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TOMOYO Linux Cross Reference
Linux/kernel/trace/trace_probe.h

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  1 /*
  2  * Common header file for probe-based Dynamic events.
  3  *
  4  * This program is free software; you can redistribute it and/or modify
  5  * it under the terms of the GNU General Public License version 2 as
  6  * published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11  * GNU General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public License
 14  * along with this program; if not, write to the Free Software
 15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 16  *
 17  * This code was copied from kernel/trace/trace_kprobe.h written by
 18  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 19  *
 20  * Updates to make this generic:
 21  * Copyright (C) IBM Corporation, 2010-2011
 22  * Author:     Srikar Dronamraju
 23  */
 24 
 25 #include <linux/seq_file.h>
 26 #include <linux/slab.h>
 27 #include <linux/smp.h>
 28 #include <linux/debugfs.h>
 29 #include <linux/types.h>
 30 #include <linux/string.h>
 31 #include <linux/ctype.h>
 32 #include <linux/ptrace.h>
 33 #include <linux/perf_event.h>
 34 #include <linux/kprobes.h>
 35 #include <linux/stringify.h>
 36 #include <linux/limits.h>
 37 #include <linux/uaccess.h>
 38 #include <asm/bitsperlong.h>
 39 
 40 #include "trace.h"
 41 #include "trace_output.h"
 42 
 43 #define MAX_TRACE_ARGS          128
 44 #define MAX_ARGSTR_LEN          63
 45 #define MAX_EVENT_NAME_LEN      64
 46 #define MAX_STRING_SIZE         PATH_MAX
 47 
 48 /* Reserved field names */
 49 #define FIELD_STRING_IP         "__probe_ip"
 50 #define FIELD_STRING_RETIP      "__probe_ret_ip"
 51 #define FIELD_STRING_FUNC       "__probe_func"
 52 
 53 #undef DEFINE_FIELD
 54 #define DEFINE_FIELD(type, item, name, is_signed)                       \
 55         do {                                                            \
 56                 ret = trace_define_field(event_call, #type, name,       \
 57                                          offsetof(typeof(field), item), \
 58                                          sizeof(field.item), is_signed, \
 59                                          FILTER_OTHER);                 \
 60                 if (ret)                                                \
 61                         return ret;                                     \
 62         } while (0)
 63 
 64 
 65 /* Flags for trace_probe */
 66 #define TP_FLAG_TRACE           1
 67 #define TP_FLAG_PROFILE         2
 68 #define TP_FLAG_REGISTERED      4
 69 
 70 
 71 /* data_rloc: data relative location, compatible with u32 */
 72 #define make_data_rloc(len, roffs)      \
 73         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
 74 #define get_rloc_len(dl)                ((u32)(dl) >> 16)
 75 #define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
 76 
 77 /*
 78  * Convert data_rloc to data_loc:
 79  *  data_rloc stores the offset from data_rloc itself, but data_loc
 80  *  stores the offset from event entry.
 81  */
 82 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
 83 
 84 static inline void *get_rloc_data(u32 *dl)
 85 {
 86         return (u8 *)dl + get_rloc_offs(*dl);
 87 }
 88 
 89 /* For data_loc conversion */
 90 static inline void *get_loc_data(u32 *dl, void *ent)
 91 {
 92         return (u8 *)ent + get_rloc_offs(*dl);
 93 }
 94 
 95 /* Data fetch function type */
 96 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
 97 /* Printing function type */
 98 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
 99 
100 /* Fetch types */
101 enum {
102         FETCH_MTD_reg = 0,
103         FETCH_MTD_stack,
104         FETCH_MTD_retval,
105         FETCH_MTD_memory,
106         FETCH_MTD_symbol,
107         FETCH_MTD_deref,
108         FETCH_MTD_bitfield,
109         FETCH_MTD_file_offset,
110         FETCH_MTD_END,
111 };
112 
113 /* Fetch type information table */
114 struct fetch_type {
115         const char              *name;          /* Name of type */
116         size_t                  size;           /* Byte size of type */
117         int                     is_signed;      /* Signed flag */
118         print_type_func_t       print;          /* Print functions */
119         const char              *fmt;           /* Fromat string */
120         const char              *fmttype;       /* Name in format file */
121         /* Fetch functions */
122         fetch_func_t            fetch[FETCH_MTD_END];
123 };
124 
125 struct fetch_param {
126         fetch_func_t            fn;
127         void                    *data;
128 };
129 
130 /* For defining macros, define string/string_size types */
131 typedef u32 string;
132 typedef u32 string_size;
133 
134 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
135 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
136 
137 /* Printing  in basic type function template */
138 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
139 __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,           \
140                                          const char *name,              \
141                                          void *data, void *ent);        \
142 extern const char PRINT_TYPE_FMT_NAME(type)[]
143 
144 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
145 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
146 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
147 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
148 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
149 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
150 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
151 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
152 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
153 
154 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
155 
156 /* Declare macro for basic types */
157 #define DECLARE_FETCH_FUNC(method, type)                                \
158 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
159                                           void *data, void *dest)
160 
161 #define DECLARE_BASIC_FETCH_FUNCS(method)       \
162 DECLARE_FETCH_FUNC(method, u8);                 \
163 DECLARE_FETCH_FUNC(method, u16);                \
164 DECLARE_FETCH_FUNC(method, u32);                \
165 DECLARE_FETCH_FUNC(method, u64)
166 
167 DECLARE_BASIC_FETCH_FUNCS(reg);
168 #define fetch_reg_string                        NULL
169 #define fetch_reg_string_size                   NULL
170 
171 DECLARE_BASIC_FETCH_FUNCS(retval);
172 #define fetch_retval_string                     NULL
173 #define fetch_retval_string_size                NULL
174 
175 DECLARE_BASIC_FETCH_FUNCS(symbol);
176 DECLARE_FETCH_FUNC(symbol, string);
177 DECLARE_FETCH_FUNC(symbol, string_size);
178 
179 DECLARE_BASIC_FETCH_FUNCS(deref);
180 DECLARE_FETCH_FUNC(deref, string);
181 DECLARE_FETCH_FUNC(deref, string_size);
182 
183 DECLARE_BASIC_FETCH_FUNCS(bitfield);
184 #define fetch_bitfield_string                   NULL
185 #define fetch_bitfield_string_size              NULL
186 
187 /*
188  * Define macro for basic types - we don't need to define s* types, because
189  * we have to care only about bitwidth at recording time.
190  */
191 #define DEFINE_BASIC_FETCH_FUNCS(method) \
192 DEFINE_FETCH_##method(u8)               \
193 DEFINE_FETCH_##method(u16)              \
194 DEFINE_FETCH_##method(u32)              \
195 DEFINE_FETCH_##method(u64)
196 
197 /* Default (unsigned long) fetch type */
198 #define __DEFAULT_FETCH_TYPE(t) u##t
199 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
200 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
201 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
202 
203 #define ASSIGN_FETCH_FUNC(method, type) \
204         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
205 
206 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
207         {.name = _name,                         \
208          .size = _size,                                 \
209          .is_signed = sign,                             \
210          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
211          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
212          .fmttype = _fmttype,                           \
213          .fetch = {                                     \
214 ASSIGN_FETCH_FUNC(reg, ftype),                          \
215 ASSIGN_FETCH_FUNC(stack, ftype),                        \
216 ASSIGN_FETCH_FUNC(retval, ftype),                       \
217 ASSIGN_FETCH_FUNC(memory, ftype),                       \
218 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
219 ASSIGN_FETCH_FUNC(deref, ftype),                        \
220 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
221 ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
222           }                                             \
223         }
224 
225 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
226         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
227 
228 #define ASSIGN_FETCH_TYPE_END {}
229 
230 #define FETCH_TYPE_STRING       0
231 #define FETCH_TYPE_STRSIZE      1
232 
233 /*
234  * Fetch type information table.
235  * It's declared as a weak symbol due to conditional compilation.
236  */
237 extern __weak const struct fetch_type kprobes_fetch_type_table[];
238 extern __weak const struct fetch_type uprobes_fetch_type_table[];
239 
240 #ifdef CONFIG_KPROBE_EVENT
241 struct symbol_cache;
242 unsigned long update_symbol_cache(struct symbol_cache *sc);
243 void free_symbol_cache(struct symbol_cache *sc);
244 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
245 #else
246 /* uprobes do not support symbol fetch methods */
247 #define fetch_symbol_u8                 NULL
248 #define fetch_symbol_u16                NULL
249 #define fetch_symbol_u32                NULL
250 #define fetch_symbol_u64                NULL
251 #define fetch_symbol_string             NULL
252 #define fetch_symbol_string_size        NULL
253 
254 struct symbol_cache {
255 };
256 static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
257 {
258         return 0;
259 }
260 
261 static inline void __used free_symbol_cache(struct symbol_cache *sc)
262 {
263 }
264 
265 static inline struct symbol_cache * __used
266 alloc_symbol_cache(const char *sym, long offset)
267 {
268         return NULL;
269 }
270 #endif /* CONFIG_KPROBE_EVENT */
271 
272 struct probe_arg {
273         struct fetch_param      fetch;
274         struct fetch_param      fetch_size;
275         unsigned int            offset; /* Offset from argument entry */
276         const char              *name;  /* Name of this argument */
277         const char              *comm;  /* Command of this argument */
278         const struct fetch_type *type;  /* Type of this argument */
279 };
280 
281 struct trace_probe {
282         unsigned int                    flags;  /* For TP_FLAG_* */
283         struct ftrace_event_class       class;
284         struct ftrace_event_call        call;
285         struct list_head                files;
286         ssize_t                         size;   /* trace entry size */
287         unsigned int                    nr_args;
288         struct probe_arg                args[];
289 };
290 
291 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
292 {
293         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
294 }
295 
296 static inline bool trace_probe_is_registered(struct trace_probe *tp)
297 {
298         return !!(tp->flags & TP_FLAG_REGISTERED);
299 }
300 
301 static inline __kprobes void call_fetch(struct fetch_param *fprm,
302                                  struct pt_regs *regs, void *dest)
303 {
304         return fprm->fn(regs, fprm->data, dest);
305 }
306 
307 /* Check the name is good for event/group/fields */
308 static inline int is_good_name(const char *name)
309 {
310         if (!isalpha(*name) && *name != '_')
311                 return 0;
312         while (*++name != '\0') {
313                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
314                         return 0;
315         }
316         return 1;
317 }
318 
319 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
320                    struct probe_arg *parg, bool is_return, bool is_kprobe);
321 
322 extern int traceprobe_conflict_field_name(const char *name,
323                                struct probe_arg *args, int narg);
324 
325 extern void traceprobe_update_arg(struct probe_arg *arg);
326 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
327 
328 extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
329 
330 extern ssize_t traceprobe_probes_write(struct file *file,
331                 const char __user *buffer, size_t count, loff_t *ppos,
332                 int (*createfn)(int, char**));
333 
334 extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
335 
336 /* Sum up total data length for dynamic arraies (strings) */
337 static inline __kprobes int
338 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
339 {
340         int i, ret = 0;
341         u32 len;
342 
343         for (i = 0; i < tp->nr_args; i++)
344                 if (unlikely(tp->args[i].fetch_size.fn)) {
345                         call_fetch(&tp->args[i].fetch_size, regs, &len);
346                         ret += len;
347                 }
348 
349         return ret;
350 }
351 
352 /* Store the value of each argument */
353 static inline __kprobes void
354 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
355                  u8 *data, int maxlen)
356 {
357         int i;
358         u32 end = tp->size;
359         u32 *dl;        /* Data (relative) location */
360 
361         for (i = 0; i < tp->nr_args; i++) {
362                 if (unlikely(tp->args[i].fetch_size.fn)) {
363                         /*
364                          * First, we set the relative location and
365                          * maximum data length to *dl
366                          */
367                         dl = (u32 *)(data + tp->args[i].offset);
368                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
369                         /* Then try to fetch string or dynamic array data */
370                         call_fetch(&tp->args[i].fetch, regs, dl);
371                         /* Reduce maximum length */
372                         end += get_rloc_len(*dl);
373                         maxlen -= get_rloc_len(*dl);
374                         /* Trick here, convert data_rloc to data_loc */
375                         *dl = convert_rloc_to_loc(*dl,
376                                  ent_size + tp->args[i].offset);
377                 } else
378                         /* Just fetching data normally */
379                         call_fetch(&tp->args[i].fetch, regs,
380                                    data + tp->args[i].offset);
381         }
382 }
383 
384 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
385 

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