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
 137extern int ftrace_text_reserved(void *start, void *end);
 138
 139enum {
 140        FTRACE_FL_FREE          = (1 << 0),
 141        FTRACE_FL_FAILED        = (1 << 1),
 142        FTRACE_FL_FILTER        = (1 << 2),
 143        FTRACE_FL_ENABLED       = (1 << 3),
 144        FTRACE_FL_NOTRACE       = (1 << 4),
 145        FTRACE_FL_CONVERTED     = (1 << 5),
 146};
 147
 148struct dyn_ftrace {
 149        union {
 150                unsigned long           ip; /* address of mcount call-site */
 151                struct dyn_ftrace       *freelist;
 152        };
 153        union {
 154                unsigned long           flags;
 155                struct dyn_ftrace       *newlist;
 156        };
 157        struct dyn_arch_ftrace          arch;
 158};
 159
 160int ftrace_force_update(void);
 161void ftrace_set_filter(unsigned char *buf, int len, int reset);
 162
 163int register_ftrace_command(struct ftrace_func_command *cmd);
 164int unregister_ftrace_command(struct ftrace_func_command *cmd);
 165
 166/* defined in arch */
 167extern int ftrace_ip_converted(unsigned long ip);
 168extern int ftrace_dyn_arch_init(void *data);
 169extern int ftrace_update_ftrace_func(ftrace_func_t func);
 170extern void ftrace_caller(void);
 171extern void ftrace_call(void);
 172extern void mcount_call(void);
 173
 174#ifndef FTRACE_ADDR
 175#define FTRACE_ADDR ((unsigned long)ftrace_caller)
 176#endif
 177#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 178extern void ftrace_graph_caller(void);
 179extern int ftrace_enable_ftrace_graph_caller(void);
 180extern int ftrace_disable_ftrace_graph_caller(void);
 181#else
 182static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
 183static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
 184#endif
 185
 186/**
 187 * ftrace_make_nop - convert code into nop
 188 * @mod: module structure if called by module load initialization
 189 * @rec: the mcount call site record
 190 * @addr: the address that the call site should be calling
 191 *
 192 * This is a very sensitive operation and great care needs
 193 * to be taken by the arch.  The operation should carefully
 194 * read the location, check to see if what is read is indeed
 195 * what we expect it to be, and then on success of the compare,
 196 * it should write to the location.
 197 *
 198 * The code segment at @rec->ip should be a caller to @addr
 199 *
 200 * Return must be:
 201 *  0 on success
 202 *  -EFAULT on error reading the location
 203 *  -EINVAL on a failed compare of the contents
 204 *  -EPERM  on error writing to the location
 205 * Any other value will be considered a failure.
 206 */
 207extern int ftrace_make_nop(struct module *mod,
 208                           struct dyn_ftrace *rec, unsigned long addr);
 209
 210/**
 211 * ftrace_make_call - convert a nop call site into a call to addr
 212 * @rec: the mcount call site record
 213 * @addr: the address that the call site should call
 214 *
 215 * This is a very sensitive operation and great care needs
 216 * to be taken by the arch.  The operation should carefully
 217 * read the location, check to see if what is read is indeed
 218 * what we expect it to be, and then on success of the compare,
 219 * it should write to the location.
 220 *
 221 * The code segment at @rec->ip should be a nop
 222 *
 223 * Return must be:
 224 *  0 on success
 225 *  -EFAULT on error reading the location
 226 *  -EINVAL on a failed compare of the contents
 227 *  -EPERM  on error writing to the location
 228 * Any other value will be considered a failure.
 229 */
 230extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 231
 232/* May be defined in arch */
 233extern int ftrace_arch_read_dyn_info(char *buf, int size);
 234
 235extern int skip_trace(unsigned long ip);
 236
 237extern void ftrace_disable_daemon(void);
 238extern void ftrace_enable_daemon(void);
 239#else
 240# define skip_trace(ip)                         ({ 0; })
 241# define ftrace_force_update()                  ({ 0; })
 242# define ftrace_set_filter(buf, len, reset)     do { } while (0)
 243# define ftrace_disable_daemon()                do { } while (0)
 244# define ftrace_enable_daemon()                 do { } while (0)
 245static inline void ftrace_release_mod(struct module *mod) {}
 246static inline int register_ftrace_command(struct ftrace_func_command *cmd)
 247{
 248        return -EINVAL;
 249}
 250static inline int unregister_ftrace_command(char *cmd_name)
 251{
 252        return -EINVAL;
 253}
 254static inline int ftrace_text_reserved(void *start, void *end)
 255{
 256        return 0;
 257}
 258#endif /* CONFIG_DYNAMIC_FTRACE */
 259
 260/* totally disable ftrace - can not re-enable after this */
 261void ftrace_kill(void);
 262
 263static inline void tracer_disable(void)
 264{
 265#ifdef CONFIG_FUNCTION_TRACER
 266        ftrace_enabled = 0;
 267#endif
 268}
 269
 270/*
 271 * Ftrace disable/restore without lock. Some synchronization mechanism
 272 * must be used to prevent ftrace_enabled to be changed between
 273 * disable/restore.
 274 */
 275static inline int __ftrace_enabled_save(void)
 276{
 277#ifdef CONFIG_FUNCTION_TRACER
 278        int saved_ftrace_enabled = ftrace_enabled;
 279        ftrace_enabled = 0;
 280        return saved_ftrace_enabled;
 281#else
 282        return 0;
 283#endif
 284}
 285
 286static inline void __ftrace_enabled_restore(int enabled)
 287{
 288#ifdef CONFIG_FUNCTION_TRACER
 289        ftrace_enabled = enabled;
 290#endif
 291}
 292
 293#ifndef HAVE_ARCH_CALLER_ADDR
 294# ifdef CONFIG_FRAME_POINTER
 295#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 296#  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 297#  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 298#  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 299#  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 300#  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 301#  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 302# else
 303#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 304#  define CALLER_ADDR1 0UL
 305#  define CALLER_ADDR2 0UL
 306#  define CALLER_ADDR3 0UL
 307#  define CALLER_ADDR4 0UL
 308#  define CALLER_ADDR5 0UL
 309#  define CALLER_ADDR6 0UL
 310# endif
 311#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 312
 313#ifdef CONFIG_IRQSOFF_TRACER
 314  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 315  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 316#else
 317# define time_hardirqs_on(a0, a1)               do { } while (0)
 318# define time_hardirqs_off(a0, a1)              do { } while (0)
 319#endif
 320
 321#ifdef CONFIG_PREEMPT_TRACER
 322  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 323  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 324#else
 325# define trace_preempt_on(a0, a1)               do { } while (0)
 326# define trace_preempt_off(a0, a1)              do { } while (0)
 327#endif
 328
 329#ifdef CONFIG_FTRACE_MCOUNT_RECORD
 330extern void ftrace_init(void);
 331#else
 332static inline void ftrace_init(void) { }
 333#endif
 334
 335/*
 336 * Structure that defines an entry function trace.
 337 */
 338struct ftrace_graph_ent {
 339        unsigned long func; /* Current function */
 340        int depth;
 341};
 342
 343/*
 344 * Structure that defines a return function trace.
 345 */
 346struct ftrace_graph_ret {
 347        unsigned long func; /* Current function */
 348        unsigned long long calltime;
 349        unsigned long long rettime;
 350        /* Number of functions that overran the depth limit for current task */
 351        unsigned long overrun;
 352        int depth;
 353};
 354
 355#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 356
 357/* for init task */
 358#define INIT_FTRACE_GRAPH               .ret_stack = NULL,
 359
 360/*
 361 * Stack of return addresses for functions
 362 * of a thread.
 363 * Used in struct thread_info
 364 */
 365struct ftrace_ret_stack {
 366        unsigned long ret;
 367        unsigned long func;
 368        unsigned long long calltime;
 369        unsigned long long subtime;
 370        unsigned long fp;
 371};
 372
 373/*
 374 * Primary handler of a function return.
 375 * It relays on ftrace_return_to_handler.
 376 * Defined in entry_32/64.S
 377 */
 378extern void return_to_handler(void);
 379
 380extern int
 381ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 382                         unsigned long frame_pointer);
 383
 384/*
 385 * Sometimes we don't want to trace a function with the function
 386 * graph tracer but we want them to keep traced by the usual function
 387 * tracer if the function graph tracer is not configured.
 388 */
 389#define __notrace_funcgraph             notrace
 390
 391/*
 392 * We want to which function is an entrypoint of a hardirq.
 393 * That will help us to put a signal on output.
 394 */
 395#define __irq_entry              __attribute__((__section__(".irqentry.text")))
 396
 397/* Limits of hardirq entrypoints */
 398extern char __irqentry_text_start[];
 399extern char __irqentry_text_end[];
 400
 401#define FTRACE_RETFUNC_DEPTH 50
 402#define FTRACE_RETSTACK_ALLOC_SIZE 32
 403/* Type of the callback handlers for tracing function graph*/
 404typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 405typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 406
 407extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 408                                trace_func_graph_ent_t entryfunc);
 409
 410extern void ftrace_graph_stop(void);
 411
 412/* The current handlers in use */
 413extern trace_func_graph_ret_t ftrace_graph_return;
 414extern trace_func_graph_ent_t ftrace_graph_entry;
 415
 416extern void unregister_ftrace_graph(void);
 417
 418extern void ftrace_graph_init_task(struct task_struct *t);
 419extern void ftrace_graph_exit_task(struct task_struct *t);
 420
 421static inline int task_curr_ret_stack(struct task_struct *t)
 422{
 423        return t->curr_ret_stack;
 424}
 425
 426static inline void pause_graph_tracing(void)
 427{
 428        atomic_inc(&current->tracing_graph_pause);
 429}
 430
 431static inline void unpause_graph_tracing(void)
 432{
 433        atomic_dec(&current->tracing_graph_pause);
 434}
 435#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
 436
 437#define __notrace_funcgraph
 438#define __irq_entry
 439#define INIT_FTRACE_GRAPH
 440
 441static inline void ftrace_graph_init_task(struct task_struct *t) { }
 442static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 443
 444static inline int task_curr_ret_stack(struct task_struct *tsk)
 445{
 446        return -1;
 447}
 448
 449static inline void pause_graph_tracing(void) { }
 450static inline void unpause_graph_tracing(void) { }
 451#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 452
 453#ifdef CONFIG_TRACING
 454
 455/* flags for current->trace */
 456enum {
 457        TSK_TRACE_FL_TRACE_BIT  = 0,
 458        TSK_TRACE_FL_GRAPH_BIT  = 1,
 459};
 460enum {
 461        TSK_TRACE_FL_TRACE      = 1 << TSK_TRACE_FL_TRACE_BIT,
 462        TSK_TRACE_FL_GRAPH      = 1 << TSK_TRACE_FL_GRAPH_BIT,
 463};
 464
 465static inline void set_tsk_trace_trace(struct task_struct *tsk)
 466{
 467        set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 468}
 469
 470static inline void clear_tsk_trace_trace(struct task_struct *tsk)
 471{
 472        clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
 473}
 474
 475static inline int test_tsk_trace_trace(struct task_struct *tsk)
 476{
 477        return tsk->trace & TSK_TRACE_FL_TRACE;
 478}
 479
 480static inline void set_tsk_trace_graph(struct task_struct *tsk)
 481{
 482        set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 483}
 484
 485static inline void clear_tsk_trace_graph(struct task_struct *tsk)
 486{
 487        clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
 488}
 489
 490static inline int test_tsk_trace_graph(struct task_struct *tsk)
 491{
 492        return tsk->trace & TSK_TRACE_FL_GRAPH;
 493}
 494
 495extern int ftrace_dump_on_oops;
 496
 497#ifdef CONFIG_PREEMPT
 498#define INIT_TRACE_RECURSION            .trace_recursion = 0,
 499#endif
 500
 501#endif /* CONFIG_TRACING */
 502
 503#ifndef INIT_TRACE_RECURSION
 504#define INIT_TRACE_RECURSION
 505#endif
 506
 507#ifdef CONFIG_HW_BRANCH_TRACER
 508
 509void trace_hw_branch(u64 from, u64 to);
 510void trace_hw_branch_oops(void);
 511
 512#else /* CONFIG_HW_BRANCH_TRACER */
 513
 514static inline void trace_hw_branch(u64 from, u64 to) {}
 515static inline void trace_hw_branch_oops(void) {}
 516
 517#endif /* CONFIG_HW_BRANCH_TRACER */
 518
 519#ifdef CONFIG_FTRACE_SYSCALLS
 520
 521unsigned long arch_syscall_addr(int nr);
 522
 523#endif /* CONFIG_FTRACE_SYSCALLS */
 524
 525#endif /* _LINUX_FTRACE_H */
 526
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