoder->packet.payload;
			err = intel_pt_get_next_packet(decoder);
			if (err)
				return err;
			if (decoder->packet.type == INTEL_PT_FUP) {
				decoder->set_fup_ptw = true;
				no_tip = true;
			} else {
				intel_pt_log_at("ERROR: Missing FUP after PTWRITE",
						decoder->pos);
			}
			goto next;

		case INTEL_PT_PTWRITE:
			decoder->state.type = INTEL_PT_PTW;
			decoder->state.from_ip = decoder->ip;
			decoder->state.to_ip = 0;
			decoder->state.ptw_payload = decoder->packet.payload;
			return 0;

		case INTEL_PT_MWAIT:
			decoder->fup_mwait_payload = decoder->packet.payload;
			decoder->set_fup_mwait = true;
			break;

		case INTEL_PT_PWRE:
			if (decoder->set_fup_mwait) {
				decoder->fup_pwre_payload =
							decoder->packet.payload;
				decoder->set_fup_pwre = true;
				break;
			}
			decoder->state.type = INTEL_PT_PWR_ENTRY;
			decoder->state.from_ip = decoder->ip;
			decoder->state.to_ip = 0;
			decoder->state.pwrx_payload = decoder->packet.payload;
			return 0;

		case INTEL_PT_EXSTOP_IP:
			err = intel_pt_get_next_packet(decoder);
			if (err)
				return err;
			if (decoder->packet.type == INTEL_PT_FUP) {
				decoder->set_fup_exstop = true;
				no_tip = true;
			} else {
				intel_pt_log_at("ERROR: Missing FUP after EXSTOP",
						decoder->pos);
			}
			goto next;

		case INTEL_PT_EXSTOP:
			decoder->state.type = INTEL_PT_EX_STOP;
			decoder->state.from_ip = decoder->ip;
			decoder->state.to_ip = 0;
			return 0;

		case INTEL_PT_PWRX:
			decoder->state.type = INTEL_PT_PWR_EXIT;
			decoder->state.from_ip = decoder->ip;
			decoder->state.to_ip = 0;
			decoder->state.pwrx_payload = decoder->packet.payload;
			return 0;

2118
		case INTEL_PT_BBP:
2119 2120 2121
			intel_pt_bbp(decoder);
			break;

2122
		case INTEL_PT_BIP:
2123 2124 2125
			intel_pt_bip(decoder);
			break;

2126
		case INTEL_PT_BEP:
2127 2128 2129 2130 2131
			decoder->state.type = INTEL_PT_BLK_ITEMS;
			decoder->state.from_ip = decoder->ip;
			decoder->state.to_ip = 0;
			return 0;

2132
		case INTEL_PT_BEP_IP:
2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143
			err = intel_pt_get_next_packet(decoder);
			if (err)
				return err;
			if (decoder->packet.type == INTEL_PT_FUP) {
				decoder->set_fup_bep = true;
				no_tip = true;
			} else {
				intel_pt_log_at("ERROR: Missing FUP after BEP",
						decoder->pos);
			}
			goto next;
2144

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		default:
			return intel_pt_bug(decoder);
		}
	}
}

2151 2152
static inline bool intel_pt_have_ip(struct intel_pt_decoder *decoder)
{
2153 2154 2155
	return decoder->packet.count &&
	       (decoder->have_last_ip || decoder->packet.count == 3 ||
		decoder->packet.count == 6);
2156 2157
}

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/* Walk PSB+ packets to get in sync. */
static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)
{
	int err;

2163 2164
	decoder->in_psb = true;

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	while (1) {
		err = intel_pt_get_next_packet(decoder);
		if (err)
2168
			goto out;
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		switch (decoder->packet.type) {
		case INTEL_PT_TIP_PGD:
			decoder->continuous_period = false;
2173
			__fallthrough;
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		case INTEL_PT_TIP_PGE:
		case INTEL_PT_TIP:
2176 2177 2178 2179 2180 2181 2182
		case INTEL_PT_PTWRITE:
		case INTEL_PT_PTWRITE_IP:
		case INTEL_PT_EXSTOP:
		case INTEL_PT_EXSTOP_IP:
		case INTEL_PT_MWAIT:
		case INTEL_PT_PWRE:
		case INTEL_PT_PWRX:
2183 2184 2185 2186
		case INTEL_PT_BBP:
		case INTEL_PT_BIP:
		case INTEL_PT_BEP:
		case INTEL_PT_BEP_IP:
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			intel_pt_log("ERROR: Unexpected packet\n");
2188 2189
			err = -ENOENT;
			goto out;
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		case INTEL_PT_FUP:
			decoder->pge = true;
2193
			if (intel_pt_have_ip(decoder)) {
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				uint64_t current_ip = decoder->ip;

				intel_pt_set_ip(decoder);
				if (current_ip)
					intel_pt_log_to("Setting IP",
							decoder->ip);
			}
			break;

2203
		case INTEL_PT_MTC:
2204
			intel_pt_calc_mtc_timestamp(decoder);
2205 2206
			break;

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		case INTEL_PT_TSC:
			intel_pt_calc_tsc_timestamp(decoder);
			break;

2211
		case INTEL_PT_TMA:
2212
			intel_pt_calc_tma(decoder);
2213 2214 2215
			break;

		case INTEL_PT_CYC:
2216
			intel_pt_calc_cyc_timestamp(decoder);
2217 2218
			break;

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		case INTEL_PT_CBR:
2220
			intel_pt_calc_cbr(decoder);
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			break;

		case INTEL_PT_PIP:
2224
			decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
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			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;

2235
		case INTEL_PT_TRACESTOP:
2236 2237 2238
			decoder->pge = false;
			decoder->continuous_period = false;
			intel_pt_clear_tx_flags(decoder);
2239 2240
			__fallthrough;

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		case INTEL_PT_TNT:
2242
			decoder->have_tma = false;
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			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;
2248 2249
			err = -ENOENT;
			goto out;
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		case INTEL_PT_BAD: /* Does not happen */
2252 2253
			err = intel_pt_bug(decoder);
			goto out;
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		case INTEL_PT_OVF:
2256 2257
			err = intel_pt_overflow(decoder);
			goto out;
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		case INTEL_PT_PSBEND:
2260 2261
			err = 0;
			goto out;
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		case INTEL_PT_PSB:
2264 2265
		case INTEL_PT_VMCS:
		case INTEL_PT_MNT:
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		case INTEL_PT_PAD:
		default:
			break;
		}
	}
2271 2272 2273 2274
out:
	decoder->in_psb = false;

	return err;
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}

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;
2289 2290 2291 2292 2293 2294 2295 2296
			decoder->pge = false;
			if (intel_pt_have_ip(decoder))
				intel_pt_set_ip(decoder);
			if (!decoder->ip)
				break;
			decoder->state.type |= INTEL_PT_TRACE_END;
			return 0;

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		case INTEL_PT_TIP_PGE:
2298
			decoder->pge = true;
2299
			intel_pt_mtc_cyc_cnt_pge(decoder);
2300 2301 2302 2303 2304 2305 2306
			if (intel_pt_have_ip(decoder))
				intel_pt_set_ip(decoder);
			if (!decoder->ip)
				break;
			decoder->state.type |= INTEL_PT_TRACE_BEGIN;
			return 0;

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		case INTEL_PT_TIP:
2308
			decoder->pge = true;
2309
			if (intel_pt_have_ip(decoder))
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				intel_pt_set_ip(decoder);
2311 2312 2313
			if (!decoder->ip)
				break;
			return 0;
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2314 2315

		case INTEL_PT_FUP:
2316 2317 2318 2319
			if (intel_pt_have_ip(decoder))
				intel_pt_set_ip(decoder);
			if (decoder->ip)
				return 0;
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			break;

2322
		case INTEL_PT_MTC:
2323
			intel_pt_calc_mtc_timestamp(decoder);
2324 2325
			break;

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		case INTEL_PT_TSC:
			intel_pt_calc_tsc_timestamp(decoder);
			break;

2330
		case INTEL_PT_TMA:
2331
			intel_pt_calc_tma(decoder);
2332 2333 2334
			break;

		case INTEL_PT_CYC:
2335
			intel_pt_calc_cyc_timestamp(decoder);
2336 2337
			break;

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		case INTEL_PT_CBR:
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			intel_pt_calc_cbr(decoder);
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			break;

		case INTEL_PT_PIP:
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			decoder->cr3 = decoder->packet.payload & (BIT63 - 1);
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			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);

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		case INTEL_PT_TRACESTOP:
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			decoder->pge = false;
			decoder->continuous_period = false;
			intel_pt_clear_tx_flags(decoder);
			decoder->have_tma = false;
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			break;

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		case INTEL_PT_PSB:
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			decoder->last_ip = 0;
			decoder->have_last_ip = true;
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			intel_pt_clear_stack(&decoder->stack);
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			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:
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		case INTEL_PT_VMCS:
		case INTEL_PT_MNT:
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		case INTEL_PT_PAD:
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		case INTEL_PT_PTWRITE:
		case INTEL_PT_PTWRITE_IP:
		case INTEL_PT_EXSTOP:
		case INTEL_PT_EXSTOP_IP:
		case INTEL_PT_MWAIT:
		case INTEL_PT_PWRE:
		case INTEL_PT_PWRX:
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		case INTEL_PT_BBP:
		case INTEL_PT_BIP:
		case INTEL_PT_BEP:
		case INTEL_PT_BEP_IP:
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		default:
			break;
		}
	}
}

static int intel_pt_sync_ip(struct intel_pt_decoder *decoder)
{
	int err;

2407
	decoder->set_fup_tx_flags = false;
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	decoder->set_fup_ptw = false;
	decoder->set_fup_mwait = false;
	decoder->set_fup_pwre = false;
	decoder->set_fup_exstop = false;
2412
	decoder->set_fup_bep = false;
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	if (!decoder->branch_enable) {
		decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
		decoder->overflow = false;
		decoder->state.type = 0; /* Do not have a sample */
		return 0;
	}

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	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;

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	ret = intel_pt_get_next_data(decoder, false);
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	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) {
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			ret = intel_pt_get_next_data(decoder, false);
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			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;
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	decoder->have_last_ip = false;
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	decoder->last_ip = 0;
	decoder->ip = 0;
	intel_pt_clear_stack(&decoder->stack);

	err = intel_pt_scan_for_psb(decoder);
	if (err)
		return err;

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	decoder->have_last_ip = true;
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	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)
{
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	uint64_t est = decoder->sample_insn_cnt << 1;
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	if (!decoder->cbr || !decoder->max_non_turbo_ratio)
		goto out;

	est *= decoder->max_non_turbo_ratio;
	est /= decoder->cbr;
out:
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	return decoder->sample_timestamp + est;
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}

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:
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			decoder->have_last_ip = false;
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			decoder->last_ip = 0;
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			decoder->ip = 0;
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			__fallthrough;
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		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:
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		case INTEL_PT_STATE_TNT_CONT:
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			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);

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	if (err) {
		decoder->state.err = intel_pt_ext_err(err);
		decoder->state.from_ip = decoder->ip;
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		intel_pt_update_sample_time(decoder);
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		decoder->sample_tot_cyc_cnt = decoder->tot_cyc_cnt;
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	} else {
		decoder->state.err = 0;
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		if (decoder->cbr != decoder->cbr_seen) {
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			decoder->cbr_seen = decoder->cbr;
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			if (!decoder->state.type) {
				decoder->state.from_ip = decoder->ip;
				decoder->state.to_ip = 0;
			}
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			decoder->state.type |= INTEL_PT_CBR_CHG;
			decoder->state.cbr_payload = decoder->cbr_payload;
		}
2637
		if (intel_pt_sample_time(decoder->pkt_state)) {
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			intel_pt_update_sample_time(decoder);
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			if (decoder->sample_cyc)
				decoder->sample_tot_cyc_cnt = decoder->tot_cyc_cnt;
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		}
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	}

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	decoder->state.timestamp = decoder->sample_timestamp;
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	decoder->state.est_timestamp = intel_pt_est_timestamp(decoder);
	decoder->state.cr3 = decoder->cr3;
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	decoder->state.tot_insn_cnt = decoder->tot_insn_cnt;
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	decoder->state.tot_cyc_cnt = decoder->sample_tot_cyc_cnt;
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	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
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 * @rem: returns remaining size when TSC is found
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 *
 * 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.
 */
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static bool intel_pt_next_tsc(unsigned char *buf, size_t len, uint64_t *tsc,
			      size_t *rem)
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{
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	enum intel_pt_pkt_ctx ctx = INTEL_PT_NO_CTX;
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	struct intel_pt_pkt packet;
	int ret;

	while (len) {
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		ret = intel_pt_get_packet(buf, len, &packet, &ctx);
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		if (ret <= 0)
			return false;
		if (packet.type == INTEL_PT_TSC) {
			*tsc = packet.payload;
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			*rem = len;
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			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;
	}
}

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#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;
}

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/**
 * 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
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 * @consecutive: returns true if there is data in buf_b that is consecutive
 *               to buf_a
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 *
 * 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,
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						size_t len_b, bool *consecutive)
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{
	uint64_t tsc_a, tsc_b;
	unsigned char *p;
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	size_t len, rem_a, rem_b;
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	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);
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	if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a)) {
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		/* 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);
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		if (!intel_pt_next_tsc(p, len, &tsc_a, &rem_a))
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			return buf_b; /* No TSC in buf_a => assume no overlap */
	}

	while (1) {
		/* Ignore PSB+ with no TSC */
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		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) {
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				unsigned char *start;

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				*consecutive = true;
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				start = buf_b + len_b - (rem_b - rem_a);
				return adj_for_padding(start, buf_a, len_a);
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			}
			if (cmp < 0)
				return buf_b; /* tsc_a < tsc_b => no overlap */
		}
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		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
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 * @consecutive: returns true if there is data in buf_b that is consecutive
 *               to buf_a
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 *
 * 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,
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				     bool have_tsc, bool *consecutive)
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{
	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) {
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		found = intel_pt_find_overlap_tsc(buf_a, len_a, buf_b, len_b,
						  consecutive);
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		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);
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		if (found) {
			*consecutive = true;
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			return adj_for_padding(buf_b + len_a, buf_a, len_a);
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		}
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		/* 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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/**
 * struct fast_forward_data - data used by intel_pt_ff_cb().
 * @timestamp: timestamp to fast forward towards
 * @buf_timestamp: buffer timestamp of last buffer with trace data earlier than
 *                 the fast forward timestamp.
 */
struct fast_forward_data {
	uint64_t timestamp;
	uint64_t buf_timestamp;
};

/**
 * intel_pt_ff_cb - fast forward lookahead callback.
 * @buffer: Intel PT trace buffer
 * @data: opaque pointer to fast forward data (struct fast_forward_data)
 *
 * Determine if @buffer trace is past the fast forward timestamp.
 *
 * Return: 1 (stop lookahead) if @buffer trace is past the fast forward
 *         timestamp, and 0 otherwise.
 */
static int intel_pt_ff_cb(struct intel_pt_buffer *buffer, void *data)
{
	struct fast_forward_data *d = data;
	unsigned char *buf;
	uint64_t tsc;
	size_t rem;
	size_t len;

	buf = (unsigned char *)buffer->buf;
	len = buffer->len;

	if (!intel_pt_next_psb(&buf, &len) ||
	    !intel_pt_next_tsc(buf, len, &tsc, &rem))
		return 0;

	tsc = intel_pt_8b_tsc(tsc, buffer->ref_timestamp);

	intel_pt_log("Buffer 1st timestamp " x64_fmt " ref timestamp " x64_fmt "\n",
		     tsc, buffer->ref_timestamp);

	/*
	 * If the buffer contains a timestamp earlier that the fast forward
	 * timestamp, then record it, else stop.
	 */
	if (tsc < d->timestamp)
		d->buf_timestamp = buffer->ref_timestamp;
	else
		return 1;

	return 0;
}

/**
 * intel_pt_fast_forward - reposition decoder forwards.
 * @decoder: Intel PT decoder
 * @timestamp: timestamp to fast forward towards
 *
 * Reposition decoder at the last PSB with a timestamp earlier than @timestamp.
 *
 * Return: 0 on success or negative error code on failure.
 */
int intel_pt_fast_forward(struct intel_pt_decoder *decoder, uint64_t timestamp)
{
	struct fast_forward_data d = { .timestamp = timestamp };
	unsigned char *buf;
	size_t len;
	int err;

	intel_pt_log("Fast forward towards timestamp " x64_fmt "\n", timestamp);

	/* Find buffer timestamp of buffer to fast forward to */
	err = decoder->lookahead(decoder->data, intel_pt_ff_cb, &d);
	if (err < 0)
		return err;

	/* Walk to buffer with same buffer timestamp */
	if (d.buf_timestamp) {
		do {
			decoder->pos += decoder->len;
			decoder->len = 0;
			err = intel_pt_get_next_data(decoder, true);
			/* -ENOLINK means non-consecutive trace */
			if (err && err != -ENOLINK)
				return err;
		} while (decoder->buf_timestamp != d.buf_timestamp);
	}

	if (!decoder->buf)
		return 0;

	buf = (unsigned char *)decoder->buf;
	len = decoder->len;

	if (!intel_pt_next_psb(&buf, &len))
		return 0;

	/*
	 * Walk PSBs while the PSB timestamp is less than the fast forward
	 * timestamp.
	 */
	do {
		uint64_t tsc;
		size_t rem;

		if (!intel_pt_next_tsc(buf, len, &tsc, &rem))
			break;
		tsc = intel_pt_8b_tsc(tsc, decoder->buf_timestamp);
		/*
		 * A TSC packet can slip past MTC packets but, after fast
		 * forward, decoding starts at the TSC timestamp. That means
		 * the timestamps may not be exactly the same as the timestamps
		 * that would have been decoded without fast forward.
		 */
		if (tsc < timestamp) {
			intel_pt_log("Fast forward to next PSB timestamp " x64_fmt "\n", tsc);
			decoder->pos += decoder->len - len;
			decoder->buf = buf;
			decoder->len = len;
			intel_pt_reposition(decoder);
		} else {
			break;
		}
	} while (intel_pt_step_psb(&buf, &len));

	return 0;
}