Commit | Line | Data |
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9f36eaed MJ |
1 | /* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) |
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> |
156a3977 MD |
13 | #include <lttng-events.h> |
14 | #include <wrapper/ringbuffer/frontend_types.h> | |
15 | #include <wrapper/vmalloc.h> | |
16 | #include <wrapper/irqflags.h> | |
17 | #include <lttng-tracer.h> | |
e58bd91a | 18 | #include <blacklist/kprobes.h> |
d6d808f3 | 19 | |
f17701fb MD |
20 | static |
21 | int lttng_kprobes_handler_pre(struct kprobe *p, struct pt_regs *regs) | |
d6d808f3 | 22 | { |
a90917c3 MD |
23 | struct lttng_event *event = |
24 | container_of(p, struct lttng_event, u.kprobe.kp); | |
79150a49 JD |
25 | struct lttng_probe_ctx lttng_probe_ctx = { |
26 | .event = event, | |
ccecf3fb | 27 | .interruptible = !lttng_regs_irqs_disabled(regs), |
79150a49 | 28 | }; |
a90917c3 | 29 | struct lttng_channel *chan = event->chan; |
d6d808f3 MD |
30 | struct lib_ring_buffer_ctx ctx; |
31 | int ret; | |
32 | unsigned long data = (unsigned long) p->addr; | |
33 | ||
a8f2d0c7 | 34 | if (unlikely(!READ_ONCE(chan->session->active))) |
f17701fb | 35 | return 0; |
a8f2d0c7 | 36 | if (unlikely(!READ_ONCE(chan->enabled))) |
e64957da | 37 | return 0; |
a8f2d0c7 | 38 | if (unlikely(!READ_ONCE(event->enabled))) |
e64957da MD |
39 | return 0; |
40 | ||
79150a49 | 41 | lib_ring_buffer_ctx_init(&ctx, chan->chan, <tng_probe_ctx, sizeof(data), |
a90917c3 | 42 | lttng_alignof(data), -1); |
4e1f08f4 | 43 | ret = chan->ops->event_reserve(&ctx, event->id); |
d6d808f3 | 44 | if (ret < 0) |
f17701fb | 45 | return 0; |
a90917c3 | 46 | lib_ring_buffer_align_ctx(&ctx, lttng_alignof(data)); |
d6d808f3 MD |
47 | chan->ops->event_write(&ctx, &data, sizeof(data)); |
48 | chan->ops->event_commit(&ctx); | |
f17701fb | 49 | return 0; |
d6d808f3 | 50 | } |
f17701fb MD |
51 | |
52 | /* | |
53 | * Create event description | |
54 | */ | |
55 | static | |
a90917c3 | 56 | int lttng_create_kprobe_event(const char *name, struct lttng_event *event) |
f17701fb MD |
57 | { |
58 | struct lttng_event_field *field; | |
d3dbe23c | 59 | struct lttng_event_desc *desc; |
f17701fb MD |
60 | int ret; |
61 | ||
d3dbe23c MD |
62 | desc = kzalloc(sizeof(*event->desc), GFP_KERNEL); |
63 | if (!desc) | |
f17701fb | 64 | return -ENOMEM; |
d3dbe23c MD |
65 | desc->name = kstrdup(name, GFP_KERNEL); |
66 | if (!desc->name) { | |
f17701fb MD |
67 | ret = -ENOMEM; |
68 | goto error_str; | |
69 | } | |
d3dbe23c MD |
70 | desc->nr_fields = 1; |
71 | desc->fields = field = | |
f17701fb | 72 | kzalloc(1 * sizeof(struct lttng_event_field), GFP_KERNEL); |
0d1a681e MD |
73 | if (!field) { |
74 | ret = -ENOMEM; | |
75 | goto error_field; | |
76 | } | |
f17701fb MD |
77 | field->name = "ip"; |
78 | field->type.atype = atype_integer; | |
ba1f5986 | 79 | field->type.u.basic.integer.size = sizeof(unsigned long) * CHAR_BIT; |
a90917c3 | 80 | field->type.u.basic.integer.alignment = lttng_alignof(unsigned long) * CHAR_BIT; |
06254b0f | 81 | field->type.u.basic.integer.signedness = lttng_is_signed_type(unsigned long); |
f17701fb | 82 | field->type.u.basic.integer.reverse_byte_order = 0; |
e0a7a7c4 MD |
83 | field->type.u.basic.integer.base = 16; |
84 | field->type.u.basic.integer.encoding = lttng_encode_none; | |
dc7f600a | 85 | desc->owner = THIS_MODULE; |
d3dbe23c | 86 | event->desc = desc; |
f17701fb MD |
87 | |
88 | return 0; | |
89 | ||
0d1a681e MD |
90 | error_field: |
91 | kfree(desc->name); | |
f17701fb | 92 | error_str: |
d3dbe23c | 93 | kfree(desc); |
f17701fb MD |
94 | return ret; |
95 | } | |
96 | ||
97 | int lttng_kprobes_register(const char *name, | |
98 | const char *symbol_name, | |
99 | uint64_t offset, | |
100 | uint64_t addr, | |
a90917c3 | 101 | struct lttng_event *event) |
f17701fb MD |
102 | { |
103 | int ret; | |
104 | ||
c37f2a9b MD |
105 | /* Kprobes expects a NULL symbol name if unused */ |
106 | if (symbol_name[0] == '\0') | |
107 | symbol_name = NULL; | |
108 | ||
f17701fb MD |
109 | ret = lttng_create_kprobe_event(name, event); |
110 | if (ret) | |
111 | goto error; | |
112 | memset(&event->u.kprobe.kp, 0, sizeof(event->u.kprobe.kp)); | |
113 | event->u.kprobe.kp.pre_handler = lttng_kprobes_handler_pre; | |
c37f2a9b MD |
114 | if (symbol_name) { |
115 | event->u.kprobe.symbol_name = | |
f8695253 | 116 | kzalloc(LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char), |
c37f2a9b MD |
117 | GFP_KERNEL); |
118 | if (!event->u.kprobe.symbol_name) { | |
119 | ret = -ENOMEM; | |
120 | goto name_error; | |
121 | } | |
122 | memcpy(event->u.kprobe.symbol_name, symbol_name, | |
f8695253 | 123 | LTTNG_KERNEL_SYM_NAME_LEN * sizeof(char)); |
c37f2a9b MD |
124 | event->u.kprobe.kp.symbol_name = |
125 | event->u.kprobe.symbol_name; | |
f17701fb | 126 | } |
f17701fb | 127 | event->u.kprobe.kp.offset = offset; |
b2c4e8fb | 128 | event->u.kprobe.kp.addr = (void *) (unsigned long) addr; |
16a9a591 MD |
129 | |
130 | /* | |
131 | * Ensure the memory we just allocated don't trigger page faults. | |
132 | * Well.. kprobes itself puts the page fault handler on the blacklist, | |
133 | * but we can never be too careful. | |
134 | */ | |
135 | wrapper_vmalloc_sync_all(); | |
136 | ||
f17701fb MD |
137 | ret = register_kprobe(&event->u.kprobe.kp); |
138 | if (ret) | |
139 | goto register_error; | |
140 | return 0; | |
141 | ||
142 | register_error: | |
143 | kfree(event->u.kprobe.symbol_name); | |
144 | name_error: | |
0d1a681e | 145 | kfree(event->desc->fields); |
f17701fb MD |
146 | kfree(event->desc->name); |
147 | kfree(event->desc); | |
148 | error: | |
149 | return ret; | |
150 | } | |
151 | EXPORT_SYMBOL_GPL(lttng_kprobes_register); | |
152 | ||
a90917c3 | 153 | void lttng_kprobes_unregister(struct lttng_event *event) |
f17701fb MD |
154 | { |
155 | unregister_kprobe(&event->u.kprobe.kp); | |
edeb3137 MD |
156 | } |
157 | EXPORT_SYMBOL_GPL(lttng_kprobes_unregister); | |
158 | ||
a90917c3 | 159 | void lttng_kprobes_destroy_private(struct lttng_event *event) |
edeb3137 | 160 | { |
f17701fb | 161 | kfree(event->u.kprobe.symbol_name); |
0d1a681e | 162 | kfree(event->desc->fields); |
f17701fb MD |
163 | kfree(event->desc->name); |
164 | kfree(event->desc); | |
165 | } | |
edeb3137 | 166 | EXPORT_SYMBOL_GPL(lttng_kprobes_destroy_private); |
d6d808f3 MD |
167 | |
168 | MODULE_LICENSE("GPL and additional rights"); | |
1c124020 MJ |
169 | MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>"); |
170 | MODULE_DESCRIPTION("LTTng kprobes probes"); | |
13ab8b0a MD |
171 | MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "." |
172 | __stringify(LTTNG_MODULES_MINOR_VERSION) "." | |
173 | __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION) | |
174 | LTTNG_MODULES_EXTRAVERSION); |