+++ /dev/null
-/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
- *
- * probes/lttng-ftrace.c
- *
- * LTTng function tracer integration module.
- *
- * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- */
-
-/*
- * Ftrace function tracer does not seem to provide synchronization between probe
- * teardown and callback execution. Therefore, we make this module permanently
- * loaded (unloadable).
- *
- * TODO: Move to register_ftrace_function() (which is exported for
- * modules) for Linux >= 3.0. It is faster (only enables the selected
- * functions), and will stay there.
- */
-
-#include <linux/module.h>
-#include <linux/ftrace.h>
-#include <linux/slab.h>
-#include <lttng-events.h>
-#include <wrapper/ringbuffer/frontend_types.h>
-#include <wrapper/ftrace.h>
-#include <wrapper/vmalloc.h>
-#include <lttng-tracer.h>
-
-#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0))
-static
-void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip,
- struct trace_array *tr, struct ftrace_probe_ops *ops,
- void *data)
-{
- struct lttng_event *event = data;
- struct lttng_probe_ctx lttng_probe_ctx = {
- .event = event,
- .interruptible = !irqs_disabled(),
- };
- struct lttng_channel *chan = event->chan;
- struct lib_ring_buffer_ctx ctx;
- struct {
- unsigned long ip;
- unsigned long parent_ip;
- } payload;
- int ret;
-
- if (unlikely(!READ_ONCE(chan->session->active)))
- return;
- if (unlikely(!READ_ONCE(chan->enabled)))
- return;
- if (unlikely(!READ_ONCE(event->enabled)))
- return;
-
- lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx,
- sizeof(payload), lttng_alignof(payload), -1);
- ret = chan->ops->event_reserve(&ctx, event->id);
- if (ret < 0)
- return;
- payload.ip = ip;
- payload.parent_ip = parent_ip;
- lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
- chan->ops->event_write(&ctx, &payload, sizeof(payload));
- chan->ops->event_commit(&ctx);
- return;
-}
-#else
-static
-void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
-{
- struct lttng_event *event = *data;
- struct lttng_probe_ctx lttng_probe_ctx = {
- .event = event,
- .interruptible = !irqs_disabled(),
- };
- struct lttng_channel *chan = event->chan;
- struct lib_ring_buffer_ctx ctx;
- struct {
- unsigned long ip;
- unsigned long parent_ip;
- } payload;
- int ret;
-
- if (unlikely(!READ_ONCE(chan->session->active)))
- return;
- if (unlikely(!READ_ONCE(chan->enabled)))
- return;
- if (unlikely(!READ_ONCE(event->enabled)))
- return;
-
- lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx,
- sizeof(payload), lttng_alignof(payload), -1);
- ret = chan->ops->event_reserve(&ctx, event->id);
- if (ret < 0)
- return;
- payload.ip = ip;
- payload.parent_ip = parent_ip;
- lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
- chan->ops->event_write(&ctx, &payload, sizeof(payload));
- chan->ops->event_commit(&ctx);
- return;
-}
-#endif
-
-/*
- * Create event description
- */
-static
-int lttng_create_ftrace_event(const char *name, struct lttng_event *event)
-{
- struct lttng_event_field *fields;
- struct lttng_event_desc *desc;
- int ret;
-
- desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
- if (!desc)
- return -ENOMEM;
- desc->name = kstrdup(name, GFP_KERNEL);
- if (!desc->name) {
- ret = -ENOMEM;
- goto error_str;
- }
- desc->nr_fields = 2;
- desc->fields = fields =
- kzalloc(2 * sizeof(struct lttng_event_field), GFP_KERNEL);
- if (!desc->fields) {
- ret = -ENOMEM;
- goto error_fields;
- }
- fields[0].name = "ip";
- fields[0].type.atype = atype_integer;
- fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
- fields[0].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
- fields[0].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
- fields[0].type.u.basic.integer.reverse_byte_order = 0;
- fields[0].type.u.basic.integer.base = 16;
- fields[0].type.u.basic.integer.encoding = lttng_encode_none;
-
- fields[1].name = "parent_ip";
- fields[1].type.atype = atype_integer;
- fields[1].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
- fields[1].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
- fields[1].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
- fields[1].type.u.basic.integer.reverse_byte_order = 0;
- fields[1].type.u.basic.integer.base = 16;
- fields[1].type.u.basic.integer.encoding = lttng_encode_none;
-
- desc->owner = THIS_MODULE;
- event->desc = desc;
-
- return 0;
-
-error_fields:
- kfree(desc->name);
-error_str:
- kfree(desc);
- return ret;
-}
-
-static
-struct ftrace_probe_ops lttng_ftrace_ops = {
- .func = lttng_ftrace_handler,
-};
-
-int lttng_ftrace_register(const char *name,
- const char *symbol_name,
- struct lttng_event *event)
-{
- int ret;
-
- ret = lttng_create_ftrace_event(name, event);
- if (ret)
- goto error;
-
- event->u.ftrace.symbol_name = kstrdup(symbol_name, GFP_KERNEL);
- if (!event->u.ftrace.symbol_name)
- goto name_error;
-
- /* Ensure the memory we just allocated don't trigger page faults */
- wrapper_vmalloc_sync_all();
-
- ret = wrapper_register_ftrace_function_probe(event->u.ftrace.symbol_name,
- <tng_ftrace_ops, event);
- if (ret < 0)
- goto register_error;
- return 0;
-
-register_error:
- kfree(event->u.ftrace.symbol_name);
-name_error:
- kfree(event->desc->name);
- kfree(event->desc);
-error:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_ftrace_register);
-
-void lttng_ftrace_unregister(struct lttng_event *event)
-{
- wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
- <tng_ftrace_ops, event);
-}
-EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
-
-void lttng_ftrace_destroy_private(struct lttng_event *event)
-{
- kfree(event->u.ftrace.symbol_name);
- kfree(event->desc->fields);
- kfree(event->desc->name);
- kfree(event->desc);
-}
-EXPORT_SYMBOL_GPL(lttng_ftrace_destroy_private);
-
-int lttng_ftrace_init(void)
-{
- wrapper_vmalloc_sync_all();
- return 0;
-}
-module_init(lttng_ftrace_init)
-
-/*
- * Ftrace takes care of waiting for a grace period (RCU sched) at probe
- * unregistration, and disables preemption around probe call.
- */
-void lttng_ftrace_exit(void)
-{
-}
-module_exit(lttng_ftrace_exit)
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
-MODULE_DESCRIPTION("LTTng ftrace probes");
-MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
- __stringify(LTTNG_MODULES_MINOR_VERSION) "."
- __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
- LTTNG_MODULES_EXTRAVERSION);
projects / lttng-modules.git / blobdiff