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 /*
  27  * The ftrace_ops must be a static and should also
  28  * be read_mostly.  These functions do modify read_mostly variables
  29  * so use them sparely. Never free an ftrace_op or modify the
  30  * next pointer after it has been registered. Even after unregistering
  31  * it, the next pointer may still be used internally.
  32  */
  33 int register_ftrace_function(struct ftrace_ops *ops);
  34 int unregister_ftrace_function(struct ftrace_ops *ops);
  35 void clear_ftrace_function(void);
  36
  37 extern void ftrace_stub(unsigned long a0, unsigned long a1);
  38
  39 #else /* !CONFIG_FUNCTION_TRACER */
  40 # define register_ftrace_function(ops) do { } while (0)
  41 # define unregister_ftrace_function(ops) do { } while (0)
  42 # define clear_ftrace_function(ops) do { } while (0)
  43 static inline void ftrace_kill(void) { }
  44 #endif /* CONFIG_FUNCTION_TRACER */
  45
  46 #ifdef CONFIG_DYNAMIC_FTRACE
  47
  48 enum {
  49         FTRACE_FL_FREE          = (1 << 0),
  50         FTRACE_FL_FAILED        = (1 << 1),
  51         FTRACE_FL_FILTER        = (1 << 2),
  52         FTRACE_FL_ENABLED       = (1 << 3),
  53         FTRACE_FL_NOTRACE       = (1 << 4),
  54         FTRACE_FL_CONVERTED     = (1 << 5),
  55         FTRACE_FL_FROZEN        = (1 << 6),
  56 };
  57
  58 struct dyn_ftrace {
  59         struct list_head        list;
  60         unsigned long           ip; /* address of mcount call-site */
  61         unsigned long           flags;
  62 };
  63
  64 int ftrace_force_update(void);
  65 void ftrace_set_filter(unsigned char *buf, int len, int reset);
  66
  67 /* defined in arch */
  68 extern int ftrace_ip_converted(unsigned long ip);
  69 extern unsigned char *ftrace_nop_replace(void);
  70 extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
  71 extern int ftrace_dyn_arch_init(void *data);
  72 extern int ftrace_update_ftrace_func(ftrace_func_t func);
  73 extern void ftrace_caller(void);
  74 extern void ftrace_call(void);
  75 extern void mcount_call(void);
  76
  77 /* May be defined in arch */
  78 extern int ftrace_arch_read_dyn_info(char *buf, int size);
  79
  80 /**
  81  * ftrace_modify_code - modify code segment
  82  * @ip: the address of the code segment
  83  * @old_code: the contents of what is expected to be there
  84  * @new_code: the code to patch in
  85  *
  86  * This is a very sensitive operation and great care needs
  87  * to be taken by the arch.  The operation should carefully
  88  * read the location, check to see if what is read is indeed
  89  * what we expect it to be, and then on success of the compare,
  90  * it should write to the location.
  91  *
  92  * Return must be:
  93  *  0 on success
  94  *  -EFAULT on error reading the location
  95  *  -EINVAL on a failed compare of the contents
  96  *  -EPERM  on error writing to the location
  97  * Any other value will be considered a failure.
  98  */
  99 extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
 100                               unsigned char *new_code);
 101
 102 extern int skip_trace(unsigned long ip);
 103
 104 extern void ftrace_release(void *start, unsigned long size);
 105
 106 extern void ftrace_disable_daemon(void);
 107 extern void ftrace_enable_daemon(void);
 108
 109 #else
 110 # define skip_trace(ip)                         ({ 0; })
 111 # define ftrace_force_update()                  ({ 0; })
 112 # define ftrace_set_filter(buf, len, reset)     do { } while (0)
 113 # define ftrace_disable_daemon()                do { } while (0)
 114 # define ftrace_enable_daemon()                 do { } while (0)
 115 static inline void ftrace_release(void *start, unsigned long size) { }
 116 #endif /* CONFIG_DYNAMIC_FTRACE */
 117
 118 /* totally disable ftrace - can not re-enable after this */
 119 void ftrace_kill(void);
 120
 121 static inline void tracer_disable(void)
 122 {
 123 #ifdef CONFIG_FUNCTION_TRACER
 124         ftrace_enabled = 0;
 125 #endif
 126 }
 127
 128 /*
 129  * Ftrace disable/restore without lock. Some synchronization mechanism
 130  * must be used to prevent ftrace_enabled to be changed between
 131  * disable/restore.
 132  */
 133 static inline int __ftrace_enabled_save(void)
 134 {
 135 #ifdef CONFIG_FUNCTION_TRACER
 136         int saved_ftrace_enabled = ftrace_enabled;
 137         ftrace_enabled = 0;
 138         return saved_ftrace_enabled;
 139 #else
 140         return 0;
 141 #endif
 142 }
 143
 144 static inline void __ftrace_enabled_restore(int enabled)
 145 {
 146 #ifdef CONFIG_FUNCTION_TRACER
 147         ftrace_enabled = enabled;
 148 #endif
 149 }
 150
 151 #ifdef CONFIG_FRAME_POINTER
 152 /* TODO: need to fix this for ARM */
 153 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 154 # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 155 # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 156 # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 157 # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 158 # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 159 # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 160 #else
 161 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 162 # define CALLER_ADDR1 0UL
 163 # define CALLER_ADDR2 0UL
 164 # define CALLER_ADDR3 0UL
 165 # define CALLER_ADDR4 0UL
 166 # define CALLER_ADDR5 0UL
 167 # define CALLER_ADDR6 0UL
 168 #endif
 169
 170 #ifdef CONFIG_IRQSOFF_TRACER
 171   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 172   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 173 #else
 174 # define time_hardirqs_on(a0, a1)               do { } while (0)
 175 # define time_hardirqs_off(a0, a1)              do { } while (0)
 176 #endif
 177
 178 #ifdef CONFIG_PREEMPT_TRACER
 179   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 180   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 181 #else
 182 # define trace_preempt_on(a0, a1)               do { } while (0)
 183 # define trace_preempt_off(a0, a1)              do { } while (0)
 184 #endif
 185
 186 #ifdef CONFIG_TRACING
 187 extern int ftrace_dump_on_oops;
 188
 189 extern void
 190 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 191
 192 /**
 193  * ftrace_printk - printf formatting in the ftrace buffer
 194  * @fmt: the printf format for printing
 195  *
 196  * Note: __ftrace_printk is an internal function for ftrace_printk and
 197  *       the @ip is passed in via the ftrace_printk macro.
 198  *
 199  * This function allows a kernel developer to debug fast path sections
 200  * that printk is not appropriate for. By scattering in various
 201  * printk like tracing in the code, a developer can quickly see
 202  * where problems are occurring.
 203  *
 204  * This is intended as a debugging tool for the developer only.
 205  * Please refrain from leaving ftrace_printks scattered around in
 206  * your code.
 207  */
 208 # define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
 209 extern int
 210 __ftrace_printk(unsigned long ip, const char *fmt, ...)
 211         __attribute__ ((format (printf, 2, 3)));
 212 extern void ftrace_dump(void);
 213 #else
 214 static inline void
 215 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 216 static inline int
 217 ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
 218
 219 static inline int
 220 ftrace_printk(const char *fmt, ...)
 221 {
 222         return 0;
 223 }
 224 static inline void ftrace_dump(void) { }
 225 #endif
 226
 227 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 228 extern void ftrace_init(void);
 229 extern void ftrace_init_module(unsigned long *start, unsigned long *end);
 230 #else
 231 static inline void ftrace_init(void) { }
 232 static inline void
 233 ftrace_init_module(unsigned long *start, unsigned long *end) { }
 234 #endif
 235
 236
 237 /*
 238  * Structure which defines the trace of an initcall.
 239  * You don't have to fill the func field since it is
 240  * only used internally by the tracer.
 241  */
 242 struct boot_trace {
 243         pid_t                   caller;
 244         char                    func[KSYM_NAME_LEN];
 245         int                     result;
 246         unsigned long long      duration;               /* usecs */
 247         ktime_t                 calltime;
 248         ktime_t                 rettime;
 249 };
 250
 251 #ifdef CONFIG_BOOT_TRACER
 252 /* Append the trace on the ring-buffer */
 253 extern void trace_boot(struct boot_trace *it, initcall_t fn);
 254
 255 /* Tells the tracer that smp_pre_initcall is finished.
 256  * So we can start the tracing
 257  */
 258 extern void start_boot_trace(void);
 259
 260 /* Resume the tracing of other necessary events
 261  * such as sched switches
 262  */
 263 extern void enable_boot_trace(void);
 264
 265 /* Suspend this tracing. Actually, only sched_switches tracing have
 266  * to be suspended. Initcalls doesn't need it.)
 267  */
 268 extern void disable_boot_trace(void);
 269 #else
 270 static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
 271 static inline void start_boot_trace(void) { }
 272 static inline void enable_boot_trace(void) { }
 273 static inline void disable_boot_trace(void) { }
 274 #endif
 275
 276
 277
 278 #endif /* _LINUX_FTRACE_H */