+++ /dev/null
-/*
- * probes/lttng-kprobes.c
- *
- * LTTng kprobes integration module.
- *
- * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#include <linux/module.h>
-#include <linux/kprobes.h>
-#include <linux/slab.h>
-#include "../lttng-events.h"
-#include "../wrapper/ringbuffer/frontend_types.h"
-#include "../wrapper/vmalloc.h"
-#include "../lttng-tracer.h"
-
-static
-int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
-{
- struct lttng_event *event =
- container_of(p, struct lttng_event, u.kprobe.kp);
- struct lttng_channel *chan = event->chan;
- struct lib_ring_buffer_ctx ctx;
- int ret;
- unsigned long data = (unsigned long) p->addr;
-
- if (unlikely(!ACCESS_ONCE(chan->session->active)))
- return 0;
- if (unlikely(!ACCESS_ONCE(chan->enabled)))
- return 0;
- if (unlikely(!ACCESS_ONCE(event->enabled)))
- return 0;
-
- lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(data),
- lttng_alignof(data), -1);
- ret = chan->ops->event_reserve(&ctx, event->id);
- if (ret < 0)
- return 0;
- lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data));
- chan->ops->event_write(&ctx, &data, sizeof(data));
- chan->ops->event_commit(&ctx);
- return 0;
-}
-
-/*
- * Create event description
- */
-static
-int lttng_create_kprobe_event(const char *name, struct lttng_event *event)
-{
- struct lttng_event_field *field;
- 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 = 1;
- desc->fields = field =
- kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL);
- if (!field) {
- ret = -ENOMEM;
- goto error_field;
- }
- field->name = "ip";
- field->type.atype = atype_integer;
- field->type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
- field->type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
- field->type.u.basic.integer.signedness = is_signed_type(unsigned long);
- field->type.u.basic.integer.reverse_byte_order = 0;
- field->type.u.basic.integer.base = 16;
- field->type.u.basic.integer.encoding = lttng_encode_none;
- desc->owner = THIS_MODULE;
- event->desc = desc;
-
- return 0;
-
-error_field:
- kfree(desc->name);
-error_str:
- kfree(desc);
- return ret;
-}
-
-int lttng_kprobes_register(const char *name,
- const char *symbol_name,
- uint64_t offset,
- uint64_t addr,
- struct lttng_event *event)
-{
- int ret;
-
- /* Kprobes expects a NULL symbol name if unused */
- if (symbol_name[0] == '\0')
- symbol_name = NULL;
-
- ret = lttng_create_kprobe_event(name, event);
- if (ret)
- goto error;
- memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp));
- event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
- if (symbol_name) {
- event->u.kprobe.symbol_name =
- kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char),
- GFP_KERNEL);
- if (!event->u.kprobe.symbol_name) {
- ret = -ENOMEM;
- goto name_error;
- }
- memcpy(event->u.kprobe.symbol_name, symbol_name,
- LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char));
- event->u.kprobe.kp.symbol_name =
- event->u.kprobe.symbol_name;
- }
- event->u.kprobe.kp.offset = offset;
- event->u.kprobe.kp.addr = (void *) (unsigned long) addr;
-
- /*
- * Ensure the memory we just allocated don't trigger page faults.
- * Well.. kprobes itself puts the page fault handler on the blacklist,
- * but we can never be too careful.
- */
- wrapper_vmalloc_sync_all();
-
- ret = register_kprobe(&event->u.kprobe.kp);
- if (ret)
- goto register_error;
- return 0;
-
-register_error:
- kfree(event->u.kprobe.symbol_name);
-name_error:
- kfree(event->desc->fields);
- kfree(event->desc->name);
- kfree(event->desc);
-error:
- return ret;
-}
-EXPORT_SYMBOL_GPL(lttng_kprobes_register);
-
-void lttng_kprobes_unregister(struct lttng_event *event)
-{
- unregister_kprobe(&event->u.kprobe.kp);
-}
-EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
-
-void lttng_kprobes_destroy_private(struct lttng_event *event)
-{
- kfree(event->u.kprobe.symbol_name);
- kfree(event->desc->fields);
- kfree(event->desc->name);
- kfree(event->desc);
-}
-EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private);
-
-MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");
projects / lttng-modules.git / blobdiff