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/module.h>
  10 #include <linux/kallsyms.h>
  11
  12 #ifdef CONFIG_FUNCTION_TRACER
  13
  14 extern int ftrace_enabled;
  15 extern int
  16 ftrace_enable_sysctl(struct ctl_table *table, int write,
  17                      struct file *filp, void __user *buffer, size_t *lenp,
  18                      loff_t *ppos);
  19
  20 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);
  21
  22 struct ftrace_ops {
  23         ftrace_func_t     func;
  24         struct ftrace_ops *next;
  25 };
  26
  27 /*
  28  * The ftrace_ops must be a static and should also
  29  * be read_mostly.  These functions do modify read_mostly variables
  30  * so use them sparely. Never free an ftrace_op or modify the
  31  * next pointer after it has been registered. Even after unregistering
  32  * it, the next pointer may still be used internally.
  33  */
  34 int register_ftrace_function(struct ftrace_ops *ops);
  35 int unregister_ftrace_function(struct ftrace_ops *ops);
  36 void clear_ftrace_function(void);
  37
  38 extern void ftrace_stub(unsigned long a0, unsigned long a1);
  39
  40 #else /* !CONFIG_FUNCTION_TRACER */
  41 # define register_ftrace_function(ops) do { } while (0)
  42 # define unregister_ftrace_function(ops) do { } while (0)
  43 # define clear_ftrace_function(ops) do { } while (0)
  44 static inline void ftrace_kill(void) { }
  45 #endif /* CONFIG_FUNCTION_TRACER */
  46
  47 #ifdef CONFIG_DYNAMIC_FTRACE
  48
  49 enum {
  50         FTRACE_FL_FREE          = (1 << 0),
  51         FTRACE_FL_FAILED        = (1 << 1),
  52         FTRACE_FL_FILTER        = (1 << 2),
  53         FTRACE_FL_ENABLED       = (1 << 3),
  54         FTRACE_FL_NOTRACE       = (1 << 4),
  55         FTRACE_FL_CONVERTED     = (1 << 5),
  56         FTRACE_FL_FROZEN        = (1 << 6),
  57 };
  58
  59 struct dyn_ftrace {
  60         struct list_head        list;
  61         unsigned long           ip; /* address of mcount call-site */
  62         unsigned long           flags;
  63 };
  64
  65 int ftrace_force_update(void);
  66 void ftrace_set_filter(unsigned char *buf, int len, int reset);
  67
  68 /* defined in arch */
  69 extern int ftrace_ip_converted(unsigned long ip);
  70 extern unsigned char *ftrace_nop_replace(void);
  71 extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
  72 extern int ftrace_dyn_arch_init(void *data);
  73 extern int ftrace_update_ftrace_func(ftrace_func_t func);
  74 extern void ftrace_caller(void);
  75 extern void ftrace_call(void);
  76 extern void mcount_call(void);
  77
  78 /**
  79  * ftrace_modify_code - modify code segment
  80  * @ip: the address of the code segment
  81  * @old_code: the contents of what is expected to be there
  82  * @new_code: the code to patch in
  83  *
  84  * This is a very sensitive operation and great care needs
  85  * to be taken by the arch.  The operation should carefully
  86  * read the location, check to see if what is read is indeed
  87  * what we expect it to be, and then on success of the compare,
  88  * it should write to the location.
  89  *
  90  * Return must be:
  91  *  0 on success
  92  *  -EFAULT on error reading the location
  93  *  -EINVAL on a failed compare of the contents
  94  *  -EPERM  on error writing to the location
  95  * Any other value will be considered a failure.
  96  */
  97 extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
  98                               unsigned char *new_code);
  99
 100 extern int skip_trace(unsigned long ip);
 101
 102 extern void ftrace_release(void *start, unsigned long size);
 103
 104 extern void ftrace_disable_daemon(void);
 105 extern void ftrace_enable_daemon(void);
 106
 107 #else
 108 # define skip_trace(ip)                         ({ 0; })
 109 # define ftrace_force_update()                  ({ 0; })
 110 # define ftrace_set_filter(buf, len, reset)     do { } while (0)
 111 # define ftrace_disable_daemon()                do { } while (0)
 112 # define ftrace_enable_daemon()                 do { } while (0)
 113 static inline void ftrace_release(void *start, unsigned long size) { }
 114 #endif /* CONFIG_DYNAMIC_FTRACE */
 115
 116 /* totally disable ftrace - can not re-enable after this */
 117 void ftrace_kill(void);
 118
 119 static inline void tracer_disable(void)
 120 {
 121 #ifdef CONFIG_FUNCTION_TRACER
 122         ftrace_enabled = 0;
 123 #endif
 124 }
 125
 126 /*
 127  * Ftrace disable/restore without lock. Some synchronization mechanism
 128  * must be used to prevent ftrace_enabled to be changed between
 129  * disable/restore.
 130  */
 131 static inline int __ftrace_enabled_save(void)
 132 {
 133 #ifdef CONFIG_FUNCTION_TRACER
 134         int saved_ftrace_enabled = ftrace_enabled;
 135         ftrace_enabled = 0;
 136         return saved_ftrace_enabled;
 137 #else
 138         return 0;
 139 #endif
 140 }
 141
 142 static inline void __ftrace_enabled_restore(int enabled)
 143 {
 144 #ifdef CONFIG_FUNCTION_TRACER
 145         ftrace_enabled = enabled;
 146 #endif
 147 }
 148
 149 #ifdef CONFIG_FRAME_POINTER
 150 /* TODO: need to fix this for ARM */
 151 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 152 # define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
 153 # define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
 154 # define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
 155 # define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
 156 # define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
 157 # define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
 158 #else
 159 # define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
 160 # define CALLER_ADDR1 0UL
 161 # define CALLER_ADDR2 0UL
 162 # define CALLER_ADDR3 0UL
 163 # define CALLER_ADDR4 0UL
 164 # define CALLER_ADDR5 0UL
 165 # define CALLER_ADDR6 0UL
 166 #endif
 167
 168 #ifdef CONFIG_IRQSOFF_TRACER
 169   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
 170   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
 171 #else
 172 # define time_hardirqs_on(a0, a1)               do { } while (0)
 173 # define time_hardirqs_off(a0, a1)              do { } while (0)
 174 #endif
 175
 176 #ifdef CONFIG_PREEMPT_TRACER
 177   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
 178   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 179 #else
 180 # define trace_preempt_on(a0, a1)               do { } while (0)
 181 # define trace_preempt_off(a0, a1)              do { } while (0)
 182 #endif
 183
 184 #ifdef CONFIG_TRACING
 185 extern void
 186 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
 187
 188 /**
 189  * ftrace_printk - printf formatting in the ftrace buffer
 190  * @fmt: the printf format for printing
 191  *
 192  * Note: __ftrace_printk is an internal function for ftrace_printk and
 193  *       the @ip is passed in via the ftrace_printk macro.
 194  *
 195  * This function allows a kernel developer to debug fast path sections
 196  * that printk is not appropriate for. By scattering in various
 197  * printk like tracing in the code, a developer can quickly see
 198  * where problems are occurring.
 199  *
 200  * This is intended as a debugging tool for the developer only.
 201  * Please refrain from leaving ftrace_printks scattered around in
 202  * your code.
 203  */
 204 # define ftrace_printk(fmt...) __ftrace_printk(_THIS_IP_, fmt)
 205 extern int
 206 __ftrace_printk(unsigned long ip, const char *fmt, ...)
 207         __attribute__ ((format (printf, 2, 3)));
 208 extern void ftrace_dump(void);
 209 #else
 210 static inline void
 211 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 212 static inline int
 213 ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
 214
 215 static inline int
 216 ftrace_printk(const char *fmt, ...)
 217 {
 218         return 0;
 219 }
 220 static inline void ftrace_dump(void) { }
 221 #endif
 222
 223 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 224 extern void ftrace_init(void);
 225 extern void ftrace_init_module(unsigned long *start, unsigned long *end);
 226 #else
 227 static inline void ftrace_init(void) { }
 228 static inline void
 229 ftrace_init_module(unsigned long *start, unsigned long *end) { }
 230 #endif
 231
 232
 233 struct boot_trace {
 234         pid_t                   caller;
 235         char                    func[KSYM_SYMBOL_LEN];
 236         int                     result;
 237         unsigned long long      duration;               /* usecs */
 238         ktime_t                 calltime;
 239         ktime_t                 rettime;
 240 };
 241
 242 #ifdef CONFIG_BOOT_TRACER
 243 extern void trace_boot(struct boot_trace *it, initcall_t fn);
 244 extern void start_boot_trace(void);
 245 extern void stop_boot_trace(void);
 246 #else
 247 static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
 248 static inline void start_boot_trace(void) { }
 249 static inline void stop_boot_trace(void) { }
 250 #endif
 251
 252
 253
 254 #endif /* _LINUX_FTRACE_H */