Commit | Line | Data |
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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
9f36eaed | 2 | * |
886d51a3 | 3 | * probes/lttng-kprobes.c |
d6d808f3 MD |
4 | * |
5 | * LTTng kprobes integration module. | |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
d6d808f3 MD |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/kprobes.h> | |
f17701fb | 12 | #include <linux/slab.h> |
2df37e95 | 13 | #include <lttng/events.h> |
a67ba386 | 14 | #include <lttng/events-internal.h> |
24591303 | 15 | #include <ringbuffer/frontend_types.h> |
156a3977 MD |
16 | #include <wrapper/vmalloc.h> |
17 | #include <wrapper/irqflags.h> | |
2df37e95 | 18 | #include <lttng/tracer.h> |
caa068b5 | 19 | #include <blacklist/kprobes.h> |
d6d808f3 | 20 | |
f17701fb | 21 | static |
8bf17deb | 22 | int lttng_kprobes_event_handler_pre(struct kprobe *p, struct pt_regs *regs) |
d6d808f3 | 23 | { |
a67ba386 MD |
24 | struct lttng_kernel_event_common_private *event_priv = |
25 | container_of(p, struct lttng_kernel_event_common_private, u.kprobe.kp); | |
e2d5dbc7 | 26 | struct lttng_kernel_event_common *event = event_priv->pub; |
a92e844e | 27 | struct lttng_kernel_probe_ctx lttng_probe_ctx = { |
e2d5dbc7 | 28 | .event = event, |
ccecf3fb | 29 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 30 | }; |
d6d808f3 MD |
31 | unsigned long data = (unsigned long) p->addr; |
32 | ||
e2d5dbc7 MD |
33 | switch (event->type) { |
34 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
35 | { | |
36 | struct lttng_kernel_event_recorder_private *event_recorder_priv = | |
37 | container_of(event_priv, struct lttng_kernel_event_recorder_private, parent); | |
38 | struct lttng_kernel_event_recorder *event_recorder = | |
39 | event_recorder_priv->pub; | |
f7d06400 | 40 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
e2d5dbc7 | 41 | |
f7d06400 | 42 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.session->active))) |
e2d5dbc7 | 43 | return 0; |
f7d06400 | 44 | if (unlikely(!LTTNG_READ_ONCE(chan->parent.enabled))) |
e2d5dbc7 MD |
45 | return 0; |
46 | break; | |
47 | } | |
48 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
49 | break; | |
50 | default: | |
51 | WARN_ON_ONCE(1); | |
52 | } | |
a67ba386 | 53 | |
e2d5dbc7 | 54 | if (unlikely(!LTTNG_READ_ONCE(event->enabled))) |
2b16f0c9 FD |
55 | return 0; |
56 | ||
e2d5dbc7 MD |
57 | switch (event->type) { |
58 | case LTTNG_KERNEL_EVENT_TYPE_RECORDER: | |
59 | { | |
60 | struct lttng_kernel_event_recorder *event_recorder = | |
61 | container_of(event, struct lttng_kernel_event_recorder, parent); | |
f7d06400 | 62 | struct lttng_kernel_channel_buffer *chan = event_recorder->chan; |
8a57ec02 | 63 | struct lttng_kernel_ring_buffer_ctx ctx; |
e2d5dbc7 MD |
64 | int ret; |
65 | ||
b1199bd3 MD |
66 | lib_ring_buffer_ctx_init(&ctx, event_recorder, sizeof(data), |
67 | lttng_alignof(data), <tng_probe_ctx); | |
c2fb9c1c | 68 | ret = chan->ops->event_reserve(&ctx); |
e2d5dbc7 MD |
69 | if (ret < 0) |
70 | return 0; | |
f5ffbd77 | 71 | chan->ops->event_write(&ctx, &data, sizeof(data), lttng_alignof(data)); |
e2d5dbc7 MD |
72 | chan->ops->event_commit(&ctx); |
73 | break; | |
74 | } | |
75 | case LTTNG_KERNEL_EVENT_TYPE_NOTIFIER: | |
76 | { | |
77 | struct lttng_kernel_event_notifier *event_notifier = | |
78 | container_of(event, struct lttng_kernel_event_notifier, parent); | |
79 | struct lttng_kernel_notification_ctx notif_ctx; | |
80 | ||
81 | notif_ctx.eval_capture = LTTNG_READ_ONCE(event_notifier->eval_capture); | |
82 | event_notifier->notification_send(event_notifier, NULL, NULL, ¬if_ctx); | |
83 | break; | |
84 | } | |
85 | default: | |
86 | WARN_ON_ONCE(1); | |
87 | } | |
2b16f0c9 FD |
88 | return 0; |
89 | } | |
90 | ||
6c8c025b MD |
91 | static const struct lttng_kernel_event_field *event_fields[] = { |
92 | lttng_kernel_static_event_field("ip", | |
93 | lttng_kernel_static_type_integer_from_type(unsigned long, __BYTE_ORDER, 16), | |
4697aac7 | 94 | false, false), |
6c8c025b MD |
95 | }; |
96 | ||
97 | static const struct lttng_kernel_tracepoint_class tp_class = { | |
98 | .nr_fields = ARRAY_SIZE(event_fields), | |
99 | .fields = event_fields, | |
100 | }; | |
437d5aa5 | 101 | |
f17701fb MD |
102 | /* |
103 | * Create event description | |
104 | */ | |
105 | static | |
6a35e5bd | 106 | int lttng_create_kprobe_event(const char *name, struct lttng_kernel_event_common *event) |
f17701fb | 107 | { |
437d5aa5 | 108 | struct lttng_kernel_event_desc *desc; |
f17701fb MD |
109 | int ret; |
110 | ||
437d5aa5 | 111 | desc = kzalloc(sizeof(*desc), GFP_KERNEL); |
d3dbe23c | 112 | if (!desc) |
f17701fb | 113 | return -ENOMEM; |
6c8c025b | 114 | desc->tp_class = &tp_class; |
437d5aa5 MD |
115 | desc->event_name = kstrdup(name, GFP_KERNEL); |
116 | if (!desc->event_name) { | |
f17701fb MD |
117 | ret = -ENOMEM; |
118 | goto error_str; | |
119 | } | |
dc7f600a | 120 | desc->owner = THIS_MODULE; |
6a35e5bd | 121 | event->priv->desc = desc; |
2b16f0c9 FD |
122 | |
123 | return 0; | |
124 | ||
125 | error_str: | |
126 | kfree(desc); | |
127 | return ret; | |
128 | } | |
129 | ||
8bf17deb FD |
130 | static |
131 | int _lttng_kprobes_register(const char *symbol_name, | |
f17701fb MD |
132 | uint64_t offset, |
133 | uint64_t addr, | |
8bf17deb FD |
134 | struct lttng_kprobe *lttng_kp, |
135 | kprobe_pre_handler_t pre_handler) | |
f17701fb MD |
136 | { |
137 | int ret; | |
138 | ||
c37f2a9b MD |
139 | /* Kprobes expects a NULL symbol name if unused */ |
140 | if (symbol_name[0] == '\0') | |
141 | symbol_name = NULL; | |
142 | ||
8bf17deb FD |
143 | memset(<tng_kp->kp, 0, sizeof(lttng_kp->kp)); |
144 | lttng_kp->kp.pre_handler = pre_handler; | |
145 | ||
c37f2a9b | 146 | if (symbol_name) { |
8bf17deb | 147 | lttng_kp->symbol_name = |
606828e4 | 148 | kzalloc(LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char), |
c37f2a9b | 149 | GFP_KERNEL); |
8bf17deb | 150 | if (!lttng_kp->symbol_name) { |
c37f2a9b MD |
151 | ret = -ENOMEM; |
152 | goto name_error; | |
153 | } | |
8bf17deb | 154 | memcpy(lttng_kp->symbol_name, symbol_name, |
606828e4 | 155 | LTTNG_KERNEL_ABI_SYM_NAME_LEN * sizeof(char)); |
8bf17deb | 156 | lttng_kp->kp.symbol_name = lttng_kp->symbol_name; |
f17701fb | 157 | } |
8bf17deb FD |
158 | |
159 | lttng_kp->kp.offset = offset; | |
160 | lttng_kp->kp.addr = (void *) (unsigned long) addr; | |
16a9a591 MD |
161 | |
162 | /* | |
196bfc6a | 163 | * Ensure the memory we just allocated don't notify page faults. |
16a9a591 MD |
164 | * Well.. kprobes itself puts the page fault handler on the blacklist, |
165 | * but we can never be too careful. | |
166 | */ | |
263b6c88 | 167 | wrapper_vmalloc_sync_mappings(); |
16a9a591 | 168 | |
8bf17deb | 169 | ret = register_kprobe(<tng_kp->kp); |
f17701fb MD |
170 | if (ret) |
171 | goto register_error; | |
8bf17deb | 172 | |
f17701fb MD |
173 | return 0; |
174 | ||
175 | register_error: | |
8bf17deb | 176 | kfree(lttng_kp->symbol_name); |
f17701fb | 177 | name_error: |
8bf17deb FD |
178 | return ret; |
179 | } | |
180 | ||
181 | int lttng_kprobes_register_event(const char *name, | |
182 | const char *symbol_name, | |
183 | uint64_t offset, | |
184 | uint64_t addr, | |
6a35e5bd | 185 | struct lttng_kernel_event_common *event) |
8bf17deb FD |
186 | { |
187 | int ret; | |
188 | ||
6a35e5bd | 189 | ret = lttng_create_kprobe_event(name, event); |
8bf17deb FD |
190 | if (ret) |
191 | goto error; | |
192 | ||
193 | ret = _lttng_kprobes_register(symbol_name, offset, addr, | |
6a35e5bd | 194 | &event->priv->u.kprobe, lttng_kprobes_event_handler_pre); |
8bf17deb FD |
195 | if (ret) |
196 | goto register_error; | |
197 | ||
198 | return 0; | |
199 | ||
200 | register_error: | |
6a35e5bd MD |
201 | kfree(event->priv->desc->event_name); |
202 | kfree(event->priv->desc); | |
f17701fb MD |
203 | error: |
204 | return ret; | |
205 | } | |
8bf17deb | 206 | EXPORT_SYMBOL_GPL(lttng_kprobes_register_event); |
f17701fb | 207 | |
6a35e5bd | 208 | void lttng_kprobes_unregister_event(struct lttng_kernel_event_common *event) |
f17701fb | 209 | { |
6a35e5bd | 210 | unregister_kprobe(&event->priv->u.kprobe.kp); |
edeb3137 | 211 | } |
8bf17deb | 212 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister_event); |
edeb3137 | 213 | |
6a35e5bd | 214 | void lttng_kprobes_destroy_event_private(struct lttng_kernel_event_common *event) |
2b16f0c9 | 215 | { |
6a35e5bd MD |
216 | kfree(event->priv->u.kprobe.symbol_name); |
217 | kfree(event->priv->desc->event_name); | |
218 | kfree(event->priv->desc); | |
f17701fb | 219 | } |
8bf17deb | 220 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_event_private); |
d6d808f3 MD |
221 | |
222 | MODULE_LICENSE("GPL and additional rights"); | |
1c124020 MJ |
223 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
224 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
225 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
226 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
227 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
228 | LTTNG_MODULES_EXTRAVERSION); |