2 * Common code for probe-based Dynamic events.
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.
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.
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
17 * This code was copied from kernel/trace/trace_kprobe.c written by
18 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
20 * Updates to make this generic:
21 * Copyright (C) IBM Corporation, 2010-2011
22 * Author: Srikar Dronamraju
25 #include "trace_probe.h"
27 const char *reserved_field_names[] = {
30 "common_preempt_count",
38 /* Printing function type */
39 #define PRINT_TYPE_FUNC_NAME(type) print_type_##type
40 #define PRINT_TYPE_FMT_NAME(type) print_type_format_##type
42 /* Printing in basic type function template */
43 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast) \
44 static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, \
46 void *data, void *ent)\
48 return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
50 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
52 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
53 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
54 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
55 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
56 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
57 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
58 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
59 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
61 static inline void *get_rloc_data(u32 *dl)
63 return (u8 *)dl + get_rloc_offs(*dl);
66 /* For data_loc conversion */
67 static inline void *get_loc_data(u32 *dl, void *ent)
69 return (u8 *)ent + get_rloc_offs(*dl);
72 /* For defining macros, define string/string_size types */
74 typedef u32 string_size;
76 /* Print type function for string type */
77 static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
79 void *data, void *ent)
81 int len = *(u32 *)data >> 16;
84 return trace_seq_printf(s, " %s=(fault)", name);
86 return trace_seq_printf(s, " %s=\"%s\"", name,
87 (const char *)get_loc_data(data, ent));
90 static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
92 #define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
94 * Define macro for basic types - we don't need to define s* types, because
95 * we have to care only about bitwidth at recording time.
97 #define DEFINE_BASIC_FETCH_FUNCS(method) \
98 DEFINE_FETCH_##method(u8) \
99 DEFINE_FETCH_##method(u16) \
100 DEFINE_FETCH_##method(u32) \
101 DEFINE_FETCH_##method(u64)
103 #define CHECK_FETCH_FUNCS(method, fn) \
104 (((FETCH_FUNC_NAME(method, u8) == fn) || \
105 (FETCH_FUNC_NAME(method, u16) == fn) || \
106 (FETCH_FUNC_NAME(method, u32) == fn) || \
107 (FETCH_FUNC_NAME(method, u64) == fn) || \
108 (FETCH_FUNC_NAME(method, string) == fn) || \
109 (FETCH_FUNC_NAME(method, string_size) == fn)) \
112 /* Data fetch function templates */
113 #define DEFINE_FETCH_reg(type) \
114 static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, \
115 void *offset, void *dest) \
117 *(type *)dest = (type)regs_get_register(regs, \
118 (unsigned int)((unsigned long)offset)); \
120 DEFINE_BASIC_FETCH_FUNCS(reg)
121 /* No string on the register */
122 #define fetch_reg_string NULL
123 #define fetch_reg_string_size NULL
125 #define DEFINE_FETCH_stack(type) \
126 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
127 void *offset, void *dest) \
129 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
130 (unsigned int)((unsigned long)offset)); \
132 DEFINE_BASIC_FETCH_FUNCS(stack)
133 /* No string on the stack entry */
134 #define fetch_stack_string NULL
135 #define fetch_stack_string_size NULL
137 #define DEFINE_FETCH_retval(type) \
138 static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
139 void *dummy, void *dest) \
141 *(type *)dest = (type)regs_return_value(regs); \
143 DEFINE_BASIC_FETCH_FUNCS(retval)
144 /* No string on the retval */
145 #define fetch_retval_string NULL
146 #define fetch_retval_string_size NULL
148 #define DEFINE_FETCH_memory(type) \
149 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
150 void *addr, void *dest) \
153 if (probe_kernel_address(addr, retval)) \
156 *(type *)dest = retval; \
158 DEFINE_BASIC_FETCH_FUNCS(memory)
160 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
161 * length and relative data location.
163 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
164 void *addr, void *dest)
167 int maxlen = get_rloc_len(*(u32 *)dest);
168 u8 *dst = get_rloc_data(dest);
170 mm_segment_t old_fs = get_fs();
176 * Try to get string again, since the string can be changed while
183 ret = __copy_from_user_inatomic(dst++, src++, 1);
184 while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
190 if (ret < 0) { /* Failed to fetch string */
191 ((u8 *)get_rloc_data(dest))[0] = '\0';
192 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
194 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
195 get_rloc_offs(*(u32 *)dest));
199 /* Return the length of string -- including null terminal byte */
200 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
201 void *addr, void *dest)
212 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
214 } while (c && ret == 0 && len < MAX_STRING_SIZE);
219 if (ret < 0) /* Failed to check the length */
225 /* Memory fetching by symbol */
226 struct symbol_cache {
232 static unsigned long update_symbol_cache(struct symbol_cache *sc)
234 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
237 sc->addr += sc->offset;
242 static void free_symbol_cache(struct symbol_cache *sc)
248 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
250 struct symbol_cache *sc;
252 if (!sym || strlen(sym) == 0)
255 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
259 sc->symbol = kstrdup(sym, GFP_KERNEL);
265 update_symbol_cache(sc);
270 #define DEFINE_FETCH_symbol(type) \
271 static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
272 void *data, void *dest) \
274 struct symbol_cache *sc = data; \
276 fetch_memory_##type(regs, (void *)sc->addr, dest); \
280 DEFINE_BASIC_FETCH_FUNCS(symbol)
281 DEFINE_FETCH_symbol(string)
282 DEFINE_FETCH_symbol(string_size)
284 /* Dereference memory access function */
285 struct deref_fetch_param {
286 struct fetch_param orig;
290 #define DEFINE_FETCH_deref(type) \
291 static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
292 void *data, void *dest) \
294 struct deref_fetch_param *dprm = data; \
295 unsigned long addr; \
296 call_fetch(&dprm->orig, regs, &addr); \
298 addr += dprm->offset; \
299 fetch_memory_##type(regs, (void *)addr, dest); \
303 DEFINE_BASIC_FETCH_FUNCS(deref)
304 DEFINE_FETCH_deref(string)
305 DEFINE_FETCH_deref(string_size)
307 static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
309 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
310 update_deref_fetch_param(data->orig.data);
311 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
312 update_symbol_cache(data->orig.data);
315 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
317 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
318 free_deref_fetch_param(data->orig.data);
319 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
320 free_symbol_cache(data->orig.data);
324 /* Bitfield fetch function */
325 struct bitfield_fetch_param {
326 struct fetch_param orig;
327 unsigned char hi_shift;
328 unsigned char low_shift;
331 #define DEFINE_FETCH_bitfield(type) \
332 static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
333 void *data, void *dest) \
335 struct bitfield_fetch_param *bprm = data; \
337 call_fetch(&bprm->orig, regs, &buf); \
339 buf <<= bprm->hi_shift; \
340 buf >>= bprm->low_shift; \
342 *(type *)dest = buf; \
345 DEFINE_BASIC_FETCH_FUNCS(bitfield)
346 #define fetch_bitfield_string NULL
347 #define fetch_bitfield_string_size NULL
349 static __kprobes void
350 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
353 * Don't check the bitfield itself, because this must be the
354 * last fetch function.
356 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
357 update_deref_fetch_param(data->orig.data);
358 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
359 update_symbol_cache(data->orig.data);
362 static __kprobes void
363 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
366 * Don't check the bitfield itself, because this must be the
367 * last fetch function.
369 if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
370 free_deref_fetch_param(data->orig.data);
371 else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
372 free_symbol_cache(data->orig.data);
377 /* Default (unsigned long) fetch type */
378 #define __DEFAULT_FETCH_TYPE(t) u##t
379 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
380 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
381 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
383 #define ASSIGN_FETCH_FUNC(method, type) \
384 [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
386 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
390 .print = PRINT_TYPE_FUNC_NAME(ptype), \
391 .fmt = PRINT_TYPE_FMT_NAME(ptype), \
392 .fmttype = _fmttype, \
394 ASSIGN_FETCH_FUNC(reg, ftype), \
395 ASSIGN_FETCH_FUNC(stack, ftype), \
396 ASSIGN_FETCH_FUNC(retval, ftype), \
397 ASSIGN_FETCH_FUNC(memory, ftype), \
398 ASSIGN_FETCH_FUNC(symbol, ftype), \
399 ASSIGN_FETCH_FUNC(deref, ftype), \
400 ASSIGN_FETCH_FUNC(bitfield, ftype), \
404 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
405 __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
407 #define FETCH_TYPE_STRING 0
408 #define FETCH_TYPE_STRSIZE 1
410 /* Fetch type information table */
411 static const struct fetch_type fetch_type_table[] = {
413 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
414 sizeof(u32), 1, "__data_loc char[]"),
415 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
416 string_size, sizeof(u32), 0, "u32"),
418 ASSIGN_FETCH_TYPE(u8, u8, 0),
419 ASSIGN_FETCH_TYPE(u16, u16, 0),
420 ASSIGN_FETCH_TYPE(u32, u32, 0),
421 ASSIGN_FETCH_TYPE(u64, u64, 0),
422 ASSIGN_FETCH_TYPE(s8, u8, 1),
423 ASSIGN_FETCH_TYPE(s16, u16, 1),
424 ASSIGN_FETCH_TYPE(s32, u32, 1),
425 ASSIGN_FETCH_TYPE(s64, u64, 1),
428 static const struct fetch_type *find_fetch_type(const char *type)
433 type = DEFAULT_FETCH_TYPE_STR;
435 /* Special case: bitfield */
439 type = strchr(type, '/');
444 if (kstrtoul(type, 0, &bs))
449 return find_fetch_type("u8");
451 return find_fetch_type("u16");
453 return find_fetch_type("u32");
455 return find_fetch_type("u64");
461 for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
462 if (strcmp(type, fetch_type_table[i].name) == 0)
463 return &fetch_type_table[i];
469 /* Special function : only accept unsigned long */
470 static __kprobes void fetch_stack_address(struct pt_regs *regs,
471 void *dummy, void *dest)
473 *(unsigned long *)dest = kernel_stack_pointer(regs);
476 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
477 fetch_func_t orig_fn)
481 if (type != &fetch_type_table[FETCH_TYPE_STRING])
482 return NULL; /* Only string type needs size function */
484 for (i = 0; i < FETCH_MTD_END; i++)
485 if (type->fetch[i] == orig_fn)
486 return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
488 WARN_ON(1); /* This should not happen */
493 /* Split symbol and offset. */
494 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
502 tmp = strchr(symbol, '+');
504 /* skip sign because kstrtoul doesn't accept '+' */
505 ret = kstrtoul(tmp + 1, 0, offset);
516 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
518 static int parse_probe_vars(char *arg, const struct fetch_type *t,
519 struct fetch_param *f, bool is_return)
524 if (strcmp(arg, "retval") == 0) {
526 f->fn = t->fetch[FETCH_MTD_retval];
529 } else if (strncmp(arg, "stack", 5) == 0) {
530 if (arg[5] == '\0') {
531 if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
532 f->fn = fetch_stack_address;
535 } else if (isdigit(arg[5])) {
536 ret = kstrtoul(arg + 5, 10, ¶m);
537 if (ret || param > PARAM_MAX_STACK)
540 f->fn = t->fetch[FETCH_MTD_stack];
541 f->data = (void *)param;
551 /* Recursive argument parser */
552 static int parse_probe_arg(char *arg, const struct fetch_type *t,
553 struct fetch_param *f, bool is_return, bool is_kprobe)
562 /* Until uprobe_events supports only reg arguments */
563 if (!is_kprobe && arg[0] != '%')
568 ret = parse_probe_vars(arg + 1, t, f, is_return);
571 case '%': /* named register */
572 ret = regs_query_register_offset(arg + 1);
574 f->fn = t->fetch[FETCH_MTD_reg];
575 f->data = (void *)(unsigned long)ret;
580 case '@': /* memory or symbol */
581 if (isdigit(arg[1])) {
582 ret = kstrtoul(arg + 1, 0, ¶m);
586 f->fn = t->fetch[FETCH_MTD_memory];
587 f->data = (void *)param;
589 ret = traceprobe_split_symbol_offset(arg + 1, &offset);
593 f->data = alloc_symbol_cache(arg + 1, offset);
595 f->fn = t->fetch[FETCH_MTD_symbol];
599 case '+': /* deref memory */
600 arg++; /* Skip '+', because kstrtol() rejects it. */
602 tmp = strchr(arg, '(');
607 ret = kstrtol(arg, 0, &offset);
613 tmp = strrchr(arg, ')');
616 struct deref_fetch_param *dprm;
617 const struct fetch_type *t2;
619 t2 = find_fetch_type(NULL);
621 dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
626 dprm->offset = offset;
627 ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
632 f->fn = t->fetch[FETCH_MTD_deref];
633 f->data = (void *)dprm;
638 if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
639 pr_info("%s type has no corresponding fetch method.\n", t->name);
646 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
648 /* Bitfield type needs to be parsed into a fetch function */
649 static int __parse_bitfield_probe_arg(const char *bf,
650 const struct fetch_type *t,
651 struct fetch_param *f)
653 struct bitfield_fetch_param *bprm;
654 unsigned long bw, bo;
660 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
665 f->fn = t->fetch[FETCH_MTD_bitfield];
666 f->data = (void *)bprm;
667 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
669 if (bw == 0 || *tail != '@')
673 bo = simple_strtoul(bf, &tail, 0);
675 if (tail == bf || *tail != '/')
678 bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
679 bprm->low_shift = bprm->hi_shift + bo;
681 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
684 /* String length checking wrapper */
685 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
686 struct probe_arg *parg, bool is_return, bool is_kprobe)
691 if (strlen(arg) > MAX_ARGSTR_LEN) {
692 pr_info("Argument is too long.: %s\n", arg);
695 parg->comm = kstrdup(arg, GFP_KERNEL);
697 pr_info("Failed to allocate memory for command '%s'.\n", arg);
700 t = strchr(parg->comm, ':');
702 arg[t - parg->comm] = '\0';
705 parg->type = find_fetch_type(t);
707 pr_info("Unsupported type: %s\n", t);
710 parg->offset = *size;
711 *size += parg->type->size;
712 ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
714 if (ret >= 0 && t != NULL)
715 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
718 parg->fetch_size.fn = get_fetch_size_function(parg->type,
720 parg->fetch_size.data = parg->fetch.data;
726 /* Return 1 if name is reserved or already used by another argument */
727 int traceprobe_conflict_field_name(const char *name,
728 struct probe_arg *args, int narg)
732 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
733 if (strcmp(reserved_field_names[i], name) == 0)
736 for (i = 0; i < narg; i++)
737 if (strcmp(args[i].name, name) == 0)
743 void traceprobe_update_arg(struct probe_arg *arg)
745 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
746 update_bitfield_fetch_param(arg->fetch.data);
747 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
748 update_deref_fetch_param(arg->fetch.data);
749 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
750 update_symbol_cache(arg->fetch.data);
753 void traceprobe_free_probe_arg(struct probe_arg *arg)
755 if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
756 free_bitfield_fetch_param(arg->fetch.data);
757 else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
758 free_deref_fetch_param(arg->fetch.data);
759 else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
760 free_symbol_cache(arg->fetch.data);
766 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
773 argv = argv_split(GFP_KERNEL, buf, &argc);
778 ret = createfn(argc, argv);
785 #define WRITE_BUFSIZE 4096
787 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
788 size_t count, loff_t *ppos,
789 int (*createfn)(int, char **))
796 kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
800 while (done < count) {
803 if (size >= WRITE_BUFSIZE)
804 size = WRITE_BUFSIZE - 1;
806 if (copy_from_user(kbuf, buffer + done, size)) {
811 tmp = strchr(kbuf, '\n');
815 size = tmp - kbuf + 1;
816 } else if (done + size < count) {
817 pr_warning("Line length is too long: "
818 "Should be less than %d.", WRITE_BUFSIZE);
823 /* Remove comments */
824 tmp = strchr(kbuf, '#');
829 ret = traceprobe_command(kbuf, createfn);