X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;ds=sidebyside;f=probes%2Flttng-kprobes.c;h=38ee4513811691273de7454f0415ee56c6da44ce;hb=5fe87d9b7e8ad3b11a1841c630865afdd1cd1946;hp=eb6e16a0c129e1afb9fc366c36ae2d39c6c36ace;hpb=d6d808f3780d0b519aaf966e66df501730db7d13;p=lttng-modules.git

diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index eb6e16a0..38ee4513 100644
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -9,11 +9,14 @@
 
 #include <linux/module.h>
 #include <linux/kprobes.h>
+#include <linux/slab.h>
 #include "../ltt-events.h"
 #include "../wrapper/ringbuffer/frontend_types.h"
+#include "../wrapper/vmalloc.h"
 #include "../ltt-tracer.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);
@@ -22,18 +25,133 @@ void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
 	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),
+	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),
 				 ltt_alignof(data), -1);
-	ret = chan->ops->event_reserve(&ctx);
+	ret = chan->ops->event_reserve(&ctx, event->id);
 	if (ret < 0)
-		return;
+		return 0;
 	lib_ring_buffer_align_ctx(&ctx, ltt_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 ltt_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 = ltt_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 ltt_event *event)
+{
+	int ret;
+
+	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;
+	event->u.kprobe.symbol_name =
+		kzalloc(LTTNG_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_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 *) 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 ltt_event *event)
+{
+	unregister_kprobe(&event->u.kprobe.kp);
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
+
+void lttng_kprobes_destroy_private(struct ltt_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");