#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);
unsigned long data = (unsigned long) p->addr;
if (!ACCESS_ONCE(chan->session->active))
- return;
+ return 0;
lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL, sizeof(data),
ltt_alignof(data), -1);
ret = chan->ops->event_reserve(&ctx);
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;
}
-EXPORT_SYMBOL_GPL(lttng_kprobes_handler_pre);
+
+/*
+ * 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);
+ field->name = "ip";
+ field->type.atype = atype_integer;
+ field->type.u.basic.integer.size = sizeof(unsigned long);
+ field->type.u.basic.integer.alignment = ltt_alignof(unsigned long);
+ field->type.u.basic.integer.signedness = 0;
+ 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;
+ event->desc = desc;
+
+ return 0;
+
+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->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);
+ kfree(event->u.kprobe.symbol_name);
+ kfree(event->desc->name);
+ kfree(event->desc);
+}
+EXPORT_SYMBOL_GPL(lttng_kprobes_unregister);
MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Mathieu Desnoyers");