tracing/probes: Implement 'memory' fetch method for uprobes
[linux-2.6-block.git] / 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
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84static inline void *get_rloc_data(u32 *dl)
85{
86 return (u8 *)dl + get_rloc_offs(*dl);
87}
88
89/* For data_loc conversion */
90static inline void *get_loc_data(u32 *dl, void *ent)
91{
92 return (u8 *)ent + get_rloc_offs(*dl);
93}
94
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95/* Data fetch function type */
96typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
97/* Printing function type */
98typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
99
100/* Fetch types */
101enum {
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_END,
110};
111
112/* Fetch type information table */
113struct fetch_type {
114 const char *name; /* Name of type */
115 size_t size; /* Byte size of type */
116 int is_signed; /* Signed flag */
117 print_type_func_t print; /* Print functions */
118 const char *fmt; /* Fromat string */
119 const char *fmttype; /* Name in format file */
120 /* Fetch functions */
121 fetch_func_t fetch[FETCH_MTD_END];
122};
123
124struct fetch_param {
125 fetch_func_t fn;
126 void *data;
127};
128
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129/* For defining macros, define string/string_size types */
130typedef u32 string;
131typedef u32 string_size;
132
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133#define PRINT_TYPE_FUNC_NAME(type) print_type_##type
134#define PRINT_TYPE_FMT_NAME(type) print_type_format_##type
135
136/* Printing in basic type function template */
137#define DECLARE_BASIC_PRINT_TYPE_FUNC(type) \
138__kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, \
139 const char *name, \
140 void *data, void *ent); \
141extern const char PRINT_TYPE_FMT_NAME(type)[]
142
143DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
144DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
145DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
146DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
147DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
148DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
149DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
150DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
151DECLARE_BASIC_PRINT_TYPE_FUNC(string);
152
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153#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
154
155/* Declare macro for basic types */
156#define DECLARE_FETCH_FUNC(method, type) \
157extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs, \
158 void *data, void *dest)
159
160#define DECLARE_BASIC_FETCH_FUNCS(method) \
161DECLARE_FETCH_FUNC(method, u8); \
162DECLARE_FETCH_FUNC(method, u16); \
163DECLARE_FETCH_FUNC(method, u32); \
164DECLARE_FETCH_FUNC(method, u64)
165
166DECLARE_BASIC_FETCH_FUNCS(reg);
167#define fetch_reg_string NULL
168#define fetch_reg_string_size NULL
169
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170DECLARE_BASIC_FETCH_FUNCS(retval);
171#define fetch_retval_string NULL
172#define fetch_retval_string_size NULL
173
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174DECLARE_BASIC_FETCH_FUNCS(symbol);
175DECLARE_FETCH_FUNC(symbol, string);
176DECLARE_FETCH_FUNC(symbol, string_size);
177
178DECLARE_BASIC_FETCH_FUNCS(deref);
179DECLARE_FETCH_FUNC(deref, string);
180DECLARE_FETCH_FUNC(deref, string_size);
181
182DECLARE_BASIC_FETCH_FUNCS(bitfield);
183#define fetch_bitfield_string NULL
184#define fetch_bitfield_string_size NULL
185
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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) \
191DEFINE_FETCH_##method(u8) \
192DEFINE_FETCH_##method(u16) \
193DEFINE_FETCH_##method(u32) \
194DEFINE_FETCH_##method(u64)
195
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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 = { \
213ASSIGN_FETCH_FUNC(reg, ftype), \
214ASSIGN_FETCH_FUNC(stack, ftype), \
215ASSIGN_FETCH_FUNC(retval, ftype), \
216ASSIGN_FETCH_FUNC(memory, ftype), \
217ASSIGN_FETCH_FUNC(symbol, ftype), \
218ASSIGN_FETCH_FUNC(deref, ftype), \
219ASSIGN_FETCH_FUNC(bitfield, ftype), \
220 } \
221 }
222
223#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
224 __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
225
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226#define ASSIGN_FETCH_TYPE_END {}
227
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228#define FETCH_TYPE_STRING 0
229#define FETCH_TYPE_STRSIZE 1
230
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231/*
232 * Fetch type information table.
233 * It's declared as a weak symbol due to conditional compilation.
234 */
235extern __weak const struct fetch_type kprobes_fetch_type_table[];
236extern __weak const struct fetch_type uprobes_fetch_type_table[];
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238#ifdef CONFIG_KPROBE_EVENT
239struct symbol_cache;
240unsigned long update_symbol_cache(struct symbol_cache *sc);
241void free_symbol_cache(struct symbol_cache *sc);
242struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
243#else
244struct symbol_cache {
245};
246static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
247{
248 return 0;
249}
250
251static inline void __used free_symbol_cache(struct symbol_cache *sc)
252{
253}
254
255static inline struct symbol_cache * __used
256alloc_symbol_cache(const char *sym, long offset)
257{
258 return NULL;
259}
260#endif /* CONFIG_KPROBE_EVENT */
261
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262struct probe_arg {
263 struct fetch_param fetch;
264 struct fetch_param fetch_size;
265 unsigned int offset; /* Offset from argument entry */
266 const char *name; /* Name of this argument */
267 const char *comm; /* Command of this argument */
268 const struct fetch_type *type; /* Type of this argument */
269};
270
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271struct trace_probe {
272 unsigned int flags; /* For TP_FLAG_* */
273 struct ftrace_event_class class;
274 struct ftrace_event_call call;
275 struct list_head files;
276 ssize_t size; /* trace entry size */
277 unsigned int nr_args;
278 struct probe_arg args[];
279};
280
281static inline bool trace_probe_is_enabled(struct trace_probe *tp)
282{
283 return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
284}
285
286static inline bool trace_probe_is_registered(struct trace_probe *tp)
287{
288 return !!(tp->flags & TP_FLAG_REGISTERED);
289}
290
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291static inline __kprobes void call_fetch(struct fetch_param *fprm,
292 struct pt_regs *regs, void *dest)
293{
294 return fprm->fn(regs, fprm->data, dest);
295}
296
297/* Check the name is good for event/group/fields */
298static inline int is_good_name(const char *name)
299{
300 if (!isalpha(*name) && *name != '_')
301 return 0;
302 while (*++name != '\0') {
303 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
304 return 0;
305 }
306 return 1;
307}
308
309extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
f3f096cf 310 struct probe_arg *parg, bool is_return, bool is_kprobe);
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311
312extern int traceprobe_conflict_field_name(const char *name,
313 struct probe_arg *args, int narg);
314
315extern void traceprobe_update_arg(struct probe_arg *arg);
316extern void traceprobe_free_probe_arg(struct probe_arg *arg);
317
318extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
319
320extern ssize_t traceprobe_probes_write(struct file *file,
321 const char __user *buffer, size_t count, loff_t *ppos,
322 int (*createfn)(int, char**));
323
324extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
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325
326/* Sum up total data length for dynamic arraies (strings) */
327static inline __kprobes int
328__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
329{
330 int i, ret = 0;
331 u32 len;
332
333 for (i = 0; i < tp->nr_args; i++)
334 if (unlikely(tp->args[i].fetch_size.fn)) {
335 call_fetch(&tp->args[i].fetch_size, regs, &len);
336 ret += len;
337 }
338
339 return ret;
340}
341
342/* Store the value of each argument */
343static inline __kprobes void
344store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
345 u8 *data, int maxlen)
346{
347 int i;
348 u32 end = tp->size;
349 u32 *dl; /* Data (relative) location */
350
351 for (i = 0; i < tp->nr_args; i++) {
352 if (unlikely(tp->args[i].fetch_size.fn)) {
353 /*
354 * First, we set the relative location and
355 * maximum data length to *dl
356 */
357 dl = (u32 *)(data + tp->args[i].offset);
358 *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
359 /* Then try to fetch string or dynamic array data */
360 call_fetch(&tp->args[i].fetch, regs, dl);
361 /* Reduce maximum length */
362 end += get_rloc_len(*dl);
363 maxlen -= get_rloc_len(*dl);
364 /* Trick here, convert data_rloc to data_loc */
365 *dl = convert_rloc_to_loc(*dl,
366 ent_size + tp->args[i].offset);
367 } else
368 /* Just fetching data normally */
369 call_fetch(&tp->args[i].fetch, regs,
370 data + tp->args[i].offset);
371 }
372}
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373
374extern int set_print_fmt(struct trace_probe *tp, bool is_return);