include/linux/ftrace.h

   1 /*
   2  * Ftrace header.  For implementation details beyond the random comments
   3  * scattered below, see: Documentation/trace/ftrace-design.txt
   4  */
   5
   6 #ifndef _LINUX_FTRACE_H
   7 #define _LINUX_FTRACE_H
   8
   9 #include <linux/trace_clock.h>
  10 #include <linux/kallsyms.h>
  11 #include <linux/linkage.h>
  12 #include <linux/bitops.h>
  13 #include <linux/module.h>
  14 #include <linux/ktime.h>
  15 #include <linux/sched.h>
  16 #include <linux/types.h>
  17 #include <linux/init.h>
  18 #include <linux/fs.h>
  19
  20 #include <asm/ftrace.h>
  21
  22 #ifdef CONFIG_FUNCTION_TRACER
  23
  24 extern int ftrace_enabled;
  25 extern int
  26 ftrace_enable_sysctl(struct ctl_table *table, int write,
  27                      void __user *buffer, size_t *lenp,
  28                      loff_t *ppos);
  29
  30 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  31
  32 struct ftrace_hash;
  33
  34 enum {
  35         FTRACE_OPS_FL_ENABLED           = 1 << 0,
  36         FTRACE_OPS_FL_GLOBAL            = 1 << 1,
  37         FTRACE_OPS_FL_DYNAMIC           = 1 << 2,
  38 };
  39
  40 struct ftrace_ops {
  41         ftrace_func_t                   func;
  42         struct ftrace_ops               *next;
  43         unsigned long                   flags;
  44 #ifdef CONFIG_DYNAMIC_FTRACE
  45         struct ftrace_hash              *notrace_hash;
  46         struct ftrace_hash              *filter_hash;
  47 #endif
  48 };
  49
  50 extern int function_trace_stop;
  51
  52 /*
  53  * Type of the current tracing.
  54  */
  55 enum ftrace_tracing_type_t {
  56         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
  57         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
  58 };
  59
  60 /* Current tracing type, default is FTRACE_TYPE_ENTER */
  61 extern enum ftrace_tracing_type_t ftrace_tracing_type;
  62
  63 /**
  64  * ftrace_stop - stop function tracer.
  65  *
  66  * A quick way to stop the function tracer. Note this an on off switch,
  67  * it is not something that is recursive like preempt_disable.
  68  * This does not disable the calling of mcount, it only stops the
  69  * calling of functions from mcount.
  70  */
  71 static inline void ftrace_stop(void)
  72 {
  73         function_trace_stop = 1;
  74 }
  75
  76 /**
  77  * ftrace_start - start the function tracer.
  78  *
  79  * This function is the inverse of ftrace_stop. This does not enable
  80  * the function tracing if the function tracer is disabled. This only
  81  * sets the function tracer flag to continue calling the functions
  82  * from mcount.
  83  */
  84 static inline void ftrace_start(void)
  85 {
  86         function_trace_stop = 0;
  87 }
  88
  89 /*
  90  * The ftrace_ops must be a static and should also
  91  * be read_mostly.  These functions do modify read_mostly variables
  92  * so use them sparely. Never free an ftrace_op or modify the
  93  * next pointer after it has been registered. Even after unregistering
  94  * it, the next pointer may still be used internally.
  95  */
  96 int register_ftrace_function(struct ftrace_ops *ops);
  97 int unregister_ftrace_function(struct ftrace_ops *ops);
  98 void clear_ftrace_function(void);
  99
 100 extern void ftrace_stub(unsigned long a0, unsigned long a1);
 101
 102 #else /* !CONFIG_FUNCTION_TRACER */
 103 /*
 104  * (un)register_ftrace_function must be a macro since the ops parameter
 105  * must not be evaluated.
 106  */
 107 #define register_ftrace_function(ops) ({ 0; })
 108 #define unregister_ftrace_function(ops) ({ 0; })
 109 static inline void clear_ftrace_function(void) { }
 110 static inline void ftrace_kill(void) { }
 111 static inline void ftrace_stop(void) { }
 112 static inline void ftrace_start(void) { }
 113 #endif /* CONFIG_FUNCTION_TRACER */
 114
 115 #ifdef CONFIG_STACK_TRACER
 116 extern int stack_tracer_enabled;
 117 int
 118 stack_trace_sysctl(struct ctl_table *table, int write,
 119                    void __user *buffer, size_t *lenp,
 120                    loff_t *ppos);
 121 #endif
 122
 123 struct ftrace_func_command {
 124         struct list_head        list;
 125         char                    *name;
 126         int                     (*func)(char *func, char *cmd,
 127                                         char *params, int enable);
 128 };
 129
 130 #ifdef CONFIG_DYNAMIC_FTRACE
 131
 132 int ftrace_arch_code_modify_prepare(void);
 133 int ftrace_arch_code_modify_post_process(void);
 134
 135 struct seq_file;
 136
 137 struct ftrace_probe_ops {
 138         void                    (*func)(unsigned long ip,
 139                                         unsigned long parent_ip,
 140                                         void **data);
 141         int                     (*callback)(unsigned long ip, void **data);
 142         void                    (*free)(void **data);
 143         int                     (*print)(struct seq_file *m,
 144                                          unsigned long ip,
 145                                          struct ftrace_probe_ops *ops,
 146                                          void *data);
 147 };
 148
 149 extern int
 150 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 151                               void *data);
 152 extern void
 153 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 154                                 void *data);
 155 extern void
 156 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 157 extern void unregister_ftrace_function_probe_all(char *glob);
 158
 159 extern int ftrace_text_reserved(void *start, void *end);
 160
 161 enum {
 162         FTRACE_FL_ENABLED       = (1 << 30),
 163         FTRACE_FL_FREE          = (1 << 31),
 164 };
 165
 166 #define FTRACE_FL_MASK          (0x3UL << 30)
 167 #define FTRACE_REF_MAX          ((1 << 30) - 1)
 168
 169 struct dyn_ftrace {
 170         union {
 171                 unsigned long           ip; /* address of mcount call-site */
 172                 struct dyn_ftrace       *freelist;
 173         };
 174         union {
 175                 unsigned long           flags;
 176                 struct dyn_ftrace       *newlist;
 177         };
 178         struct dyn_arch_ftrace          arch;
 179 };
 180
 181 int ftrace_force_update(void);
 182 void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 183                        int len, int reset);
 184 void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 185                         int len, int reset);
 186 void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
 187 void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
 188
 189 int register_ftrace_command(struct ftrace_func_command *cmd);
 190 int unregister_ftrace_command(struct ftrace_func_command *cmd);
 191
 192 /* defined in arch */
 193 extern int ftrace_ip_converted(unsigned long ip);
 194 extern int ftrace_dyn_arch_init(void *data);
 195 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 196 extern void ftrace_caller(void);
 197 extern void ftrace_call(void);
 198 extern void mcount_call(void);
 199
 200 #ifndef FTRACE_ADDR
 201 #define FTRACE_ADDR ((unsigned long)ftrace_caller)
 202 #endif
 203 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 204 extern void ftrace_graph_caller(void);
 205 extern int ftrace_enable_ftrace_graph_caller(void);
 206 extern int ftrace_disable_ftrace_graph_caller(void);
 207 #else
 208 static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 209 static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 210 #endif
 211
 212 /**
 213  * ftrace_make_nop - convert code into nop
 214  * @mod: module structure if called by module load initialization
 215  * @rec: the mcount call site record
 216  * @addr: the address that the call site should be calling
 217  *
 218  * This is a very sensitive operation and great care needs
 219  * to be taken by the arch.  The operation should carefully
 220  * read the location, check to see if what is read is indeed
 221  * what we expect it to be, and then on success of the compare,
 222  * it should write to the location.
 223  *
 224  * The code segment at @rec->ip should be a caller to @addr
 225  *
 226  * Return must be:
 227  *  0 on success
 228  *  -EFAULT on error reading the location
 229  *  -EINVAL on a failed compare of the contents
 230  *  -EPERM  on error writing to the location
 231  * Any other value will be considered a failure.
 232  */
 233 extern int ftrace_make_nop(struct module *mod,
 234                            struct dyn_ftrace *rec, unsigned long addr);
 235
 236 /**
 237  * ftrace_make_call - convert a nop call site into a call to addr
 238  * @rec: the mcount call site record
 239  * @addr: the address that the call site should call
 240  *
 241  * This is a very sensitive operation and great care needs
 242  * to be taken by the arch.  The operation should carefully
 243  * read the location, check to see if what is read is indeed
 244  * what we expect it to be, and then on success of the compare,
 245  * it should write to the location.
 246  *
 247  * The code segment at @rec->ip should be a nop
 248  *
 249  * Return must be:
 250  *  0 on success
 251  *  -EFAULT on error reading the location
 252  *  -EINVAL on a failed compare of the contents
 253  *  -EPERM  on error writing to the location
 254  * Any other value will be considered a failure.
 255  */
 256 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 257
 258 /* May be defined in arch */
 259 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 260
 261 extern int skip_trace(unsigned long ip);
 262
 263 extern void ftrace_disable_daemon(void);
 264 extern void ftrace_enable_daemon(void);
 265 #else
 266 static inline int skip_trace(unsigned long ip) { return 0; }
 267 static inline int ftrace_force_update(void) { return 0; }
 268 static inline void ftrace_set_filter(unsigned char *buf, int len, int reset)
 269 {
 270 }
 271 static inline void ftrace_disable_daemon(void) { }
 272 static inline void ftrace_enable_daemon(void) { }
 273 static inline void ftrace_release_mod(struct module *mod) {}
 274 static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 275 {
 276         return -EINVAL;
 277 }
 278 static inline int unregister_ftrace_command(char *cmd_name)
 279 {
 280         return -EINVAL;
 281 }
 282 static inline int ftrace_text_reserved(void *start, void *end)
 283 {
 284         return 0;
 285 }
 286 #endif /* CONFIG_DYNAMIC_FTRACE */
 287
 288 /* totally disable ftrace - can not re-enable after this */
 289 void ftrace_kill(void);
 290
 291 static inline void tracer_disable(void)
 292 {
 293 #ifdef CONFIG_FUNCTION_TRACER
 294         ftrace_enabled = 0;
 295 #endif
 296 }
 297
 298 /*
 299  * Ftrace disable/restore without lock. Some synchronization mechanism
 300  * must be used to prevent ftrace_enabled to be changed between
 301  * disable/restore.
 302  */
 303 static inline int __ftrace_enabled_save(void)
 304 {
 305 #ifdef CONFIG_FUNCTION_TRACER
 306         int saved_ftrace_enabled = ftrace_enabled;
 307         ftrace_enabled = 0;
 308         return saved_ftrace_enabled;
 309 #else
 310         return 0;
 311 #endif
 312 }
 313
 314 static inline void __ftrace_enabled_restore(int enabled)
 315 {
 316 #ifdef CONFIG_FUNCTION_TRACER
 317         ftrace_enabled = enabled;
 318 #endif
 319 }
 320
 321 #ifndef HAVE_ARCH_CALLER_ADDR
 322 # ifdef CONFIG_FRAME_POINTER
 323 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 324 #  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 325 #  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 326 #  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 327 #  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 328 #  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 329 #  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 330 # else
 331 #  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 332 #  define CALLER_ADDR1 0UL
 333 #  define CALLER_ADDR2 0UL
 334 #  define CALLER_ADDR3 0UL
 335 #  define CALLER_ADDR4 0UL
 336 #  define CALLER_ADDR5 0UL
 337 #  define CALLER_ADDR6 0UL
 338 # endif
 339 #endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 340
 341 #ifdef CONFIG_IRQSOFF_TRACER
 342   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 343   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 344 #else
 345   static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
 346   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 347 #endif
 348
 349 #ifdef CONFIG_PREEMPT_TRACER
 350   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 351   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 352 #else
 353   static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { }
 354   static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { }
 355 #endif
 356
 357 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 358 extern void ftrace_init(void);
 359 #else
 360 static inline void ftrace_init(void) { }
 361 #endif
 362
 363 /*
 364  * Structure that defines an entry function trace.
 365  */
 366 struct ftrace_graph_ent {
 367         unsigned long func; /* Current function */
 368         int depth;
 369 };
 370
 371 /*
 372  * Structure that defines a return function trace.
 373  */
 374 struct ftrace_graph_ret {
 375         unsigned long func; /* Current function */
 376         unsigned long long calltime;
 377         unsigned long long rettime;
 378         /* Number of functions that overran the depth limit for current task */
 379         unsigned long overrun;
 380         int depth;
 381 };
 382
 383 /* Type of the callback handlers for tracing function graph*/
 384 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 385 typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 386
 387 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 388
 389 /* for init task */
 390 #define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 391
 392 /*
 393  * Stack of return addresses for functions
 394  * of a thread.
 395  * Used in struct thread_info
 396  */
 397 struct ftrace_ret_stack {
 398         unsigned long ret;
 399         unsigned long func;
 400         unsigned long long calltime;
 401         unsigned long long subtime;
 402         unsigned long fp;
 403 };
 404
 405 /*
 406  * Primary handler of a function return.
 407  * It relays on ftrace_return_to_handler.
 408  * Defined in entry_32/64.S
 409  */
 410 extern void return_to_handler(void);
 411
 412 extern int
 413 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 414                          unsigned long frame_pointer);
 415
 416 /*
 417  * Sometimes we don't want to trace a function with the function
 418  * graph tracer but we want them to keep traced by the usual function
 419  * tracer if the function graph tracer is not configured.
 420  */
 421 #define __notrace_funcgraph             notrace
 422
 423 /*
 424  * We want to which function is an entrypoint of a hardirq.
 425  * That will help us to put a signal on output.
 426  */
 427 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
 428
 429 /* Limits of hardirq entrypoints */
 430 extern char __irqentry_text_start[];
 431 extern char __irqentry_text_end[];
 432
 433 #define FTRACE_RETFUNC_DEPTH 50
 434 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 435 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 436                                 trace_func_graph_ent_t entryfunc);
 437
 438 extern void ftrace_graph_stop(void);
 439
 440 /* The current handlers in use */
 441 extern trace_func_graph_ret_t ftrace_graph_return;
 442 extern trace_func_graph_ent_t ftrace_graph_entry;
 443
 444 extern void unregister_ftrace_graph(void);
 445
 446 extern void ftrace_graph_init_task(struct task_struct *t);
 447 extern void ftrace_graph_exit_task(struct task_struct *t);
 448 extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
 449
 450 static inline int task_curr_ret_stack(struct task_struct *t)
 451 {
 452         return t->curr_ret_stack;
 453 }
 454
 455 static inline void pause_graph_tracing(void)
 456 {
 457         atomic_inc(&current->tracing_graph_pause);
 458 }
 459
 460 static inline void unpause_graph_tracing(void)
 461 {
 462         atomic_dec(&current->tracing_graph_pause);
 463 }
 464 #else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 465
 466 #define __notrace_funcgraph
 467 #define __irq_entry
 468 #define INIT_FTRACE_GRAPH
 469
 470 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 471 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 472 static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
 473
 474 static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 475                           trace_func_graph_ent_t entryfunc)
 476 {
 477         return -1;
 478 }
 479 static inline void unregister_ftrace_graph(void) { }
 480
 481 static inline int task_curr_ret_stack(struct task_struct *tsk)
 482 {
 483         return -1;
 484 }
 485
 486 static inline void pause_graph_tracing(void) { }
 487 static inline void unpause_graph_tracing(void) { }
 488 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 489
 490 #ifdef CONFIG_TRACING
 491
 492 /* flags for current->trace */
 493 enum {
 494         TSK_TRACE_FL_TRACE_BIT  = 0,
 495         TSK_TRACE_FL_GRAPH_BIT  = 1,
 496 };
 497 enum {
 498         TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 499         TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 500 };
 501
 502 static inline void set_tsk_trace_trace(struct task_struct *tsk)
 503 {
 504         set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 505 }
 506
 507 static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 508 {
 509         clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 510 }
 511
 512 static inline int test_tsk_trace_trace(struct task_struct *tsk)
 513 {
 514         return tsk->trace & TSK_TRACE_FL_TRACE;
 515 }
 516
 517 static inline void set_tsk_trace_graph(struct task_struct *tsk)
 518 {
 519         set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 520 }
 521
 522 static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 523 {
 524         clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 525 }
 526
 527 static inline int test_tsk_trace_graph(struct task_struct *tsk)
 528 {
 529         return tsk->trace & TSK_TRACE_FL_GRAPH;
 530 }
 531
 532 enum ftrace_dump_mode;
 533
 534 extern enum ftrace_dump_mode ftrace_dump_on_oops;
 535
 536 #ifdef CONFIG_PREEMPT
 537 #define INIT_TRACE_RECURSION            .trace_recursion = 0,
 538 #endif
 539
 540 #endif /* CONFIG_TRACING */
 541
 542 #ifndef INIT_TRACE_RECURSION
 543 #define INIT_TRACE_RECURSION
 544 #endif
 545
 546 #ifdef CONFIG_FTRACE_SYSCALLS
 547
 548 unsigned long arch_syscall_addr(int nr);
 549
 550 #endif /* CONFIG_FTRACE_SYSCALLS */
 551
 552 #endif /* _LINUX_FTRACE_H */