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