Fix: ACCESS_ONCE() removed in kernel 4.15
[lttng-modules.git] / probes / lttng-ftrace.c
index c866876e6f07dcf5b4d7612d27d4d9e6de08f223..50675a4fa6096ead0a9191ada6642cc335abeffc 100644 (file)
@@ -1,32 +1,92 @@
 /*
- * (C) Copyright       2009-2011 -
- *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * probes/lttng-ftrace.c
  *
  * LTTng function tracer integration module.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * 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
  */
 
 /*
  * Ftrace function tracer does not seem to provide synchronization between probe
  * teardown and callback execution. Therefore, we make this module permanently
  * loaded (unloadable).
+ *
+ * TODO: Move to register_ftrace_function() (which is exported for
+ * modules) for Linux >= 3.0. It is faster (only enables the selected
+ * functions), and will stay there.
  */
 
 #include <linux/module.h>
 #include <linux/ftrace.h>
 #include <linux/slab.h>
-#include "../ltt-events.h"
-#include "../wrapper/ringbuffer/frontend_types.h"
-#include "../wrapper/ftrace.h"
-#include "../wrapper/vmalloc.h"
-#include "../ltt-tracer.h"
+#include <lttng-events.h>
+#include <wrapper/ringbuffer/frontend_types.h>
+#include <wrapper/ftrace.h>
+#include <wrapper/vmalloc.h>
+#include <lttng-tracer.h>
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,12,0))
+static
+void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+               struct trace_array *tr, struct ftrace_probe_ops *ops,
+               void *data)
+{
+       struct lttng_event *event = data;
+       struct lttng_probe_ctx lttng_probe_ctx = {
+               .event = event,
+               .interruptible = !irqs_disabled(),
+       };
+       struct lttng_channel *chan = event->chan;
+       struct lib_ring_buffer_ctx ctx;
+       struct {
+               unsigned long ip;
+               unsigned long parent_ip;
+       } payload;
+       int ret;
+
+       if (unlikely(!READ_ONCE(chan->session->active)))
+               return;
+       if (unlikely(!READ_ONCE(chan->enabled)))
+               return;
+       if (unlikely(!READ_ONCE(event->enabled)))
+               return;
 
+       lib_ring_buffer_ctx_init(&ctx, chan->chan, &lttng_probe_ctx,
+                                sizeof(payload), lttng_alignof(payload), -1);
+       ret = chan->ops->event_reserve(&ctx, event->id);
+       if (ret < 0)
+               return;
+       payload.ip = ip;
+       payload.parent_ip = parent_ip;
+       lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
+       chan->ops->event_write(&ctx, &payload, sizeof(payload));
+       chan->ops->event_commit(&ctx);
+       return;
+}
+#else
 static
 void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data)
 {
-       struct ltt_event *event = *data;
-       struct ltt_channel *chan = event->chan;
+       struct lttng_event *event = *data;
+       struct lttng_probe_ctx lttng_probe_ctx = {
+               .event = event,
+               .interruptible = !irqs_disabled(),
+       };
+       struct lttng_channel *chan = event->chan;
        struct lib_ring_buffer_ctx ctx;
        struct {
                unsigned long ip;
@@ -34,26 +94,32 @@ void lttng_ftrace_handler(unsigned long ip, unsigned long parent_ip, void **data
        } payload;
        int ret;
 
-       if (!ACCESS_ONCE(chan->session->active))
+       if (unlikely(!READ_ONCE(chan->session->active)))
                return;
-       lib_ring_buffer_ctx_init(&ctx, chan->chan, NULL,
-                                sizeof(payload), ltt_alignof(payload), -1);
+       if (unlikely(!READ_ONCE(chan->enabled)))
+               return;
+       if (unlikely(!READ_ONCE(event->enabled)))
+               return;
+
+       lib_ring_buffer_ctx_init(&ctx, chan->chan, &lttng_probe_ctx,
+                                sizeof(payload), lttng_alignof(payload), -1);
        ret = chan->ops->event_reserve(&ctx, event->id);
        if (ret < 0)
                return;
        payload.ip = ip;
        payload.parent_ip = parent_ip;
-       lib_ring_buffer_align_ctx(&ctx, ltt_alignof(payload));
+       lib_ring_buffer_align_ctx(&ctx, lttng_alignof(payload));
        chan->ops->event_write(&ctx, &payload, sizeof(payload));
        chan->ops->event_commit(&ctx);
        return;
 }
+#endif
 
 /*
  * Create event description
  */
 static
-int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
+int lttng_create_ftrace_event(const char *name, struct lttng_event *event)
 {
        struct lttng_event_field *fields;
        struct lttng_event_desc *desc;
@@ -77,8 +143,8 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
        fields[0].name = "ip";
        fields[0].type.atype = atype_integer;
        fields[0].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
-       fields[0].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
-       fields[0].type.u.basic.integer.signedness = 0;
+       fields[0].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+       fields[0].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
        fields[0].type.u.basic.integer.reverse_byte_order = 0;
        fields[0].type.u.basic.integer.base = 16;
        fields[0].type.u.basic.integer.encoding = lttng_encode_none;
@@ -86,8 +152,8 @@ int lttng_create_ftrace_event(const char *name, struct ltt_event *event)
        fields[1].name = "parent_ip";
        fields[1].type.atype = atype_integer;
        fields[1].type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT;
-       fields[1].type.u.basic.integer.alignment = ltt_alignof(unsigned long) * CHAR_BIT;
-       fields[1].type.u.basic.integer.signedness = 0;
+       fields[1].type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT;
+       fields[1].type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long);
        fields[1].type.u.basic.integer.reverse_byte_order = 0;
        fields[1].type.u.basic.integer.base = 16;
        fields[1].type.u.basic.integer.encoding = lttng_encode_none;
@@ -111,7 +177,7 @@ struct ftrace_probe_ops lttng_ftrace_ops = {
 
 int lttng_ftrace_register(const char *name,
                          const char *symbol_name,
-                         struct ltt_event *event)
+                         struct lttng_event *event)
 {
        int ret;
 
@@ -142,16 +208,21 @@ error:
 }
 EXPORT_SYMBOL_GPL(lttng_ftrace_register);
 
-void lttng_ftrace_unregister(struct ltt_event *event)
+void lttng_ftrace_unregister(struct lttng_event *event)
 {
        wrapper_unregister_ftrace_function_probe(event->u.ftrace.symbol_name,
                        &lttng_ftrace_ops, event);
+}
+EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
+
+void lttng_ftrace_destroy_private(struct lttng_event *event)
+{
        kfree(event->u.ftrace.symbol_name);
        kfree(event->desc->fields);
        kfree(event->desc->name);
        kfree(event->desc);
 }
-EXPORT_SYMBOL_GPL(lttng_ftrace_unregister);
+EXPORT_SYMBOL_GPL(lttng_ftrace_destroy_private);
 
 int lttng_ftrace_init(void)
 {
@@ -172,3 +243,7 @@ module_exit(lttng_ftrace_exit)
 MODULE_LICENSE("GPL and additional rights");
 MODULE_AUTHOR("Mathieu Desnoyers");
 MODULE_DESCRIPTION("Linux Trace Toolkit Ftrace Support");
+MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
+       __stringify(LTTNG_MODULES_MINOR_VERSION) "."
+       __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
+       LTTNG_MODULES_EXTRAVERSION);
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