-/*
- * (C) Copyright 2009-2011 -
- * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+/* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
+ *
+ * probes/lttng-kprobes.c
*
* LTTng kprobes integration module.
*
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
#include <linux/module.h>
#include <linux/kprobes.h>
-#include "../ltt-events.h"
-#include "../wrapper/ringbuffer/frontend_types.h"
-#include "../ltt-tracer.h"
+#include <linux/slab.h>
+#include <lttng-events.h>
+#include <ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <wrapper/irqflags.h>
+#include <lttng-tracer.h>
+#include <blacklist/kprobes.h>
-void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
+static
+int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
{
- struct ltt_event *event =
- container_of(p, struct ltt_event, u.kprobe.kp);
- struct ltt_channel *chan = event->chan;
+ struct lttng_event *event =
+ container_of(p, struct lttng_event, u.kprobe.kp);
+ struct lttng_probe_ctx lttng_probe_ctx = {
+ .event = event,
+ .interruptible = !lttng_regs_irqs_disabled(regs),
+ };
+ struct lttng_channel *chan = event->chan;
struct lib_ring_buffer_ctx ctx;
int ret;
unsigned long data = (unsigned long) p->addr;
- if (!ACCESS_ONCE(chan->session->active))
- return;
- lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
- ltt_alignof(data), -1);
- ret = chan->ops->event_reserve(&ctx);
+ if (unlikely(!READ_ONCE(chan->session->active)))
+ return 0;
+ if (unlikely(!READ_ONCE(chan->enabled)))
+ return 0;
+ if (unlikely(!READ_ONCE(event->enabled)))
+ return 0;
+
+ lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data),
+ lttng_alignof(data), -1);
+ ret = chan->ops->event_reserve(&ctx, event->id);
if (ret < 0)
- return;
- lib_ring_buffer_align_ctx(&ctx, ltt_alignof(data));
+ 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.integer.size = sizeof(unsigned long) * CHAR_BIT;
+ field->type.u.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+ field->type.u.integer.signedness = lttng_is_signed_type(unsigned long);
+ field->type.u.integer.reverse_byte_order = 0;
+ field->type.u.integer.base = 16;
+ field->type.u.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_mappings();
+
+ 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_handler_pre);
+EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private);
MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit Kprobes Support");
+MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
+MODULE_DESCRIPTION("LTTng kprobes 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