Merge tag 'trace-v4.19-rc8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rosted...
[muen/linux.git] / kernel / trace / trace_probe.h
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Common header file for probe-based Dynamic events.
4  *
5  * This code was copied from kernel/trace/trace_kprobe.h written by
6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
7  *
8  * Updates to make this generic:
9  * Copyright (C) IBM Corporation, 2010-2011
10  * Author:     Srikar Dronamraju
11  */
12
13 #include <linux/seq_file.h>
14 #include <linux/slab.h>
15 #include <linux/smp.h>
16 #include <linux/tracefs.h>
17 #include <linux/types.h>
18 #include <linux/string.h>
19 #include <linux/ctype.h>
20 #include <linux/ptrace.h>
21 #include <linux/perf_event.h>
22 #include <linux/kprobes.h>
23 #include <linux/stringify.h>
24 #include <linux/limits.h>
25 #include <linux/uaccess.h>
26 #include <asm/bitsperlong.h>
27
28 #include "trace.h"
29 #include "trace_output.h"
30
31 #define MAX_TRACE_ARGS          128
32 #define MAX_ARGSTR_LEN          63
33 #define MAX_STRING_SIZE         PATH_MAX
34
35 /* Reserved field names */
36 #define FIELD_STRING_IP         "__probe_ip"
37 #define FIELD_STRING_RETIP      "__probe_ret_ip"
38 #define FIELD_STRING_FUNC       "__probe_func"
39
40 #undef DEFINE_FIELD
41 #define DEFINE_FIELD(type, item, name, is_signed)                       \
42         do {                                                            \
43                 ret = trace_define_field(event_call, #type, name,       \
44                                          offsetof(typeof(field), item), \
45                                          sizeof(field.item), is_signed, \
46                                          FILTER_OTHER);                 \
47                 if (ret)                                                \
48                         return ret;                                     \
49         } while (0)
50
51
52 /* Flags for trace_probe */
53 #define TP_FLAG_TRACE           1
54 #define TP_FLAG_PROFILE         2
55 #define TP_FLAG_REGISTERED      4
56
57
58 /* data_rloc: data relative location, compatible with u32 */
59 #define make_data_rloc(len, roffs)      \
60         (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
61 #define get_rloc_len(dl)                ((u32)(dl) >> 16)
62 #define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
63
64 /*
65  * Convert data_rloc to data_loc:
66  *  data_rloc stores the offset from data_rloc itself, but data_loc
67  *  stores the offset from event entry.
68  */
69 #define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
70
71 static nokprobe_inline void *get_rloc_data(u32 *dl)
72 {
73         return (u8 *)dl + get_rloc_offs(*dl);
74 }
75
76 /* For data_loc conversion */
77 static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
78 {
79         return (u8 *)ent + get_rloc_offs(*dl);
80 }
81
82 /* Data fetch function type */
83 typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
84 /* Printing function type */
85 typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
86
87 /* Fetch types */
88 enum {
89         FETCH_MTD_reg = 0,
90         FETCH_MTD_stack,
91         FETCH_MTD_retval,
92         FETCH_MTD_comm,
93         FETCH_MTD_memory,
94         FETCH_MTD_symbol,
95         FETCH_MTD_deref,
96         FETCH_MTD_bitfield,
97         FETCH_MTD_file_offset,
98         FETCH_MTD_END,
99 };
100
101 /* Fetch type information table */
102 struct fetch_type {
103         const char              *name;          /* Name of type */
104         size_t                  size;           /* Byte size of type */
105         int                     is_signed;      /* Signed flag */
106         print_type_func_t       print;          /* Print functions */
107         const char              *fmt;           /* Fromat string */
108         const char              *fmttype;       /* Name in format file */
109         /* Fetch functions */
110         fetch_func_t            fetch[FETCH_MTD_END];
111 };
112
113 struct fetch_param {
114         fetch_func_t            fn;
115         void                    *data;
116 };
117
118 /* For defining macros, define string/string_size types */
119 typedef u32 string;
120 typedef u32 string_size;
121
122 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
123 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
124
125 /* Printing  in basic type function template */
126 #define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
127 int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
128                                 void *data, void *ent);                 \
129 extern const char PRINT_TYPE_FMT_NAME(type)[]
130
131 DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
132 DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
133 DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
134 DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
135 DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
136 DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
137 DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
138 DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
139 DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
140 DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
141 DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
142 DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
143
144 DECLARE_BASIC_PRINT_TYPE_FUNC(string);
145
146 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
147
148 /* Declare macro for basic types */
149 #define DECLARE_FETCH_FUNC(method, type)                                \
150 extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
151                                           void *data, void *dest)
152
153 #define DECLARE_BASIC_FETCH_FUNCS(method)       \
154 DECLARE_FETCH_FUNC(method, u8);                 \
155 DECLARE_FETCH_FUNC(method, u16);                \
156 DECLARE_FETCH_FUNC(method, u32);                \
157 DECLARE_FETCH_FUNC(method, u64)
158
159 DECLARE_BASIC_FETCH_FUNCS(reg);
160 #define fetch_reg_string                        NULL
161 #define fetch_reg_string_size                   NULL
162
163 DECLARE_BASIC_FETCH_FUNCS(retval);
164 #define fetch_retval_string                     NULL
165 #define fetch_retval_string_size                NULL
166
167 DECLARE_BASIC_FETCH_FUNCS(symbol);
168 DECLARE_FETCH_FUNC(symbol, string);
169 DECLARE_FETCH_FUNC(symbol, string_size);
170
171 DECLARE_BASIC_FETCH_FUNCS(deref);
172 DECLARE_FETCH_FUNC(deref, string);
173 DECLARE_FETCH_FUNC(deref, string_size);
174
175 DECLARE_BASIC_FETCH_FUNCS(bitfield);
176 #define fetch_bitfield_string                   NULL
177 #define fetch_bitfield_string_size              NULL
178
179 /* comm only makes sense as a string */
180 #define fetch_comm_u8           NULL
181 #define fetch_comm_u16          NULL
182 #define fetch_comm_u32          NULL
183 #define fetch_comm_u64          NULL
184 DECLARE_FETCH_FUNC(comm, string);
185 DECLARE_FETCH_FUNC(comm, string_size);
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) x##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(comm, ftype),                         \
218 ASSIGN_FETCH_FUNC(memory, ftype),                       \
219 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
220 ASSIGN_FETCH_FUNC(deref, ftype),                        \
221 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
222 ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
223           }                                             \
224         }
225
226 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
227         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
228
229 /* If ptype is an alias of atype, use this macro (show atype in format) */
230 #define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign)              \
231         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #atype)
232
233 #define ASSIGN_FETCH_TYPE_END {}
234
235 #define FETCH_TYPE_STRING       0
236 #define FETCH_TYPE_STRSIZE      1
237
238 #ifdef CONFIG_KPROBE_EVENTS
239 struct symbol_cache;
240 unsigned long update_symbol_cache(struct symbol_cache *sc);
241 void free_symbol_cache(struct symbol_cache *sc);
242 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
243 bool trace_kprobe_on_func_entry(struct trace_event_call *call);
244 bool trace_kprobe_error_injectable(struct trace_event_call *call);
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
271 static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
272 {
273         return false;
274 }
275
276 static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
277 {
278         return false;
279 }
280 #endif /* CONFIG_KPROBE_EVENTS */
281
282 struct probe_arg {
283         struct fetch_param      fetch;
284         struct fetch_param      fetch_size;
285         unsigned int            offset; /* Offset from argument entry */
286         const char              *name;  /* Name of this argument */
287         const char              *comm;  /* Command of this argument */
288         const struct fetch_type *type;  /* Type of this argument */
289 };
290
291 struct trace_probe {
292         unsigned int                    flags;  /* For TP_FLAG_* */
293         struct trace_event_class        class;
294         struct trace_event_call         call;
295         struct list_head                files;
296         ssize_t                         size;   /* trace entry size */
297         unsigned int                    nr_args;
298         struct probe_arg                args[];
299 };
300
301 struct event_file_link {
302         struct trace_event_file         *file;
303         struct list_head                list;
304 };
305
306 static inline bool trace_probe_is_enabled(struct trace_probe *tp)
307 {
308         return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
309 }
310
311 static inline bool trace_probe_is_registered(struct trace_probe *tp)
312 {
313         return !!(tp->flags & TP_FLAG_REGISTERED);
314 }
315
316 static nokprobe_inline void call_fetch(struct fetch_param *fprm,
317                                  struct pt_regs *regs, void *dest)
318 {
319         return fprm->fn(regs, fprm->data, dest);
320 }
321
322 /* Check the name is good for event/group/fields */
323 static inline bool is_good_name(const char *name)
324 {
325         if (!isalpha(*name) && *name != '_')
326                 return false;
327         while (*++name != '\0') {
328                 if (!isalpha(*name) && !isdigit(*name) && *name != '_')
329                         return false;
330         }
331         return true;
332 }
333
334 static inline struct event_file_link *
335 find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
336 {
337         struct event_file_link *link;
338
339         list_for_each_entry(link, &tp->files, list)
340                 if (link->file == file)
341                         return link;
342
343         return NULL;
344 }
345
346 extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
347                    struct probe_arg *parg, bool is_return, bool is_kprobe,
348                    const struct fetch_type *ftbl);
349
350 extern int traceprobe_conflict_field_name(const char *name,
351                                struct probe_arg *args, int narg);
352
353 extern void traceprobe_update_arg(struct probe_arg *arg);
354 extern void traceprobe_free_probe_arg(struct probe_arg *arg);
355
356 extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
357
358 /* Sum up total data length for dynamic arraies (strings) */
359 static nokprobe_inline int
360 __get_data_size(struct trace_probe *tp, struct pt_regs *regs)
361 {
362         int i, ret = 0;
363         u32 len;
364
365         for (i = 0; i < tp->nr_args; i++)
366                 if (unlikely(tp->args[i].fetch_size.fn)) {
367                         call_fetch(&tp->args[i].fetch_size, regs, &len);
368                         ret += len;
369                 }
370
371         return ret;
372 }
373
374 /* Store the value of each argument */
375 static nokprobe_inline void
376 store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
377                  u8 *data, int maxlen)
378 {
379         int i;
380         u32 end = tp->size;
381         u32 *dl;        /* Data (relative) location */
382
383         for (i = 0; i < tp->nr_args; i++) {
384                 if (unlikely(tp->args[i].fetch_size.fn)) {
385                         /*
386                          * First, we set the relative location and
387                          * maximum data length to *dl
388                          */
389                         dl = (u32 *)(data + tp->args[i].offset);
390                         *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
391                         /* Then try to fetch string or dynamic array data */
392                         call_fetch(&tp->args[i].fetch, regs, dl);
393                         /* Reduce maximum length */
394                         end += get_rloc_len(*dl);
395                         maxlen -= get_rloc_len(*dl);
396                         /* Trick here, convert data_rloc to data_loc */
397                         *dl = convert_rloc_to_loc(*dl,
398                                  ent_size + tp->args[i].offset);
399                 } else
400                         /* Just fetching data normally */
401                         call_fetch(&tp->args[i].fetch, regs,
402                                    data + tp->args[i].offset);
403         }
404 }
405
406 extern int set_print_fmt(struct trace_probe *tp, bool is_return);
407
408 #ifdef CONFIG_PERF_EVENTS
409 extern struct trace_event_call *
410 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
411                           bool is_return);
412 extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);
413
414 extern struct trace_event_call *
415 create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);
416 extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
417 #endif