ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

3 files changed, 921 insertions, 0 deletions

diff --git a/tools/perf/util/cs-etm-decoder/Build b/tools/perf/util/cs-etm-decoder/Build
new file mode 100644
index 000000000..27550db2a
--- /dev/null
+++ b/tools/perf/util/cs-etm-decoder/Build
@@ -0,0 +1 @@
+perf-util-y += cs-etm-decoder.o
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
new file mode 100644
index 000000000..26940f1f1
--- /dev/null
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -0,0 +1,809 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2015-2018 Linaro Limited.
+ *
+ * Author: Tor Jeremiassen <tor@ti.com>
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ */
+
+#include <asm/bug.h>
+#include <linux/coresight-pmu.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/zalloc.h>
+#include <stdlib.h>
+#include <opencsd/c_api/opencsd_c_api.h>
+
+#include "cs-etm.h"
+#include "cs-etm-decoder.h"
+#include "debug.h"
+#include "intlist.h"
+
+/* use raw logging */
+#ifdef CS_DEBUG_RAW
+#define CS_LOG_RAW_FRAMES
+#define CS_PKT_MON	1
+#ifdef CS_RAW_PACKED
+#define CS_RAW_DEBUG_FLAGS (OCSD_DFRMTR_UNPACKED_RAW_OUT | \
+			    OCSD_DFRMTR_PACKED_RAW_OUT)
+#else
+#define CS_RAW_DEBUG_FLAGS (OCSD_DFRMTR_UNPACKED_RAW_OUT)
+#endif
+#else
+#define CS_PKT_MON	0
+#endif
+
+/*
+ * Assume a maximum of 0.1ns elapsed per instruction. This would be the
+ * case with a theoretical 10GHz core executing 1 instruction per cycle.
+ * Used to estimate the sample time for synthesized instructions because
+ * Coresight only emits a timestamp for a range of instructions rather
+ * than per instruction.
+ */
+const u32 INSTR_PER_NS = 10;
+
+struct cs_etm_decoder {
+	void *data;
+	void (*packet_printer)(const char *msg, void *data);
+	bool suppress_printing;
+	dcd_tree_handle_t dcd_tree;
+	cs_etm_mem_cb_type mem_access;
+	ocsd_datapath_resp_t prev_return;
+	const char *decoder_name;
+};
+
+static u32
+cs_etm_decoder__mem_access(const void *context,
+			   const ocsd_vaddr_t address,
+			   const ocsd_mem_space_acc_t mem_space,
+			   const u8 trace_chan_id,
+			   const u32 req_size,
+			   u8 *buffer)
+{
+	struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
+
+	return decoder->mem_access(decoder->data, trace_chan_id, address,
+				   req_size, buffer, mem_space);
+}
+
+int cs_etm_decoder__add_mem_access_cb(struct cs_etm_decoder *decoder,
+				      u64 start, u64 end,
+				      cs_etm_mem_cb_type cb_func)
+{
+	decoder->mem_access = cb_func;
+
+	if (ocsd_dt_add_callback_trcid_mem_acc(decoder->dcd_tree, start, end,
+					       OCSD_MEM_SPACE_ANY,
+					       cs_etm_decoder__mem_access,
+					       decoder))
+		return -1;
+
+	return 0;
+}
+
+int cs_etm_decoder__reset(struct cs_etm_decoder *decoder)
+{
+	ocsd_datapath_resp_t dp_ret;
+
+	decoder->prev_return = OCSD_RESP_CONT;
+	decoder->suppress_printing = true;
+	dp_ret = ocsd_dt_process_data(decoder->dcd_tree, OCSD_OP_RESET,
+				      0, 0, NULL, NULL);
+	decoder->suppress_printing = false;
+	if (OCSD_DATA_RESP_IS_FATAL(dp_ret))
+		return -1;
+
+	return 0;
+}
+
+int cs_etm_decoder__get_packet(struct cs_etm_packet_queue *packet_queue,
+			       struct cs_etm_packet *packet)
+{
+	if (!packet_queue || !packet)
+		return -EINVAL;
+
+	/* Nothing to do, might as well just return */
+	if (packet_queue->packet_count == 0)
+		return 0;
+	/*
+	 * The queueing process in function cs_etm_decoder__buffer_packet()
+	 * increments the tail *before* using it.  This is somewhat counter
+	 * intuitive but it has the advantage of centralizing tail management
+	 * at a single location.  Because of that we need to follow the same
+	 * heuristic with the head, i.e we increment it before using its
+	 * value.  Otherwise the first element of the packet queue is not
+	 * used.
+	 */
+	packet_queue->head = (packet_queue->head + 1) &
+			     (CS_ETM_PACKET_MAX_BUFFER - 1);
+
+	*packet = packet_queue->packet_buffer[packet_queue->head];
+
+	packet_queue->packet_count--;
+
+	return 1;
+}
+
+/*
+ * Calculate the number of nanoseconds elapsed.
+ *
+ * instr_count is updated in place with the remainder of the instructions
+ * which didn't make up a whole nanosecond.
+ */
+static u32 cs_etm_decoder__dec_instr_count_to_ns(u32 *instr_count)
+{
+	const u32 instr_copy = *instr_count;
+
+	*instr_count %= INSTR_PER_NS;
+	return instr_copy / INSTR_PER_NS;
+}
+
+static int cs_etm_decoder__gen_etmv3_config(struct cs_etm_trace_params *params,
+					    ocsd_etmv3_cfg *config)
+{
+	config->reg_idr = params->etmv3.reg_idr;
+	config->reg_ctrl = params->etmv3.reg_ctrl;
+	config->reg_ccer = params->etmv3.reg_ccer;
+	config->reg_trc_id = params->etmv3.reg_trc_id;
+	config->arch_ver = ARCH_V7;
+	config->core_prof = profile_CortexA;
+
+	return 0;
+}
+
+#define TRCIDR1_TRCARCHMIN_SHIFT 4
+#define TRCIDR1_TRCARCHMIN_MASK  GENMASK(7, 4)
+#define TRCIDR1_TRCARCHMIN(x)    (((x) & TRCIDR1_TRCARCHMIN_MASK) >> TRCIDR1_TRCARCHMIN_SHIFT)
+
+static enum _ocsd_arch_version cs_etm_decoder__get_etmv4_arch_ver(u32 reg_idr1)
+{
+	/*
+	 * For ETMv4 if the trace minor version is 4 or more then we can assume
+	 * the architecture is ARCH_AA64 rather than just V8.
+	 * ARCH_V8 = V8 architecture
+	 * ARCH_AA64 = Min v8r3 plus additional AA64 PE features
+	 */
+	return TRCIDR1_TRCARCHMIN(reg_idr1) >= 4 ? ARCH_AA64 : ARCH_V8;
+}
+
+static void cs_etm_decoder__gen_etmv4_config(struct cs_etm_trace_params *params,
+					     ocsd_etmv4_cfg *config)
+{
+	config->reg_configr = params->etmv4.reg_configr;
+	config->reg_traceidr = params->etmv4.reg_traceidr;
+	config->reg_idr0 = params->etmv4.reg_idr0;
+	config->reg_idr1 = params->etmv4.reg_idr1;
+	config->reg_idr2 = params->etmv4.reg_idr2;
+	config->reg_idr8 = params->etmv4.reg_idr8;
+	config->reg_idr9 = 0;
+	config->reg_idr10 = 0;
+	config->reg_idr11 = 0;
+	config->reg_idr12 = 0;
+	config->reg_idr13 = 0;
+	config->arch_ver = cs_etm_decoder__get_etmv4_arch_ver(params->etmv4.reg_idr1);
+	config->core_prof = profile_CortexA;
+}
+
+static void cs_etm_decoder__gen_ete_config(struct cs_etm_trace_params *params,
+					   ocsd_ete_cfg *config)
+{
+	config->reg_configr = params->ete.reg_configr;
+	config->reg_traceidr = params->ete.reg_traceidr;
+	config->reg_idr0 = params->ete.reg_idr0;
+	config->reg_idr1 = params->ete.reg_idr1;
+	config->reg_idr2 = params->ete.reg_idr2;
+	config->reg_idr8 = params->ete.reg_idr8;
+	config->reg_devarch = params->ete.reg_devarch;
+	config->arch_ver = ARCH_AA64;
+	config->core_prof = profile_CortexA;
+}
+
+static void cs_etm_decoder__print_str_cb(const void *p_context,
+					 const char *msg,
+					 const int str_len)
+{
+	const struct cs_etm_decoder *decoder = p_context;
+
+	if (p_context && str_len && !decoder->suppress_printing)
+		decoder->packet_printer(msg, decoder->data);
+}
+
+static int
+cs_etm_decoder__init_def_logger_printing(struct cs_etm_decoder_params *d_params,
+					 struct cs_etm_decoder *decoder)
+{
+	int ret = 0;
+
+	if (d_params->packet_printer == NULL)
+		return -1;
+
+	decoder->packet_printer = d_params->packet_printer;
+
+	/*
+	 * Set up a library default logger to process any printers
+	 * (packet/raw frame) we add later.
+	 */
+	ret = ocsd_def_errlog_init(OCSD_ERR_SEV_ERROR, 1);
+	if (ret != 0)
+		return -1;
+
+	/* no stdout / err / file output */
+	ret = ocsd_def_errlog_config_output(C_API_MSGLOGOUT_FLG_NONE, NULL);
+	if (ret != 0)
+		return -1;
+
+	/*
+	 * Set the string CB for the default logger, passes strings to
+	 * perf print logger.
+	 */
+	ret = ocsd_def_errlog_set_strprint_cb(decoder->dcd_tree,
+					      (void *)decoder,
+					      cs_etm_decoder__print_str_cb);
+	if (ret != 0)
+		return -1;
+
+#ifdef CS_LOG_RAW_FRAMES
+	/*
+	 * Only log raw frames if --dump operation and hardware is actually
+	 * generating formatted CoreSight trace frames
+	 */
+	if ((d_params->operation == CS_ETM_OPERATION_PRINT) &&
+	    (d_params->formatted == true)) {
+		/* use the built in library printer for the raw frames */
+		ret = ocsd_dt_set_raw_frame_printer(decoder->dcd_tree,
+						    CS_RAW_DEBUG_FLAGS);
+		if (ret != 0)
+			return -1;
+	}
+#endif
+	return 0;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__do_soft_timestamp(struct cs_etm_queue *etmq,
+				  struct cs_etm_packet_queue *packet_queue,
+				  const uint8_t trace_chan_id)
+{
+	u64 estimated_ts;
+
+	/* No timestamp packet has been received, nothing to do */
+	if (!packet_queue->next_cs_timestamp)
+		return OCSD_RESP_CONT;
+
+	estimated_ts = packet_queue->cs_timestamp +
+			cs_etm_decoder__dec_instr_count_to_ns(&packet_queue->instr_count);
+
+	/* Estimated TS can never be higher than the next real one in the trace */
+	packet_queue->cs_timestamp = min(packet_queue->next_cs_timestamp, estimated_ts);
+
+	/* Tell the front end which traceid_queue needs attention */
+	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);
+
+	return OCSD_RESP_WAIT;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__do_hard_timestamp(struct cs_etm_queue *etmq,
+				  const ocsd_generic_trace_elem *elem,
+				  const uint8_t trace_chan_id,
+				  const ocsd_trc_index_t indx)
+{
+	struct cs_etm_packet_queue *packet_queue;
+	u64 converted_timestamp;
+	u64 estimated_first_ts;
+
+	/* First get the packet queue for this traceID */
+	packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id);
+	if (!packet_queue)
+		return OCSD_RESP_FATAL_SYS_ERR;
+
+	/*
+	 * Coresight timestamps are raw timer values which need to be scaled to ns. Assume
+	 * 0 is a bad value so don't try to convert it.
+	 */
+	converted_timestamp = elem->timestamp ?
+				cs_etm__convert_sample_time(etmq, elem->timestamp) : 0;
+
+	/*
+	 * We've seen a timestamp packet before - simply record the new value.
+	 * Function do_soft_timestamp() will report the value to the front end,
+	 * hence asking the decoder to keep decoding rather than stopping.
+	 */
+	if (packet_queue->next_cs_timestamp) {
+		/*
+		 * What was next is now where new ranges start from, overwriting
+		 * any previous estimate in cs_timestamp
+		 */
+		packet_queue->cs_timestamp = packet_queue->next_cs_timestamp;
+		packet_queue->next_cs_timestamp = converted_timestamp;
+		return OCSD_RESP_CONT;
+	}
+
+	if (!converted_timestamp) {
+		/*
+		 * Zero timestamps can be seen due to misconfiguration or hardware bugs.
+		 * Warn once, and don't try to subtract instr_count as it would result in an
+		 * underflow.
+		 */
+		packet_queue->cs_timestamp = 0;
+		if (!cs_etm__etmq_is_timeless(etmq))
+			pr_warning_once("Zero Coresight timestamp found at Idx:%" OCSD_TRC_IDX_STR
+					". Decoding may be improved by prepending 'Z' to your current --itrace arguments.\n",
+					indx);
+
+	} else if (packet_queue->instr_count / INSTR_PER_NS > converted_timestamp) {
+		/*
+		 * Sanity check that the elem->timestamp - packet_queue->instr_count would not
+		 * result in an underflow. Warn and clamp at 0 if it would.
+		 */
+		packet_queue->cs_timestamp = 0;
+		pr_err("Timestamp calculation underflow at Idx:%" OCSD_TRC_IDX_STR "\n", indx);
+	} else {
+		/*
+		 * This is the first timestamp we've seen since the beginning of traces
+		 * or a discontinuity.  Since timestamps packets are generated *after*
+		 * range packets have been generated, we need to estimate the time at
+		 * which instructions started by subtracting the number of instructions
+		 * executed to the timestamp. Don't estimate earlier than the last used
+		 * timestamp though.
+		 */
+		estimated_first_ts = converted_timestamp -
+					(packet_queue->instr_count / INSTR_PER_NS);
+		packet_queue->cs_timestamp = max(packet_queue->cs_timestamp, estimated_first_ts);
+	}
+	packet_queue->next_cs_timestamp = converted_timestamp;
+	packet_queue->instr_count = 0;
+
+	/* Tell the front end which traceid_queue needs attention */
+	cs_etm__etmq_set_traceid_queue_timestamp(etmq, trace_chan_id);
+
+	/* Halt processing until we are being told to proceed */
+	return OCSD_RESP_WAIT;
+}
+
+static void
+cs_etm_decoder__reset_timestamp(struct cs_etm_packet_queue *packet_queue)
+{
+	packet_queue->next_cs_timestamp = 0;
+	packet_queue->instr_count = 0;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__buffer_packet(struct cs_etm_queue *etmq,
+			      struct cs_etm_packet_queue *packet_queue,
+			      const u8 trace_chan_id,
+			      enum cs_etm_sample_type sample_type)
+{
+	u32 et = 0;
+	int cpu;
+
+	if (packet_queue->packet_count >= CS_ETM_PACKET_MAX_BUFFER - 1)
+		return OCSD_RESP_FATAL_SYS_ERR;
+
+	if (cs_etm__get_cpu(etmq, trace_chan_id, &cpu) < 0)
+		return OCSD_RESP_FATAL_SYS_ERR;
+
+	et = packet_queue->tail;
+	et = (et + 1) & (CS_ETM_PACKET_MAX_BUFFER - 1);
+	packet_queue->tail = et;
+	packet_queue->packet_count++;
+
+	packet_queue->packet_buffer[et].sample_type = sample_type;
+	packet_queue->packet_buffer[et].isa = CS_ETM_ISA_UNKNOWN;
+	packet_queue->packet_buffer[et].cpu = cpu;
+	packet_queue->packet_buffer[et].start_addr = CS_ETM_INVAL_ADDR;
+	packet_queue->packet_buffer[et].end_addr = CS_ETM_INVAL_ADDR;
+	packet_queue->packet_buffer[et].instr_count = 0;
+	packet_queue->packet_buffer[et].last_instr_taken_branch = false;
+	packet_queue->packet_buffer[et].last_instr_size = 0;
+	packet_queue->packet_buffer[et].last_instr_type = 0;
+	packet_queue->packet_buffer[et].last_instr_subtype = 0;
+	packet_queue->packet_buffer[et].last_instr_cond = 0;
+	packet_queue->packet_buffer[et].flags = 0;
+	packet_queue->packet_buffer[et].exception_number = UINT32_MAX;
+	packet_queue->packet_buffer[et].trace_chan_id = trace_chan_id;
+	packet_queue->packet_buffer[et].el = ocsd_EL_unknown;
+	packet_queue->packet_buffer[et].tid = -1;
+
+	if (packet_queue->packet_count == CS_ETM_PACKET_MAX_BUFFER - 1)
+		return OCSD_RESP_WAIT;
+
+	return OCSD_RESP_CONT;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__buffer_range(struct cs_etm_queue *etmq,
+			     struct cs_etm_packet_queue *packet_queue,
+			     const ocsd_generic_trace_elem *elem,
+			     const uint8_t trace_chan_id)
+{
+	int ret = 0;
+	struct cs_etm_packet *packet;
+
+	ret = cs_etm_decoder__buffer_packet(etmq, packet_queue, trace_chan_id,
+					    CS_ETM_RANGE);
+	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
+		return ret;
+
+	packet = &packet_queue->packet_buffer[packet_queue->tail];
+
+	switch (elem->isa) {
+	case ocsd_isa_aarch64:
+		packet->isa = CS_ETM_ISA_A64;
+		break;
+	case ocsd_isa_arm:
+		packet->isa = CS_ETM_ISA_A32;
+		break;
+	case ocsd_isa_thumb2:
+		packet->isa = CS_ETM_ISA_T32;
+		break;
+	case ocsd_isa_tee:
+	case ocsd_isa_jazelle:
+	case ocsd_isa_custom:
+	case ocsd_isa_unknown:
+	default:
+		packet->isa = CS_ETM_ISA_UNKNOWN;
+	}
+
+	packet->start_addr = elem->st_addr;
+	packet->end_addr = elem->en_addr;
+	packet->instr_count = elem->num_instr_range;
+	packet->last_instr_type = elem->last_i_type;
+	packet->last_instr_subtype = elem->last_i_subtype;
+	packet->last_instr_cond = elem->last_instr_cond;
+	packet->el = elem->context.exception_level;
+
+	if (elem->last_i_type == OCSD_INSTR_BR || elem->last_i_type == OCSD_INSTR_BR_INDIRECT)
+		packet->last_instr_taken_branch = elem->last_instr_exec;
+	else
+		packet->last_instr_taken_branch = false;
+
+	packet->last_instr_size = elem->last_instr_sz;
+
+	/* per-thread scenario, no need to generate a timestamp */
+	if (cs_etm__etmq_is_timeless(etmq))
+		goto out;
+
+	/*
+	 * The packet queue is full and we haven't seen a timestamp (had we
+	 * seen one the packet queue wouldn't be full).  Let the front end
+	 * deal with it.
+	 */
+	if (ret == OCSD_RESP_WAIT)
+		goto out;
+
+	packet_queue->instr_count += elem->num_instr_range;
+	/* Tell the front end we have a new timestamp to process */
+	ret = cs_etm_decoder__do_soft_timestamp(etmq, packet_queue,
+						trace_chan_id);
+out:
+	return ret;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__buffer_discontinuity(struct cs_etm_queue *etmq,
+				     struct cs_etm_packet_queue *queue,
+				     const uint8_t trace_chan_id)
+{
+	/*
+	 * Something happened and who knows when we'll get new traces so
+	 * reset time statistics.
+	 */
+	cs_etm_decoder__reset_timestamp(queue);
+	return cs_etm_decoder__buffer_packet(etmq, queue, trace_chan_id,
+					     CS_ETM_DISCONTINUITY);
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__buffer_exception(struct cs_etm_queue *etmq,
+				 struct cs_etm_packet_queue *queue,
+				 const ocsd_generic_trace_elem *elem,
+				 const uint8_t trace_chan_id)
+{	int ret = 0;
+	struct cs_etm_packet *packet;
+
+	ret = cs_etm_decoder__buffer_packet(etmq, queue, trace_chan_id,
+					    CS_ETM_EXCEPTION);
+	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
+		return ret;
+
+	packet = &queue->packet_buffer[queue->tail];
+	packet->exception_number = elem->exception_number;
+
+	return ret;
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__buffer_exception_ret(struct cs_etm_queue *etmq,
+				     struct cs_etm_packet_queue *queue,
+				     const uint8_t trace_chan_id)
+{
+	return cs_etm_decoder__buffer_packet(etmq, queue, trace_chan_id,
+					     CS_ETM_EXCEPTION_RET);
+}
+
+static ocsd_datapath_resp_t
+cs_etm_decoder__set_tid(struct cs_etm_queue *etmq,
+			struct cs_etm_packet_queue *packet_queue,
+			const ocsd_generic_trace_elem *elem,
+			const uint8_t trace_chan_id)
+{
+	struct cs_etm_packet *packet;
+	pid_t tid = -1;
+	int ret;
+
+	/*
+	 * Process the PE_CONTEXT packets if we have a valid contextID or VMID.
+	 * If the kernel is running at EL2, the PID is traced in CONTEXTIDR_EL2
+	 * as VMID, Format attribute 'contextid2' is set in this case.
+	 */
+	switch (cs_etm__get_pid_fmt(etmq)) {
+	case CS_ETM_PIDFMT_CTXTID:
+		if (elem->context.ctxt_id_valid)
+			tid = elem->context.context_id;
+		break;
+	case CS_ETM_PIDFMT_CTXTID2:
+		if (elem->context.vmid_valid)
+			tid = elem->context.vmid;
+		break;
+	case CS_ETM_PIDFMT_NONE:
+	default:
+		break;
+	}
+
+	if (cs_etm__etmq_update_decode_context(etmq, trace_chan_id,
+				elem->context.exception_level, tid))
+		return OCSD_RESP_FATAL_SYS_ERR;
+
+	ret = cs_etm_decoder__buffer_packet(etmq, packet_queue, trace_chan_id,
+					    CS_ETM_CONTEXT);
+	if (ret != OCSD_RESP_CONT && ret != OCSD_RESP_WAIT)
+		return ret;
+
+	packet = &packet_queue->packet_buffer[packet_queue->tail];
+	packet->tid = tid;
+	packet->el = elem->context.exception_level;
+
+	/*
+	 * A timestamp is generated after a PE_CONTEXT element so make sure
+	 * to rely on that coming one.
+	 */
+	cs_etm_decoder__reset_timestamp(packet_queue);
+
+	return ret;
+}
+
+static ocsd_datapath_resp_t cs_etm_decoder__gen_trace_elem_printer(
+				const void *context,
+				const ocsd_trc_index_t indx,
+				const u8 trace_chan_id __maybe_unused,
+				const ocsd_generic_trace_elem *elem)
+{
+	ocsd_datapath_resp_t resp = OCSD_RESP_CONT;
+	ocsd_gen_trc_elem_t type;
+	struct cs_etm_decoder *decoder = (struct cs_etm_decoder *) context;
+	struct cs_etm_queue *etmq = decoder->data;
+	struct cs_etm_packet_queue *packet_queue;
+
+	/* First get the packet queue for this traceID */
+	packet_queue = cs_etm__etmq_get_packet_queue(etmq, trace_chan_id);
+	if (!packet_queue)
+		return OCSD_RESP_FATAL_SYS_ERR;
+
+	type = elem->elem_type;
+
+	if (type == OCSD_GEN_TRC_ELEM_EO_TRACE ||
+	    type == OCSD_GEN_TRC_ELEM_NO_SYNC ||
+	    type == OCSD_GEN_TRC_ELEM_TRACE_ON)
+		resp = cs_etm_decoder__buffer_discontinuity(etmq, packet_queue,
+							    trace_chan_id);
+	else if (type == OCSD_GEN_TRC_ELEM_INSTR_RANGE)
+		resp = cs_etm_decoder__buffer_range(etmq, packet_queue, elem,
+						    trace_chan_id);
+	else if (type == OCSD_GEN_TRC_ELEM_EXCEPTION)
+		resp = cs_etm_decoder__buffer_exception(etmq, packet_queue, elem,
+							trace_chan_id);
+	else if (type == OCSD_GEN_TRC_ELEM_EXCEPTION_RET)
+		resp = cs_etm_decoder__buffer_exception_ret(etmq, packet_queue,
+							    trace_chan_id);
+	else if (type == OCSD_GEN_TRC_ELEM_TIMESTAMP)
+		resp = cs_etm_decoder__do_hard_timestamp(etmq, elem,
+							 trace_chan_id,
+							 indx);
+	else if (type == OCSD_GEN_TRC_ELEM_PE_CONTEXT)
+		resp = cs_etm_decoder__set_tid(etmq, packet_queue,
+					       elem, trace_chan_id);
+
+	return resp;
+}
+
+static int
+cs_etm_decoder__create_etm_decoder(struct cs_etm_decoder_params *d_params,
+				   struct cs_etm_trace_params *t_params,
+				   struct cs_etm_decoder *decoder)
+{
+	ocsd_etmv3_cfg config_etmv3;
+	ocsd_etmv4_cfg trace_config_etmv4;
+	ocsd_ete_cfg trace_config_ete;
+	void *trace_config;
+	u8 csid;
+
+	switch (t_params->protocol) {
+	case CS_ETM_PROTO_ETMV3:
+	case CS_ETM_PROTO_PTM:
+		csid = (t_params->etmv3.reg_idr & CORESIGHT_TRACE_ID_VAL_MASK);
+		cs_etm_decoder__gen_etmv3_config(t_params, &config_etmv3);
+		decoder->decoder_name = (t_params->protocol == CS_ETM_PROTO_ETMV3) ?
+							OCSD_BUILTIN_DCD_ETMV3 :
+							OCSD_BUILTIN_DCD_PTM;
+		trace_config = &config_etmv3;
+		break;
+	case CS_ETM_PROTO_ETMV4i:
+		csid = (t_params->etmv4.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
+		cs_etm_decoder__gen_etmv4_config(t_params, &trace_config_etmv4);
+		decoder->decoder_name = OCSD_BUILTIN_DCD_ETMV4I;
+		trace_config = &trace_config_etmv4;
+		break;
+	case CS_ETM_PROTO_ETE:
+		csid = (t_params->ete.reg_traceidr & CORESIGHT_TRACE_ID_VAL_MASK);
+		cs_etm_decoder__gen_ete_config(t_params, &trace_config_ete);
+		decoder->decoder_name = OCSD_BUILTIN_DCD_ETE;
+		trace_config = &trace_config_ete;
+		break;
+	default:
+		return -1;
+	}
+
+	if (d_params->operation == CS_ETM_OPERATION_DECODE) {
+		int decode_flags = OCSD_CREATE_FLG_FULL_DECODER;
+#ifdef OCSD_OPFLG_N_UNCOND_DIR_BR_CHK
+		decode_flags |= OCSD_OPFLG_N_UNCOND_DIR_BR_CHK | OCSD_OPFLG_CHK_RANGE_CONTINUE |
+				ETM4_OPFLG_PKTDEC_AA64_OPCODE_CHK;
+#endif
+		if (ocsd_dt_create_decoder(decoder->dcd_tree,
+					   decoder->decoder_name,
+					   decode_flags,
+					   trace_config, &csid))
+			return -1;
+
+		if (ocsd_dt_set_gen_elem_outfn(decoder->dcd_tree,
+					       cs_etm_decoder__gen_trace_elem_printer,
+					       decoder))
+			return -1;
+
+		return 0;
+	} else if (d_params->operation == CS_ETM_OPERATION_PRINT) {
+		if (ocsd_dt_create_decoder(decoder->dcd_tree, decoder->decoder_name,
+					   OCSD_CREATE_FLG_PACKET_PROC,
+					   trace_config, &csid))
+			return -1;
+
+		if (ocsd_dt_set_pkt_protocol_printer(decoder->dcd_tree, csid, CS_PKT_MON))
+			return -1;
+
+		return 0;
+	}
+
+	return -1;
+}
+
+struct cs_etm_decoder *
+cs_etm_decoder__new(int decoders, struct cs_etm_decoder_params *d_params,
+		    struct cs_etm_trace_params t_params[])
+{
+	struct cs_etm_decoder *decoder;
+	ocsd_dcd_tree_src_t format;
+	u32 flags;
+	int i, ret;
+
+	if ((!t_params) || (!d_params))
+		return NULL;
+
+	decoder = zalloc(sizeof(*decoder));
+
+	if (!decoder)
+		return NULL;
+
+	decoder->data = d_params->data;
+	decoder->prev_return = OCSD_RESP_CONT;
+	format = (d_params->formatted ? OCSD_TRC_SRC_FRAME_FORMATTED :
+					 OCSD_TRC_SRC_SINGLE);
+	flags = 0;
+	flags |= (d_params->fsyncs ? OCSD_DFRMTR_HAS_FSYNCS : 0);
+	flags |= (d_params->hsyncs ? OCSD_DFRMTR_HAS_HSYNCS : 0);
+	flags |= (d_params->frame_aligned ? OCSD_DFRMTR_FRAME_MEM_ALIGN : 0);
+
+	/*
+	 * Drivers may add barrier frames when used with perf, set up to
+	 * handle this. Barriers const of FSYNC packet repeated 4 times.
+	 */
+	flags |= OCSD_DFRMTR_RESET_ON_4X_FSYNC;
+
+	/* Create decode tree for the data source */
+	decoder->dcd_tree = ocsd_create_dcd_tree(format, flags);
+
+	if (decoder->dcd_tree == 0)
+		goto err_free_decoder;
+
+	/* init library print logging support */
+	ret = cs_etm_decoder__init_def_logger_printing(d_params, decoder);
+	if (ret != 0)
+		goto err_free_decoder;
+
+	for (i = 0; i < decoders; i++) {
+		ret = cs_etm_decoder__create_etm_decoder(d_params,
+							 &t_params[i],
+							 decoder);
+		if (ret != 0)
+			goto err_free_decoder;
+	}
+
+	return decoder;
+
+err_free_decoder:
+	cs_etm_decoder__free(decoder);
+	return NULL;
+}
+
+int cs_etm_decoder__process_data_block(struct cs_etm_decoder *decoder,
+				       u64 indx, const u8 *buf,
+				       size_t len, size_t *consumed)
+{
+	int ret = 0;
+	ocsd_datapath_resp_t cur = OCSD_RESP_CONT;
+	ocsd_datapath_resp_t prev_return = decoder->prev_return;
+	size_t processed = 0;
+	u32 count;
+
+	while (processed < len) {
+		if (OCSD_DATA_RESP_IS_WAIT(prev_return)) {
+			cur = ocsd_dt_process_data(decoder->dcd_tree,
+						   OCSD_OP_FLUSH,
+						   0,
+						   0,
+						   NULL,
+						   NULL);
+		} else if (OCSD_DATA_RESP_IS_CONT(prev_return)) {
+			cur = ocsd_dt_process_data(decoder->dcd_tree,
+						   OCSD_OP_DATA,
+						   indx + processed,
+						   len - processed,
+						   &buf[processed],
+						   &count);
+			processed += count;
+		} else {
+			ret = -EINVAL;
+			break;
+		}
+
+		/*
+		 * Return to the input code if the packet buffer is full.
+		 * Flushing will get done once the packet buffer has been
+		 * processed.
+		 */
+		if (OCSD_DATA_RESP_IS_WAIT(cur))
+			break;
+
+		prev_return = cur;
+	}
+
+	decoder->prev_return = cur;
+	*consumed = processed;
+
+	return ret;
+}
+
+void cs_etm_decoder__free(struct cs_etm_decoder *decoder)
+{
+	if (!decoder)
+		return;
+
+	ocsd_destroy_dcd_tree(decoder->dcd_tree);
+	decoder->dcd_tree = NULL;
+	free(decoder);
+}
+
+const char *cs_etm_decoder__get_name(struct cs_etm_decoder *decoder)
+{
+	return decoder->decoder_name;
+}
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
new file mode 100644
index 000000000..12c782fa6
--- /dev/null
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
@@ -0,0 +1,111 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * Copyright(C) 2015-2018 Linaro Limited.
+ *
+ * Author: Tor Jeremiassen <tor@ti.com>
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ */
+
+#ifndef INCLUDE__CS_ETM_DECODER_H__
+#define INCLUDE__CS_ETM_DECODER_H__
+
+#include <linux/types.h>
+#include <opencsd/ocsd_if_types.h>
+#include <stdio.h>
+
+struct cs_etm_decoder;
+struct cs_etm_packet;
+struct cs_etm_packet_queue;
+
+struct cs_etm_queue;
+
+typedef u32 (*cs_etm_mem_cb_type)(struct cs_etm_queue *, u8, u64, size_t, u8 *,
+				  const ocsd_mem_space_acc_t);
+
+struct cs_etmv3_trace_params {
+	u32 reg_ctrl;
+	u32 reg_trc_id;
+	u32 reg_ccer;
+	u32 reg_idr;
+};
+
+struct cs_etmv4_trace_params {
+	u32 reg_idr0;
+	u32 reg_idr1;
+	u32 reg_idr2;
+	u32 reg_idr8;
+	u32 reg_configr;
+	u32 reg_traceidr;
+};
+
+struct cs_ete_trace_params {
+	u32 reg_idr0;
+	u32 reg_idr1;
+	u32 reg_idr2;
+	u32 reg_idr8;
+	u32 reg_configr;
+	u32 reg_traceidr;
+	u32 reg_devarch;
+};
+
+struct cs_etm_trace_params {
+	int protocol;
+	union {
+		struct cs_etmv3_trace_params etmv3;
+		struct cs_etmv4_trace_params etmv4;
+		struct cs_ete_trace_params ete;
+	};
+};
+
+struct cs_etm_decoder_params {
+	int operation;
+	void (*packet_printer)(const char *msg, void *data);
+	cs_etm_mem_cb_type mem_acc_cb;
+	bool formatted;
+	bool fsyncs;
+	bool hsyncs;
+	bool frame_aligned;
+	void *data;
+};
+
+/*
+ * The following enums are indexed starting with 1 to align with the
+ * open source coresight trace decoder library.
+ */
+enum {
+	CS_ETM_PROTO_ETMV3 = 1,
+	CS_ETM_PROTO_ETMV4i,
+	CS_ETM_PROTO_ETMV4d,
+	CS_ETM_PROTO_PTM,
+	CS_ETM_PROTO_ETE
+};
+
+enum cs_etm_decoder_operation {
+	CS_ETM_OPERATION_PRINT = 1,
+	CS_ETM_OPERATION_DECODE,
+	CS_ETM_OPERATION_MAX,
+};
+
+int cs_etm_decoder__process_data_block(struct cs_etm_decoder *decoder,
+				       u64 indx, const u8 *buf,
+				       size_t len, size_t *consumed);
+
+struct cs_etm_decoder *
+cs_etm_decoder__new(int num_cpu,
+		    struct cs_etm_decoder_params *d_params,
+		    struct cs_etm_trace_params t_params[]);
+
+void cs_etm_decoder__free(struct cs_etm_decoder *decoder);
+
+int cs_etm_decoder__add_mem_access_cb(struct cs_etm_decoder *decoder,
+				      u64 start, u64 end,
+				      cs_etm_mem_cb_type cb_func);
+
+int cs_etm_decoder__get_packet(struct cs_etm_packet_queue *packet_queue,
+			       struct cs_etm_packet *packet);
+
+int cs_etm_decoder__reset(struct cs_etm_decoder *decoder);
+const char *cs_etm_decoder__get_name(struct cs_etm_decoder *decoder);
+
+#endif /* INCLUDE__CS_ETM_DECODER_H__ */