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