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/tracefs.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
get_rloc_data(u32 * dl)84 static nokprobe_inline void *get_rloc_data(u32 *dl)
85 {
86 return (u8 *)dl + get_rloc_offs(*dl);
87 }
88
89 /* For data_loc conversion */
get_loc_data(u32 * dl,void * ent)90 static nokprobe_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 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
140 void *data, void *ent); \
141 extern const char PRINT_TYPE_FMT_NAME(type)[]
142
143 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
144 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
145 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
146 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
147 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
148 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
149 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
150 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
151 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
152
153 #define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
154
155 /* Declare macro for basic types */
156 #define DECLARE_FETCH_FUNC(method, type) \
157 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs, \
158 void *data, void *dest)
159
160 #define DECLARE_BASIC_FETCH_FUNCS(method) \
161 DECLARE_FETCH_FUNC(method, u8); \
162 DECLARE_FETCH_FUNC(method, u16); \
163 DECLARE_FETCH_FUNC(method, u32); \
164 DECLARE_FETCH_FUNC(method, u64)
165
166 DECLARE_BASIC_FETCH_FUNCS(reg);
167 #define fetch_reg_string NULL
168 #define fetch_reg_string_size NULL
169
170 DECLARE_BASIC_FETCH_FUNCS(retval);
171 #define fetch_retval_string NULL
172 #define fetch_retval_string_size NULL
173
174 DECLARE_BASIC_FETCH_FUNCS(symbol);
175 DECLARE_FETCH_FUNC(symbol, string);
176 DECLARE_FETCH_FUNC(symbol, string_size);
177
178 DECLARE_BASIC_FETCH_FUNCS(deref);
179 DECLARE_FETCH_FUNC(deref, string);
180 DECLARE_FETCH_FUNC(deref, string_size);
181
182 DECLARE_BASIC_FETCH_FUNCS(bitfield);
183 #define fetch_bitfield_string NULL
184 #define fetch_bitfield_string_size NULL
185
186 /*
187 * Define macro for basic types - we don't need to define s* types, because
188 * we have to care only about bitwidth at recording time.
189 */
190 #define DEFINE_BASIC_FETCH_FUNCS(method) \
191 DEFINE_FETCH_##method(u8) \
192 DEFINE_FETCH_##method(u16) \
193 DEFINE_FETCH_##method(u32) \
194 DEFINE_FETCH_##method(u64)
195
196 /* Default (unsigned long) fetch type */
197 #define __DEFAULT_FETCH_TYPE(t) u##t
198 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
199 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
200 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
201
202 #define ASSIGN_FETCH_FUNC(method, type) \
203 [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
204
205 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
206 {.name = _name, \
207 .size = _size, \
208 .is_signed = sign, \
209 .print = PRINT_TYPE_FUNC_NAME(ptype), \
210 .fmt = PRINT_TYPE_FMT_NAME(ptype), \
211 .fmttype = _fmttype, \
212 .fetch = { \
213 ASSIGN_FETCH_FUNC(reg, ftype), \
214 ASSIGN_FETCH_FUNC(stack, ftype), \
215 ASSIGN_FETCH_FUNC(retval, ftype), \
216 ASSIGN_FETCH_FUNC(memory, ftype), \
217 ASSIGN_FETCH_FUNC(symbol, ftype), \
218 ASSIGN_FETCH_FUNC(deref, ftype), \
219 ASSIGN_FETCH_FUNC(bitfield, ftype), \
220 ASSIGN_FETCH_FUNC(file_offset, ftype), \
221 } \
222 }
223
224 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
225 __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
226
227 #define ASSIGN_FETCH_TYPE_END {}
228
229 #define FETCH_TYPE_STRING 0
230 #define FETCH_TYPE_STRSIZE 1
231
232 #ifdef CONFIG_KPROBE_EVENT
233 struct symbol_cache;
234 unsigned long update_symbol_cache(struct symbol_cache *sc);
235 void free_symbol_cache(struct symbol_cache *sc);
236 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
237 #else
238 /* uprobes do not support symbol fetch methods */
239 #define fetch_symbol_u8 NULL
240 #define fetch_symbol_u16 NULL
241 #define fetch_symbol_u32 NULL
242 #define fetch_symbol_u64 NULL
243 #define fetch_symbol_string NULL
244 #define fetch_symbol_string_size NULL
245
246 struct symbol_cache {
247 };
update_symbol_cache(struct symbol_cache * sc)248 static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
249 {
250 return 0;
251 }
252
free_symbol_cache(struct symbol_cache * sc)253 static inline void __used free_symbol_cache(struct symbol_cache *sc)
254 {
255 }
256
257 static inline struct symbol_cache * __used
alloc_symbol_cache(const char * sym,long offset)258 alloc_symbol_cache(const char *sym, long offset)
259 {
260 return NULL;
261 }
262 #endif /* CONFIG_KPROBE_EVENT */
263
264 struct probe_arg {
265 struct fetch_param fetch;
266 struct fetch_param fetch_size;
267 unsigned int offset; /* Offset from argument entry */
268 const char *name; /* Name of this argument */
269 const char *comm; /* Command of this argument */
270 const struct fetch_type *type; /* Type of this argument */
271 };
272
273 struct trace_probe {
274 unsigned int flags; /* For TP_FLAG_* */
275 struct trace_event_class class;
276 struct trace_event_call call;
277 struct list_head files;
278 ssize_t size; /* trace entry size */
279 unsigned int nr_args;
280 struct probe_arg args[];
281 };
282
283 struct event_file_link {
284 struct trace_event_file *file;
285 struct list_head list;
286 };
287
trace_probe_is_enabled(struct trace_probe * tp)288 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
289 {
290 return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
291 }
292
trace_probe_is_registered(struct trace_probe * tp)293 static inline bool trace_probe_is_registered(struct trace_probe *tp)
294 {
295 return !!(tp->flags & TP_FLAG_REGISTERED);
296 }
297
call_fetch(struct fetch_param * fprm,struct pt_regs * regs,void * dest)298 static nokprobe_inline void call_fetch(struct fetch_param *fprm,
299 struct pt_regs *regs, void *dest)
300 {
301 return fprm->fn(regs, fprm->data, dest);
302 }
303
304 /* Check the name is good for event/group/fields */
is_good_name(const char * name)305 static inline bool is_good_name(const char *name)
306 {
307 if (!isalpha(*name) && *name != '_')
308 return false;
309 while (*++name != '\0') {
310 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
311 return false;
312 }
313 return true;
314 }
315
316 static inline struct event_file_link *
find_event_file_link(struct trace_probe * tp,struct trace_event_file * file)317 find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
318 {
319 struct event_file_link *link;
320
321 list_for_each_entry(link, &tp->files, list)
322 if (link->file == file)
323 return link;
324
325 return NULL;
326 }
327
328 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
329 struct probe_arg *parg, bool is_return, bool is_kprobe,
330 const struct fetch_type *ftbl);
331
332 extern int traceprobe_conflict_field_name(const char *name,
333 struct probe_arg *args, int narg);
334
335 extern void traceprobe_update_arg(struct probe_arg *arg);
336 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
337
338 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
339
340 extern ssize_t traceprobe_probes_write(struct file *file,
341 const char __user *buffer, size_t count, loff_t *ppos,
342 int (*createfn)(int, char**));
343
344 extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
345
346 /* Sum up total data length for dynamic arraies (strings) */
347 static nokprobe_inline int
__get_data_size(struct trace_probe * tp,struct pt_regs * regs)348 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
349 {
350 int i, ret = 0;
351 u32 len;
352
353 for (i = 0; i < tp->nr_args; i++)
354 if (unlikely(tp->args[i].fetch_size.fn)) {
355 call_fetch(&tp->args[i].fetch_size, regs, &len);
356 ret += len;
357 }
358
359 return ret;
360 }
361
362 /* Store the value of each argument */
363 static nokprobe_inline void
store_trace_args(int ent_size,struct trace_probe * tp,struct pt_regs * regs,u8 * data,int maxlen)364 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
365 u8 *data, int maxlen)
366 {
367 int i;
368 u32 end = tp->size;
369 u32 *dl; /* Data (relative) location */
370
371 for (i = 0; i < tp->nr_args; i++) {
372 if (unlikely(tp->args[i].fetch_size.fn)) {
373 /*
374 * First, we set the relative location and
375 * maximum data length to *dl
376 */
377 dl = (u32 *)(data + tp->args[i].offset);
378 *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
379 /* Then try to fetch string or dynamic array data */
380 call_fetch(&tp->args[i].fetch, regs, dl);
381 /* Reduce maximum length */
382 end += get_rloc_len(*dl);
383 maxlen -= get_rloc_len(*dl);
384 /* Trick here, convert data_rloc to data_loc */
385 *dl = convert_rloc_to_loc(*dl,
386 ent_size + tp->args[i].offset);
387 } else
388 /* Just fetching data normally */
389 call_fetch(&tp->args[i].fetch, regs,
390 data + tp->args[i].offset);
391 }
392 }
393
394 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
395