[PATCH V6 07/17] perf tools: Add Intel PT decoder

[Adrian Hunter]

Add support for decoding an Intel Processor Trace.

Intel PT trace data must be 'decoded' which involves walking
the object code and matching the trace data packets.

The decoder requests a buffer of binary data via a get_trace()
call-back, which it decodes using instruction information which
it gets via another call-back walk_insn().

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 tools/perf/util/intel-pt-decoder/Build             |    2 +-
 .../perf/util/intel-pt-decoder/intel-pt-decoder.c  | 1759 ++++++++++++++++++++
 .../perf/util/intel-pt-decoder/intel-pt-decoder.h  |  102 ++
 3 files changed, 1862 insertions(+), 1 deletion(-)
 create mode 100644 tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
 create mode 100644 tools/perf/util/intel-pt-decoder/intel-pt-decoder.h

diff --git a/tools/perf/util/intel-pt-decoder/Build b/tools/perf/util/intel-pt-decoder/Build
index 587321a..fa12eac 100644
--- a/tools/perf/util/intel-pt-decoder/Build
+++ b/tools/perf/util/intel-pt-decoder/Build
@@ -1,4 +1,4 @@
-libperf-$(CONFIG_AUXTRACE) += intel-pt-pkt-decoder.o intel-pt-insn-decoder.o intel-pt-log.o
+libperf-$(CONFIG_AUXTRACE) += intel-pt-pkt-decoder.o intel-pt-insn-decoder.o intel-pt-log.o intel-pt-decoder.o
 
 inat_tables_script = ../../arch/x86/tools/gen-insn-attr-x86.awk
 inat_tables_maps = ../../arch/x86/lib/x86-opcode-map.txt
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
new file mode 100644
index 0000000..748a7a0
--- /dev/null
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.c
@@ -0,0 +1,1759 @@
+/*
+ * intel_pt_decoder.c: Intel Processor Trace support
+ * Copyright (c) 2013-2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <errno.h>
+#include <stdint.h>
+#include <inttypes.h>
+
+#include "../cache.h"
+#include "../util.h"
+
+#include "intel-pt-insn-decoder.h"
+#include "intel-pt-pkt-decoder.h"
+#include "intel-pt-decoder.h"
+#include "intel-pt-log.h"
+
+#define INTEL_PT_BLK_SIZE 1024
+
+#define BIT63 (((uint64_t)1 << 63))
+
+#define INTEL_PT_RETURN 1
+
+struct intel_pt_blk {
+	struct intel_pt_blk *prev;
+	uint64_t ip[INTEL_PT_BLK_SIZE];
+};
+
+struct intel_pt_stack {
+	struct intel_pt_blk *blk;
+	struct intel_pt_blk *spare;
+	int pos;
+};
+
+enum intel_pt_pkt_state {
+	INTEL_PT_STATE_NO_PSB,
+	INTEL_PT_STATE_NO_IP,
+	INTEL_PT_STATE_ERR_RESYNC,
+	INTEL_PT_STATE_IN_SYNC,
+	INTEL_PT_STATE_TNT,
+	INTEL_PT_STATE_TIP,
+	INTEL_PT_STATE_TIP_PGD,
+	INTEL_PT_STATE_FUP,
+	INTEL_PT_STATE_FUP_NO_TIP,
+};
+
+#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);
+	void *data;
+	struct intel_pt_state state;
+	const unsigned char *buf;
+	size_t len;
+	bool return_compression;
+	bool pge;
+	uint64_t pos;
+	uint64_t last_ip;
+	uint64_t ip;
+	uint64_t cr3;
+	uint64_t timestamp;
+	uint64_t tsc_timestamp;
+	uint64_t ref_timestamp;
+	uint64_t ret_addr;
+	struct intel_pt_stack stack;
+	enum intel_pt_pkt_state pkt_state;
+	struct intel_pt_pkt packet;
+	struct intel_pt_pkt tnt;
+	int pkt_step;
+	int pkt_len;
+	unsigned int cbr;
+	int exec_mode;
+	unsigned int insn_bytes;
+	uint64_t sign_bit;
+	uint64_t sign_bits;
+	uint64_t period;
+	enum intel_pt_period_type period_type;
+	uint64_t period_insn_cnt;
+	uint64_t period_mask;
+	uint64_t period_ticks;
+	uint64_t last_masked_timestamp;
+	bool continuous_period;
+	bool overflow;
+	bool set_fup_tx_flags;
+	unsigned int fup_tx_flags;
+	unsigned int tx_flags;
+	uint64_t timestamp_insn_cnt;
+	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;
+	}
+}
+
+struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params)
+{
+	struct intel_pt_decoder *decoder;
+
+	if (!params->get_trace || !params->walk_insn)
+		return NULL;
+
+	decoder = zalloc(sizeof(struct intel_pt_decoder));
+	if (!decoder)
+		return NULL;
+
+	decoder->get_trace          = params->get_trace;
+	decoder->walk_insn          = params->walk_insn;
+	decoder->data               = params->data;
+	decoder->return_compression = params->return_compression;
+
+	decoder->sign_bit           = (uint64_t)1 << 47;
+	decoder->sign_bits          = ~(((uint64_t)1 << 48) - 1);
+
+	decoder->period             = params->period;
+	decoder->period_type        = params->period_type;
+
+	intel_pt_setup_period(decoder);
+
+	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;
+	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!",
+};
+
+int intel_pt__strerror(int code, char *buf, size_t buflen)
+{
+	if (code < 1 || code > INTEL_PT_ERR_MAX)
+		code = INTEL_PT_ERR_UNK;
+	strlcpy(buf, intel_pt_err_msgs[code], buflen);
+	return 0;
+}
+
+static uint64_t intel_pt_calc_ip(struct intel_pt_decoder *decoder,
+				 const struct intel_pt_pkt *packet,
+				 uint64_t last_ip)
+{
+	uint64_t ip;
+
+	switch (packet->count) {
+	case 2:
+		ip = (last_ip & (uint64_t)0xffffffffffff0000ULL) |
+		     packet->payload;
+		break;
+	case 4:
+		ip = (last_ip & (uint64_t)0xffffffff00000000ULL) |
+		     packet->payload;
+		break;
+	case 6:
+		ip = packet->payload;
+		break;
+	default:
+		return 0;
+	}
+
+	if (ip & decoder->sign_bit)
+		return ip | decoder->sign_bits;
+
+	return ip;
+}
+
+static inline void intel_pt_set_last_ip(struct intel_pt_decoder *decoder)
+{
+	decoder->last_ip = intel_pt_calc_ip(decoder, &decoder->packet,
+					    decoder->last_ip);
+}
+
+static inline void intel_pt_set_ip(struct intel_pt_decoder *decoder)
+{
+	intel_pt_set_last_ip(decoder);
+	decoder->ip = decoder->last_ip;
+}
+
+static void intel_pt_decoder_log_packet(struct intel_pt_decoder *decoder)
+{
+	intel_pt_log_packet(&decoder->packet, decoder->pkt_len, decoder->pos,
+			    decoder->buf);
+}
+
+static int intel_pt_bug(struct intel_pt_decoder *decoder)
+{
+	intel_pt_log("ERROR: Internal error\n");
+	decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
+	return -ENOSYS;
+}
+
+static inline void intel_pt_clear_tx_flags(struct intel_pt_decoder *decoder)
+{
+	decoder->tx_flags = 0;
+}
+
+static inline void intel_pt_update_in_tx(struct intel_pt_decoder *decoder)
+{
+	decoder->tx_flags = decoder->packet.payload & INTEL_PT_IN_TX;
+}
+
+static int intel_pt_bad_packet(struct intel_pt_decoder *decoder)
+{
+	intel_pt_clear_tx_flags(decoder);
+	decoder->pkt_len = 1;
+	decoder->pkt_step = 1;
+	intel_pt_decoder_log_packet(decoder);
+	if (decoder->pkt_state != INTEL_PT_STATE_NO_PSB) {
+		intel_pt_log("ERROR: Bad packet\n");
+		decoder->pkt_state = INTEL_PT_STATE_ERR1;
+	}
+	return -EBADMSG;
+}
+
+static int intel_pt_get_data(struct intel_pt_decoder *decoder)
+{
+	struct intel_pt_buffer buffer = { .buf = 0, };
+	int ret;
+
+	decoder->pkt_step = 0;
+
+	intel_pt_log("Getting more data\n");
+	ret = decoder->get_trace(&buffer, decoder->data);
+	if (ret)
+		return ret;
+	decoder->buf = buffer.buf;
+	decoder->len = buffer.len;
+	if (!decoder->len) {
+		intel_pt_log("No more data\n");
+		return -ENODATA;
+	}
+	if (!buffer.consecutive) {
+		decoder->ip = 0;
+		decoder->pkt_state = INTEL_PT_STATE_NO_PSB;
+		decoder->ref_timestamp = buffer.ref_timestamp;
+		decoder->timestamp = 0;
+		decoder->state.trace_nr = buffer.trace_nr;
+		intel_pt_log("Reference timestamp 0x%" PRIx64 "\n",
+			     decoder->ref_timestamp);
+		return -ENOLINK;
+	}
+
+	return 0;
+}
+
+static int intel_pt_get_next_data(struct intel_pt_decoder *decoder)
+{
+	if (!decoder->next_buf)
+		return intel_pt_get_data(decoder);
+
+	decoder->buf = decoder->next_buf;
+	decoder->len = decoder->next_len;
+	decoder->next_buf = 0;
+	decoder->next_len = 0;
+	return 0;
+}
+
+static int intel_pt_get_split_packet(struct intel_pt_decoder *decoder)
+{
+	unsigned char *buf = decoder->temp_buf;
+	size_t old_len, len, n;
+	int ret;
+
+	old_len = decoder->len;
+	len = decoder->len;
+	memcpy(buf, decoder->buf, len);
+
+	ret = intel_pt_get_data(decoder);
+	if (ret) {
+		decoder->pos += old_len;
+		return ret < 0 ? ret : -EINVAL;
+	}
+
+	n = INTEL_PT_PKT_MAX_SZ - len;
+	if (n > decoder->len)
+		n = decoder->len;
+	memcpy(buf + len, decoder->buf, n);
+	len += n;
+
+	ret = intel_pt_get_packet(buf, len, &decoder->packet);
+	if (ret < (int)old_len) {
+		decoder->next_buf = decoder->buf;
+		decoder->next_len = decoder->len;
+		decoder->buf = buf;
+		decoder->len = old_len;
+		return intel_pt_bad_packet(decoder);
+	}
+
+	decoder->next_buf = decoder->buf + (ret - old_len);
+	decoder->next_len = decoder->len - (ret - old_len);
+
+	decoder->buf = buf;
+	decoder->len = ret;
+
+	return ret;
+}
+
+static int intel_pt_get_next_packet(struct intel_pt_decoder *decoder)
+{
+	int ret;
+
+	do {
+		decoder->pos += decoder->pkt_step;
+		decoder->buf += decoder->pkt_step;
+		decoder->len -= decoder->pkt_step;
+
+		if (!decoder->len) {
+			ret = intel_pt_get_next_data(decoder);
+			if (ret)
+				return ret;
+		}
+
+		ret = intel_pt_get_packet(decoder->buf, decoder->len,
+					  &decoder->packet);
+		if (ret == INTEL_PT_NEED_MORE_BYTES &&
+		    decoder->len < INTEL_PT_PKT_MAX_SZ && !decoder->next_buf) {
+			ret = intel_pt_get_split_packet(decoder);
+			if (ret < 0)
+				return ret;
+		}
+		if (ret <= 0)
+			return intel_pt_bad_packet(decoder);
+
+		decoder->pkt_len = ret;
+		decoder->pkt_step = ret;
+		intel_pt_decoder_log_packet(decoder);
+	} while (decoder->packet.type == INTEL_PT_PAD);
+
+	return 0;
+}
+
+static uint64_t intel_pt_next_period(struct intel_pt_decoder *decoder)
+{
+	uint64_t timestamp, masked_timestamp;
+
+	timestamp = decoder->timestamp + decoder->timestamp_insn_cnt;
+	masked_timestamp = timestamp & decoder->period_mask;
+	if (decoder->continuous_period) {
+		if (masked_timestamp != decoder->last_masked_timestamp)
+			return 1;
+	} else {
+		timestamp += 1;
+		masked_timestamp = timestamp & decoder->period_mask;
+		if (masked_timestamp != decoder->last_masked_timestamp) {
+			decoder->last_masked_timestamp = masked_timestamp;
+			decoder->continuous_period = true;
+		}
+	}
+	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:
+	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;
+		decoder->last_masked_timestamp = masked_timestamp;
+		break;
+	case INTEL_PT_PERIOD_NONE:
+	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;
+
+	max_insn_cnt = intel_pt_next_sample(decoder);
+
+	err = decoder->walk_insn(intel_pt_insn, &insn_cnt, &decoder->ip, ip,
+				 max_insn_cnt, decoder->data);
+
+	decoder->timestamp_insn_cnt += insn_cnt;
+	decoder->period_insn_cnt += insn_cnt;
+
+	if (err) {
+		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) {
+		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;
+	}
+out:
+	decoder->state.insn_op = intel_pt_insn->op;
+	decoder->state.insn_len = intel_pt_insn->length;
+
+	if (decoder->tx_flags & INTEL_PT_IN_TX)
+		decoder->state.flags |= INTEL_PT_IN_TX;
+
+	return err;
+}
+
+static int intel_pt_walk_fup(struct intel_pt_decoder *decoder)
+{
+	struct intel_pt_insn intel_pt_insn;
+	uint64_t ip;
+	int err;
+
+	ip = decoder->last_ip;
+
+	while (1) {
+		err = intel_pt_walk_insn(decoder, &intel_pt_insn, ip);
+		if (err == INTEL_PT_RETURN)
+			return 0;
+		if (err == -EAGAIN) {
+			if (decoder->set_fup_tx_flags) {
+				decoder->set_fup_tx_flags = false;
+				decoder->tx_flags = decoder->fup_tx_flags;
+				decoder->state.type = INTEL_PT_TRANSACTION;
+				decoder->state.from_ip = decoder->ip;
+				decoder->state.to_ip = 0;
+				decoder->state.flags = decoder->fup_tx_flags;
+				return 0;
+			}
+			return err;
+		}
+		decoder->set_fup_tx_flags = false;
+		if (err)
+			return err;
+
+		if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
+			intel_pt_log_at("ERROR: Unexpected indirect branch",
+					decoder->ip);
+			decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
+			return -ENOENT;
+		}
+
+		if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
+			intel_pt_log_at("ERROR: Unexpected conditional branch",
+					decoder->ip);
+			decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
+			return -ENOENT;
+		}
+
+		intel_pt_bug(decoder);
+	}
+}
+
+static int intel_pt_walk_tip(struct intel_pt_decoder *decoder)
+{
+	struct intel_pt_insn intel_pt_insn;
+	int err;
+
+	err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
+	if (err == INTEL_PT_RETURN)
+		return 0;
+	if (err)
+		return err;
+
+	if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
+		if (decoder->pkt_state == INTEL_PT_STATE_TIP_PGD) {
+			decoder->pge = false;
+			decoder->continuous_period = false;
+			decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
+			decoder->state.from_ip = decoder->ip;
+			decoder->state.to_ip = 0;
+			if (decoder->packet.count != 0)
+				decoder->ip = decoder->last_ip;
+		} else {
+			decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
+			decoder->state.from_ip = decoder->ip;
+			if (decoder->packet.count == 0) {
+				decoder->state.to_ip = 0;
+			} else {
+				decoder->state.to_ip = decoder->last_ip;
+				decoder->ip = decoder->last_ip;
+			}
+		}
+		return 0;
+	}
+
+	if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
+		intel_pt_log_at("ERROR: Conditional branch when expecting indirect branch",
+				decoder->ip);
+		decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
+		return -ENOENT;
+	}
+
+	return intel_pt_bug(decoder);
+}
+
+static int intel_pt_walk_tnt(struct intel_pt_decoder *decoder)
+{
+	struct intel_pt_insn intel_pt_insn;
+	int err;
+
+	while (1) {
+		err = intel_pt_walk_insn(decoder, &intel_pt_insn, 0);
+		if (err == INTEL_PT_RETURN)
+			return 0;
+		if (err)
+			return err;
+
+		if (intel_pt_insn.op == INTEL_PT_OP_RET) {
+			if (!decoder->return_compression) {
+				intel_pt_log_at("ERROR: RET when expecting conditional branch",
+						decoder->ip);
+				decoder->pkt_state = INTEL_PT_STATE_ERR3;
+				return -ENOENT;
+			}
+			if (!decoder->ret_addr) {
+				intel_pt_log_at("ERROR: Bad RET compression (stack empty)",
+						decoder->ip);
+				decoder->pkt_state = INTEL_PT_STATE_ERR3;
+				return -ENOENT;
+			}
+			if (!(decoder->tnt.payload & BIT63)) {
+				intel_pt_log_at("ERROR: Bad RET compression (TNT=N)",
+						decoder->ip);
+				decoder->pkt_state = INTEL_PT_STATE_ERR3;
+				return -ENOENT;
+			}
+			decoder->tnt.count -= 1;
+			if (!decoder->tnt.count)
+				decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
+			decoder->tnt.payload <<= 1;
+			decoder->state.from_ip = decoder->ip;
+			decoder->ip = decoder->ret_addr;
+			decoder->state.to_ip = decoder->ip;
+			return 0;
+		}
+
+		if (intel_pt_insn.branch == INTEL_PT_BR_INDIRECT) {
+			/* Handle deferred TIPs */
+			err = intel_pt_get_next_packet(decoder);
+			if (err)
+				return err;
+			if (decoder->packet.type != INTEL_PT_TIP ||
+			    decoder->packet.count == 0) {
+				intel_pt_log_at("ERROR: Missing deferred TIP for indirect branch",
+						decoder->ip);
+				decoder->pkt_state = INTEL_PT_STATE_ERR3;
+				decoder->pkt_step = 0;
+				return -ENOENT;
+			}
+			intel_pt_set_last_ip(decoder);
+			decoder->state.from_ip = decoder->ip;
+			decoder->state.to_ip = decoder->last_ip;
+			decoder->ip = decoder->last_ip;
+			return 0;
+		}
+
+		if (intel_pt_insn.branch == INTEL_PT_BR_CONDITIONAL) {
+			decoder->tnt.count -= 1;
+			if (!decoder->tnt.count)
+				decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
+			if (decoder->tnt.payload & BIT63) {
+				decoder->tnt.payload <<= 1;
+				decoder->state.from_ip = decoder->ip;
+				decoder->ip += intel_pt_insn.length +
+					       intel_pt_insn.rel;
+				decoder->state.to_ip = decoder->ip;
+				return 0;
+			}
+			/* Instruction sample for a non-taken branch */
+			if (decoder->state.type & INTEL_PT_INSTRUCTION) {
+				decoder->tnt.payload <<= 1;
+				decoder->state.type = INTEL_PT_INSTRUCTION;
+				decoder->state.from_ip = decoder->ip;
+				decoder->state.to_ip = 0;
+				decoder->ip += intel_pt_insn.length;
+				return 0;
+			}
+			decoder->ip += intel_pt_insn.length;
+			if (!decoder->tnt.count)
+				return -EAGAIN;
+			decoder->tnt.payload <<= 1;
+			continue;
+		}
+
+		return intel_pt_bug(decoder);
+	}
+}
+
+static int intel_pt_mode_tsx(struct intel_pt_decoder *decoder, bool *no_tip)
+{
+	unsigned int fup_tx_flags;
+	int err;
+
+	fup_tx_flags = decoder->packet.payload &
+		       (INTEL_PT_IN_TX | INTEL_PT_ABORT_TX);
+	err = intel_pt_get_next_packet(decoder);
+	if (err)
+		return err;
+	if (decoder->packet.type == INTEL_PT_FUP) {
+		decoder->fup_tx_flags = fup_tx_flags;
+		decoder->set_fup_tx_flags = true;
+		if (!(decoder->fup_tx_flags & INTEL_PT_ABORT_TX))
+			*no_tip = true;
+	} else {
+		intel_pt_log_at("ERROR: Missing FUP after MODE.TSX",
+				decoder->pos);
+		intel_pt_update_in_tx(decoder);
+	}
+	return 0;
+}
+
+static void intel_pt_calc_tsc_timestamp(struct intel_pt_decoder *decoder)
+{
+	uint64_t timestamp;
+
+	if (decoder->ref_timestamp) {
+		timestamp = decoder->packet.payload |
+			    (decoder->ref_timestamp & (0xffULL << 56));
+		if (timestamp < decoder->ref_timestamp) {
+			if (decoder->ref_timestamp - timestamp > (1ULL << 55))
+				timestamp += (1ULL << 56);
+		} else {
+			if (timestamp - decoder->ref_timestamp > (1ULL << 55))
+				timestamp -= (1ULL << 56);
+		}
+		decoder->tsc_timestamp = timestamp;
+		decoder->timestamp = timestamp;
+		decoder->ref_timestamp = 0;
+		decoder->timestamp_insn_cnt = 0;
+	} else if (decoder->timestamp) {
+		timestamp = decoder->packet.payload |
+			    (decoder->timestamp & (0xffULL << 56));
+		if (timestamp < decoder->timestamp &&
+		    decoder->timestamp - timestamp < 0x100) {
+			intel_pt_log_to("ERROR: Suppressing backwards timestamp",
+					timestamp);
+			timestamp = decoder->timestamp;
+		}
+		while (timestamp < decoder->timestamp) {
+			intel_pt_log_to("Wraparound timestamp", timestamp);
+			timestamp += (1ULL << 56);
+		}
+		decoder->tsc_timestamp = timestamp;
+		decoder->timestamp = timestamp;
+		decoder->timestamp_insn_cnt = 0;
+	}
+
+	intel_pt_log_to("Setting timestamp", decoder->timestamp);
+}
+
+static int intel_pt_overflow(struct intel_pt_decoder *decoder)
+{
+	intel_pt_log("ERROR: Buffer overflow\n");
+	intel_pt_clear_tx_flags(decoder);
+	decoder->pkt_state = INTEL_PT_STATE_ERR_RESYNC;
+	decoder->overflow = true;
+	return -EOVERFLOW;
+}
+
+/* Walk PSB+ packets when already in sync. */
+static int intel_pt_walk_psbend(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	while (1) {
+		err = intel_pt_get_next_packet(decoder);
+		if (err)
+			return err;
+
+		switch (decoder->packet.type) {
+		case INTEL_PT_PSBEND:
+			return 0;
+
+		case INTEL_PT_TIP_PGD:
+		case INTEL_PT_TIP_PGE:
+		case INTEL_PT_TIP:
+		case INTEL_PT_TNT:
+		case INTEL_PT_BAD:
+		case INTEL_PT_PSB:
+			intel_pt_log("ERROR: Unexpected packet\n");
+			return -EAGAIN;
+
+		case INTEL_PT_OVF:
+			return intel_pt_overflow(decoder);
+
+		case INTEL_PT_TSC:
+			intel_pt_calc_tsc_timestamp(decoder);
+			break;
+
+		case INTEL_PT_CBR:
+			decoder->cbr = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_EXEC:
+			decoder->exec_mode = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_PIP:
+			decoder->cr3 = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_FUP:
+			decoder->pge = true;
+			intel_pt_set_last_ip(decoder);
+			break;
+
+		case INTEL_PT_MODE_TSX:
+			intel_pt_update_in_tx(decoder);
+			break;
+
+		case INTEL_PT_PAD:
+		default:
+			break;
+		}
+	}
+}
+
+static int intel_pt_walk_fup_tip(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	if (decoder->tx_flags & INTEL_PT_ABORT_TX) {
+		decoder->tx_flags = 0;
+		decoder->state.flags &= ~INTEL_PT_IN_TX;
+		decoder->state.flags |= INTEL_PT_ABORT_TX;
+	} else {
+		decoder->state.flags |= INTEL_PT_ASYNC;
+	}
+
+	while (1) {
+		err = intel_pt_get_next_packet(decoder);
+		if (err)
+			return err;
+
+		switch (decoder->packet.type) {
+		case INTEL_PT_TNT:
+		case INTEL_PT_FUP:
+		case INTEL_PT_PSB:
+		case INTEL_PT_TSC:
+		case INTEL_PT_CBR:
+		case INTEL_PT_MODE_TSX:
+		case INTEL_PT_BAD:
+		case INTEL_PT_PSBEND:
+			intel_pt_log("ERROR: Missing TIP after FUP\n");
+			decoder->pkt_state = INTEL_PT_STATE_ERR3;
+			return -ENOENT;
+
+		case INTEL_PT_OVF:
+			return intel_pt_overflow(decoder);
+
+		case INTEL_PT_TIP_PGD:
+			decoder->state.from_ip = decoder->ip;
+			decoder->state.to_ip = 0;
+			if (decoder->packet.count != 0) {
+				intel_pt_set_ip(decoder);
+				intel_pt_log("Omitting PGD ip " x64_fmt "\n",
+					     decoder->ip);
+			}
+			decoder->pge = false;
+			decoder->continuous_period = false;
+			return 0;
+
+		case INTEL_PT_TIP_PGE:
+			decoder->pge = true;
+			intel_pt_log("Omitting PGE ip " x64_fmt "\n",
+				     decoder->ip);
+			decoder->state.from_ip = 0;
+			if (decoder->packet.count == 0) {
+				decoder->state.to_ip = 0;
+			} else {
+				intel_pt_set_ip(decoder);
+				decoder->state.to_ip = decoder->ip;
+			}
+			return 0;
+
+		case INTEL_PT_TIP:
+			decoder->state.from_ip = decoder->ip;
+			if (decoder->packet.count == 0) {
+				decoder->state.to_ip = 0;
+			} else {
+				intel_pt_set_ip(decoder);
+				decoder->state.to_ip = decoder->ip;
+			}
+			return 0;
+
+		case INTEL_PT_PIP:
+			decoder->cr3 = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_EXEC:
+			decoder->exec_mode = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_PAD:
+			break;
+
+		default:
+			return intel_pt_bug(decoder);
+		}
+	}
+}
+
+static int intel_pt_walk_trace(struct intel_pt_decoder *decoder)
+{
+	bool no_tip = false;
+	int err;
+
+	while (1) {
+		err = intel_pt_get_next_packet(decoder);
+		if (err)
+			return err;
+next:
+		switch (decoder->packet.type) {
+		case INTEL_PT_TNT:
+			if (!decoder->packet.count)
+				break;
+			decoder->tnt = decoder->packet;
+			decoder->pkt_state = INTEL_PT_STATE_TNT;
+			err = intel_pt_walk_tnt(decoder);
+			if (err == -EAGAIN)
+				break;
+			return err;
+
+		case INTEL_PT_TIP_PGD:
+			if (decoder->packet.count != 0)
+				intel_pt_set_last_ip(decoder);
+			decoder->pkt_state = INTEL_PT_STATE_TIP_PGD;
+			return intel_pt_walk_tip(decoder);
+
+		case INTEL_PT_TIP_PGE: {
+			decoder->pge = true;
+			if (decoder->packet.count == 0) {
+				intel_pt_log_at("Skipping zero TIP.PGE",
+						decoder->pos);
+				break;
+			}
+			intel_pt_set_ip(decoder);
+			decoder->state.from_ip = 0;
+			decoder->state.to_ip = decoder->ip;
+			return 0;
+		}
+
+		case INTEL_PT_OVF:
+			return intel_pt_overflow(decoder);
+
+		case INTEL_PT_TIP:
+			if (decoder->packet.count != 0)
+				intel_pt_set_last_ip(decoder);
+			decoder->pkt_state = INTEL_PT_STATE_TIP;
+			return intel_pt_walk_tip(decoder);
+
+		case INTEL_PT_FUP:
+			if (decoder->packet.count == 0) {
+				intel_pt_log_at("Skipping zero FUP",
+						decoder->pos);
+				no_tip = false;
+				break;
+			}
+			intel_pt_set_last_ip(decoder);
+			err = intel_pt_walk_fup(decoder);
+			if (err != -EAGAIN) {
+				if (err)
+					return err;
+				if (no_tip)
+					decoder->pkt_state =
+						INTEL_PT_STATE_FUP_NO_TIP;
+				else
+					decoder->pkt_state = INTEL_PT_STATE_FUP;
+				return 0;
+			}
+			if (no_tip) {
+				no_tip = false;
+				break;
+			}
+			return intel_pt_walk_fup_tip(decoder);
+
+		case INTEL_PT_PSB:
+			intel_pt_clear_stack(&decoder->stack);
+			err = intel_pt_walk_psbend(decoder);
+			if (err == -EAGAIN)
+				goto next;
+			if (err)
+				return err;
+			break;
+
+		case INTEL_PT_PIP:
+			decoder->cr3 = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_TSC:
+			intel_pt_calc_tsc_timestamp(decoder);
+			break;
+
+		case INTEL_PT_CBR:
+			decoder->cbr = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_EXEC:
+			decoder->exec_mode = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_TSX:
+			/* MODE_TSX need not be followed by FUP */
+			if (!decoder->pge) {
+				intel_pt_update_in_tx(decoder);
+				break;
+			}
+			err = intel_pt_mode_tsx(decoder, &no_tip);
+			if (err)
+				return err;
+			goto next;
+
+		case INTEL_PT_BAD: /* Does not happen */
+			return intel_pt_bug(decoder);
+
+		case INTEL_PT_PSBEND:
+		case INTEL_PT_PAD:
+			break;
+
+		default:
+			return intel_pt_bug(decoder);
+		}
+	}
+}
+
+/* Walk PSB+ packets to get in sync. */
+static int intel_pt_walk_psb(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	while (1) {
+		err = intel_pt_get_next_packet(decoder);
+		if (err)
+			return err;
+
+		switch (decoder->packet.type) {
+		case INTEL_PT_TIP_PGD:
+			decoder->continuous_period = false;
+		case INTEL_PT_TIP_PGE:
+		case INTEL_PT_TIP:
+			intel_pt_log("ERROR: Unexpected packet\n");
+			return -ENOENT;
+
+		case INTEL_PT_FUP:
+			decoder->pge = true;
+			if (decoder->last_ip || decoder->packet.count == 6 ||
+			    decoder->packet.count == 0) {
+				uint64_t current_ip = decoder->ip;
+
+				intel_pt_set_ip(decoder);
+				if (current_ip)
+					intel_pt_log_to("Setting IP",
+							decoder->ip);
+			}
+			break;
+
+		case INTEL_PT_TSC:
+			intel_pt_calc_tsc_timestamp(decoder);
+			break;
+
+		case INTEL_PT_CBR:
+			decoder->cbr = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_PIP:
+			decoder->cr3 = decoder->packet.payload;
+			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_TNT:
+			intel_pt_log("ERROR: Unexpected packet\n");
+			if (decoder->ip)
+				decoder->pkt_state = INTEL_PT_STATE_ERR4;
+			else
+				decoder->pkt_state = INTEL_PT_STATE_ERR3;
+			return -ENOENT;
+
+		case INTEL_PT_BAD: /* Does not happen */
+			return intel_pt_bug(decoder);
+
+		case INTEL_PT_OVF:
+			return intel_pt_overflow(decoder);
+
+		case INTEL_PT_PSBEND:
+			return 0;
+
+		case INTEL_PT_PSB:
+		case INTEL_PT_PAD:
+		default:
+			break;
+		}
+	}
+}
+
+static int intel_pt_walk_to_ip(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	while (1) {
+		err = intel_pt_get_next_packet(decoder);
+		if (err)
+			return err;
+
+		switch (decoder->packet.type) {
+		case INTEL_PT_TIP_PGD:
+			decoder->continuous_period = false;
+		case INTEL_PT_TIP_PGE:
+		case INTEL_PT_TIP:
+			decoder->pge = decoder->packet.type != INTEL_PT_TIP_PGD;
+			if (decoder->last_ip || decoder->packet.count == 6 ||
+			    decoder->packet.count == 0)
+				intel_pt_set_ip(decoder);
+			if (decoder->ip)
+				return 0;
+			break;
+
+		case INTEL_PT_FUP:
+			if (decoder->overflow) {
+				if (decoder->last_ip ||
+				    decoder->packet.count == 6 ||
+				    decoder->packet.count == 0)
+					intel_pt_set_ip(decoder);
+				if (decoder->ip)
+					return 0;
+			}
+			if (decoder->packet.count)
+				intel_pt_set_last_ip(decoder);
+			break;
+
+		case INTEL_PT_TSC:
+			intel_pt_calc_tsc_timestamp(decoder);
+			break;
+
+		case INTEL_PT_CBR:
+			decoder->cbr = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_PIP:
+			decoder->cr3 = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_EXEC:
+			decoder->exec_mode = decoder->packet.payload;
+			break;
+
+		case INTEL_PT_MODE_TSX:
+			intel_pt_update_in_tx(decoder);
+			break;
+
+		case INTEL_PT_OVF:
+			return intel_pt_overflow(decoder);
+
+		case INTEL_PT_BAD: /* Does not happen */
+			return intel_pt_bug(decoder);
+
+		case INTEL_PT_PSB:
+			err = intel_pt_walk_psb(decoder);
+			if (err)
+				return err;
+			if (decoder->ip) {
+				/* Do not have a sample */
+				decoder->state.type = 0;
+				return 0;
+			}
+			break;
+
+		case INTEL_PT_TNT:
+		case INTEL_PT_PSBEND:
+		case INTEL_PT_PAD:
+		default:
+			break;
+		}
+	}
+}
+
+static int intel_pt_sync_ip(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	intel_pt_log("Scanning for full IP\n");
+	err = intel_pt_walk_to_ip(decoder);
+	if (err)
+		return err;
+
+	decoder->pkt_state = INTEL_PT_STATE_IN_SYNC;
+	decoder->overflow = false;
+
+	decoder->state.from_ip = 0;
+	decoder->state.to_ip = decoder->ip;
+	intel_pt_log_to("Setting IP", decoder->ip);
+
+	return 0;
+}
+
+static int intel_pt_part_psb(struct intel_pt_decoder *decoder)
+{
+	const unsigned char *end = decoder->buf + decoder->len;
+	size_t i;
+
+	for (i = INTEL_PT_PSB_LEN - 1; i; i--) {
+		if (i > decoder->len)
+			continue;
+		if (!memcmp(end - i, INTEL_PT_PSB_STR, i))
+			return i;
+	}
+	return 0;
+}
+
+static int intel_pt_rest_psb(struct intel_pt_decoder *decoder, int part_psb)
+{
+	size_t rest_psb = INTEL_PT_PSB_LEN - part_psb;
+	const char *psb = INTEL_PT_PSB_STR;
+
+	if (rest_psb > decoder->len ||
+	    memcmp(decoder->buf, psb + part_psb, rest_psb))
+		return 0;
+
+	return rest_psb;
+}
+
+static int intel_pt_get_split_psb(struct intel_pt_decoder *decoder,
+				  int part_psb)
+{
+	int rest_psb, ret;
+
+	decoder->pos += decoder->len;
+	decoder->len = 0;
+
+	ret = intel_pt_get_next_data(decoder);
+	if (ret)
+		return ret;
+
+	rest_psb = intel_pt_rest_psb(decoder, part_psb);
+	if (!rest_psb)
+		return 0;
+
+	decoder->pos -= part_psb;
+	decoder->next_buf = decoder->buf + rest_psb;
+	decoder->next_len = decoder->len - rest_psb;
+	memcpy(decoder->temp_buf, INTEL_PT_PSB_STR, INTEL_PT_PSB_LEN);
+	decoder->buf = decoder->temp_buf;
+	decoder->len = INTEL_PT_PSB_LEN;
+
+	return 0;
+}
+
+static int intel_pt_scan_for_psb(struct intel_pt_decoder *decoder)
+{
+	unsigned char *next;
+	int ret;
+
+	intel_pt_log("Scanning for PSB\n");
+	while (1) {
+		if (!decoder->len) {
+			ret = intel_pt_get_next_data(decoder);
+			if (ret)
+				return ret;
+		}
+
+		next = memmem(decoder->buf, decoder->len, INTEL_PT_PSB_STR,
+			      INTEL_PT_PSB_LEN);
+		if (!next) {
+			int part_psb;
+
+			part_psb = intel_pt_part_psb(decoder);
+			if (part_psb) {
+				ret = intel_pt_get_split_psb(decoder, part_psb);
+				if (ret)
+					return ret;
+			} else {
+				decoder->pos += decoder->len;
+				decoder->len = 0;
+			}
+			continue;
+		}
+
+		decoder->pkt_step = next - decoder->buf;
+		return intel_pt_get_next_packet(decoder);
+	}
+}
+
+static int intel_pt_sync(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	decoder->pge = false;
+	decoder->continuous_period = false;
+	decoder->last_ip = 0;
+	decoder->ip = 0;
+	intel_pt_clear_stack(&decoder->stack);
+
+	err = intel_pt_scan_for_psb(decoder);
+	if (err)
+		return err;
+
+	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;
+}
+
+const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder)
+{
+	int err;
+
+	do {
+		decoder->state.type = INTEL_PT_BRANCH;
+		decoder->state.flags = 0;
+
+		switch (decoder->pkt_state) {
+		case INTEL_PT_STATE_NO_PSB:
+			err = intel_pt_sync(decoder);
+			break;
+		case INTEL_PT_STATE_NO_IP:
+			decoder->last_ip = 0;
+			/* Fall through */
+		case INTEL_PT_STATE_ERR_RESYNC:
+			err = intel_pt_sync_ip(decoder);
+			break;
+		case INTEL_PT_STATE_IN_SYNC:
+			err = intel_pt_walk_trace(decoder);
+			break;
+		case INTEL_PT_STATE_TNT:
+			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);
+
+	decoder->state.err = err ? intel_pt_ext_err(err) : 0;
+	decoder->state.timestamp = decoder->timestamp;
+	decoder->state.est_timestamp = decoder->timestamp +
+				       (decoder->timestamp_insn_cnt << 1);
+	decoder->state.cr3 = decoder->cr3;
+
+	if (err)
+		decoder->state.from_ip = decoder->ip;
+
+	return &decoder->state;
+}
+
+static bool intel_pt_at_psb(unsigned char *buf, size_t len)
+{
+	if (len < INTEL_PT_PSB_LEN)
+		return false;
+	return memmem(buf, INTEL_PT_PSB_LEN, INTEL_PT_PSB_STR,
+		      INTEL_PT_PSB_LEN);
+}
+
+/**
+ * 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
+ *
+ * Find a TSC packet in @buf and return the TSC value.  This function assumes
+ * that @buf starts at a PSB and that PSB+ will contain TSC and so stops if a
+ * PSBEND packet is found.
+ *
+ * Return: %true if TSC is found, false otherwise.
+ */
+static bool intel_pt_next_tsc(unsigned char *buf, size_t len, uint64_t *tsc)
+{
+	struct intel_pt_pkt packet;
+	int ret;
+
+	while (len) {
+		ret = intel_pt_get_packet(buf, len, &packet);
+		if (ret <= 0)
+			return false;
+		if (packet.type == INTEL_PT_TSC) {
+			*tsc = packet.payload;
+			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;
+	}
+}
+
+/**
+ * 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
+ *
+ * If the trace contains TSC we can look at the last TSC of @buf_a and the
+ * first TSC of @buf_b in order to determine if the buffers overlap, and then
+ * walk forward in @buf_b until a later TSC is found.  A precondition is that
+ * @buf_a and @buf_b are positioned at a PSB.
+ *
+ * Return: A pointer into @buf_b from where non-overlapped data starts, or
+ * @buf_b + @len_b if there is no non-overlapped data.
+ */
+static unsigned char *intel_pt_find_overlap_tsc(unsigned char *buf_a,
+						size_t len_a,
+						unsigned char *buf_b,
+						size_t len_b)
+{
+	uint64_t tsc_a, tsc_b;
+	unsigned char *p;
+	size_t len;
+
+	p = intel_pt_last_psb(buf_a, len_a);
+	if (!p)
+		return buf_b; /* No PSB in buf_a => no overlap */
+
+	len = len_a - (p - buf_a);
+	if (!intel_pt_next_tsc(p, len, &tsc_a)) {
+		/* The last PSB+ in buf_a is incomplete, so go back one more */
+		len_a -= len;
+		p = intel_pt_last_psb(buf_a, len_a);
+		if (!p)
+			return buf_b; /* No full PSB+ => assume no overlap */
+		len = len_a - (p - buf_a);
+		if (!intel_pt_next_tsc(p, len, &tsc_a))
+			return buf_b; /* No TSC in buf_a => assume no overlap */
+	}
+
+	while (1) {
+		/* Ignore PSB+ with no TSC */
+		if (intel_pt_next_tsc(buf_b, len_b, &tsc_b) &&
+		    intel_pt_tsc_cmp(tsc_a, tsc_b) < 0)
+			return buf_b; /* tsc_a < tsc_b => no overlap */
+
+		if (!intel_pt_step_psb(&buf_b, &len_b))
+			return buf_b + len_b; /* No PSB in buf_b => no data */
+	}
+}
+
+/**
+ * intel_pt_find_overlap - determine start of non-overlapped trace data.
+ * @buf_a: first buffer
+ * @len_a: size of first buffer
+ * @buf_b: second buffer
+ * @len_b: size of second buffer
+ * @have_tsc: can use TSC packets to detect overlap
+ *
+ * When trace samples or snapshots are recorded there is the possibility that
+ * the data overlaps.  Note that, for the purposes of decoding, data is only
+ * useful if it begins with a PSB packet.
+ *
+ * Return: A pointer into @buf_b from where non-overlapped data starts, or
+ * @buf_b + @len_b if there is no non-overlapped data.
+ */
+unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a,
+				     unsigned char *buf_b, size_t len_b,
+				     bool have_tsc)
+{
+	unsigned char *found;
+
+	/* Buffer 'b' must start at PSB so throw away everything before that */
+	if (!intel_pt_next_psb(&buf_b, &len_b))
+		return buf_b + len_b; /* No PSB */
+
+	if (!intel_pt_next_psb(&buf_a, &len_a))
+		return buf_b; /* No overlap */
+
+	if (have_tsc) {
+		found = intel_pt_find_overlap_tsc(buf_a, len_a, buf_b, len_b);
+		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 */
+	if (len_b > len_a) {
+		/* The leftover buffer 'b' must start at a PSB */
+		while (!intel_pt_at_psb(buf_b + len_a, len_b - len_a)) {
+			if (!intel_pt_step_psb(&buf_a, &len_a))
+				return buf_b; /* No overlap */
+		}
+	}
+
+	while (1) {
+		/* Potential overlap so check the bytes */
+		found = memmem(buf_a, len_a, buf_b, len_a);
+		if (found)
+			return buf_b + len_a;
+
+		/* Try again at next PSB in buffer 'a' */
+		if (!intel_pt_step_psb(&buf_a, &len_a))
+			return buf_b; /* No overlap */
+
+		/* The leftover buffer 'b' must start at a PSB */
+		while (!intel_pt_at_psb(buf_b + len_a, len_b - len_a)) {
+			if (!intel_pt_step_psb(&buf_a, &len_a))
+				return buf_b; /* No overlap */
+		}
+	}
+}
diff --git a/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
new file mode 100644
index 0000000..955263a
--- /dev/null
+++ b/tools/perf/util/intel-pt-decoder/intel-pt-decoder.h
@@ -0,0 +1,102 @@
+/*
+ * intel_pt_decoder.h: Intel Processor Trace support
+ * Copyright (c) 2013-2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#ifndef INCLUDE__INTEL_PT_DECODER_H__
+#define INCLUDE__INTEL_PT_DECODER_H__
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdbool.h>
+
+#include "intel-pt-insn-decoder.h"
+
+#define INTEL_PT_IN_TX		(1 << 0)
+#define INTEL_PT_ABORT_TX	(1 << 1)
+#define INTEL_PT_ASYNC		(1 << 2)
+
+enum intel_pt_sample_type {
+	INTEL_PT_BRANCH		= 1 << 0,
+	INTEL_PT_INSTRUCTION	= 1 << 1,
+	INTEL_PT_TRANSACTION	= 1 << 2,
+};
+
+enum intel_pt_period_type {
+	INTEL_PT_PERIOD_NONE,
+	INTEL_PT_PERIOD_INSTRUCTIONS,
+	INTEL_PT_PERIOD_TICKS,
+};
+
+enum {
+	INTEL_PT_ERR_NOMEM = 1,
+	INTEL_PT_ERR_INTERN,
+	INTEL_PT_ERR_BADPKT,
+	INTEL_PT_ERR_NODATA,
+	INTEL_PT_ERR_NOINSN,
+	INTEL_PT_ERR_MISMAT,
+	INTEL_PT_ERR_OVR,
+	INTEL_PT_ERR_LOST,
+	INTEL_PT_ERR_UNK,
+	INTEL_PT_ERR_MAX,
+};
+
+struct intel_pt_state {
+	enum intel_pt_sample_type type;
+	int err;
+	uint64_t from_ip;
+	uint64_t to_ip;
+	uint64_t cr3;
+	uint64_t timestamp;
+	uint64_t est_timestamp;
+	uint64_t trace_nr;
+	uint32_t flags;
+	enum intel_pt_insn_op insn_op;
+	int insn_len;
+};
+
+struct intel_pt_insn;
+
+struct intel_pt_buffer {
+	const unsigned char *buf;
+	size_t len;
+	bool consecutive;
+	uint64_t ref_timestamp;
+	uint64_t trace_nr;
+};
+
+struct intel_pt_params {
+	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);
+	void *data;
+	bool return_compression;
+	uint64_t period;
+	enum intel_pt_period_type period_type;
+};
+
+struct intel_pt_decoder;
+
+struct intel_pt_decoder *intel_pt_decoder_new(struct intel_pt_params *params);
+void intel_pt_decoder_free(struct intel_pt_decoder *decoder);
+
+const struct intel_pt_state *intel_pt_decode(struct intel_pt_decoder *decoder);
+
+unsigned char *intel_pt_find_overlap(unsigned char *buf_a, size_t len_a,
+				     unsigned char *buf_b, size_t len_b,
+				     bool have_tsc);
+
+int intel_pt__strerror(int code, char *buf, size_t buflen);
+
+#endif
-- 
1.9.1

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