Add event description for each kprobe event

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/ltt-debugfs-abi.h b/ltt-debugfs-abi.h
index ecbd5413825f6fe8d877293ace6320b81d1fd56c..411c37b78ff0d0f88787c20420f7337ab1db27f9 100644 (file)
--- a/ltt-debugfs-abi.h
+++ b/ltt-debugfs-abi.h
@@ -16,6 +16,7 @@
 enum lttng_kernel_instrumentation {
        LTTNG_KERNEL_TRACEPOINTS,
        LTTNG_KERNEL_KPROBES,
+       LTTNG_KERNEL_FUNCTION_TRACER,
 };
 
 /*
@@ -40,13 +41,18 @@ struct lttng_kernel_kprobe {
        char symbol_name[LTTNG_KPROBE_SYM_NAME_LEN];
 };
 
+struct lttng_kernel_function_tracer {
+       char symbol_name[LTTNG_KPROBE_SYM_NAME_LEN];
+};
+
 struct lttng_kernel_event {
        enum lttng_kernel_instrumentation instrumentation;
        /* Per instrumentation type configuration */
        union {
                struct lttng_kernel_kprobe kprobe;
+               struct lttng_kernel_function_tracer ftrace;
        } u;
-       char name[];
+       char name[];    /* event name */
 };
 
 struct lttng_kernel_tracer_version {

diff --git a/ltt-events.c b/ltt-events.c
index ec5d6830d4355fa64d91b1870d9443874dae8bd3..29d0ed749b78db62258e22506231452c0397bf19 100644 (file)
--- a/ltt-events.c
+++ b/ltt-events.c
@@ -237,24 +237,13 @@ struct ltt_event *ltt_event_create(struct ltt_channel *chan, char *name,
                        goto register_error;
                break;
        case LTTNG_KERNEL_KPROBES:
-               event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre;
-               event->u.kprobe.symbol_name =
-                       kzalloc(LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char),
-                               GFP_KERNEL);
-               if (!event->u.kprobe.symbol_name)
-                       goto register_error;
-               memcpy(event->u.kprobe.symbol_name,
-                      event_param->u.kprobe.symbol_name,
-                      LTTNG_KPROBE_SYM_NAME_LEN * sizeof(char));
-               event->u.kprobe.kp.symbol_name =
-                       event->u.kprobe.symbol_name;
-               event->u.kprobe.kp.offset = event_param->u.kprobe.offset;
-               event->u.kprobe.kp.addr = (void *) event_param->u.kprobe.addr;
-               ret = register_kprobe(&event->u.kprobe.kp);
-               if (ret) {
-                       kfree(event->u.kprobe.symbol_name);
+               ret = lttng_kprobes_register(name,
+                               event_param->u.kprobe.symbol_name,
+                               event_param->u.kprobe.offset,
+                               event_param->u.kprobe.addr,
+                               event);
+               if (ret)
                        goto register_error;
-               }
                break;
        default:
                WARN_ON_ONCE(1);
@@ -294,8 +283,7 @@ int _ltt_event_unregister(struct ltt_event *event)
                        return ret;
                break;
        case LTTNG_KERNEL_KPROBES:
-               unregister_kprobe(&event->u.kprobe.kp);
-               kfree(event->u.kprobe.symbol_name);
+               lttng_kprobes_unregister(event);
                ret = 0;
                break;
        default:

diff --git a/ltt-events.h b/ltt-events.h
index 42e12c0af19172c6ddc5f67b44cbf73b0d851edd..a26638c43f8e2a5fe6dc12520487d39e569c382b 100644 (file)
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -104,7 +104,7 @@ struct lttng_enum {
 
 struct lttng_event_field {
        const char *name;
-       const struct lttng_type type;
+       struct lttng_type type;
 };
 
 struct lttng_event_desc {
@@ -127,7 +127,7 @@ struct lttng_probe_desc {
 struct ltt_event {
        unsigned int id;
        struct ltt_channel *chan;
-       const struct lttng_event_desc *desc;
+       struct lttng_event_desc *desc;
        void *filter;
        enum lttng_kernel_instrumentation instrumentation;
        union {
@@ -234,6 +234,11 @@ void ltt_event_put(const struct lttng_event_desc *desc);
 int ltt_probes_init(void);
 void ltt_probes_exit(void);
 
-void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs);
+int lttng_kprobes_register(const char *name,
+               const char *symbol_name,
+               uint64_t offset,
+               uint64_t addr,
+               struct ltt_event *event);
+void lttng_kprobes_unregister(struct ltt_event *event);
 
 #endif /* _LTT_EVENTS_H */

diff --git a/probes/lttng-kprobes.c b/probes/lttng-kprobes.c
index eb6e16a0c129e1afb9fc366c36ae2d39c6c36ace..bee935f779bfe699ecd1e97e299c41c8e32155a6 100644 (file)
--- a/probes/lttng-kprobes.c
+++ b/probes/lttng-kprobes.c
@@ -9,11 +9,13 @@
 
 #include <linux/module.h>
 #include <linux/kprobes.h>
+#include <linux/slab.h>
 #include "../ltt-events.h"
 #include "../wrapper/ringbuffer/frontend_types.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);
@@ -23,17 +25,101 @@ void lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs)
        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;
+       int ret;
+
+       event->desc = kzalloc(sizeof(*event->desc), GFP_KERNEL);
+       if (!event->desc)
+               return -ENOMEM;
+       event->desc->name = kstrdup(name, GFP_KERNEL);
+       if (!event->desc->name) {
+               ret = -ENOMEM;
+               goto error_str;
+       }
+       event->desc->nr_fields = 1;
+       event->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;
+
+       return 0;
+
+error_str:
+       kfree(event->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_KPROBE_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_KPROBE_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;
+       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");