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 | * lttng-context-prio.c |
a8ad3613 MD |
4 | * |
5 | * LTTng priority context. | |
6 | * | |
886d51a3 | 7 | * Copyright (C) 2009-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
a8ad3613 MD |
8 | */ |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/sched.h> | |
241ae9a8 MD |
13 | #include <lttng-events.h> |
14 | #include <wrapper/ringbuffer/frontend_types.h> | |
241ae9a8 MD |
15 | #include <wrapper/kallsyms.h> |
16 | #include <lttng-tracer.h> | |
a8ad3613 | 17 | |
979133c5 MD |
18 | static |
19 | int (*wrapper_task_prio_sym)(struct task_struct *t); | |
20 | ||
21 | int wrapper_task_prio_init(void) | |
22 | { | |
c539a324 | 23 | wrapper_task_prio_sym = (void *) kallsyms_lookup_funcptr("task_prio"); |
979133c5 MD |
24 | if (!wrapper_task_prio_sym) { |
25 | printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n"); | |
26 | return -EINVAL; | |
27 | } | |
28 | return 0; | |
29 | } | |
30 | ||
a8ad3613 MD |
31 | static |
32 | size_t prio_get_size(size_t offset) | |
33 | { | |
34 | size_t size = 0; | |
35 | ||
a90917c3 | 36 | size += lib_ring_buffer_align(offset, lttng_alignof(int)); |
a8ad3613 MD |
37 | size += sizeof(int); |
38 | return size; | |
39 | } | |
40 | ||
41 | static | |
42 | void prio_record(struct lttng_ctx_field *field, | |
43 | struct lib_ring_buffer_ctx *ctx, | |
a90917c3 | 44 | struct lttng_channel *chan) |
a8ad3613 MD |
45 | { |
46 | int prio; | |
47 | ||
8fefc8a2 | 48 | prio = wrapper_task_prio_sym(current); |
a90917c3 | 49 | lib_ring_buffer_align_ctx(ctx, lttng_alignof(prio)); |
53f1f0ca | 50 | chan->ops->event_write(ctx, &prio, sizeof(prio)); |
a8ad3613 MD |
51 | } |
52 | ||
f127e61e MD |
53 | static |
54 | void prio_get_value(struct lttng_ctx_field *field, | |
79150a49 | 55 | struct lttng_probe_ctx *lttng_probe_ctx, |
f127e61e MD |
56 | union lttng_ctx_value *value) |
57 | { | |
58 | value->s64 = wrapper_task_prio_sym(current); | |
59 | } | |
60 | ||
a8ad3613 MD |
61 | int lttng_add_prio_to_ctx(struct lttng_ctx **ctx) |
62 | { | |
63 | struct lttng_ctx_field *field; | |
64 | int ret; | |
65 | ||
979133c5 MD |
66 | if (!wrapper_task_prio_sym) { |
67 | ret = wrapper_task_prio_init(); | |
68 | if (ret) | |
69 | return ret; | |
70 | } | |
71 | ||
a8ad3613 MD |
72 | field = lttng_append_context(ctx); |
73 | if (!field) | |
09fec6b4 | 74 | return -ENOMEM; |
44252f0f MD |
75 | if (lttng_find_context(*ctx, "prio")) { |
76 | lttng_remove_context_field(ctx, field); | |
77 | return -EEXIST; | |
78 | } | |
a8ad3613 MD |
79 | field->event_field.name = "prio"; |
80 | field->event_field.type.atype = atype_integer; | |
ceabb767 MD |
81 | field->event_field.type.u.integer.size = sizeof(int) * CHAR_BIT; |
82 | field->event_field.type.u.integer.alignment = lttng_alignof(int) * CHAR_BIT; | |
83 | field->event_field.type.u.integer.signedness = lttng_is_signed_type(int); | |
84 | field->event_field.type.u.integer.reverse_byte_order = 0; | |
85 | field->event_field.type.u.integer.base = 10; | |
86 | field->event_field.type.u.integer.encoding = lttng_encode_none; | |
a8ad3613 MD |
87 | field->get_size = prio_get_size; |
88 | field->record = prio_record; | |
f127e61e | 89 | field->get_value = prio_get_value; |
a9dd15da | 90 | lttng_context_update(*ctx); |
a8ad3613 MD |
91 | return 0; |
92 | } | |
93 | EXPORT_SYMBOL_GPL(lttng_add_prio_to_ctx); |