lttng abi documentation: clarify getter usage requirements

[lttng-modules.git] / probes / lttng-kretprobes.c

diff --git a/probes/lttng-kretprobes.c b/probes/lttng-kretprobes.c
index 6b75848accb95ff9f6361b44591d48c3ebeb16e6..4b18d46077df8749c7c01dfea52c67384b3f0406 100644 (file)
--- a/probes/lttng-kretprobes.c
+++ b/probes/lttng-kretprobes.c
@@ -1,20 +1,22 @@
-/*
- * (C) Copyright       2009-2011 -
- *             Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
+ * probes/lttng-kretprobes.c
  *
  * LTTng kretprobes 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 <linux/slab.h>
 #include <linux/kref.h>
-#include "../lttng-events.h"
-#include "../wrapper/ringbuffer/frontend_types.h"
-#include "../wrapper/vmalloc.h"
-#include "../lttng-tracer.h"
+#include <lttng-events.h>
+#include <wrapper/ringbuffer/frontend_types.h>
+#include <wrapper/vmalloc.h>
+#include <wrapper/irqflags.h>
+#include <lttng-tracer.h>
+#include <blacklist/kprobes.h>
 
 enum lttng_kretprobe_type {
        EVENT_ENTRY = 0,
@@ -37,6 +39,10 @@ int _lttng_kretprobes_handler(struct kretprobe_instance *krpi,
                container_of(krpi->rp, struct lttng_krp, krp);
        struct lttng_event *event =
                lttng_krp->event[type];
+       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;
@@ -45,17 +51,17 @@ int _lttng_kretprobes_handler(struct kretprobe_instance *krpi,
                unsigned long parent_ip;
        } payload;
 
-       if (unlikely(!ACCESS_ONCE(chan->session->active)))
+       if (unlikely(!READ_ONCE(chan->session->active)))
                return 0;
-       if (unlikely(!ACCESS_ONCE(chan->enabled)))
+       if (unlikely(!READ_ONCE(chan->enabled)))
                return 0;
-       if (unlikely(!ACCESS_ONCE(event->enabled)))
+       if (unlikely(!READ_ONCE(event->enabled)))
                return 0;
 
        payload.ip = (unsigned long) krpi->rp->kp.addr;
        payload.parent_ip = (unsigned long) krpi->ret_addr;
 
-       lib_ring_buffer_ctx_init(&ctx, chan->chan, event, sizeof(payload),
+       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)
@@ -126,7 +132,7 @@ int lttng_create_kprobe_event(const char *name, struct lttng_event *event,
        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 = lttng_alignof(unsigned long) * CHAR_BIT;
-       fields[0].type.u.basic.integer.signedness = is_signed_type(unsigned long);
+       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;
@@ -135,7 +141,7 @@ int lttng_create_kprobe_event(const char *name, struct lttng_event *event,
        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 = lttng_alignof(unsigned long) * CHAR_BIT;
-       fields[1].type.u.basic.integer.signedness = is_signed_type(unsigned long);
+       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;
@@ -206,9 +212,9 @@ int lttng_kretprobes_register(const char *name,
         * unregistered. Same for memory allocation.
         */
        kref_init(&lttng_krp->kref_alloc);
-       kref_get(&lttng_krp->kref_alloc);       /* inc refcount to 2 */
+       kref_get(&lttng_krp->kref_alloc);       /* inc refcount to 2, no overflow. */
        kref_init(&lttng_krp->kref_register);
-       kref_get(&lttng_krp->kref_register);    /* inc refcount to 2 */
+       kref_get(&lttng_krp->kref_register);    /* inc refcount to 2, no overflow. */
 
        /*
         * Ensure the memory we just allocated don't trigger page faults.
@@ -272,6 +278,30 @@ void lttng_kretprobes_destroy_private(struct lttng_event *event)
 }
 EXPORT_SYMBOL_GPL(lttng_kretprobes_destroy_private);
 
+int lttng_kretprobes_event_enable_state(struct lttng_event *event,
+               int enable)
+{
+       struct lttng_event *event_return;
+       struct lttng_krp *lttng_krp;
+
+       if (event->instrumentation != LTTNG_KERNEL_KRETPROBE) {
+               return -EINVAL;
+       }
+       if (event->enabled == enable) {
+               return -EBUSY;
+       }
+       lttng_krp = event->u.kretprobe.lttng_krp;
+       event_return = lttng_krp->event[EVENT_RETURN];
+       WRITE_ONCE(event->enabled, enable);
+       WRITE_ONCE(event_return->enabled, enable);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(lttng_kretprobes_event_enable_state);
+
 MODULE_LICENSE("GPL and additional rights");
-MODULE_AUTHOR("Mathieu Desnoyers");
-MODULE_DESCRIPTION("Linux Trace Toolkit Kretprobes Support");
+MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
+MODULE_DESCRIPTION("LTTng kretprobes probes");
+MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
+       __stringify(LTTNG_MODULES_MINOR_VERSION) "."
+       __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
+       LTTNG_MODULES_EXTRAVERSION);