// SPDX-License-Identifier: GPL-2.0
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/*
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* Test module for in-kernel sythetic event creation and generation.
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*
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* Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org>
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*/
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#include <linux/module.h>
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#include <linux/trace_events.h>
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/*
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* This module is a simple test of basic functionality for in-kernel
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* synthetic event creation and generation, the first and second tests
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* using synth_event_gen_cmd_start() and synth_event_add_field(), the
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* third uses synth_event_create() to do it all at once with a static
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* field array.
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*
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* Following that are a few examples using the created events to test
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* various ways of tracing a synthetic event.
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*
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* To test, select CONFIG_SYNTH_EVENT_GEN_TEST and build the module.
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* Then:
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*
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* # insmod kernel/trace/synth_event_gen_test.ko
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* # cat /sys/kernel/debug/tracing/trace
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*
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* You should see several events in the trace buffer -
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* "create_synth_test", "empty_synth_test", and several instances of
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* "gen_synth_test".
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*
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* To remove the events, remove the module:
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*
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* # rmmod synth_event_gen_test
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*
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*/
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static struct trace_event_file *create_synth_test;
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static struct trace_event_file *empty_synth_test;
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static struct trace_event_file *gen_synth_test;
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/*
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* Test to make sure we can create a synthetic event, then add more
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* fields.
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*/
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static int __init test_gen_synth_cmd(void)
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{
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struct dynevent_cmd cmd;
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u64 vals[7];
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char *buf;
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int ret;
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/* Create a buffer to hold the generated command */
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buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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/* Before generating the command, initialize the cmd object */
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synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
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/*
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* Create the empty gen_synth_test synthetic event with the
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* first 4 fields.
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*/
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ret = synth_event_gen_cmd_start(&cmd, "gen_synth_test", THIS_MODULE,
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"pid_t", "next_pid_field",
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"char[16]", "next_comm_field",
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"u64", "ts_ns",
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"u64", "ts_ms");
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if (ret)
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goto free;
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/* Use synth_event_add_field to add the rest of the fields */
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ret = synth_event_add_field(&cmd, "unsigned int", "cpu");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "char[64]", "my_string_field");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "int", "my_int_field");
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if (ret)
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goto free;
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ret = synth_event_gen_cmd_end(&cmd);
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if (ret)
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goto free;
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/*
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* Now get the gen_synth_test event file. We need to prevent
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* the instance and event from disappearing from underneath
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* us, which trace_get_event_file() does (though in this case
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* we're using the top-level instance which never goes away).
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*/
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gen_synth_test = trace_get_event_file(NULL, "synthetic",
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"gen_synth_test");
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if (IS_ERR(gen_synth_test)) {
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ret = PTR_ERR(gen_synth_test);
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goto delete;
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}
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/* Enable the event or you won't see anything */
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ret = trace_array_set_clr_event(gen_synth_test->tr,
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"synthetic", "gen_synth_test", true);
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if (ret) {
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trace_put_event_file(gen_synth_test);
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goto delete;
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}
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/* Create some bogus values just for testing */
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vals[0] = 777; /* next_pid_field */
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vals[1] = (u64)(long)"hula hoops"; /* next_comm_field */
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vals[2] = 1000000; /* ts_ns */
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vals[3] = 1000; /* ts_ms */
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vals[4] = raw_smp_processor_id(); /* cpu */
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vals[5] = (u64)(long)"thneed"; /* my_string_field */
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vals[6] = 598; /* my_int_field */
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/* Now generate a gen_synth_test event */
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ret = synth_event_trace_array(gen_synth_test, vals, ARRAY_SIZE(vals));
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free:
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kfree(buf);
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return ret;
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delete:
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/* We got an error after creating the event, delete it */
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synth_event_delete("gen_synth_test");
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goto free;
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}
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/*
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* Test to make sure we can create an initially empty synthetic event,
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* then add all the fields.
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*/
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static int __init test_empty_synth_event(void)
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{
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struct dynevent_cmd cmd;
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u64 vals[7];
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char *buf;
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int ret;
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/* Create a buffer to hold the generated command */
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buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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/* Before generating the command, initialize the cmd object */
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synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
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/*
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* Create the empty_synth_test synthetic event with no fields.
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*/
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ret = synth_event_gen_cmd_start(&cmd, "empty_synth_test", THIS_MODULE);
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if (ret)
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goto free;
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/* Use synth_event_add_field to add all of the fields */
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ret = synth_event_add_field(&cmd, "pid_t", "next_pid_field");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "char[16]", "next_comm_field");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "u64", "ts_ns");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "u64", "ts_ms");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "unsigned int", "cpu");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "char[64]", "my_string_field");
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if (ret)
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goto free;
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ret = synth_event_add_field(&cmd, "int", "my_int_field");
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if (ret)
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goto free;
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/* All fields have been added, close and register the synth event */
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ret = synth_event_gen_cmd_end(&cmd);
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if (ret)
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goto free;
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/*
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* Now get the empty_synth_test event file. We need to
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* prevent the instance and event from disappearing from
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* underneath us, which trace_get_event_file() does (though in
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* this case we're using the top-level instance which never
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* goes away).
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*/
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empty_synth_test = trace_get_event_file(NULL, "synthetic",
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"empty_synth_test");
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if (IS_ERR(empty_synth_test)) {
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ret = PTR_ERR(empty_synth_test);
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goto delete;
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}
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/* Enable the event or you won't see anything */
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ret = trace_array_set_clr_event(empty_synth_test->tr,
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"synthetic", "empty_synth_test", true);
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if (ret) {
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trace_put_event_file(empty_synth_test);
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goto delete;
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}
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/* Create some bogus values just for testing */
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vals[0] = 777; /* next_pid_field */
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vals[1] = (u64)(long)"tiddlywinks"; /* next_comm_field */
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vals[2] = 1000000; /* ts_ns */
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vals[3] = 1000; /* ts_ms */
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vals[4] = raw_smp_processor_id(); /* cpu */
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vals[5] = (u64)(long)"thneed_2.0"; /* my_string_field */
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vals[6] = 399; /* my_int_field */
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/* Now trace an empty_synth_test event */
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ret = synth_event_trace_array(empty_synth_test, vals, ARRAY_SIZE(vals));
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free:
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kfree(buf);
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return ret;
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delete:
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/* We got an error after creating the event, delete it */
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synth_event_delete("empty_synth_test");
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goto free;
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}
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static struct synth_field_desc create_synth_test_fields[] = {
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{ .type = "pid_t", .name = "next_pid_field" },
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{ .type = "char[16]", .name = "next_comm_field" },
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{ .type = "u64", .name = "ts_ns" },
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{ .type = "char[]", .name = "dynstring_field_1" },
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{ .type = "u64", .name = "ts_ms" },
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{ .type = "unsigned int", .name = "cpu" },
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{ .type = "char[64]", .name = "my_string_field" },
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{ .type = "char[]", .name = "dynstring_field_2" },
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{ .type = "int", .name = "my_int_field" },
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};
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/*
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* Test synthetic event creation all at once from array of field
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* descriptors.
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*/
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static int __init test_create_synth_event(void)
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{
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u64 vals[9];
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int ret;
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/* Create the create_synth_test event with the fields above */
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ret = synth_event_create("create_synth_test",
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create_synth_test_fields,
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ARRAY_SIZE(create_synth_test_fields),
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THIS_MODULE);
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if (ret)
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goto out;
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/*
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* Now get the create_synth_test event file. We need to
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* prevent the instance and event from disappearing from
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* underneath us, which trace_get_event_file() does (though in
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* this case we're using the top-level instance which never
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* goes away).
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*/
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create_synth_test = trace_get_event_file(NULL, "synthetic",
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"create_synth_test");
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if (IS_ERR(create_synth_test)) {
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ret = PTR_ERR(create_synth_test);
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goto delete;
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}
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/* Enable the event or you won't see anything */
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ret = trace_array_set_clr_event(create_synth_test->tr,
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"synthetic", "create_synth_test", true);
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if (ret) {
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trace_put_event_file(create_synth_test);
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goto delete;
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}
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/* Create some bogus values just for testing */
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vals[0] = 777; /* next_pid_field */
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vals[1] = (u64)(long)"tiddlywinks"; /* next_comm_field */
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vals[2] = 1000000; /* ts_ns */
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vals[3] = (u64)(long)"xrayspecs"; /* dynstring_field_1 */
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vals[4] = 1000; /* ts_ms */
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vals[5] = raw_smp_processor_id(); /* cpu */
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vals[6] = (u64)(long)"thneed"; /* my_string_field */
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vals[7] = (u64)(long)"kerplunk"; /* dynstring_field_2 */
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vals[8] = 398; /* my_int_field */
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/* Now generate a create_synth_test event */
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ret = synth_event_trace_array(create_synth_test, vals, ARRAY_SIZE(vals));
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out:
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return ret;
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delete:
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/* We got an error after creating the event, delete it */
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ret = synth_event_delete("create_synth_test");
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goto out;
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}
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/*
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* Test tracing a synthetic event by reserving trace buffer space,
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* then filling in fields one after another.
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*/
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static int __init test_add_next_synth_val(void)
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{
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struct synth_event_trace_state trace_state;
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int ret;
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/* Start by reserving space in the trace buffer */
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ret = synth_event_trace_start(gen_synth_test, &trace_state);
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if (ret)
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return ret;
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/* Write some bogus values into the trace buffer, one after another */
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/* next_pid_field */
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ret = synth_event_add_next_val(777, &trace_state);
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if (ret)
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goto out;
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/* next_comm_field */
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ret = synth_event_add_next_val((u64)(long)"slinky", &trace_state);
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if (ret)
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goto out;
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/* ts_ns */
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ret = synth_event_add_next_val(1000000, &trace_state);
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if (ret)
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goto out;
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/* ts_ms */
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ret = synth_event_add_next_val(1000, &trace_state);
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if (ret)
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goto out;
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/* cpu */
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ret = synth_event_add_next_val(raw_smp_processor_id(), &trace_state);
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if (ret)
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goto out;
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/* my_string_field */
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ret = synth_event_add_next_val((u64)(long)"thneed_2.01", &trace_state);
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if (ret)
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goto out;
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/* my_int_field */
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ret = synth_event_add_next_val(395, &trace_state);
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out:
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/* Finally, commit the event */
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ret = synth_event_trace_end(&trace_state);
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return ret;
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}
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/*
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* Test tracing a synthetic event by reserving trace buffer space,
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* then filling in fields using field names, which can be done in any
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* order.
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*/
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static int __init test_add_synth_val(void)
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{
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struct synth_event_trace_state trace_state;
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int ret;
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/* Start by reserving space in the trace buffer */
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ret = synth_event_trace_start(gen_synth_test, &trace_state);
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if (ret)
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return ret;
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/* Write some bogus values into the trace buffer, using field names */
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ret = synth_event_add_val("ts_ns", 1000000, &trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("ts_ms", 1000, &trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("cpu", raw_smp_processor_id(), &trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("next_pid_field", 777, &trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("next_comm_field", (u64)(long)"silly putty",
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&trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("my_string_field", (u64)(long)"thneed_9",
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&trace_state);
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if (ret)
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goto out;
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ret = synth_event_add_val("my_int_field", 3999, &trace_state);
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out:
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/* Finally, commit the event */
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ret = synth_event_trace_end(&trace_state);
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return ret;
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}
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/*
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* Test tracing a synthetic event all at once from array of values.
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*/
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static int __init test_trace_synth_event(void)
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{
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int ret;
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/* Trace some bogus values just for testing */
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ret = synth_event_trace(create_synth_test, 9, /* number of values */
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(u64)444, /* next_pid_field */
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(u64)(long)"clackers", /* next_comm_field */
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(u64)1000000, /* ts_ns */
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(u64)(long)"viewmaster",/* dynstring_field_1 */
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(u64)1000, /* ts_ms */
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(u64)raw_smp_processor_id(), /* cpu */
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(u64)(long)"Thneed", /* my_string_field */
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(u64)(long)"yoyos", /* dynstring_field_2 */
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(u64)999); /* my_int_field */
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return ret;
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}
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static int __init synth_event_gen_test_init(void)
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{
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int ret;
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ret = test_gen_synth_cmd();
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if (ret)
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return ret;
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ret = test_empty_synth_event();
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if (ret) {
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WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
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"synthetic",
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"gen_synth_test", false));
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trace_put_event_file(gen_synth_test);
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WARN_ON(synth_event_delete("gen_synth_test"));
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goto out;
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}
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ret = test_create_synth_event();
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if (ret) {
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WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
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"synthetic",
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"gen_synth_test", false));
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trace_put_event_file(gen_synth_test);
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WARN_ON(synth_event_delete("gen_synth_test"));
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WARN_ON(trace_array_set_clr_event(empty_synth_test->tr,
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"synthetic",
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"empty_synth_test", false));
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trace_put_event_file(empty_synth_test);
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WARN_ON(synth_event_delete("empty_synth_test"));
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goto out;
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}
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ret = test_add_next_synth_val();
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WARN_ON(ret);
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ret = test_add_synth_val();
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WARN_ON(ret);
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ret = test_trace_synth_event();
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WARN_ON(ret);
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out:
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return ret;
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}
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static void __exit synth_event_gen_test_exit(void)
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{
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/* Disable the event or you can't remove it */
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WARN_ON(trace_array_set_clr_event(gen_synth_test->tr,
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"synthetic",
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"gen_synth_test", false));
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/* Now give the file and instance back */
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trace_put_event_file(gen_synth_test);
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/* Now unregister and free the synthetic event */
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WARN_ON(synth_event_delete("gen_synth_test"));
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/* Disable the event or you can't remove it */
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WARN_ON(trace_array_set_clr_event(empty_synth_test->tr,
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"synthetic",
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"empty_synth_test", false));
|
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/* Now give the file and instance back */
|
trace_put_event_file(empty_synth_test);
|
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/* Now unregister and free the synthetic event */
|
WARN_ON(synth_event_delete("empty_synth_test"));
|
|
/* Disable the event or you can't remove it */
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WARN_ON(trace_array_set_clr_event(create_synth_test->tr,
|
"synthetic",
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"create_synth_test", false));
|
|
/* Now give the file and instance back */
|
trace_put_event_file(create_synth_test);
|
|
/* Now unregister and free the synthetic event */
|
WARN_ON(synth_event_delete("create_synth_test"));
|
}
|
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module_init(synth_event_gen_test_init)
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module_exit(synth_event_gen_test_exit)
|
|
MODULE_AUTHOR("Tom Zanussi");
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MODULE_DESCRIPTION("synthetic event generation test");
|
MODULE_LICENSE("GPL v2");
|
