Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Infrastructure for profiling code inserted by 'gcc -pg'. |
| 3 | * |
| 4 | * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> |
| 5 | * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com> |
| 6 | * |
| 7 | * Originally ported from the -rt patch by: |
| 8 | * Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com> |
| 9 | * |
| 10 | * Based on code in the latency_tracer, that is: |
| 11 | * |
| 12 | * Copyright (C) 2004-2006 Ingo Molnar |
| 13 | * Copyright (C) 2004 William Lee Irwin III |
| 14 | */ |
| 15 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 16 | #include <linux/stop_machine.h> |
| 17 | #include <linux/clocksource.h> |
| 18 | #include <linux/kallsyms.h> |
| 19 | #include <linux/kthread.h> |
| 20 | #include <linux/hardirq.h> |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 21 | #include <linux/ftrace.h> |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 22 | #include <linux/module.h> |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 23 | #include <linux/sysctl.h> |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 24 | #include <linux/hash.h> |
| 25 | #include <linux/list.h> |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 26 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 27 | #include "trace.h" |
| 28 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 29 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 30 | # define FTRACE_ENABLED_INIT 1 |
| 31 | #else |
| 32 | # define FTRACE_ENABLED_INIT 0 |
| 33 | #endif |
| 34 | |
| 35 | int ftrace_enabled = FTRACE_ENABLED_INIT; |
| 36 | static int last_ftrace_enabled = FTRACE_ENABLED_INIT; |
| 37 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 38 | static DEFINE_SPINLOCK(ftrace_lock); |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 39 | static DEFINE_MUTEX(ftrace_sysctl_lock); |
| 40 | |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 41 | static struct ftrace_ops ftrace_list_end __read_mostly = |
| 42 | { |
| 43 | .func = ftrace_stub, |
| 44 | }; |
| 45 | |
| 46 | static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end; |
| 47 | ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; |
| 48 | |
| 49 | /* mcount is defined per arch in assembly */ |
| 50 | EXPORT_SYMBOL(mcount); |
| 51 | |
| 52 | notrace void ftrace_list_func(unsigned long ip, unsigned long parent_ip) |
| 53 | { |
| 54 | struct ftrace_ops *op = ftrace_list; |
| 55 | |
| 56 | /* in case someone actually ports this to alpha! */ |
| 57 | read_barrier_depends(); |
| 58 | |
| 59 | while (op != &ftrace_list_end) { |
| 60 | /* silly alpha */ |
| 61 | read_barrier_depends(); |
| 62 | op->func(ip, parent_ip); |
| 63 | op = op->next; |
| 64 | }; |
| 65 | } |
| 66 | |
| 67 | /** |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 68 | * clear_ftrace_function - reset the ftrace function |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 69 | * |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 70 | * This NULLs the ftrace function and in essence stops |
| 71 | * tracing. There may be lag |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 72 | */ |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 73 | void clear_ftrace_function(void) |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 74 | { |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 75 | ftrace_trace_function = ftrace_stub; |
| 76 | } |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 77 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 78 | static int notrace __register_ftrace_function(struct ftrace_ops *ops) |
| 79 | { |
| 80 | /* Should never be called by interrupts */ |
| 81 | spin_lock(&ftrace_lock); |
| 82 | |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 83 | ops->next = ftrace_list; |
| 84 | /* |
| 85 | * We are entering ops into the ftrace_list but another |
| 86 | * CPU might be walking that list. We need to make sure |
| 87 | * the ops->next pointer is valid before another CPU sees |
| 88 | * the ops pointer included into the ftrace_list. |
| 89 | */ |
| 90 | smp_wmb(); |
| 91 | ftrace_list = ops; |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 92 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 93 | if (ftrace_enabled) { |
| 94 | /* |
| 95 | * For one func, simply call it directly. |
| 96 | * For more than one func, call the chain. |
| 97 | */ |
| 98 | if (ops->next == &ftrace_list_end) |
| 99 | ftrace_trace_function = ops->func; |
| 100 | else |
| 101 | ftrace_trace_function = ftrace_list_func; |
| 102 | } |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 103 | |
| 104 | spin_unlock(&ftrace_lock); |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 105 | |
| 106 | return 0; |
| 107 | } |
| 108 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 109 | static int notrace __unregister_ftrace_function(struct ftrace_ops *ops) |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 110 | { |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 111 | struct ftrace_ops **p; |
| 112 | int ret = 0; |
| 113 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 114 | spin_lock(&ftrace_lock); |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 115 | |
| 116 | /* |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 117 | * If we are removing the last function, then simply point |
| 118 | * to the ftrace_stub. |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 119 | */ |
| 120 | if (ftrace_list == ops && ops->next == &ftrace_list_end) { |
| 121 | ftrace_trace_function = ftrace_stub; |
| 122 | ftrace_list = &ftrace_list_end; |
| 123 | goto out; |
| 124 | } |
| 125 | |
| 126 | for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next) |
| 127 | if (*p == ops) |
| 128 | break; |
| 129 | |
| 130 | if (*p != ops) { |
| 131 | ret = -1; |
| 132 | goto out; |
| 133 | } |
| 134 | |
| 135 | *p = (*p)->next; |
| 136 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 137 | if (ftrace_enabled) { |
| 138 | /* If we only have one func left, then call that directly */ |
| 139 | if (ftrace_list == &ftrace_list_end || |
| 140 | ftrace_list->next == &ftrace_list_end) |
| 141 | ftrace_trace_function = ftrace_list->func; |
| 142 | } |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 143 | |
| 144 | out: |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 145 | spin_unlock(&ftrace_lock); |
| 146 | |
| 147 | return ret; |
| 148 | } |
| 149 | |
| 150 | #ifdef CONFIG_DYNAMIC_FTRACE |
| 151 | |
| 152 | static struct hlist_head ftrace_hash[FTRACE_HASHSIZE]; |
| 153 | |
| 154 | static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu); |
| 155 | |
| 156 | static DEFINE_SPINLOCK(ftrace_shutdown_lock); |
| 157 | static DEFINE_MUTEX(ftraced_lock); |
| 158 | |
| 159 | static int ftraced_trigger; |
| 160 | static int ftraced_suspend; |
| 161 | |
| 162 | static int ftrace_record_suspend; |
| 163 | |
| 164 | static inline int |
| 165 | notrace ftrace_ip_in_hash(unsigned long ip, unsigned long key) |
| 166 | { |
| 167 | struct dyn_ftrace *p; |
| 168 | struct hlist_node *t; |
| 169 | int found = 0; |
| 170 | |
| 171 | hlist_for_each_entry(p, t, &ftrace_hash[key], node) { |
| 172 | if (p->ip == ip) { |
| 173 | found = 1; |
| 174 | break; |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | return found; |
| 179 | } |
| 180 | |
| 181 | static inline void notrace |
| 182 | ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) |
| 183 | { |
| 184 | hlist_add_head(&node->node, &ftrace_hash[key]); |
| 185 | } |
| 186 | |
| 187 | static void notrace |
| 188 | ftrace_record_ip(unsigned long ip, unsigned long parent_ip) |
| 189 | { |
| 190 | struct dyn_ftrace *node; |
| 191 | unsigned long flags; |
| 192 | unsigned long key; |
| 193 | int resched; |
| 194 | int atomic; |
| 195 | |
| 196 | resched = need_resched(); |
| 197 | preempt_disable_notrace(); |
| 198 | |
| 199 | /* We simply need to protect against recursion */ |
| 200 | __get_cpu_var(ftrace_shutdown_disable_cpu)++; |
| 201 | if (__get_cpu_var(ftrace_shutdown_disable_cpu) != 1) |
| 202 | goto out; |
| 203 | |
| 204 | if (unlikely(ftrace_record_suspend)) |
| 205 | goto out; |
| 206 | |
| 207 | key = hash_long(ip, FTRACE_HASHBITS); |
| 208 | |
| 209 | WARN_ON_ONCE(key >= FTRACE_HASHSIZE); |
| 210 | |
| 211 | if (ftrace_ip_in_hash(ip, key)) |
| 212 | goto out; |
| 213 | |
| 214 | atomic = irqs_disabled(); |
| 215 | |
| 216 | spin_lock_irqsave(&ftrace_shutdown_lock, flags); |
| 217 | |
| 218 | /* This ip may have hit the hash before the lock */ |
| 219 | if (ftrace_ip_in_hash(ip, key)) |
| 220 | goto out_unlock; |
| 221 | |
| 222 | /* |
| 223 | * There's a slight race that the ftraced will update the |
| 224 | * hash and reset here. The arch alloc is responsible |
| 225 | * for seeing if the IP has already changed, and if |
| 226 | * it has, the alloc will fail. |
| 227 | */ |
| 228 | node = ftrace_alloc_shutdown_node(ip); |
| 229 | if (!node) |
| 230 | goto out_unlock; |
| 231 | |
| 232 | node->ip = ip; |
| 233 | |
| 234 | ftrace_add_hash(node, key); |
| 235 | |
| 236 | ftraced_trigger = 1; |
| 237 | |
| 238 | out_unlock: |
| 239 | spin_unlock_irqrestore(&ftrace_shutdown_lock, flags); |
| 240 | out: |
| 241 | __get_cpu_var(ftrace_shutdown_disable_cpu)--; |
| 242 | |
| 243 | /* prevent recursion with scheduler */ |
| 244 | if (resched) |
| 245 | preempt_enable_no_resched_notrace(); |
| 246 | else |
| 247 | preempt_enable_notrace(); |
| 248 | } |
| 249 | |
| 250 | static struct ftrace_ops ftrace_shutdown_ops __read_mostly = |
| 251 | { |
| 252 | .func = ftrace_record_ip, |
| 253 | }; |
| 254 | |
| 255 | |
| 256 | static int notrace __ftrace_modify_code(void *data) |
| 257 | { |
| 258 | void (*func)(void) = data; |
| 259 | |
| 260 | func(); |
| 261 | return 0; |
| 262 | } |
| 263 | |
| 264 | static void notrace ftrace_run_startup_code(void) |
| 265 | { |
| 266 | stop_machine_run(__ftrace_modify_code, ftrace_startup_code, NR_CPUS); |
| 267 | } |
| 268 | |
| 269 | static void notrace ftrace_run_shutdown_code(void) |
| 270 | { |
| 271 | stop_machine_run(__ftrace_modify_code, ftrace_shutdown_code, NR_CPUS); |
| 272 | } |
| 273 | |
| 274 | static void notrace ftrace_startup(void) |
| 275 | { |
| 276 | mutex_lock(&ftraced_lock); |
| 277 | ftraced_suspend++; |
| 278 | if (ftraced_suspend != 1) |
| 279 | goto out; |
| 280 | __unregister_ftrace_function(&ftrace_shutdown_ops); |
| 281 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 282 | if (ftrace_enabled) |
| 283 | ftrace_run_startup_code(); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 284 | out: |
| 285 | mutex_unlock(&ftraced_lock); |
| 286 | } |
| 287 | |
| 288 | static void notrace ftrace_shutdown(void) |
| 289 | { |
| 290 | mutex_lock(&ftraced_lock); |
| 291 | ftraced_suspend--; |
| 292 | if (ftraced_suspend) |
| 293 | goto out; |
| 294 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 295 | if (ftrace_enabled) |
| 296 | ftrace_run_shutdown_code(); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 297 | |
| 298 | __register_ftrace_function(&ftrace_shutdown_ops); |
| 299 | out: |
| 300 | mutex_unlock(&ftraced_lock); |
| 301 | } |
| 302 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 303 | static void notrace ftrace_startup_sysctl(void) |
| 304 | { |
| 305 | mutex_lock(&ftraced_lock); |
| 306 | /* ftraced_suspend is true if we want ftrace running */ |
| 307 | if (ftraced_suspend) |
| 308 | ftrace_run_startup_code(); |
| 309 | mutex_unlock(&ftraced_lock); |
| 310 | } |
| 311 | |
| 312 | static void notrace ftrace_shutdown_sysctl(void) |
| 313 | { |
| 314 | mutex_lock(&ftraced_lock); |
| 315 | /* ftraced_suspend is true if ftrace is running */ |
| 316 | if (ftraced_suspend) |
| 317 | ftrace_run_shutdown_code(); |
| 318 | mutex_unlock(&ftraced_lock); |
| 319 | } |
| 320 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 321 | static cycle_t ftrace_update_time; |
| 322 | static unsigned long ftrace_update_cnt; |
| 323 | unsigned long ftrace_update_tot_cnt; |
| 324 | |
| 325 | static int notrace __ftrace_update_code(void *ignore) |
| 326 | { |
| 327 | struct dyn_ftrace *p; |
| 328 | struct hlist_head head; |
| 329 | struct hlist_node *t; |
| 330 | cycle_t start, stop; |
| 331 | int i; |
| 332 | |
| 333 | /* Don't be calling ftrace ops now */ |
| 334 | __unregister_ftrace_function(&ftrace_shutdown_ops); |
| 335 | |
| 336 | start = now(raw_smp_processor_id()); |
| 337 | ftrace_update_cnt = 0; |
| 338 | |
| 339 | /* No locks needed, the machine is stopped! */ |
| 340 | for (i = 0; i < FTRACE_HASHSIZE; i++) { |
| 341 | if (hlist_empty(&ftrace_hash[i])) |
| 342 | continue; |
| 343 | |
| 344 | head = ftrace_hash[i]; |
| 345 | INIT_HLIST_HEAD(&ftrace_hash[i]); |
| 346 | |
| 347 | /* all CPUS are stopped, we are safe to modify code */ |
| 348 | hlist_for_each_entry(p, t, &head, node) { |
| 349 | ftrace_code_disable(p); |
| 350 | ftrace_update_cnt++; |
| 351 | } |
| 352 | |
| 353 | } |
| 354 | |
| 355 | stop = now(raw_smp_processor_id()); |
| 356 | ftrace_update_time = stop - start; |
| 357 | ftrace_update_tot_cnt += ftrace_update_cnt; |
| 358 | |
| 359 | __register_ftrace_function(&ftrace_shutdown_ops); |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 360 | |
| 361 | return 0; |
| 362 | } |
| 363 | |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 364 | static void notrace ftrace_update_code(void) |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 365 | { |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 366 | stop_machine_run(__ftrace_update_code, NULL, NR_CPUS); |
| 367 | } |
| 368 | |
| 369 | static int notrace ftraced(void *ignore) |
| 370 | { |
| 371 | unsigned long usecs; |
| 372 | |
| 373 | set_current_state(TASK_INTERRUPTIBLE); |
| 374 | |
| 375 | while (!kthread_should_stop()) { |
| 376 | |
| 377 | /* check once a second */ |
| 378 | schedule_timeout(HZ); |
| 379 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 380 | mutex_lock(&ftrace_sysctl_lock); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 381 | mutex_lock(&ftraced_lock); |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 382 | if (ftrace_enabled && ftraced_trigger && !ftraced_suspend) { |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 383 | ftrace_record_suspend++; |
| 384 | ftrace_update_code(); |
| 385 | usecs = nsecs_to_usecs(ftrace_update_time); |
| 386 | if (ftrace_update_tot_cnt > 100000) { |
| 387 | ftrace_update_tot_cnt = 0; |
| 388 | pr_info("hm, dftrace overflow: %lu change%s" |
| 389 | " (%lu total) in %lu usec%s\n", |
| 390 | ftrace_update_cnt, |
| 391 | ftrace_update_cnt != 1 ? "s" : "", |
| 392 | ftrace_update_tot_cnt, |
| 393 | usecs, usecs != 1 ? "s" : ""); |
| 394 | WARN_ON_ONCE(1); |
| 395 | } |
| 396 | ftraced_trigger = 0; |
| 397 | ftrace_record_suspend--; |
| 398 | } |
| 399 | mutex_unlock(&ftraced_lock); |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 400 | mutex_unlock(&ftrace_sysctl_lock); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 401 | |
| 402 | ftrace_shutdown_replenish(); |
| 403 | |
| 404 | set_current_state(TASK_INTERRUPTIBLE); |
| 405 | } |
| 406 | __set_current_state(TASK_RUNNING); |
| 407 | return 0; |
| 408 | } |
| 409 | |
| 410 | static int __init notrace ftrace_shutdown_init(void) |
| 411 | { |
| 412 | struct task_struct *p; |
| 413 | int ret; |
| 414 | |
| 415 | ret = ftrace_shutdown_arch_init(); |
| 416 | if (ret) |
| 417 | return ret; |
| 418 | |
| 419 | p = kthread_run(ftraced, NULL, "ftraced"); |
| 420 | if (IS_ERR(p)) |
| 421 | return -1; |
| 422 | |
| 423 | __register_ftrace_function(&ftrace_shutdown_ops); |
| 424 | |
| 425 | return 0; |
| 426 | } |
| 427 | |
| 428 | core_initcall(ftrace_shutdown_init); |
| 429 | #else |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 430 | # define ftrace_startup() do { } while (0) |
| 431 | # define ftrace_shutdown() do { } while (0) |
| 432 | # define ftrace_startup_sysctl() do { } while (0) |
| 433 | # define ftrace_shutdown_sysctl() do { } while (0) |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 434 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
| 435 | |
| 436 | /** |
| 437 | * register_ftrace_function - register a function for profiling |
| 438 | * @ops - ops structure that holds the function for profiling. |
| 439 | * |
| 440 | * Register a function to be called by all functions in the |
| 441 | * kernel. |
| 442 | * |
| 443 | * Note: @ops->func and all the functions it calls must be labeled |
| 444 | * with "notrace", otherwise it will go into a |
| 445 | * recursive loop. |
| 446 | */ |
| 447 | int register_ftrace_function(struct ftrace_ops *ops) |
| 448 | { |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 449 | int ret; |
| 450 | |
| 451 | mutex_lock(&ftrace_sysctl_lock); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 452 | ftrace_startup(); |
| 453 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 454 | ret = __register_ftrace_function(ops); |
| 455 | mutex_unlock(&ftrace_sysctl_lock); |
| 456 | |
| 457 | return ret; |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 458 | } |
| 459 | |
| 460 | /** |
| 461 | * unregister_ftrace_function - unresgister a function for profiling. |
| 462 | * @ops - ops structure that holds the function to unregister |
| 463 | * |
| 464 | * Unregister a function that was added to be called by ftrace profiling. |
| 465 | */ |
| 466 | int unregister_ftrace_function(struct ftrace_ops *ops) |
| 467 | { |
| 468 | int ret; |
| 469 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 470 | mutex_lock(&ftrace_sysctl_lock); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 471 | ret = __unregister_ftrace_function(ops); |
| 472 | |
| 473 | if (ftrace_list == &ftrace_list_end) |
| 474 | ftrace_shutdown(); |
| 475 | |
Steven Rostedt | b0fc494 | 2008-05-12 21:20:43 +0200 | [diff] [blame^] | 476 | mutex_unlock(&ftrace_sysctl_lock); |
| 477 | |
| 478 | return ret; |
| 479 | } |
| 480 | |
| 481 | notrace int |
| 482 | ftrace_enable_sysctl(struct ctl_table *table, int write, |
| 483 | struct file *filp, void __user *buffer, size_t *lenp, |
| 484 | loff_t *ppos) |
| 485 | { |
| 486 | int ret; |
| 487 | |
| 488 | mutex_lock(&ftrace_sysctl_lock); |
| 489 | |
| 490 | ret = proc_dointvec(table, write, filp, buffer, lenp, ppos); |
| 491 | |
| 492 | if (ret || !write || (last_ftrace_enabled == ftrace_enabled)) |
| 493 | goto out; |
| 494 | |
| 495 | last_ftrace_enabled = ftrace_enabled; |
| 496 | |
| 497 | if (ftrace_enabled) { |
| 498 | |
| 499 | ftrace_startup_sysctl(); |
| 500 | |
| 501 | /* we are starting ftrace again */ |
| 502 | if (ftrace_list != &ftrace_list_end) { |
| 503 | if (ftrace_list->next == &ftrace_list_end) |
| 504 | ftrace_trace_function = ftrace_list->func; |
| 505 | else |
| 506 | ftrace_trace_function = ftrace_list_func; |
| 507 | } |
| 508 | |
| 509 | } else { |
| 510 | /* stopping ftrace calls (just send to ftrace_stub) */ |
| 511 | ftrace_trace_function = ftrace_stub; |
| 512 | |
| 513 | ftrace_shutdown_sysctl(); |
| 514 | } |
| 515 | |
| 516 | out: |
| 517 | mutex_unlock(&ftrace_sysctl_lock); |
Steven Rostedt | 3d08339 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 518 | return ret; |
Arnaldo Carvalho de Melo | 16444a8 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 519 | } |