diff options
| author | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
|---|---|---|
| committer | Jonathan Herman <hermanjl@cs.unc.edu> | 2013-01-22 10:38:37 -0500 |
| commit | fcc9d2e5a6c89d22b8b773a64fb4ad21ac318446 (patch) | |
| tree | a57612d1888735a2ec7972891b68c1ac5ec8faea /kernel/trace/tracelevel.c | |
| parent | 8dea78da5cee153b8af9c07a2745f6c55057fe12 (diff) | |
Diffstat (limited to 'kernel/trace/tracelevel.c')
| -rw-r--r-- | kernel/trace/tracelevel.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/kernel/trace/tracelevel.c b/kernel/trace/tracelevel.c new file mode 100644 index 00000000000..9f8b8eedbb5 --- /dev/null +++ b/kernel/trace/tracelevel.c | |||
| @@ -0,0 +1,142 @@ | |||
| 1 | /* | ||
| 2 | * kernel/trace/tracelevel.c | ||
| 3 | * | ||
| 4 | * Copyright (c) 2011, NVIDIA CORPORATION. All rights reserved. | ||
| 5 | * | ||
| 6 | * This program is free software; you can redistribute it and/or modify it | ||
| 7 | * under the terms and conditions of the GNU General Public License, | ||
| 8 | * version 2, as published by the Free Software Foundation. | ||
| 9 | * | ||
| 10 | * This program is distributed in the hope it will be useful, but WITHOUT | ||
| 11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | ||
| 13 | * more details. | ||
| 14 | * | ||
| 15 | * You should have received a copy of the GNU General Public License along with | ||
| 16 | * this program; if not, write to the Free Software Foundation, Inc., | ||
| 17 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 18 | * | ||
| 19 | */ | ||
| 20 | |||
| 21 | #include <linux/ftrace_event.h> | ||
| 22 | #include <linux/list.h> | ||
| 23 | #include <linux/moduleparam.h> | ||
| 24 | #include <linux/mutex.h> | ||
| 25 | #include <linux/tracelevel.h> | ||
| 26 | #include <linux/vmalloc.h> | ||
| 27 | |||
| 28 | #include "trace.h" | ||
| 29 | |||
| 30 | #define TAG KERN_ERR "tracelevel: " | ||
| 31 | |||
| 32 | struct tracelevel_record { | ||
| 33 | struct list_head list; | ||
| 34 | char *name; | ||
| 35 | int level; | ||
| 36 | }; | ||
| 37 | |||
| 38 | static LIST_HEAD(tracelevel_list); | ||
| 39 | |||
| 40 | static bool started; | ||
| 41 | static unsigned int tracelevel_level = TRACELEVEL_DEFAULT; | ||
| 42 | |||
| 43 | static DEFINE_MUTEX(tracelevel_record_lock); | ||
| 44 | |||
| 45 | /* tracelevel_set_event sets a single event if set = 1, or | ||
| 46 | * clears an event if set = 0. | ||
| 47 | */ | ||
| 48 | static int tracelevel_set_event(struct tracelevel_record *evt, bool set) | ||
| 49 | { | ||
| 50 | if (trace_set_clr_event(NULL, evt->name, set) < 0) { | ||
| 51 | printk(TAG "failed to set event %s\n", evt->name); | ||
| 52 | return -EINVAL; | ||
| 53 | } | ||
| 54 | return 0; | ||
| 55 | } | ||
| 56 | |||
| 57 | /* Registers an event. If possible, it also sets it. | ||
| 58 | * If not, we'll set it in tracelevel_init. | ||
| 59 | */ | ||
| 60 | int __tracelevel_register(char *name, unsigned int level) | ||
| 61 | { | ||
| 62 | struct tracelevel_record *evt = (struct tracelevel_record *) | ||
| 63 | vmalloc(sizeof(struct tracelevel_record)); | ||
| 64 | if (!evt) { | ||
| 65 | printk(TAG "failed to allocate tracelevel_record for %s\n", | ||
| 66 | name); | ||
| 67 | return -ENOMEM; | ||
| 68 | } | ||
| 69 | |||
| 70 | evt->name = name; | ||
| 71 | evt->level = level; | ||
| 72 | |||
| 73 | mutex_lock(&tracelevel_record_lock); | ||
| 74 | list_add(&evt->list, &tracelevel_list); | ||
| 75 | mutex_unlock(&tracelevel_record_lock); | ||
| 76 | |||
| 77 | if (level >= tracelevel_level && started) | ||
| 78 | tracelevel_set_event(evt, 1); | ||
| 79 | return 0; | ||
| 80 | } | ||
| 81 | |||
| 82 | /* tracelevel_set_level sets the global level, clears events | ||
| 83 | * lower than that level, and enables events greater or equal. | ||
| 84 | */ | ||
| 85 | int tracelevel_set_level(int level) | ||
| 86 | { | ||
| 87 | struct tracelevel_record *evt = NULL; | ||
| 88 | |||
| 89 | if (level < 0 || level > TRACELEVEL_MAX) | ||
| 90 | return -EINVAL; | ||
| 91 | tracelevel_level = level; | ||
| 92 | |||
| 93 | mutex_lock(&tracelevel_record_lock); | ||
| 94 | list_for_each_entry(evt, &tracelevel_list, list) { | ||
| 95 | if (evt->level >= level) | ||
| 96 | tracelevel_set_event(evt, 1); | ||
| 97 | else | ||
| 98 | tracelevel_set_event(evt, 0); | ||
| 99 | } | ||
| 100 | mutex_unlock(&tracelevel_record_lock); | ||
| 101 | return 0; | ||
| 102 | } | ||
| 103 | |||
| 104 | static int param_set_level(const char *val, const struct kernel_param *kp) | ||
| 105 | { | ||
| 106 | int level, ret; | ||
| 107 | ret = strict_strtol(val, 0, &level); | ||
| 108 | if (ret < 0) | ||
| 109 | return ret; | ||
| 110 | return tracelevel_set_level(level); | ||
| 111 | } | ||
| 112 | |||
| 113 | static int param_get_level(char *buffer, const struct kernel_param *kp) | ||
| 114 | { | ||
| 115 | return param_get_int(buffer, kp); | ||
| 116 | } | ||
| 117 | |||
| 118 | static struct kernel_param_ops tracelevel_level_ops = { | ||
| 119 | .set = param_set_level, | ||
| 120 | .get = param_get_level | ||
| 121 | }; | ||
| 122 | |||
| 123 | module_param_cb(level, &tracelevel_level_ops, &tracelevel_level, 0644); | ||
| 124 | |||
| 125 | /* Turn on the tracing that has been registered thus far. */ | ||
| 126 | static int __init tracelevel_init(void) | ||
| 127 | { | ||
| 128 | int ret; | ||
| 129 | started = true; | ||
| 130 | |||
| 131 | /* Ring buffer is initialize to 1 page until the user sets a tracer. | ||
| 132 | * Since we're doing this manually, we need to ask for expanded buffer. | ||
| 133 | */ | ||
| 134 | ret = tracing_update_buffers(); | ||
| 135 | if (ret < 0) | ||
| 136 | return ret; | ||
| 137 | |||
| 138 | return tracelevel_set_level(tracelevel_level); | ||
| 139 | } | ||
| 140 | |||
| 141 | /* Tracing mechanism is set up during fs_initcall. */ | ||
| 142 | fs_initcall_sync(tracelevel_init); | ||
