linux/include/linux/ftrace.h
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   1#ifndef _LINUX_FTRACE_H
   2#define _LINUX_FTRACE_H
   3
   4#include <linux/trace_clock.h>
   5#include <linux/kallsyms.h>
   6#include <linux/linkage.h>
   7#include <linux/bitops.h>
   8#include <linux/module.h>
   9#include <linux/ktime.h>
  10#include <linux/sched.h>
  11#include <linux/types.h>
  12#include <linux/init.h>
  13#include <linux/fs.h>
  14
  15#include <asm/ftrace.h>
  16
  17#ifdef CONFIG_FUNCTION_TRACER
  18
  19extern int ftrace_enabled;
  20extern int
  21ftrace_enable_sysctl(struct ctl_table *table, int write,
  22                     void __user *buffer, size_t *lenp,
  23                     loff_t *ppos);
  24
  25typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  26
  27struct ftrace_ops {
  28        ftrace_func_t     func;
  29        struct ftrace_ops *next;
  30};
  31
  32extern int function_trace_stop;
  33
  34/*
  35 * Type of the current tracing.
  36 */
  37enum ftrace_tracing_type_t {
  38        FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
  39        FTRACE_TYPE_RETURN,     /* Hook the return of the function */
  40};
  41
  42/* Current tracing type, default is FTRACE_TYPE_ENTER */
  43extern enum ftrace_tracing_type_t ftrace_tracing_type;
  44
  45/**
  46 * ftrace_stop - stop function tracer.
  47 *
  48 * A quick way to stop the function tracer. Note this an on off switch,
  49 * it is not something that is recursive like preempt_disable.
  50 * This does not disable the calling of mcount, it only stops the
  51 * calling of functions from mcount.
  52 */
  53static inline void ftrace_stop(void)
  54{
  55        function_trace_stop = 1;
  56}
  57
  58/**
  59 * ftrace_start - start the function tracer.
  60 *
  61 * This function is the inverse of ftrace_stop. This does not enable
  62 * the function tracing if the function tracer is disabled. This only
  63 * sets the function tracer flag to continue calling the functions
  64 * from mcount.
  65 */
  66static inline void ftrace_start(void)
  67{
  68        function_trace_stop = 0;
  69}
  70
  71/*
  72 * The ftrace_ops must be a static and should also
  73 * be read_mostly.  These functions do modify read_mostly variables
  74 * so use them sparely. Never free an ftrace_op or modify the
  75 * next pointer after it has been registered. Even after unregistering
  76 * it, the next pointer may still be used internally.
  77 */
  78int register_ftrace_function(struct ftrace_ops *ops);
  79int unregister_ftrace_function(struct ftrace_ops *ops);
  80void clear_ftrace_function(void);
  81
  82extern void ftrace_stub(unsigned long a0, unsigned long a1);
  83
  84#else /* !CONFIG_FUNCTION_TRACER */
  85# define register_ftrace_function(ops) do { } while (0)
  86# define unregister_ftrace_function(ops) do { } while (0)
  87# define clear_ftrace_function(ops) do { } while (0)
  88static inline void ftrace_kill(void) { }
  89static inline void ftrace_stop(void) { }
  90static inline void ftrace_start(void) { }
  91#endif /* CONFIG_FUNCTION_TRACER */
  92
  93#ifdef CONFIG_STACK_TRACER
  94extern int stack_tracer_enabled;
  95int
  96stack_trace_sysctl(struct ctl_table *table, int write,
  97                   void __user *buffer, size_t *lenp,
  98                   loff_t *ppos);
  99#endif
 100
 101struct ftrace_func_command {
 102        struct list_head        list;
 103        char                    *name;
 104        int                     (*func)(char *func, char *cmd,
 105                                        char *params, int enable);
 106};
 107
 108#ifdef CONFIG_DYNAMIC_FTRACE
 109
 110int ftrace_arch_code_modify_prepare(void);
 111int ftrace_arch_code_modify_post_process(void);
 112
 113struct seq_file;
 114
 115struct ftrace_probe_ops {
 116        void                    (*func)(unsigned long ip,
 117                                        unsigned long parent_ip,
 118                                        void **data);
 119        int                     (*callback)(unsigned long ip, void **data);
 120        void                    (*free)(void **data);
 121        int                     (*print)(struct seq_file *m,
 122                                         unsigned long ip,
 123                                         struct ftrace_probe_ops *ops,
 124                                         void *data);
 125};
 126
 127extern int
 128register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 129                              void *data);
 130extern void
 131unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 132                                void *data);
 133extern void
 134unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
 135extern void unregister_ftrace_function_probe_all(char *glob);
 136
 137enum {
 138        FTRACE_FL_FREE          = (1 << 0),
 139        FTRACE_FL_FAILED        = (1 << 1),
 140        FTRACE_FL_FILTER        = (1 << 2),
 141        FTRACE_FL_ENABLED       = (1 << 3),
 142        FTRACE_FL_NOTRACE       = (1 << 4),
 143        FTRACE_FL_CONVERTED     = (1 << 5),
 144        FTRACE_FL_FROZEN        = (1 << 6),
 145};
 146
 147struct dyn_ftrace {
 148        union {
 149                unsigned long           ip; /* address of mcount call-site */
 150                struct dyn_ftrace       *freelist;
 151        };
 152        union {
 153                unsigned long           flags;
 154                struct dyn_ftrace       *newlist;
 155        };
 156        struct dyn_arch_ftrace          arch;
 157};
 158
 159int ftrace_force_update(void);
 160void ftrace_set_filter(unsigned char *buf, int len, int reset);
 161
 162int register_ftrace_command(struct ftrace_func_command *cmd);
 163int unregister_ftrace_command(struct ftrace_func_command *cmd);
 164
 165/* defined in arch */
 166extern int ftrace_ip_converted(unsigned long ip);
 167extern int ftrace_dyn_arch_init(void *data);
 168extern int ftrace_update_ftrace_func(ftrace_func_t func);
 169extern void ftrace_caller(void);
 170extern void ftrace_call(void);
 171extern void mcount_call(void);
 172
 173#ifndef FTRACE_ADDR
 174#define FTRACE_ADDR ((unsigned long)ftrace_caller)
 175#endif
 176#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 177extern void ftrace_graph_caller(void);
 178extern int ftrace_enable_ftrace_graph_caller(void);
 179extern int ftrace_disable_ftrace_graph_caller(void);
 180#else
 181static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 182static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 183#endif
 184
 185/**
 186 * ftrace_make_nop - convert code into nop
 187 * @mod: module structure if called by module load initialization
 188 * @rec: the mcount call site record
 189 * @addr: the address that the call site should be calling
 190 *
 191 * This is a very sensitive operation and great care needs
 192 * to be taken by the arch.  The operation should carefully
 193 * read the location, check to see if what is read is indeed
 194 * what we expect it to be, and then on success of the compare,
 195 * it should write to the location.
 196 *
 197 * The code segment at @rec->ip should be a caller to @addr
 198 *
 199 * Return must be:
 200 *  0 on success
 201 *  -EFAULT on error reading the location
 202 *  -EINVAL on a failed compare of the contents
 203 *  -EPERM  on error writing to the location
 204 * Any other value will be considered a failure.
 205 */
 206extern int ftrace_make_nop(struct module *mod,
 207                           struct dyn_ftrace *rec, unsigned long addr);
 208
 209/**
 210 * ftrace_make_call - convert a nop call site into a call to addr
 211 * @rec: the mcount call site record
 212 * @addr: the address that the call site should call
 213 *
 214 * This is a very sensitive operation and great care needs
 215 * to be taken by the arch.  The operation should carefully
 216 * read the location, check to see if what is read is indeed
 217 * what we expect it to be, and then on success of the compare,
 218 * it should write to the location.
 219 *
 220 * The code segment at @rec->ip should be a nop
 221 *
 222 * Return must be:
 223 *  0 on success
 224 *  -EFAULT on error reading the location
 225 *  -EINVAL on a failed compare of the contents
 226 *  -EPERM  on error writing to the location
 227 * Any other value will be considered a failure.
 228 */
 229extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 230
 231/* May be defined in arch */
 232extern int ftrace_arch_read_dyn_info(char *buf, int size);
 233
 234extern int skip_trace(unsigned long ip);
 235
 236extern void ftrace_disable_daemon(void);
 237extern void ftrace_enable_daemon(void);
 238#else
 239# define skip_trace(ip)                         ({ 0; })
 240# define ftrace_force_update()                  ({ 0; })
 241# define ftrace_set_filter(buf, len, reset)     do { } while (0)
 242# define ftrace_disable_daemon()                do { } while (0)
 243# define ftrace_enable_daemon()                 do { } while (0)
 244static inline void ftrace_release_mod(struct module *mod) {}
 245static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 246{
 247        return -EINVAL;
 248}
 249static inline int unregister_ftrace_command(char *cmd_name)
 250{
 251        return -EINVAL;
 252}
 253#endif /* CONFIG_DYNAMIC_FTRACE */
 254
 255/* totally disable ftrace - can not re-enable after this */
 256void ftrace_kill(void);
 257
 258static inline void tracer_disable(void)
 259{
 260#ifdef CONFIG_FUNCTION_TRACER
 261        ftrace_enabled = 0;
 262#endif
 263}
 264
 265/*
 266 * Ftrace disable/restore without lock. Some synchronization mechanism
 267 * must be used to prevent ftrace_enabled to be changed between
 268 * disable/restore.
 269 */
 270static inline int __ftrace_enabled_save(void)
 271{
 272#ifdef CONFIG_FUNCTION_TRACER
 273        int saved_ftrace_enabled = ftrace_enabled;
 274        ftrace_enabled = 0;
 275        return saved_ftrace_enabled;
 276#else
 277        return 0;
 278#endif
 279}
 280
 281static inline void __ftrace_enabled_restore(int enabled)
 282{
 283#ifdef CONFIG_FUNCTION_TRACER
 284        ftrace_enabled = enabled;
 285#endif
 286}
 287
 288#ifndef HAVE_ARCH_CALLER_ADDR
 289# ifdef CONFIG_FRAME_POINTER
 290#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 291#  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 292#  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 293#  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 294#  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 295#  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 296#  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 297# else
 298#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 299#  define CALLER_ADDR1 0UL
 300#  define CALLER_ADDR2 0UL
 301#  define CALLER_ADDR3 0UL
 302#  define CALLER_ADDR4 0UL
 303#  define CALLER_ADDR5 0UL
 304#  define CALLER_ADDR6 0UL
 305# endif
 306#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 307
 308#ifdef CONFIG_IRQSOFF_TRACER
 309  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 310  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 311#else
 312# define time_hardirqs_on(a0, a1)               do { } while (0)
 313# define time_hardirqs_off(a0, a1)              do { } while (0)
 314#endif
 315
 316#ifdef CONFIG_PREEMPT_TRACER
 317  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 318  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 319#else
 320# define trace_preempt_on(a0, a1)               do { } while (0)
 321# define trace_preempt_off(a0, a1)              do { } while (0)
 322#endif
 323
 324#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 325extern void ftrace_init(void);
 326#else
 327static inline void ftrace_init(void) { }
 328#endif
 329
 330/*
 331 * Structure that defines an entry function trace.
 332 */
 333struct ftrace_graph_ent {
 334        unsigned long func; /* Current function */
 335        int depth;
 336};
 337
 338/*
 339 * Structure that defines a return function trace.
 340 */
 341struct ftrace_graph_ret {
 342        unsigned long func; /* Current function */
 343        unsigned long long calltime;
 344        unsigned long long rettime;
 345        /* Number of functions that overran the depth limit for current task */
 346        unsigned long overrun;
 347        int depth;
 348};
 349
 350#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 351
 352/* for init task */
 353#define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 354
 355/*
 356 * Stack of return addresses for functions
 357 * of a thread.
 358 * Used in struct thread_info
 359 */
 360struct ftrace_ret_stack {
 361        unsigned long ret;
 362        unsigned long func;
 363        unsigned long long calltime;
 364        unsigned long long subtime;
 365        unsigned long fp;
 366};
 367
 368/*
 369 * Primary handler of a function return.
 370 * It relays on ftrace_return_to_handler.
 371 * Defined in entry_32/64.S
 372 */
 373extern void return_to_handler(void);
 374
 375extern int
 376ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 377                         unsigned long frame_pointer);
 378
 379/*
 380 * Sometimes we don't want to trace a function with the function
 381 * graph tracer but we want them to keep traced by the usual function
 382 * tracer if the function graph tracer is not configured.
 383 */
 384#define __notrace_funcgraph             notrace
 385
 386/*
 387 * We want to which function is an entrypoint of a hardirq.
 388 * That will help us to put a signal on output.
 389 */
 390#define __irq_entry              __attribute__((__section__(".irqentry.text")))
 391
 392/* Limits of hardirq entrypoints */
 393extern char __irqentry_text_start[];
 394extern char __irqentry_text_end[];
 395
 396#define FTRACE_RETFUNC_DEPTH 50
 397#define FTRACE_RETSTACK_ALLOC_SIZE 32
 398/* Type of the callback handlers for tracing function graph*/
 399typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 400typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 401
 402extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 403                                trace_func_graph_ent_t entryfunc);
 404
 405extern void ftrace_graph_stop(void);
 406
 407/* The current handlers in use */
 408extern trace_func_graph_ret_t ftrace_graph_return;
 409extern trace_func_graph_ent_t ftrace_graph_entry;
 410
 411extern void unregister_ftrace_graph(void);
 412
 413extern void ftrace_graph_init_task(struct task_struct *t);
 414extern void ftrace_graph_exit_task(struct task_struct *t);
 415
 416static inline int task_curr_ret_stack(struct task_struct *t)
 417{
 418        return t->curr_ret_stack;
 419}
 420
 421static inline void pause_graph_tracing(void)
 422{
 423        atomic_inc(&current->tracing_graph_pause);
 424}
 425
 426static inline void unpause_graph_tracing(void)
 427{
 428        atomic_dec(&current->tracing_graph_pause);
 429}
 430#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 431
 432#define __notrace_funcgraph
 433#define __irq_entry
 434#define INIT_FTRACE_GRAPH
 435
 436static inline void ftrace_graph_init_task(struct task_struct *t) { }
 437static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 438
 439static inline int task_curr_ret_stack(struct task_struct *tsk)
 440{
 441        return -1;
 442}
 443
 444static inline void pause_graph_tracing(void) { }
 445static inline void unpause_graph_tracing(void) { }
 446#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 447
 448#ifdef CONFIG_TRACING
 449
 450/* flags for current->trace */
 451enum {
 452        TSK_TRACE_FL_TRACE_BIT  = 0,
 453        TSK_TRACE_FL_GRAPH_BIT  = 1,
 454};
 455enum {
 456        TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 457        TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 458};
 459
 460static inline void set_tsk_trace_trace(struct task_struct *tsk)
 461{
 462        set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 463}
 464
 465static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 466{
 467        clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 468}
 469
 470static inline int test_tsk_trace_trace(struct task_struct *tsk)
 471{
 472        return tsk->trace & TSK_TRACE_FL_TRACE;
 473}
 474
 475static inline void set_tsk_trace_graph(struct task_struct *tsk)
 476{
 477        set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 478}
 479
 480static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 481{
 482        clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 483}
 484
 485static inline int test_tsk_trace_graph(struct task_struct *tsk)
 486{
 487        return tsk->trace & TSK_TRACE_FL_GRAPH;
 488}
 489
 490extern int ftrace_dump_on_oops;
 491
 492#ifdef CONFIG_PREEMPT
 493#define INIT_TRACE_RECURSION            .trace_recursion = 0,
 494#endif
 495
 496#endif /* CONFIG_TRACING */
 497
 498#ifndef INIT_TRACE_RECURSION
 499#define INIT_TRACE_RECURSION
 500#endif
 501
 502#ifdef CONFIG_HW_BRANCH_TRACER
 503
 504void trace_hw_branch(u64 from, u64 to);
 505void trace_hw_branch_oops(void);
 506
 507#else /* CONFIG_HW_BRANCH_TRACER */
 508
 509static inline void trace_hw_branch(u64 from, u64 to) {}
 510static inline void trace_hw_branch_oops(void) {}
 511
 512#endif /* CONFIG_HW_BRANCH_TRACER */
 513
 514#endif /* _LINUX_FTRACE_H */
 515