From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5574C32771 for ; Fri, 24 Jan 2020 22:56:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9661D22464 for ; Fri, 24 Jan 2020 22:56:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579906602; bh=BZ24rNXNnEWMgqioQfJk/5pdtgaudTTDXR88DPBdOqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=RxqGiPW6MZBzDaQ/FPxzJRVb7ioL4pXBCkNAPqf9jhDXZro4GuStuzI0vHO+stLf+ nX/w74YeUPg5SGctgmomv5DqhrIklQT194PMdBMtg5ZHFSsjgRvIOS0yF7c7E/L3mo woUCG02ShY3eTIG7fpHYTDd5XOiixFcMi+P+EySo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729441AbgAXW4k (ORCPT ); Fri, 24 Jan 2020 17:56:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:39544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729416AbgAXW4j (ORCPT ); Fri, 24 Jan 2020 17:56:39 -0500 Received: from localhost.localdomain (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B070920838; Fri, 24 Jan 2020 22:56:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579906598; bh=BZ24rNXNnEWMgqioQfJk/5pdtgaudTTDXR88DPBdOqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=cfZot1Bg5sloimUIK17Wlu23QNJ9SB5Y8NLvC9neQzYJgUQy/vsXfw0qHFMqNuoKR LyCQkeBtya/8du3+l27ZXaexwtJZIxM0Ja+c0cXdO/6Lf3R7fxO2b5fomkQqxex+ex OOPQfmFXynPOhKePPNZC/3Qq9i0umzVH9vPy6/G4= From: Tom Zanussi To: rostedt@goodmis.org Cc: artem.bityutskiy@linux.intel.com, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, ndesaulniers@google.com Subject: [PATCH v3 05/12] tracing: Add synthetic event command generation functions Date: Fri, 24 Jan 2020 16:56:16 -0600 Message-Id: <1e76e618a5c5e3cedcda4bbf8ca9f5954ebc44de.1579904761.git.zanussi@kernel.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Add functions used to generate synthetic event commands, built on top of the dynevent_cmd interface. synth_event_gen_cmd_start() is used to create a synthetic event command using a variable arg list and synth_event_gen_cmd_array_start() does the same thing but using an array of field descriptors. synth_event_add_field(), synth_event_add_field_str() and synth_event_add_fields() can be used to add single fields one by one or as a group. Once all desired fields are added, synth_event_gen_cmd_end() is used to actually execute the command and create the event. synth_event_create() does everything, including creating the event, in a single call. Signed-off-by: Tom Zanussi --- include/linux/trace_events.h | 37 ++++ kernel/trace/trace_events_hist.c | 379 ++++++++++++++++++++++++++++++++++++++- 2 files changed, 412 insertions(+), 4 deletions(-) diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 651b03d5e272..07b83532a3c6 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -357,6 +357,7 @@ extern void trace_put_event_file(struct trace_event_file *file); #define MAX_DYNEVENT_CMD_LEN (2048) enum dynevent_type { + DYNEVENT_TYPE_SYNTH = 1, DYNEVENT_TYPE_NONE, }; @@ -379,6 +380,42 @@ extern int dynevent_create(struct dynevent_cmd *cmd); extern int synth_event_delete(const char *name); +extern void synth_event_cmd_init(struct dynevent_cmd *cmd, + char *buf, int maxlen); + +extern int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, + const char *name, + struct module *mod, ...); + +#define synth_event_gen_cmd_start(cmd, name, mod, ...) \ + __synth_event_gen_cmd_start(cmd, name, mod, ## __VA_ARGS__, NULL) + +struct synth_field_desc { + const char *type; + const char *name; +}; + +extern int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, + const char *name, + struct module *mod, + struct synth_field_desc *fields, + unsigned int n_fields); +extern int synth_event_create(const char *name, + struct synth_field_desc *fields, + unsigned int n_fields, struct module *mod); + +extern int synth_event_add_field(struct dynevent_cmd *cmd, + const char *type, + const char *name); +extern int synth_event_add_field_str(struct dynevent_cmd *cmd, + const char *type_name); +extern int synth_event_add_fields(struct dynevent_cmd *cmd, + struct synth_field_desc *fields, + unsigned int n_fields); + +#define synth_event_gen_cmd_end(cmd) \ + dynevent_create(cmd) + /* * Event file flags: * ENABLED - The event is enabled diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 94ee1e576a1e..2e7181ce51aa 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -374,7 +374,7 @@ struct hist_trigger_data { unsigned int n_save_var_str; }; -static int synth_event_create(int argc, const char **argv); +static int create_synth_event(int argc, const char **argv); static int synth_event_show(struct seq_file *m, struct dyn_event *ev); static int synth_event_release(struct dyn_event *ev); static bool synth_event_is_busy(struct dyn_event *ev); @@ -382,7 +382,7 @@ static bool synth_event_match(const char *system, const char *event, int argc, const char **argv, struct dyn_event *ev); static struct dyn_event_operations synth_event_ops = { - .create = synth_event_create, + .create = create_synth_event, .show = synth_event_show, .is_busy = synth_event_is_busy, .free = synth_event_release, @@ -407,6 +407,7 @@ struct synth_event { struct trace_event_class class; struct trace_event_call call; struct tracepoint *tp; + struct module *mod; }; static bool is_synth_event(struct dyn_event *ev) @@ -1286,6 +1287,273 @@ struct hist_var_data { struct hist_trigger_data *hist_data; }; +static int synth_event_check_arg_fn(void *data) +{ + struct dynevent_arg_pair *arg_pair = data; + int size; + + size = synth_field_size((char *)arg_pair->lhs); + + return size ? 0 : -EINVAL; +} + +/** + * synth_event_add_field - Add a new field to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @type: The type of the new field to add + * @name: The name of the new field to add + * + * Add a new field to a synthetic event cmd object. Field ordering is in + * the same order the fields are added. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_field(struct dynevent_cmd *cmd, const char *type, + const char *name) +{ + struct dynevent_arg_pair arg_pair; + int ret; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (!type || !name) + return -EINVAL; + + dynevent_arg_pair_init(&arg_pair, synth_event_check_arg_fn, 0, ';'); + + arg_pair.lhs = type; + arg_pair.rhs = name; + + ret = dynevent_arg_pair_add(cmd, &arg_pair); + if (ret) + return ret; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) + ret = -EINVAL; + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_field); + +/** + * synth_event_add_field_str - Add a new field to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @type_name: The type and name of the new field to add, as a single string + * + * Add a new field to a synthetic event cmd object, as a single + * string. The @type_name string is expected to be of the form 'type + * name', which will be appended by ';'. No sanity checking is done - + * what's passed in is assumed to already be well-formed. Field + * ordering is in the same order the fields are added. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name) +{ + struct dynevent_arg arg; + int ret; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (!type_name) + return -EINVAL; + + dynevent_arg_init(&arg, NULL, ';'); + + arg.str = type_name; + + ret = dynevent_arg_add(cmd, &arg); + if (ret) + return ret; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) + ret = -EINVAL; + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_field_str); + +/** + * synth_event_add_fields - Add multiple fields to a synthetic event cmd + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * + * Add a new set of fields to a synthetic event cmd object. The event + * fields that will be defined for the event should be passed in as an + * array of struct synth_field_desc, and the number of elements in the + * array passed in as n_fields. Field ordering will retain the + * ordering given in the fields array. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_add_fields(struct dynevent_cmd *cmd, + struct synth_field_desc *fields, + unsigned int n_fields) +{ + unsigned int i; + int ret = 0; + + for (i = 0; i < n_fields; i++) { + if (fields[i].type == NULL || fields[i].name == NULL) { + ret = -EINVAL; + break; + } + + ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); + if (ret) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_add_fields); + +/** + * __synth_event_gen_cmd_start - Start a synthetic event command from arg list + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @name: The name of the synthetic event + * @mod: The module creating the event, NULL if not created from a module + * @args: Variable number of arg (pairs), one pair for each field + * + * NOTE: Users normally won't want to call this function directly, but + * rather use the synth_event_gen_cmd_start() wrapper, which + * automatically adds a NULL to the end of the arg list. If this + * function is used directly, make sure the last arg in the variable + * arg list is NULL. + * + * Generate a synthetic event command to be executed by + * synth_event_gen_cmd_end(). This function can be used to generate + * the complete command or only the first part of it; in the latter + * case, synth_event_add_field(), synth_event_add_field_str(), or + * synth_event_add_fields() can be used to add more fields following + * this. + * + * There should be an even number variable args, each pair consisting + * of a type followed by a field name. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name, + struct module *mod, ...) +{ + struct dynevent_arg arg; + va_list args; + int ret; + + cmd->event_name = name; + cmd->private_data = mod; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + dynevent_arg_init(&arg, NULL, 0); + arg.str = name; + ret = dynevent_arg_add(cmd, &arg); + if (ret) + return ret; + + va_start(args, mod); + for (;;) { + const char *type, *name; + + type = va_arg(args, const char *); + if (!type) + break; + name = va_arg(args, const char *); + if (!name) + break; + + if (++cmd->n_fields > SYNTH_FIELDS_MAX) { + ret = -EINVAL; + break; + } + + ret = synth_event_add_field(cmd, type, name); + if (ret) + break; + } + va_end(args); + + return ret; +} +EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start); + +/** + * synth_event_gen_cmd_array_start - Start synthetic event command from an array + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @name: The name of the synthetic event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * + * Generate a synthetic event command to be executed by + * synth_event_gen_cmd_end(). This function can be used to generate + * the complete command or only the first part of it; in the latter + * case, synth_event_add_field(), synth_event_add_field_str(), or + * synth_event_add_fields() can be used to add more fields following + * this. + * + * The event fields that will be defined for the event should be + * passed in as an array of struct synth_field_desc, and the number of + * elements in the array passed in as n_fields. Field ordering will + * retain the ordering given in the fields array. + * + * See synth_field_size() for available types. If field_name contains + * [n] the field is considered to be an array. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name, + struct module *mod, + struct synth_field_desc *fields, + unsigned int n_fields) +{ + struct dynevent_arg arg; + unsigned int i; + int ret = 0; + + cmd->event_name = name; + cmd->private_data = mod; + + if (cmd->type != DYNEVENT_TYPE_SYNTH) + return -EINVAL; + + if (n_fields > SYNTH_FIELDS_MAX) + return -EINVAL; + + dynevent_arg_init(&arg, NULL, 0); + arg.str = name; + ret = dynevent_arg_add(cmd, &arg); + if (ret) + return ret; + + for (i = 0; i < n_fields; i++) { + if (fields[i].type == NULL || fields[i].name == NULL) + return -EINVAL; + + ret = synth_event_add_field(cmd, fields[i].type, fields[i].name); + if (ret) + break; + } + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start); + static int __create_synth_event(int argc, const char *name, const char **argv) { struct synth_field *field, *fields[SYNTH_FIELDS_MAX]; @@ -1354,6 +1622,56 @@ static int __create_synth_event(int argc, const char *name, const char **argv) goto out; } +/** + * synth_event_create - Create a new synthetic event + * @name: The name of the new sythetic event + * @fields: An array of type/name field descriptions + * @n_fields: The number of field descriptions contained in the fields array + * @mod: The module creating the event, NULL if not created from a module + * + * Create a new synthetic event with the given name under the + * trace/events/synthetic/ directory. The event fields that will be + * defined for the event should be passed in as an array of struct + * synth_field_desc, and the number elements in the array passed in as + * n_fields. Field ordering will retain the ordering given in the + * fields array. + * + * If the new synthetic event is being created from a module, the mod + * param must be non-NULL. This will ensure that the trace buffer + * won't contain unreadable events. + * + * The new synth event should be deleted using synth_event_delete() + * function. The new synthetic event can be generated from modules or + * other kernel code using trace_synth_event() and related functions. + * + * Return: 0 if successful, error otherwise. + */ +int synth_event_create(const char *name, struct synth_field_desc *fields, + unsigned int n_fields, struct module *mod) +{ + struct dynevent_cmd cmd; + char *buf; + int ret; + + buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN); + + ret = synth_event_gen_cmd_array_start(&cmd, name, mod, + fields, n_fields); + if (ret) + goto out; + + ret = synth_event_gen_cmd_end(&cmd); + out: + kfree(buf); + + return ret; +} +EXPORT_SYMBOL_GPL(synth_event_create); + static int destroy_synth_event(struct synth_event *se) { int ret; @@ -1382,14 +1700,33 @@ static int destroy_synth_event(struct synth_event *se) int synth_event_delete(const char *event_name) { struct synth_event *se = NULL; + struct module *mod = NULL; int ret = -ENOENT; mutex_lock(&event_mutex); se = find_synth_event(event_name); - if (se) + if (se) { + mod = se->mod; ret = destroy_synth_event(se); + } mutex_unlock(&event_mutex); + if (mod) { + mutex_lock(&trace_types_lock); + /* + * It is safest to reset the ring buffer if the module + * being unloaded registered any events that were + * used. The only worry is if a new module gets + * loaded, and takes on the same id as the events of + * this module. When printing out the buffer, traced + * events left over from this module may be passed to + * the new module events and unexpected results may + * occur. + */ + tracing_reset_all_online_cpus(); + mutex_unlock(&trace_types_lock); + } + return ret; } EXPORT_SYMBOL_GPL(synth_event_delete); @@ -1414,7 +1751,41 @@ int synth_event_run_command(const char *command) return trace_run_command(command, create_or_delete_synth_event); } -static int synth_event_create(int argc, const char **argv) +static int synth_event_run_cmd(struct dynevent_cmd *cmd) +{ + struct synth_event *se; + int ret; + + ret = trace_run_command(cmd->buf, create_or_delete_synth_event); + if (ret) + return ret; + + se = find_synth_event(cmd->event_name); + if (WARN_ON(!se)) + return -ENOENT; + + se->mod = cmd->private_data; + + return ret; +} + +/** + * synth_event_cmd_init - Initialize a synthetic event command object + * @cmd: A pointer to the dynevent_cmd struct representing the new event + * @buf: A pointer to the buffer used to build the command + * @maxlen: The length of the buffer passed in @buf + * + * Initialize a synthetic event command object. Use this before + * calling any of the other dyenvent_cmd functions. + */ +void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) +{ + dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH, + synth_event_run_cmd); +} +EXPORT_SYMBOL_GPL(synth_event_cmd_init); + +static int create_synth_event(int argc, const char **argv) { const char *name = argv[0]; int len; -- 2.14.1