include/linux/ftrace.h

   1 #ifndef _LINUX_FTRACE_H
   2 #define _LINUX_FTRACE_H
   3
   4 #include <linux/linkage.h>
   5 #include <linux/fs.h>
   6 #include <linux/ktime.h>
   7 #include <linux/init.h>
   8 #include <linux/types.h>
   9 #include <linux/kallsyms.h>
  10
  11 #ifdef CONFIG_FUNCTION_TRACER
  12
  13 extern int ftrace_enabled;
  14 extern int
  15 ftrace_enable_sysctl(struct ctl_table *table, int write,
  16                      struct file *filp, void __user *buffer, size_t *lenp,
  17                      loff_t *ppos);
  18
  19 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  20
  21 struct ftrace_ops {
  22         ftrace_func_t     func;
  23         struct ftrace_ops *next;
  24 };
  25
  26 extern int function_trace_stop;
  27
  28 /*
  29  * Type of the current tracing.
  30  */
  31 enum ftrace_tracing_type_t {
  32         FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
  33         FTRACE_TYPE_RETURN,     /* Hook the return of the function */
  34 };
  35
  36 /* Current tracing type, default is FTRACE_TYPE_ENTER */
  37 extern enum ftrace_tracing_type_t ftrace_tracing_type;
  38
  39 /**
  40  * ftrace_stop - stop function tracer.
  41  *
  42  * A quick way to stop the function tracer. Note this an on off switch,
  43  * it is not something that is recursive like preempt_disable.
  44  * This does not disable the calling of mcount, it only stops the
  45  * calling of functions from mcount.
  46  */
  47 static inline void ftrace_stop(void)
  48 {
  49         function_trace_stop = 1;
  50 }
  51
  52 /**
  53  * ftrace_start - start the function tracer.
  54  *
  55  * This function is the inverse of ftrace_stop. This does not enable
  56  * the function tracing if the function tracer is disabled. This only
  57  * sets the function tracer flag to continue calling the functions
  58  * from mcount.
  59  */
  60 static inline void ftrace_start(void)
  61 {
  62         function_trace_stop = 0;
  63 }
  64
  65 /*
  66  * The ftrace_ops must be a static and should also
  67  * be read_mostly.  These functions do modify read_mostly variables
  68  * so use them sparely. Never free an ftrace_op or modify the
  69  * next pointer after it has been registered. Even after unregistering
  70  * it, the next pointer may still be used internally.
  71  */
  72 int register_ftrace_function(struct ftrace_ops *ops);
  73 int unregister_ftrace_function(struct ftrace_ops *ops);
  74 void clear_ftrace_function(void);
  75
  76 extern void ftrace_stub(unsigned long a0, unsigned long a1);
  77
  78 #else /* !CONFIG_FUNCTION_TRACER */
  79 # define register_ftrace_function(ops) do { } while (0)
  80 # define unregister_ftrace_function(ops) do { } while (0)
  81 # define clear_ftrace_function(ops) do { } while (0)
  82 static inline void ftrace_kill(void) { }
  83 static inline void ftrace_stop(void) { }
  84 static inline void ftrace_start(void) { }
  85 #endif /* CONFIG_FUNCTION_TRACER */
  86
  87 #ifdef CONFIG_DYNAMIC_FTRACE
  88 /* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
  89 #include <asm/ftrace.h>
  90
  91 enum {
  92         FTRACE_FL_FREE          = (1 << 0),
  93         FTRACE_FL_FAILED        = (1 << 1),
  94         FTRACE_FL_FILTER        = (1 << 2),
  95         FTRACE_FL_ENABLED       = (1 << 3),
  96         FTRACE_FL_NOTRACE       = (1 << 4),
  97         FTRACE_FL_CONVERTED     = (1 << 5),
  98         FTRACE_FL_FROZEN        = (1 << 6),
  99 };
 100
 101 struct dyn_ftrace {
 102         struct list_head        list;
 103         unsigned long           ip; /* address of mcount call-site */
 104         unsigned long           flags;
 105         struct dyn_arch_ftrace  arch;
 106 };
 107
 108 int ftrace_force_update(void);
 109 void ftrace_set_filter(unsigned char *buf, int len, int reset);
 110
 111 /* defined in arch */
 112 extern int ftrace_ip_converted(unsigned long ip);
 113 extern int ftrace_dyn_arch_init(void *data);
 114 extern int ftrace_update_ftrace_func(ftrace_func_t func);
 115 extern void ftrace_caller(void);
 116 extern void ftrace_call(void);
 117 extern void mcount_call(void);
 118 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 119 extern void ftrace_graph_caller(void);
 120 #endif
 121
 122 /**
 123  * ftrace_make_nop - convert code into top
 124  * @mod: module structure if called by module load initialization
 125  * @rec: the mcount call site record
 126  * @addr: the address that the call site should be calling
 127  *
 128  * This is a very sensitive operation and great care needs
 129  * to be taken by the arch.  The operation should carefully
 130  * read the location, check to see if what is read is indeed
 131  * what we expect it to be, and then on success of the compare,
 132  * it should write to the location.
 133  *
 134  * The code segment at @rec->ip should be a caller to @addr
 135  *
 136  * Return must be:
 137  *  0 on success
 138  *  -EFAULT on error reading the location
 139  *  -EINVAL on a failed compare of the contents
 140  *  -EPERM  on error writing to the location
 141  * Any other value will be considered a failure.
 142  */
 143 extern int ftrace_make_nop(struct module *mod,
 144                            struct dyn_ftrace *rec, unsigned long addr);
 145
 146 /**
 147  * ftrace_make_call - convert a nop call site into a call to addr
 148  * @rec: the mcount call site record
 149  * @addr: the address that the call site should call
 150  *
 151  * This is a very sensitive operation and great care needs
 152  * to be taken by the arch.  The operation should carefully
 153  * read the location, check to see if what is read is indeed
 154  * what we expect it to be, and then on success of the compare,
 155  * it should write to the location.
 156  *
 157  * The code segment at @rec->ip should be a nop
 158  *
 159  * Return must be:
 160  *  0 on success
 161  *  -EFAULT on error reading the location
 162  *  -EINVAL on a failed compare of the contents
 163  *  -EPERM  on error writing to the location
 164  * Any other value will be considered a failure.
 165  */
 166 extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
 167
 168
 169 /* May be defined in arch */
 170 extern int ftrace_arch_read_dyn_info(char *buf, int size);
 171
 172 extern int skip_trace(unsigned long ip);
 173
 174 extern void ftrace_release(void *start, unsigned long size);
 175
 176 extern void ftrace_disable_daemon(void);
 177 extern void ftrace_enable_daemon(void);
 178 #else
 179 # define skip_trace(ip)                         ({ 0; })
 180 # define ftrace_force_update()                  ({ 0; })
 181 # define ftrace_set_filter(buf, len, reset)     do { } while (0)
 182 # define ftrace_disable_daemon()                do { } while (0)
 183 # define ftrace_enable_daemon()                 do { } while (0)
 184 static inline void ftrace_release(void *start, unsigned long size) { }
 185 #endif /* CONFIG_DYNAMIC_FTRACE */
 186
 187 /* totally disable ftrace - can not re-enable after this */
 188 void ftrace_kill(void);
 189
 190 static inline void tracer_disable(void)
 191 {
 192 #ifdef CONFIG_FUNCTION_TRACER
 193         ftrace_enabled = 0;
 194 #endif
 195 }
 196
 197 /*
 198  * Ftrace disable/restore without lock. Some synchronization mechanism
 199  * must be used to prevent ftrace_enabled to be changed between
 200  * disable/restore.
 201  */
 202 static inline int __ftrace_enabled_save(void)
 203 {
 204 #ifdef CONFIG_FUNCTION_TRACER
 205         int saved_ftrace_enabled = ftrace_enabled;
 206         ftrace_enabled = 0;
 207         return saved_ftrace_enabled;
 208 #else
 209         return 0;
 210 #endif
 211 }
 212
 213 static inline void __ftrace_enabled_restore(int enabled)
 214 {
 215 #ifdef CONFIG_FUNCTION_TRACER
 216         ftrace_enabled = enabled;
 217 #endif
 218 }
 219
 220 #ifdef CONFIG_FRAME_POINTER
 221 /* TODO: need to fix this for ARM */
 222 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 223 # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 224 # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 225 # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 226 # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 227 # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 228 # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 229 #else
 230 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 231 # define CALLER_ADDR1 0UL
 232 # define CALLER_ADDR2 0UL
 233 # define CALLER_ADDR3 0UL
 234 # define CALLER_ADDR4 0UL
 235 # define CALLER_ADDR5 0UL
 236 # define CALLER_ADDR6 0UL
 237 #endif
 238
 239 #ifdef CONFIG_IRQSOFF_TRACER
 240   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 241   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 242 #else
 243 # define time_hardirqs_on(a0, a1)               do { } while (0)
 244 # define time_hardirqs_off(a0, a1)              do { } while (0)
 245 #endif
 246
 247 #ifdef CONFIG_PREEMPT_TRACER
 248   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 249   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 250 #else
 251 # define trace_preempt_on(a0, a1)               do { } while (0)
 252 # define trace_preempt_off(a0, a1)              do { } while (0)
 253 #endif
 254
 255 #ifdef CONFIG_TRACING
 256 extern int ftrace_dump_on_oops;
 257
 258 extern void tracing_start(void);
 259 extern void tracing_stop(void);
 260 extern void ftrace_off_permanent(void);
 261
 262 extern void
 263 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 264
 265 /**
 266  * ftrace_printk - printf formatting in the ftrace buffer
 267  * @fmt: the printf format for printing
 268  *
 269  * Note: __ftrace_printk is an internal function for ftrace_printk and
 270  *       the @ip is passed in via the ftrace_printk macro.
 271  *
 272  * This function allows a kernel developer to debug fast path sections
 273  * that printk is not appropriate for. By scattering in various
 274  * printk like tracing in the code, a developer can quickly see
 275  * where problems are occurring.
 276  *
 277  * This is intended as a debugging tool for the developer only.
 278  * Please refrain from leaving ftrace_printks scattered around in
 279  * your code.
 280  */
 281 # define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
 282 extern int
 283 __ftrace_printk(unsigned long ip, const char *fmt, ...)
 284         __attribute__ ((format (printf, 2, 3)));
 285 extern void ftrace_dump(void);
 286 #else
 287 static inline void
 288 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 289 static inline int
 290 ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
 291
 292 static inline void tracing_start(void) { }
 293 static inline void tracing_stop(void) { }
 294 static inline void ftrace_off_permanent(void) { }
 295 static inline int
 296 ftrace_printk(const char *fmt, ...)
 297 {
 298         return 0;
 299 }
 300 static inline void ftrace_dump(void) { }
 301 #endif
 302
 303 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 304 extern void ftrace_init(void);
 305 extern void ftrace_init_module(struct module *mod,
 306                                unsigned long *start, unsigned long *end);
 307 #else
 308 static inline void ftrace_init(void) { }
 309 static inline void
 310 ftrace_init_module(struct module *mod,
 311                    unsigned long *start, unsigned long *end) { }
 312 #endif
 313
 314
 315 /*
 316  * Structure that defines an entry function trace.
 317  */
 318 struct ftrace_graph_ent {
 319         unsigned long func; /* Current function */
 320         int depth;
 321 };
 322
 323 /*
 324  * Structure that defines a return function trace.
 325  */
 326 struct ftrace_graph_ret {
 327         unsigned long func; /* Current function */
 328         unsigned long long calltime;
 329         unsigned long long rettime;
 330         /* Number of functions that overran the depth limit for current task */
 331         unsigned long overrun;
 332         int depth;
 333 };
 334
 335 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 336 #define FTRACE_RETFUNC_DEPTH 50
 337 #define FTRACE_RETSTACK_ALLOC_SIZE 32
 338 /* Type of the callback handlers for tracing function graph*/
 339 typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
 340 typedef void (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */
 341
 342 extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 343                                 trace_func_graph_ent_t entryfunc);
 344
 345 /* The current handlers in use */
 346 extern trace_func_graph_ret_t ftrace_graph_return;
 347 extern trace_func_graph_ent_t ftrace_graph_entry;
 348
 349 extern void unregister_ftrace_graph(void);
 350
 351 extern void ftrace_graph_init_task(struct task_struct *t);
 352 extern void ftrace_graph_exit_task(struct task_struct *t);
 353 #else
 354 static inline void ftrace_graph_init_task(struct task_struct *t) { }
 355 static inline void ftrace_graph_exit_task(struct task_struct *t) { }
 356 #endif
 357
 358 #endif /* _LINUX_FTRACE_H */