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