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Diffstat (limited to '')
| -rw-r--r-- | kernel/trace/synth_event_gen_test.c | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/kernel/trace/synth_event_gen_test.c b/kernel/trace/synth_event_gen_test.c new file mode 100644 index 000000000..d944924cd --- /dev/null +++ b/kernel/trace/synth_event_gen_test.c @@ -0,0 +1,536 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test module for in-kernel synthetic event creation and generation. + * + * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org> + */ + +#include <linux/module.h> +#include <linux/trace_events.h> + +/* + * This module is a simple test of basic functionality for in-kernel + * synthetic event creation and generation, the first and second tests + * using synth_event_gen_cmd_start() and synth_event_add_field(), the + * third uses synth_event_create() to do it all at once with a static + * field array. + * + * Following that are a few examples using the created events to test + * various ways of tracing a synthetic event. + * + * To test, select CONFIG_SYNTH_EVENT_GEN_TEST and build the module. + * Then: + * + * # insmod kernel/trace/synth_event_gen_test.ko + * # cat /sys/kernel/debug/tracing/trace + * + * You should see several events in the trace buffer - + * "create_synth_test", "empty_synth_test", and several instances of + * "gen_synth_test". + * + * To remove the events, remove the module: + * + * # rmmod synth_event_gen_test + * + */ + +static struct trace_event_file *create_synth_test; +static struct trace_event_file *empty_synth_test; +static struct trace_event_file *gen_synth_test; + +/* + * Test to make sure we can create a synthetic event, then add more + * fields. + */ +static int __init test_gen_synth_cmd(void) +{ + struct dynevent_cmd cmd; + u64 vals[7]; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Create the empty gen_synth_test synthetic event with the + * first 4 fields. + */ + ret = synth_event_gen_cmd_start(&cmd, "gen_synth_test", THIS_MODULE, + "pid_t", "next_pid_field", + "char[16]", "next_comm_field", + "u64", "ts_ns", + "u64", "ts_ms"); + if (ret) + goto free; + + /* Use synth_event_add_field to add the rest of the fields */ + + ret = synth_event_add_field(&cmd, "unsigned int", "cpu"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "char[64]", "my_string_field"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "int", "my_int_field"); + if (ret) + goto free; + + ret = synth_event_gen_cmd_end(&cmd); + if (ret) + goto free; + + /* + * Now get the gen_synth_test event file. We need to prevent + * the instance and event from disappearing from underneath + * us, which trace_get_event_file() does (though in this case + * we're using the top-level instance which never goes away). + */ + gen_synth_test = trace_get_event_file(NULL, "synthetic", + "gen_synth_test"); + if (IS_ERR(gen_synth_test)) { + ret = PTR_ERR(gen_synth_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(gen_synth_test->tr, + "synthetic", "gen_synth_test", true); + if (ret) { + trace_put_event_file(gen_synth_test); + goto delete; + } + + /* Create some bogus values just for testing */ + + vals[0] = 777; /* next_pid_field */ + vals[1] = (u64)(long)"hula hoops"; /* next_comm_field */ + vals[2] = 1000000; /* ts_ns */ + vals[3] = 1000; /* ts_ms */ + vals[4] = raw_smp_processor_id(); /* cpu */ + vals[5] = (u64)(long)"thneed"; /* my_string_field */ + vals[6] = 598; /* my_int_field */ + + /* Now generate a gen_synth_test event */ + ret = synth_event_trace_array(gen_synth_test, vals, ARRAY_SIZE(vals)); + free: + kfree(buf); + return ret; + delete: + /* We got an error after creating the event, delete it */ + synth_event_delete("gen_synth_test"); + goto free; +} + +/* + * Test to make sure we can create an initially empty synthetic event, + * then add all the fields. + */ +static int __init test_empty_synth_event(void) +{ + struct dynevent_cmd cmd; + u64 vals[7]; + char *buf; + int ret; + + /* Create a buffer to hold the generated command */ + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* Before generating the command, initialize the cmd object */ + synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + /* + * Create the empty_synth_test synthetic event with no fields. + */ + ret = synth_event_gen_cmd_start(&cmd, "empty_synth_test", THIS_MODULE); + if (ret) + goto free; + + /* Use synth_event_add_field to add all of the fields */ + + ret = synth_event_add_field(&cmd, "pid_t", "next_pid_field"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "char[16]", "next_comm_field"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "u64", "ts_ns"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "u64", "ts_ms"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "unsigned int", "cpu"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "char[64]", "my_string_field"); + if (ret) + goto free; + + ret = synth_event_add_field(&cmd, "int", "my_int_field"); + if (ret) + goto free; + + /* All fields have been added, close and register the synth event */ + + ret = synth_event_gen_cmd_end(&cmd); + if (ret) + goto free; + + /* + * Now get the empty_synth_test event file. We need to + * prevent the instance and event from disappearing from + * underneath us, which trace_get_event_file() does (though in + * this case we're using the top-level instance which never + * goes away). + */ + empty_synth_test = trace_get_event_file(NULL, "synthetic", + "empty_synth_test"); + if (IS_ERR(empty_synth_test)) { + ret = PTR_ERR(empty_synth_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(empty_synth_test->tr, + "synthetic", "empty_synth_test", true); + if (ret) { + trace_put_event_file(empty_synth_test); + goto delete; + } + + /* Create some bogus values just for testing */ + + vals[0] = 777; /* next_pid_field */ + vals[1] = (u64)(long)"tiddlywinks"; /* next_comm_field */ + vals[2] = 1000000; /* ts_ns */ + vals[3] = 1000; /* ts_ms */ + vals[4] = raw_smp_processor_id(); /* cpu */ + vals[5] = (u64)(long)"thneed_2.0"; /* my_string_field */ + vals[6] = 399; /* my_int_field */ + + /* Now trace an empty_synth_test event */ + ret = synth_event_trace_array(empty_synth_test, vals, ARRAY_SIZE(vals)); + free: + kfree(buf); + return ret; + delete: + /* We got an error after creating the event, delete it */ + synth_event_delete("empty_synth_test"); + goto free; +} + +static struct synth_field_desc create_synth_test_fields[] = { + { .type = "pid_t", .name = "next_pid_field" }, + { .type = "char[16]", .name = "next_comm_field" }, + { .type = "u64", .name = "ts_ns" }, + { .type = "char[]", .name = "dynstring_field_1" }, + { .type = "u64", .name = "ts_ms" }, + { .type = "unsigned int", .name = "cpu" }, + { .type = "char[64]", .name = "my_string_field" }, + { .type = "char[]", .name = "dynstring_field_2" }, + { .type = "int", .name = "my_int_field" }, +}; + +/* + * Test synthetic event creation all at once from array of field + * descriptors. + */ +static int __init test_create_synth_event(void) +{ + u64 vals[9]; + int ret; + + /* Create the create_synth_test event with the fields above */ + ret = synth_event_create("create_synth_test", + create_synth_test_fields, + ARRAY_SIZE(create_synth_test_fields), + THIS_MODULE); + if (ret) + goto out; + + /* + * Now get the create_synth_test event file. We need to + * prevent the instance and event from disappearing from + * underneath us, which trace_get_event_file() does (though in + * this case we're using the top-level instance which never + * goes away). + */ + create_synth_test = trace_get_event_file(NULL, "synthetic", + "create_synth_test"); + if (IS_ERR(create_synth_test)) { + ret = PTR_ERR(create_synth_test); + goto delete; + } + + /* Enable the event or you won't see anything */ + ret = trace_array_set_clr_event(create_synth_test->tr, + "synthetic", "create_synth_test", true); + if (ret) { + trace_put_event_file(create_synth_test); + goto delete; + } + + /* Create some bogus values just for testing */ + + vals[0] = 777; /* next_pid_field */ + vals[1] = (u64)(long)"tiddlywinks"; /* next_comm_field */ + vals[2] = 1000000; /* ts_ns */ + vals[3] = (u64)(long)"xrayspecs"; /* dynstring_field_1 */ + vals[4] = 1000; /* ts_ms */ + vals[5] = raw_smp_processor_id(); /* cpu */ + vals[6] = (u64)(long)"thneed"; /* my_string_field */ + vals[7] = (u64)(long)"kerplunk"; /* dynstring_field_2 */ + vals[8] = 398; /* my_int_field */ + + /* Now generate a create_synth_test event */ + ret = synth_event_trace_array(create_synth_test, vals, ARRAY_SIZE(vals)); + out: + return ret; + delete: + /* We got an error after creating the event, delete it */ + synth_event_delete("create_synth_test"); + + goto out; +} + +/* + * Test tracing a synthetic event by reserving trace buffer space, + * then filling in fields one after another. + */ +static int __init test_add_next_synth_val(void) +{ + struct synth_event_trace_state trace_state; + int ret; + + /* Start by reserving space in the trace buffer */ + ret = synth_event_trace_start(gen_synth_test, &trace_state); + if (ret) + return ret; + + /* Write some bogus values into the trace buffer, one after another */ + + /* next_pid_field */ + ret = synth_event_add_next_val(777, &trace_state); + if (ret) + goto out; + + /* next_comm_field */ + ret = synth_event_add_next_val((u64)(long)"slinky", &trace_state); + if (ret) + goto out; + + /* ts_ns */ + ret = synth_event_add_next_val(1000000, &trace_state); + if (ret) + goto out; + + /* ts_ms */ + ret = synth_event_add_next_val(1000, &trace_state); + if (ret) + goto out; + + /* cpu */ + ret = synth_event_add_next_val(raw_smp_processor_id(), &trace_state); + if (ret) + goto out; + + /* my_string_field */ + ret = synth_event_add_next_val((u64)(long)"thneed_2.01", &trace_state); + if (ret) + goto out; + + /* my_int_field */ + ret = synth_event_add_next_val(395, &trace_state); + out: + /* Finally, commit the event */ + ret = synth_event_trace_end(&trace_state); + + return ret; +} + +/* + * Test tracing a synthetic event by reserving trace buffer space, + * then filling in fields using field names, which can be done in any + * order. + */ +static int __init test_add_synth_val(void) +{ + struct synth_event_trace_state trace_state; + int ret; + + /* Start by reserving space in the trace buffer */ + ret = synth_event_trace_start(gen_synth_test, &trace_state); + if (ret) + return ret; + + /* Write some bogus values into the trace buffer, using field names */ + + ret = synth_event_add_val("ts_ns", 1000000, &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("ts_ms", 1000, &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("cpu", raw_smp_processor_id(), &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("next_pid_field", 777, &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("next_comm_field", (u64)(long)"silly putty", + &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("my_string_field", (u64)(long)"thneed_9", + &trace_state); + if (ret) + goto out; + + ret = synth_event_add_val("my_int_field", 3999, &trace_state); + out: + /* Finally, commit the event */ + ret = synth_event_trace_end(&trace_state); + + return ret; +} + +/* + * Test tracing a synthetic event all at once from array of values. + */ +static int __init test_trace_synth_event(void) +{ + int ret; + + /* Trace some bogus values just for testing */ + ret = synth_event_trace(create_synth_test, 9, /* number of values */ + (u64)444, /* next_pid_field */ + (u64)(long)"clackers", /* next_comm_field */ + (u64)1000000, /* ts_ns */ + (u64)(long)"viewmaster",/* dynstring_field_1 */ + (u64)1000, /* ts_ms */ + (u64)raw_smp_processor_id(), /* cpu */ + (u64)(long)"Thneed", /* my_string_field */ + (u64)(long)"yoyos", /* dynstring_field_2 */ + (u64)999); /* my_int_field */ + return ret; +} + +static int __init synth_event_gen_test_init(void) +{ + int ret; + + ret = test_gen_synth_cmd(); + if (ret) + return ret; + + ret = test_empty_synth_event(); + if (ret) { + WARN_ON(trace_array_set_clr_event(gen_synth_test->tr, + "synthetic", + "gen_synth_test", false)); + trace_put_event_file(gen_synth_test); + WARN_ON(synth_event_delete("gen_synth_test")); + goto out; + } + + ret = test_create_synth_event(); + if (ret) { + WARN_ON(trace_array_set_clr_event(gen_synth_test->tr, + "synthetic", + "gen_synth_test", false)); + trace_put_event_file(gen_synth_test); + WARN_ON(synth_event_delete("gen_synth_test")); + + WARN_ON(trace_array_set_clr_event(empty_synth_test->tr, + "synthetic", + "empty_synth_test", false)); + trace_put_event_file(empty_synth_test); + WARN_ON(synth_event_delete("empty_synth_test")); + goto out; + } + + ret = test_add_next_synth_val(); + WARN_ON(ret); + + ret = test_add_synth_val(); + WARN_ON(ret); + + ret = test_trace_synth_event(); + WARN_ON(ret); + + /* Disable when done */ + trace_array_set_clr_event(gen_synth_test->tr, + "synthetic", + "gen_synth_test", false); + trace_array_set_clr_event(empty_synth_test->tr, + "synthetic", + "empty_synth_test", false); + trace_array_set_clr_event(create_synth_test->tr, + "synthetic", + "create_synth_test", false); + out: + return ret; +} + +static void __exit synth_event_gen_test_exit(void) +{ + /* Disable the event or you can't remove it */ + WARN_ON(trace_array_set_clr_event(gen_synth_test->tr, + "synthetic", + "gen_synth_test", false)); + + /* Now give the file and instance back */ + trace_put_event_file(gen_synth_test); + + /* Now unregister and free the synthetic event */ + WARN_ON(synth_event_delete("gen_synth_test")); + + /* Disable the event or you can't remove it */ + WARN_ON(trace_array_set_clr_event(empty_synth_test->tr, + "synthetic", + "empty_synth_test", false)); + + /* Now give the file and instance back */ + trace_put_event_file(empty_synth_test); + + /* Now unregister and free the synthetic event */ + WARN_ON(synth_event_delete("empty_synth_test")); + + /* Disable the event or you can't remove it */ + WARN_ON(trace_array_set_clr_event(create_synth_test->tr, + "synthetic", + "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")); +} + +module_init(synth_event_gen_test_init) +module_exit(synth_event_gen_test_exit) + +MODULE_AUTHOR("Tom Zanussi"); +MODULE_DESCRIPTION("synthetic event generation test"); +MODULE_LICENSE("GPL v2"); |