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