Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 Mathieu Desnoyers |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License as published by |
| 6 | * the Free Software Foundation; either version 2 of the License, or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 17 | */ |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/mutex.h> |
| 20 | #include <linux/types.h> |
| 21 | #include <linux/jhash.h> |
| 22 | #include <linux/list.h> |
| 23 | #include <linux/rcupdate.h> |
| 24 | #include <linux/tracepoint.h> |
| 25 | #include <linux/err.h> |
| 26 | #include <linux/slab.h> |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 27 | #include <linux/sched.h> |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 28 | #include <linux/static_key.h> |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 29 | |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 30 | extern struct tracepoint * const __start___tracepoints_ptrs[]; |
| 31 | extern struct tracepoint * const __stop___tracepoints_ptrs[]; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 32 | |
| 33 | /* Set to 1 to enable tracepoint debug output */ |
| 34 | static const int tracepoint_debug; |
| 35 | |
| 36 | /* |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 37 | * Tracepoints mutex protects the builtin and module tracepoints and the hash |
| 38 | * table, as well as the local module list. |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 39 | */ |
| 40 | static DEFINE_MUTEX(tracepoints_mutex); |
| 41 | |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 42 | #ifdef CONFIG_MODULES |
| 43 | /* Local list of struct module */ |
| 44 | static LIST_HEAD(tracepoint_module_list); |
| 45 | #endif /* CONFIG_MODULES */ |
| 46 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 47 | /* |
| 48 | * Tracepoint hash table, containing the active tracepoints. |
| 49 | * Protected by tracepoints_mutex. |
| 50 | */ |
| 51 | #define TRACEPOINT_HASH_BITS 6 |
| 52 | #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 53 | static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 54 | |
| 55 | /* |
| 56 | * Note about RCU : |
Anand Gadiyar | fd589a8 | 2009-07-16 17:13:03 +0200 | [diff] [blame] | 57 | * It is used to delay the free of multiple probes array until a quiescent |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 58 | * state is reached. |
| 59 | * Tracepoint entries modifications are protected by the tracepoints_mutex. |
| 60 | */ |
| 61 | struct tracepoint_entry { |
| 62 | struct hlist_node hlist; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 63 | struct tracepoint_func *funcs; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 64 | int refcount; /* Number of times armed. 0 if disarmed. */ |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 65 | int enabled; /* Tracepoint enabled */ |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 66 | char name[0]; |
| 67 | }; |
| 68 | |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 69 | struct tp_probes { |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 70 | union { |
| 71 | struct rcu_head rcu; |
| 72 | struct list_head list; |
| 73 | } u; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 74 | struct tracepoint_func probes[0]; |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 75 | }; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 76 | |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 77 | static inline void *allocate_probes(int count) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 78 | { |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 79 | struct tp_probes *p = kmalloc(count * sizeof(struct tracepoint_func) |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 80 | + sizeof(struct tp_probes), GFP_KERNEL); |
| 81 | return p == NULL ? NULL : p->probes; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 82 | } |
| 83 | |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 84 | static void rcu_free_old_probes(struct rcu_head *head) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 85 | { |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 86 | kfree(container_of(head, struct tp_probes, u.rcu)); |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 87 | } |
| 88 | |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 89 | static inline void release_probes(struct tracepoint_func *old) |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 90 | { |
| 91 | if (old) { |
| 92 | struct tp_probes *tp_probes = container_of(old, |
| 93 | struct tp_probes, probes[0]); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 94 | call_rcu_sched(&tp_probes->u.rcu, rcu_free_old_probes); |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 95 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 96 | } |
| 97 | |
| 98 | static void debug_print_probes(struct tracepoint_entry *entry) |
| 99 | { |
| 100 | int i; |
| 101 | |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 102 | if (!tracepoint_debug || !entry->funcs) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 103 | return; |
| 104 | |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 105 | for (i = 0; entry->funcs[i].func; i++) |
| 106 | printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i].func); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 107 | } |
| 108 | |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 109 | static struct tracepoint_func * |
| 110 | tracepoint_entry_add_probe(struct tracepoint_entry *entry, |
| 111 | void *probe, void *data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 112 | { |
| 113 | int nr_probes = 0; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 114 | struct tracepoint_func *old, *new; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 115 | |
Sahara | 4c69e6e | 2013-04-15 11:13:15 +0900 | [diff] [blame] | 116 | if (WARN_ON(!probe)) |
| 117 | return ERR_PTR(-EINVAL); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 118 | |
| 119 | debug_print_probes(entry); |
| 120 | old = entry->funcs; |
| 121 | if (old) { |
| 122 | /* (N -> N+1), (N != 0, 1) probes */ |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 123 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) |
| 124 | if (old[nr_probes].func == probe && |
| 125 | old[nr_probes].data == data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 126 | return ERR_PTR(-EEXIST); |
| 127 | } |
| 128 | /* + 2 : one for new probe, one for NULL func */ |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 129 | new = allocate_probes(nr_probes + 2); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 130 | if (new == NULL) |
| 131 | return ERR_PTR(-ENOMEM); |
| 132 | if (old) |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 133 | memcpy(new, old, nr_probes * sizeof(struct tracepoint_func)); |
| 134 | new[nr_probes].func = probe; |
| 135 | new[nr_probes].data = data; |
| 136 | new[nr_probes + 1].func = NULL; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 137 | entry->refcount = nr_probes + 1; |
| 138 | entry->funcs = new; |
| 139 | debug_print_probes(entry); |
| 140 | return old; |
| 141 | } |
| 142 | |
| 143 | static void * |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 144 | tracepoint_entry_remove_probe(struct tracepoint_entry *entry, |
| 145 | void *probe, void *data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 146 | { |
| 147 | int nr_probes = 0, nr_del = 0, i; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 148 | struct tracepoint_func *old, *new; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 149 | |
| 150 | old = entry->funcs; |
| 151 | |
Frederic Weisbecker | f66af45 | 2008-10-22 19:14:55 +0200 | [diff] [blame] | 152 | if (!old) |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 153 | return ERR_PTR(-ENOENT); |
Frederic Weisbecker | f66af45 | 2008-10-22 19:14:55 +0200 | [diff] [blame] | 154 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 155 | debug_print_probes(entry); |
| 156 | /* (N -> M), (N > 1, M >= 0) probes */ |
Sahara | 4c69e6e | 2013-04-15 11:13:15 +0900 | [diff] [blame] | 157 | if (probe) { |
| 158 | for (nr_probes = 0; old[nr_probes].func; nr_probes++) { |
| 159 | if (old[nr_probes].func == probe && |
| 160 | old[nr_probes].data == data) |
| 161 | nr_del++; |
| 162 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 163 | } |
| 164 | |
Sahara | 4c69e6e | 2013-04-15 11:13:15 +0900 | [diff] [blame] | 165 | /* |
| 166 | * If probe is NULL, then nr_probes = nr_del = 0, and then the |
| 167 | * entire entry will be removed. |
| 168 | */ |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 169 | if (nr_probes - nr_del == 0) { |
| 170 | /* N -> 0, (N > 1) */ |
| 171 | entry->funcs = NULL; |
| 172 | entry->refcount = 0; |
| 173 | debug_print_probes(entry); |
| 174 | return old; |
| 175 | } else { |
| 176 | int j = 0; |
| 177 | /* N -> M, (N > 1, M > 0) */ |
| 178 | /* + 1 for NULL */ |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 179 | new = allocate_probes(nr_probes - nr_del + 1); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 180 | if (new == NULL) |
| 181 | return ERR_PTR(-ENOMEM); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 182 | for (i = 0; old[i].func; i++) |
Sahara | 4c69e6e | 2013-04-15 11:13:15 +0900 | [diff] [blame] | 183 | if (old[i].func != probe || old[i].data != data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 184 | new[j++] = old[i]; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 185 | new[nr_probes - nr_del].func = NULL; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 186 | entry->refcount = nr_probes - nr_del; |
| 187 | entry->funcs = new; |
| 188 | } |
| 189 | debug_print_probes(entry); |
| 190 | return old; |
| 191 | } |
| 192 | |
| 193 | /* |
| 194 | * Get tracepoint if the tracepoint is present in the tracepoint hash table. |
| 195 | * Must be called with tracepoints_mutex held. |
| 196 | * Returns NULL if not present. |
| 197 | */ |
| 198 | static struct tracepoint_entry *get_tracepoint(const char *name) |
| 199 | { |
| 200 | struct hlist_head *head; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 201 | struct tracepoint_entry *e; |
| 202 | u32 hash = jhash(name, strlen(name), 0); |
| 203 | |
Mathieu Desnoyers | 9795302 | 2008-07-24 16:37:23 -0400 | [diff] [blame] | 204 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 205 | hlist_for_each_entry(e, head, hlist) { |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 206 | if (!strcmp(name, e->name)) |
| 207 | return e; |
| 208 | } |
| 209 | return NULL; |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | * Add the tracepoint to the tracepoint hash table. Must be called with |
| 214 | * tracepoints_mutex held. |
| 215 | */ |
| 216 | static struct tracepoint_entry *add_tracepoint(const char *name) |
| 217 | { |
| 218 | struct hlist_head *head; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 219 | struct tracepoint_entry *e; |
| 220 | size_t name_len = strlen(name) + 1; |
| 221 | u32 hash = jhash(name, name_len-1, 0); |
| 222 | |
Mathieu Desnoyers | 9795302 | 2008-07-24 16:37:23 -0400 | [diff] [blame] | 223 | head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)]; |
Sasha Levin | b67bfe0 | 2013-02-27 17:06:00 -0800 | [diff] [blame] | 224 | hlist_for_each_entry(e, head, hlist) { |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 225 | if (!strcmp(name, e->name)) { |
| 226 | printk(KERN_NOTICE |
| 227 | "tracepoint %s busy\n", name); |
| 228 | return ERR_PTR(-EEXIST); /* Already there */ |
| 229 | } |
| 230 | } |
| 231 | /* |
| 232 | * Using kmalloc here to allocate a variable length element. Could |
| 233 | * cause some memory fragmentation if overused. |
| 234 | */ |
| 235 | e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); |
| 236 | if (!e) |
| 237 | return ERR_PTR(-ENOMEM); |
| 238 | memcpy(&e->name[0], name, name_len); |
| 239 | e->funcs = NULL; |
| 240 | e->refcount = 0; |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 241 | e->enabled = 0; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 242 | hlist_add_head(&e->hlist, head); |
| 243 | return e; |
| 244 | } |
| 245 | |
| 246 | /* |
| 247 | * Remove the tracepoint from the tracepoint hash table. Must be called with |
| 248 | * mutex_lock held. |
| 249 | */ |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 250 | static inline void remove_tracepoint(struct tracepoint_entry *e) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 251 | { |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 252 | hlist_del(&e->hlist); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 253 | kfree(e); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 254 | } |
| 255 | |
| 256 | /* |
| 257 | * Sets the probe callback corresponding to one tracepoint. |
| 258 | */ |
| 259 | static void set_tracepoint(struct tracepoint_entry **entry, |
| 260 | struct tracepoint *elem, int active) |
| 261 | { |
| 262 | WARN_ON(strcmp((*entry)->name, elem->name) != 0); |
| 263 | |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 264 | if (elem->regfunc && !static_key_enabled(&elem->key) && active) |
Josh Stone | 9741987 | 2009-08-24 14:43:13 -0700 | [diff] [blame] | 265 | elem->regfunc(); |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 266 | else if (elem->unregfunc && static_key_enabled(&elem->key) && !active) |
Josh Stone | 9741987 | 2009-08-24 14:43:13 -0700 | [diff] [blame] | 267 | elem->unregfunc(); |
| 268 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 269 | /* |
| 270 | * rcu_assign_pointer has a smp_wmb() which makes sure that the new |
| 271 | * probe callbacks array is consistent before setting a pointer to it. |
| 272 | * This array is referenced by __DO_TRACE from |
| 273 | * include/linux/tracepoints.h. A matching smp_read_barrier_depends() |
| 274 | * is used. |
| 275 | */ |
| 276 | rcu_assign_pointer(elem->funcs, (*entry)->funcs); |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 277 | if (active && !static_key_enabled(&elem->key)) |
| 278 | static_key_slow_inc(&elem->key); |
| 279 | else if (!active && static_key_enabled(&elem->key)) |
| 280 | static_key_slow_dec(&elem->key); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 281 | } |
| 282 | |
| 283 | /* |
| 284 | * Disable a tracepoint and its probe callback. |
| 285 | * Note: only waiting an RCU period after setting elem->call to the empty |
| 286 | * function insures that the original callback is not used anymore. This insured |
| 287 | * by preempt_disable around the call site. |
| 288 | */ |
| 289 | static void disable_tracepoint(struct tracepoint *elem) |
| 290 | { |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 291 | if (elem->unregfunc && static_key_enabled(&elem->key)) |
Josh Stone | 9741987 | 2009-08-24 14:43:13 -0700 | [diff] [blame] | 292 | elem->unregfunc(); |
| 293 | |
Ingo Molnar | c5905af | 2012-02-24 08:31:31 +0100 | [diff] [blame] | 294 | if (static_key_enabled(&elem->key)) |
| 295 | static_key_slow_dec(&elem->key); |
Mathieu Desnoyers | de0baf9 | 2008-11-14 17:47:42 -0500 | [diff] [blame] | 296 | rcu_assign_pointer(elem->funcs, NULL); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 297 | } |
| 298 | |
| 299 | /** |
| 300 | * tracepoint_update_probe_range - Update a probe range |
| 301 | * @begin: beginning of the range |
| 302 | * @end: end of the range |
| 303 | * |
| 304 | * Updates the probe callback corresponding to a range of tracepoints. |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 305 | * Called with tracepoints_mutex held. |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 306 | */ |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 307 | static void tracepoint_update_probe_range(struct tracepoint * const *begin, |
| 308 | struct tracepoint * const *end) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 309 | { |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 310 | struct tracepoint * const *iter; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 311 | struct tracepoint_entry *mark_entry; |
| 312 | |
Ingo Molnar | ec625cb | 2009-03-18 19:54:04 +0100 | [diff] [blame] | 313 | if (!begin) |
Jaswinder Singh Rajput | 09933a1 | 2009-03-18 22:18:56 +0530 | [diff] [blame] | 314 | return; |
Jaswinder Singh Rajput | 09933a1 | 2009-03-18 22:18:56 +0530 | [diff] [blame] | 315 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 316 | for (iter = begin; iter < end; iter++) { |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 317 | mark_entry = get_tracepoint((*iter)->name); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 318 | if (mark_entry) { |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 319 | set_tracepoint(&mark_entry, *iter, |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 320 | !!mark_entry->refcount); |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 321 | mark_entry->enabled = !!mark_entry->refcount; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 322 | } else { |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 323 | disable_tracepoint(*iter); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 324 | } |
| 325 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 326 | } |
| 327 | |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 328 | #ifdef CONFIG_MODULES |
| 329 | void module_update_tracepoints(void) |
| 330 | { |
| 331 | struct tp_module *tp_mod; |
| 332 | |
| 333 | list_for_each_entry(tp_mod, &tracepoint_module_list, list) |
| 334 | tracepoint_update_probe_range(tp_mod->tracepoints_ptrs, |
| 335 | tp_mod->tracepoints_ptrs + tp_mod->num_tracepoints); |
| 336 | } |
| 337 | #else /* CONFIG_MODULES */ |
| 338 | void module_update_tracepoints(void) |
| 339 | { |
| 340 | } |
| 341 | #endif /* CONFIG_MODULES */ |
| 342 | |
| 343 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 344 | /* |
| 345 | * Update probes, removing the faulty probes. |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 346 | * Called with tracepoints_mutex held. |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 347 | */ |
| 348 | static void tracepoint_update_probes(void) |
| 349 | { |
| 350 | /* Core kernel tracepoints */ |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 351 | tracepoint_update_probe_range(__start___tracepoints_ptrs, |
| 352 | __stop___tracepoints_ptrs); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 353 | /* tracepoints in modules. */ |
| 354 | module_update_tracepoints(); |
| 355 | } |
| 356 | |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 357 | static struct tracepoint_func * |
| 358 | tracepoint_add_probe(const char *name, void *probe, void *data) |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 359 | { |
| 360 | struct tracepoint_entry *entry; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 361 | struct tracepoint_func *old; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 362 | |
| 363 | entry = get_tracepoint(name); |
| 364 | if (!entry) { |
| 365 | entry = add_tracepoint(name); |
| 366 | if (IS_ERR(entry)) |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 367 | return (struct tracepoint_func *)entry; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 368 | } |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 369 | old = tracepoint_entry_add_probe(entry, probe, data); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 370 | if (IS_ERR(old) && !entry->refcount) |
| 371 | remove_tracepoint(entry); |
| 372 | return old; |
| 373 | } |
| 374 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 375 | /** |
| 376 | * tracepoint_probe_register - Connect a probe to a tracepoint |
| 377 | * @name: tracepoint name |
| 378 | * @probe: probe handler |
Mathieu Desnoyers | 4c11628 | 2014-03-11 21:32:28 -0400 | [diff] [blame] | 379 | * @data: probe private data |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 380 | * |
Mathieu Desnoyers | 3bbc8db | 2014-03-10 21:04:58 -0400 | [diff] [blame] | 381 | * Returns: |
| 382 | * - 0 if the probe was successfully registered, and tracepoint |
| 383 | * callsites are currently loaded for that probe, |
| 384 | * - -ENODEV if the probe was successfully registered, but no tracepoint |
| 385 | * callsite is currently loaded for that probe, |
| 386 | * - other negative error value on error. |
| 387 | * |
| 388 | * When tracepoint_probe_register() returns either 0 or -ENODEV, |
| 389 | * parameters @name, @probe, and @data may be used by the tracepoint |
| 390 | * infrastructure until the probe is unregistered. |
| 391 | * |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 392 | * The probe address must at least be aligned on the architecture pointer size. |
| 393 | */ |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 394 | int tracepoint_probe_register(const char *name, void *probe, void *data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 395 | { |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 396 | struct tracepoint_func *old; |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 397 | struct tracepoint_entry *entry; |
| 398 | int ret = 0; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 399 | |
| 400 | mutex_lock(&tracepoints_mutex); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 401 | old = tracepoint_add_probe(name, probe, data); |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 402 | if (IS_ERR(old)) { |
| 403 | mutex_unlock(&tracepoints_mutex); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 404 | return PTR_ERR(old); |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 405 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 406 | tracepoint_update_probes(); /* may update entry */ |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 407 | entry = get_tracepoint(name); |
| 408 | /* Make sure the entry was enabled */ |
| 409 | if (!entry || !entry->enabled) |
| 410 | ret = -ENODEV; |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 411 | mutex_unlock(&tracepoints_mutex); |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 412 | release_probes(old); |
Steven Rostedt | b196e2b | 2014-02-13 15:45:07 -0500 | [diff] [blame] | 413 | return ret; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 414 | } |
| 415 | EXPORT_SYMBOL_GPL(tracepoint_probe_register); |
| 416 | |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 417 | static struct tracepoint_func * |
| 418 | tracepoint_remove_probe(const char *name, void *probe, void *data) |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 419 | { |
| 420 | struct tracepoint_entry *entry; |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 421 | struct tracepoint_func *old; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 422 | |
| 423 | entry = get_tracepoint(name); |
| 424 | if (!entry) |
| 425 | return ERR_PTR(-ENOENT); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 426 | old = tracepoint_entry_remove_probe(entry, probe, data); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 427 | if (IS_ERR(old)) |
| 428 | return old; |
| 429 | if (!entry->refcount) |
| 430 | remove_tracepoint(entry); |
| 431 | return old; |
| 432 | } |
| 433 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 434 | /** |
| 435 | * tracepoint_probe_unregister - Disconnect a probe from a tracepoint |
| 436 | * @name: tracepoint name |
| 437 | * @probe: probe function pointer |
Mathieu Desnoyers | 4c11628 | 2014-03-11 21:32:28 -0400 | [diff] [blame] | 438 | * @data: probe private data |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 439 | * |
| 440 | * We do not need to call a synchronize_sched to make sure the probes have |
| 441 | * finished running before doing a module unload, because the module unload |
| 442 | * itself uses stop_machine(), which insures that every preempt disabled section |
| 443 | * have finished. |
| 444 | */ |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 445 | int tracepoint_probe_unregister(const char *name, void *probe, void *data) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 446 | { |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 447 | struct tracepoint_func *old; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 448 | |
| 449 | mutex_lock(&tracepoints_mutex); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 450 | old = tracepoint_remove_probe(name, probe, data); |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 451 | if (IS_ERR(old)) { |
| 452 | mutex_unlock(&tracepoints_mutex); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 453 | return PTR_ERR(old); |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 454 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 455 | tracepoint_update_probes(); /* may update entry */ |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 456 | mutex_unlock(&tracepoints_mutex); |
Lai Jiangshan | 19dba33 | 2008-10-28 10:51:49 +0800 | [diff] [blame] | 457 | release_probes(old); |
| 458 | return 0; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 459 | } |
| 460 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); |
| 461 | |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 462 | static LIST_HEAD(old_probes); |
| 463 | static int need_update; |
| 464 | |
| 465 | static void tracepoint_add_old_probes(void *old) |
| 466 | { |
| 467 | need_update = 1; |
| 468 | if (old) { |
| 469 | struct tp_probes *tp_probes = container_of(old, |
| 470 | struct tp_probes, probes[0]); |
| 471 | list_add(&tp_probes->u.list, &old_probes); |
| 472 | } |
| 473 | } |
| 474 | |
| 475 | /** |
| 476 | * tracepoint_probe_register_noupdate - register a probe but not connect |
| 477 | * @name: tracepoint name |
| 478 | * @probe: probe handler |
Mathieu Desnoyers | 4c11628 | 2014-03-11 21:32:28 -0400 | [diff] [blame] | 479 | * @data: probe private data |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 480 | * |
| 481 | * caller must call tracepoint_probe_update_all() |
| 482 | */ |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 483 | int tracepoint_probe_register_noupdate(const char *name, void *probe, |
| 484 | void *data) |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 485 | { |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 486 | struct tracepoint_func *old; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 487 | |
| 488 | mutex_lock(&tracepoints_mutex); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 489 | old = tracepoint_add_probe(name, probe, data); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 490 | if (IS_ERR(old)) { |
| 491 | mutex_unlock(&tracepoints_mutex); |
| 492 | return PTR_ERR(old); |
| 493 | } |
| 494 | tracepoint_add_old_probes(old); |
| 495 | mutex_unlock(&tracepoints_mutex); |
| 496 | return 0; |
| 497 | } |
| 498 | EXPORT_SYMBOL_GPL(tracepoint_probe_register_noupdate); |
| 499 | |
| 500 | /** |
| 501 | * tracepoint_probe_unregister_noupdate - remove a probe but not disconnect |
| 502 | * @name: tracepoint name |
| 503 | * @probe: probe function pointer |
Mathieu Desnoyers | 4c11628 | 2014-03-11 21:32:28 -0400 | [diff] [blame] | 504 | * @data: probe private data |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 505 | * |
| 506 | * caller must call tracepoint_probe_update_all() |
| 507 | */ |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 508 | int tracepoint_probe_unregister_noupdate(const char *name, void *probe, |
| 509 | void *data) |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 510 | { |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 511 | struct tracepoint_func *old; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 512 | |
| 513 | mutex_lock(&tracepoints_mutex); |
Steven Rostedt | 38516ab | 2010-04-20 17:04:50 -0400 | [diff] [blame] | 514 | old = tracepoint_remove_probe(name, probe, data); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 515 | if (IS_ERR(old)) { |
| 516 | mutex_unlock(&tracepoints_mutex); |
| 517 | return PTR_ERR(old); |
| 518 | } |
| 519 | tracepoint_add_old_probes(old); |
| 520 | mutex_unlock(&tracepoints_mutex); |
| 521 | return 0; |
| 522 | } |
| 523 | EXPORT_SYMBOL_GPL(tracepoint_probe_unregister_noupdate); |
| 524 | |
| 525 | /** |
| 526 | * tracepoint_probe_update_all - update tracepoints |
| 527 | */ |
| 528 | void tracepoint_probe_update_all(void) |
| 529 | { |
| 530 | LIST_HEAD(release_probes); |
| 531 | struct tp_probes *pos, *next; |
| 532 | |
| 533 | mutex_lock(&tracepoints_mutex); |
| 534 | if (!need_update) { |
| 535 | mutex_unlock(&tracepoints_mutex); |
| 536 | return; |
| 537 | } |
| 538 | if (!list_empty(&old_probes)) |
| 539 | list_replace_init(&old_probes, &release_probes); |
| 540 | need_update = 0; |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 541 | tracepoint_update_probes(); |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 542 | mutex_unlock(&tracepoints_mutex); |
Lai Jiangshan | 127cafb | 2008-10-28 10:51:53 +0800 | [diff] [blame] | 543 | list_for_each_entry_safe(pos, next, &release_probes, u.list) { |
| 544 | list_del(&pos->u.list); |
| 545 | call_rcu_sched(&pos->u.rcu, rcu_free_old_probes); |
| 546 | } |
| 547 | } |
| 548 | EXPORT_SYMBOL_GPL(tracepoint_probe_update_all); |
| 549 | |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 550 | /** |
| 551 | * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. |
| 552 | * @tracepoint: current tracepoints (in), next tracepoint (out) |
| 553 | * @begin: beginning of the range |
| 554 | * @end: end of the range |
| 555 | * |
| 556 | * Returns whether a next tracepoint has been found (1) or not (0). |
| 557 | * Will return the first tracepoint in the range if the input tracepoint is |
| 558 | * NULL. |
| 559 | */ |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 560 | static int tracepoint_get_iter_range(struct tracepoint * const **tracepoint, |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 561 | struct tracepoint * const *begin, struct tracepoint * const *end) |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 562 | { |
| 563 | if (!*tracepoint && begin != end) { |
| 564 | *tracepoint = begin; |
| 565 | return 1; |
| 566 | } |
| 567 | if (*tracepoint >= begin && *tracepoint < end) |
| 568 | return 1; |
| 569 | return 0; |
| 570 | } |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 571 | |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 572 | #ifdef CONFIG_MODULES |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 573 | static void tracepoint_get_iter(struct tracepoint_iter *iter) |
| 574 | { |
| 575 | int found = 0; |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 576 | struct tp_module *iter_mod; |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 577 | |
| 578 | /* Core kernel tracepoints */ |
| 579 | if (!iter->module) { |
| 580 | found = tracepoint_get_iter_range(&iter->tracepoint, |
Mathieu Desnoyers | 6549864 | 2011-01-26 17:26:22 -0500 | [diff] [blame] | 581 | __start___tracepoints_ptrs, |
| 582 | __stop___tracepoints_ptrs); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 583 | if (found) |
| 584 | goto end; |
| 585 | } |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 586 | /* Tracepoints in modules */ |
| 587 | mutex_lock(&tracepoints_mutex); |
| 588 | list_for_each_entry(iter_mod, &tracepoint_module_list, list) { |
| 589 | /* |
| 590 | * Sorted module list |
| 591 | */ |
| 592 | if (iter_mod < iter->module) |
| 593 | continue; |
| 594 | else if (iter_mod > iter->module) |
| 595 | iter->tracepoint = NULL; |
| 596 | found = tracepoint_get_iter_range(&iter->tracepoint, |
| 597 | iter_mod->tracepoints_ptrs, |
| 598 | iter_mod->tracepoints_ptrs |
| 599 | + iter_mod->num_tracepoints); |
| 600 | if (found) { |
| 601 | iter->module = iter_mod; |
| 602 | break; |
| 603 | } |
| 604 | } |
| 605 | mutex_unlock(&tracepoints_mutex); |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 606 | end: |
| 607 | if (!found) |
| 608 | tracepoint_iter_reset(iter); |
| 609 | } |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 610 | #else /* CONFIG_MODULES */ |
| 611 | static void tracepoint_get_iter(struct tracepoint_iter *iter) |
| 612 | { |
| 613 | int found = 0; |
| 614 | |
| 615 | /* Core kernel tracepoints */ |
| 616 | found = tracepoint_get_iter_range(&iter->tracepoint, |
| 617 | __start___tracepoints_ptrs, |
| 618 | __stop___tracepoints_ptrs); |
| 619 | if (!found) |
| 620 | tracepoint_iter_reset(iter); |
| 621 | } |
| 622 | #endif /* CONFIG_MODULES */ |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 623 | |
| 624 | void tracepoint_iter_start(struct tracepoint_iter *iter) |
| 625 | { |
| 626 | tracepoint_get_iter(iter); |
| 627 | } |
| 628 | EXPORT_SYMBOL_GPL(tracepoint_iter_start); |
| 629 | |
| 630 | void tracepoint_iter_next(struct tracepoint_iter *iter) |
| 631 | { |
| 632 | iter->tracepoint++; |
| 633 | /* |
| 634 | * iter->tracepoint may be invalid because we blindly incremented it. |
| 635 | * Make sure it is valid by marshalling on the tracepoints, getting the |
| 636 | * tracepoints from following modules if necessary. |
| 637 | */ |
| 638 | tracepoint_get_iter(iter); |
| 639 | } |
| 640 | EXPORT_SYMBOL_GPL(tracepoint_iter_next); |
| 641 | |
| 642 | void tracepoint_iter_stop(struct tracepoint_iter *iter) |
| 643 | { |
| 644 | } |
| 645 | EXPORT_SYMBOL_GPL(tracepoint_iter_stop); |
| 646 | |
| 647 | void tracepoint_iter_reset(struct tracepoint_iter *iter) |
| 648 | { |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 649 | #ifdef CONFIG_MODULES |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 650 | iter->module = NULL; |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 651 | #endif /* CONFIG_MODULES */ |
Mathieu Desnoyers | 97e1c18 | 2008-07-18 12:16:16 -0400 | [diff] [blame] | 652 | iter->tracepoint = NULL; |
| 653 | } |
| 654 | EXPORT_SYMBOL_GPL(tracepoint_iter_reset); |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 655 | |
Ingo Molnar | 227a837 | 2008-11-16 09:50:34 +0100 | [diff] [blame] | 656 | #ifdef CONFIG_MODULES |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 657 | static int tracepoint_module_coming(struct module *mod) |
| 658 | { |
| 659 | struct tp_module *tp_mod, *iter; |
| 660 | int ret = 0; |
| 661 | |
Steven Rostedt (Red Hat) | 7dec935 | 2014-02-26 10:54:36 -0500 | [diff] [blame] | 662 | if (!mod->num_tracepoints) |
| 663 | return 0; |
| 664 | |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 665 | /* |
Steven Rostedt | c10076c | 2012-01-13 21:40:59 -0500 | [diff] [blame] | 666 | * We skip modules that taint the kernel, especially those with different |
| 667 | * module headers (for forced load), to make sure we don't cause a crash. |
| 668 | * Staging and out-of-tree GPL modules are fine. |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 669 | */ |
Steven Rostedt | c10076c | 2012-01-13 21:40:59 -0500 | [diff] [blame] | 670 | if (mod->taints & ~((1 << TAINT_OOT_MODULE) | (1 << TAINT_CRAP))) |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 671 | return 0; |
| 672 | mutex_lock(&tracepoints_mutex); |
| 673 | tp_mod = kmalloc(sizeof(struct tp_module), GFP_KERNEL); |
| 674 | if (!tp_mod) { |
| 675 | ret = -ENOMEM; |
| 676 | goto end; |
| 677 | } |
| 678 | tp_mod->num_tracepoints = mod->num_tracepoints; |
| 679 | tp_mod->tracepoints_ptrs = mod->tracepoints_ptrs; |
| 680 | |
| 681 | /* |
| 682 | * tracepoint_module_list is kept sorted by struct module pointer |
| 683 | * address for iteration on tracepoints from a seq_file that can release |
| 684 | * the mutex between calls. |
| 685 | */ |
| 686 | list_for_each_entry_reverse(iter, &tracepoint_module_list, list) { |
| 687 | BUG_ON(iter == tp_mod); /* Should never be in the list twice */ |
| 688 | if (iter < tp_mod) { |
| 689 | /* We belong to the location right after iter. */ |
| 690 | list_add(&tp_mod->list, &iter->list); |
| 691 | goto module_added; |
| 692 | } |
| 693 | } |
| 694 | /* We belong to the beginning of the list */ |
| 695 | list_add(&tp_mod->list, &tracepoint_module_list); |
| 696 | module_added: |
| 697 | tracepoint_update_probe_range(mod->tracepoints_ptrs, |
| 698 | mod->tracepoints_ptrs + mod->num_tracepoints); |
| 699 | end: |
| 700 | mutex_unlock(&tracepoints_mutex); |
| 701 | return ret; |
| 702 | } |
| 703 | |
| 704 | static int tracepoint_module_going(struct module *mod) |
| 705 | { |
| 706 | struct tp_module *pos; |
| 707 | |
Steven Rostedt (Red Hat) | 7dec935 | 2014-02-26 10:54:36 -0500 | [diff] [blame] | 708 | if (!mod->num_tracepoints) |
| 709 | return 0; |
| 710 | |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 711 | mutex_lock(&tracepoints_mutex); |
| 712 | tracepoint_update_probe_range(mod->tracepoints_ptrs, |
| 713 | mod->tracepoints_ptrs + mod->num_tracepoints); |
| 714 | list_for_each_entry(pos, &tracepoint_module_list, list) { |
| 715 | if (pos->tracepoints_ptrs == mod->tracepoints_ptrs) { |
| 716 | list_del(&pos->list); |
| 717 | kfree(pos); |
| 718 | break; |
| 719 | } |
| 720 | } |
| 721 | /* |
| 722 | * In the case of modules that were tainted at "coming", we'll simply |
| 723 | * walk through the list without finding it. We cannot use the "tainted" |
| 724 | * flag on "going", in case a module taints the kernel only after being |
| 725 | * loaded. |
| 726 | */ |
| 727 | mutex_unlock(&tracepoints_mutex); |
| 728 | return 0; |
| 729 | } |
Ingo Molnar | 227a837 | 2008-11-16 09:50:34 +0100 | [diff] [blame] | 730 | |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 731 | int tracepoint_module_notify(struct notifier_block *self, |
| 732 | unsigned long val, void *data) |
| 733 | { |
| 734 | struct module *mod = data; |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 735 | int ret = 0; |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 736 | |
| 737 | switch (val) { |
| 738 | case MODULE_STATE_COMING: |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 739 | ret = tracepoint_module_coming(mod); |
| 740 | break; |
| 741 | case MODULE_STATE_LIVE: |
| 742 | break; |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 743 | case MODULE_STATE_GOING: |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 744 | ret = tracepoint_module_going(mod); |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 745 | break; |
| 746 | } |
Mathieu Desnoyers | b75ef8b | 2011-08-10 15:18:39 -0400 | [diff] [blame] | 747 | return ret; |
Mathieu Desnoyers | 32f8574 | 2008-11-14 17:47:46 -0500 | [diff] [blame] | 748 | } |
| 749 | |
| 750 | struct notifier_block tracepoint_module_nb = { |
| 751 | .notifier_call = tracepoint_module_notify, |
| 752 | .priority = 0, |
| 753 | }; |
| 754 | |
| 755 | static int init_tracepoints(void) |
| 756 | { |
| 757 | return register_module_notifier(&tracepoint_module_nb); |
| 758 | } |
| 759 | __initcall(init_tracepoints); |
Ingo Molnar | 227a837 | 2008-11-16 09:50:34 +0100 | [diff] [blame] | 760 | #endif /* CONFIG_MODULES */ |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 761 | |
Josh Stone | 3d27d8c | 2009-08-24 14:43:12 -0700 | [diff] [blame] | 762 | #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS |
Ingo Molnar | 60d970c | 2009-08-13 23:37:26 +0200 | [diff] [blame] | 763 | |
Josh Stone | 9741987 | 2009-08-24 14:43:13 -0700 | [diff] [blame] | 764 | /* NB: reg/unreg are called while guarded with the tracepoints_mutex */ |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 765 | static int sys_tracepoint_refcount; |
| 766 | |
| 767 | void syscall_regfunc(void) |
| 768 | { |
| 769 | unsigned long flags; |
| 770 | struct task_struct *g, *t; |
| 771 | |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 772 | if (!sys_tracepoint_refcount) { |
| 773 | read_lock_irqsave(&tasklist_lock, flags); |
| 774 | do_each_thread(g, t) { |
Hendrik Brueckner | cc3b13c | 2009-08-25 18:02:37 +0200 | [diff] [blame] | 775 | /* Skip kernel threads. */ |
| 776 | if (t->mm) |
| 777 | set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 778 | } while_each_thread(g, t); |
| 779 | read_unlock_irqrestore(&tasklist_lock, flags); |
| 780 | } |
| 781 | sys_tracepoint_refcount++; |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 782 | } |
| 783 | |
| 784 | void syscall_unregfunc(void) |
| 785 | { |
| 786 | unsigned long flags; |
| 787 | struct task_struct *g, *t; |
| 788 | |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 789 | sys_tracepoint_refcount--; |
| 790 | if (!sys_tracepoint_refcount) { |
| 791 | read_lock_irqsave(&tasklist_lock, flags); |
| 792 | do_each_thread(g, t) { |
Josh Stone | 6670000 | 2009-08-24 14:43:11 -0700 | [diff] [blame] | 793 | clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 794 | } while_each_thread(g, t); |
| 795 | read_unlock_irqrestore(&tasklist_lock, flags); |
| 796 | } |
Jason Baron | a871bd3 | 2009-08-10 16:52:31 -0400 | [diff] [blame] | 797 | } |
Ingo Molnar | 60d970c | 2009-08-13 23:37:26 +0200 | [diff] [blame] | 798 | #endif |