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Root/kernel/trace/trace_kprobe.c

1	/*
2	* Kprobes-based tracing events
3	*
4	* Created by Masami Hiramatsu <mhiramat@redhat.com>
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License version 2 as
8	* published by the Free Software Foundation.
9	*
10	* This program is distributed in the hope that it will be useful,
11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13	* GNU General Public License for more details.
14	*
15	* You should have received a copy of the GNU General Public License
16	* along with this program; if not, write to the Free Software
17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18	*/
19
20	#include <linux/module.h>
21	#include <linux/uaccess.h>
22	#include <linux/kprobes.h>
23	#include <linux/seq_file.h>
24	#include <linux/slab.h>
25	#include <linux/smp.h>
26	#include <linux/debugfs.h>
27	#include <linux/types.h>
28	#include <linux/string.h>
29	#include <linux/ctype.h>
30	#include <linux/ptrace.h>
31	#include <linux/perf_event.h>
32	#include <linux/stringify.h>
33	#include <linux/limits.h>
34	#include <asm/bitsperlong.h>
35
36	#include "trace.h"
37	#include "trace_output.h"
38
39	#define MAX_TRACE_ARGS 128
40	#define MAX_ARGSTR_LEN 63
41	#define MAX_EVENT_NAME_LEN 64
42	#define MAX_STRING_SIZE PATH_MAX
43	#define KPROBE_EVENT_SYSTEM "kprobes"
44
45	/* Reserved field names */
46	#define FIELD_STRING_IP "__probe_ip"
47	#define FIELD_STRING_RETIP "__probe_ret_ip"
48	#define FIELD_STRING_FUNC "__probe_func"
49
50	const char *reserved_field_names[] = {
51	"common_type",
52	"common_flags",
53	"common_preempt_count",
54	"common_pid",
55	"common_tgid",
56	FIELD_STRING_IP,
57	FIELD_STRING_RETIP,
58	FIELD_STRING_FUNC,
59	};
60
61	/* Printing function type */
62	typedef int (print_type_func_t)(struct trace_seq , const char , void ,
63	void *);
64	#define PRINT_TYPE_FUNC_NAME(type) print_type_##type
65	#define PRINT_TYPE_FMT_NAME(type) print_type_format_##type
66
67	/* Printing in basic type function template */
68	#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast) \
69	static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, \
70	const char *name, \
71	void data, void ent)\
72	{ \
73	return trace_seq_printf(s, " %s=" fmt, name, (cast)(type )data);\
74	} \
75	static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
76
77	DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
78	DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
79	DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
80	DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
81	DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
82	DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
83	DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
84	DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
85
86	/* data_rloc: data relative location, compatible with u32 */
87	#define make_data_rloc(len, roffs) \
88	(((u32)(len) << 16) \| ((u32)(roffs) & 0xffff))
89	#define get_rloc_len(dl) ((u32)(dl) >> 16)
90	#define get_rloc_offs(dl) ((u32)(dl) & 0xffff)
91
92	static inline void get_rloc_data(u32 dl)
93	{
94	return (u8 )dl + get_rloc_offs(dl);
95	}
96
97	/* For data_loc conversion */
98	static inline void get_loc_data(u32 dl, void *ent)
99	{
100	return (u8 )ent + get_rloc_offs(dl);
101	}
102
103	/*
104	* Convert data_rloc to data_loc:
105	* data_rloc stores the offset from data_rloc itself, but data_loc
106	* stores the offset from event entry.
107	*/
108	#define convert_rloc_to_loc(dl, offs) ((u32)(dl) + (offs))
109
110	/* For defining macros, define string/string_size types */
111	typedef u32 string;
112	typedef u32 string_size;
113
114	/* Print type function for string type */
115	static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
116	const char *name,
117	void data, void ent)
118	{
119	int len = (u32 )data >> 16;
120
121	if (!len)
122	return trace_seq_printf(s, " %s=(fault)", name);
123	else
124	return trace_seq_printf(s, " %s=\"%s\"", name,
125	(const char *)get_loc_data(data, ent));
126	}
127	static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
128
129	/* Data fetch function type */
130	typedef void (fetch_func_t)(struct pt_regs , void , void );
131
132	struct fetch_param {
133	fetch_func_t fn;
134	void *data;
135	};
136
137	static __kprobes void call_fetch(struct fetch_param *fprm,
138	struct pt_regs regs, void dest)
139	{
140	return fprm->fn(regs, fprm->data, dest);
141	}
142
143	#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
144	/*
145	* Define macro for basic types - we don't need to define s* types, because
146	* we have to care only about bitwidth at recording time.
147	*/
148	#define DEFINE_BASIC_FETCH_FUNCS(method) \
149	DEFINE_FETCH_##method(u8) \
150	DEFINE_FETCH_##method(u16) \
151	DEFINE_FETCH_##method(u32) \
152	DEFINE_FETCH_##method(u64)
153
154	#define CHECK_FETCH_FUNCS(method, fn) \
155	(((FETCH_FUNC_NAME(method, u8) == fn) \|\| \
156	(FETCH_FUNC_NAME(method, u16) == fn) \|\| \
157	(FETCH_FUNC_NAME(method, u32) == fn) \|\| \
158	(FETCH_FUNC_NAME(method, u64) == fn) \|\| \
159	(FETCH_FUNC_NAME(method, string) == fn) \|\| \
160	(FETCH_FUNC_NAME(method, string_size) == fn)) \
161	&& (fn != NULL))
162
163	/* Data fetch function templates */
164	#define DEFINE_FETCH_reg(type) \
165	static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, \
166	void offset, void dest) \
167	{ \
168	(type )dest = (type)regs_get_register(regs, \
169	(unsigned int)((unsigned long)offset)); \
170	}
171	DEFINE_BASIC_FETCH_FUNCS(reg)
172	/* No string on the register */
173	#define fetch_reg_string NULL
174	#define fetch_reg_string_size NULL
175
176	#define DEFINE_FETCH_stack(type) \
177	static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
178	void offset, void dest) \
179	{ \
180	(type )dest = (type)regs_get_kernel_stack_nth(regs, \
181	(unsigned int)((unsigned long)offset)); \
182	}
183	DEFINE_BASIC_FETCH_FUNCS(stack)
184	/* No string on the stack entry */
185	#define fetch_stack_string NULL
186	#define fetch_stack_string_size NULL
187
188	#define DEFINE_FETCH_retval(type) \
189	static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
190	void dummy, void dest) \
191	{ \
192	(type )dest = (type)regs_return_value(regs); \
193	}
194	DEFINE_BASIC_FETCH_FUNCS(retval)
195	/* No string on the retval */
196	#define fetch_retval_string NULL
197	#define fetch_retval_string_size NULL
198
199	#define DEFINE_FETCH_memory(type) \
200	static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
201	void addr, void dest) \
202	{ \
203	type retval; \
204	if (probe_kernel_address(addr, retval)) \
205	(type )dest = 0; \
206	else \
207	(type )dest = retval; \
208	}
209	DEFINE_BASIC_FETCH_FUNCS(memory)
210	/*
211	* Fetch a null-terminated string. Caller MUST set (u32 )dest with max
212	* length and relative data location.
213	*/
214	static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
215	void addr, void dest)
216	{
217	long ret;
218	int maxlen = get_rloc_len((u32 )dest);
219	u8 *dst = get_rloc_data(dest);
220	u8 *src = addr;
221	mm_segment_t old_fs = get_fs();
222	if (!maxlen)
223	return;
224	/*
225	* Try to get string again, since the string can be changed while
226	* probing.
227	*/
228	set_fs(KERNEL_DS);
229	pagefault_disable();
230	do
231	ret = __copy_from_user_inatomic(dst++, src++, 1);
232	while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
233	dst[-1] = '\0';
234	pagefault_enable();
235	set_fs(old_fs);
236
237	if (ret < 0) { /* Failed to fetch string */
238	((u8 *)get_rloc_data(dest))[0] = '\0';
239	(u32 )dest = make_data_rloc(0, get_rloc_offs((u32 )dest));
240	} else
241	(u32 )dest = make_data_rloc(src - (u8 *)addr,
242	get_rloc_offs((u32 )dest));
243	}
244	/* Return the length of string -- including null terminal byte */
245	static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
246	void addr, void dest)
247	{
248	int ret, len = 0;
249	u8 c;
250	mm_segment_t old_fs = get_fs();
251
252	set_fs(KERNEL_DS);
253	pagefault_disable();
254	do {
255	ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
256	len++;
257	} while (c && ret == 0 && len < MAX_STRING_SIZE);
258	pagefault_enable();
259	set_fs(old_fs);
260
261	if (ret < 0) /* Failed to check the length */
262	(u32 )dest = 0;
263	else
264	(u32 )dest = len;
265	}
266
267	/* Memory fetching by symbol */
268	struct symbol_cache {
269	char *symbol;
270	long offset;
271	unsigned long addr;
272	};
273
274	static unsigned long update_symbol_cache(struct symbol_cache *sc)
275	{
276	sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
277	if (sc->addr)
278	sc->addr += sc->offset;
279	return sc->addr;
280	}
281
282	static void free_symbol_cache(struct symbol_cache *sc)
283	{
284	kfree(sc->symbol);
285	kfree(sc);
286	}
287
288	static struct symbol_cache alloc_symbol_cache(const char sym, long offset)
289	{
290	struct symbol_cache *sc;
291
292	if (!sym \|\| strlen(sym) == 0)
293	return NULL;
294	sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
295	if (!sc)
296	return NULL;
297
298	sc->symbol = kstrdup(sym, GFP_KERNEL);
299	if (!sc->symbol) {
300	kfree(sc);
301	return NULL;
302	}
303	sc->offset = offset;
304
305	update_symbol_cache(sc);
306	return sc;
307	}
308
309	#define DEFINE_FETCH_symbol(type) \
310	static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
311	void data, void dest) \
312	{ \
313	struct symbol_cache *sc = data; \
314	if (sc->addr) \
315	fetch_memory_##type(regs, (void *)sc->addr, dest); \
316	else \
317	(type )dest = 0; \
318	}
319	DEFINE_BASIC_FETCH_FUNCS(symbol)
320	DEFINE_FETCH_symbol(string)
321	DEFINE_FETCH_symbol(string_size)
322
323	/* Dereference memory access function */
324	struct deref_fetch_param {
325	struct fetch_param orig;
326	long offset;
327	};
328
329	#define DEFINE_FETCH_deref(type) \
330	static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
331	void data, void dest) \
332	{ \
333	struct deref_fetch_param *dprm = data; \
334	unsigned long addr; \
335	call_fetch(&dprm->orig, regs, &addr); \
336	if (addr) { \
337	addr += dprm->offset; \
338	fetch_memory_##type(regs, (void *)addr, dest); \
339	} else \
340	(type )dest = 0; \
341	}
342	DEFINE_BASIC_FETCH_FUNCS(deref)
343	DEFINE_FETCH_deref(string)
344	DEFINE_FETCH_deref(string_size)
345
346	static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
347	{
348	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
349	free_deref_fetch_param(data->orig.data);
350	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
351	free_symbol_cache(data->orig.data);
352	kfree(data);
353	}
354
355	/* Bitfield fetch function */
356	struct bitfield_fetch_param {
357	struct fetch_param orig;
358	unsigned char hi_shift;
359	unsigned char low_shift;
360	};
361
362	#define DEFINE_FETCH_bitfield(type) \
363	static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
364	void data, void dest) \
365	{ \
366	struct bitfield_fetch_param *bprm = data; \
367	type buf = 0; \
368	call_fetch(&bprm->orig, regs, &buf); \
369	if (buf) { \
370	buf <<= bprm->hi_shift; \
371	buf >>= bprm->low_shift; \
372	} \
373	(type )dest = buf; \
374	}
375	DEFINE_BASIC_FETCH_FUNCS(bitfield)
376	#define fetch_bitfield_string NULL
377	#define fetch_bitfield_string_size NULL
378
379	static __kprobes void
380	free_bitfield_fetch_param(struct bitfield_fetch_param *data)
381	{
382	/*
383	* Don't check the bitfield itself, because this must be the
384	* last fetch function.
385	*/
386	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
387	free_deref_fetch_param(data->orig.data);
388	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
389	free_symbol_cache(data->orig.data);
390	kfree(data);
391	}
392	/* Default (unsigned long) fetch type */
393	#define __DEFAULT_FETCH_TYPE(t) u##t
394	#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
395	#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
396	#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
397
398	/* Fetch types */
399	enum {
400	FETCH_MTD_reg = 0,
401	FETCH_MTD_stack,
402	FETCH_MTD_retval,
403	FETCH_MTD_memory,
404	FETCH_MTD_symbol,
405	FETCH_MTD_deref,
406	FETCH_MTD_bitfield,
407	FETCH_MTD_END,
408	};
409
410	#define ASSIGN_FETCH_FUNC(method, type) \
411	[FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
412
413	#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
414	{.name = _name, \
415	.size = _size, \
416	.is_signed = sign, \
417	.print = PRINT_TYPE_FUNC_NAME(ptype), \
418	.fmt = PRINT_TYPE_FMT_NAME(ptype), \
419	.fmttype = _fmttype, \
420	.fetch = { \
421	ASSIGN_FETCH_FUNC(reg, ftype), \
422	ASSIGN_FETCH_FUNC(stack, ftype), \
423	ASSIGN_FETCH_FUNC(retval, ftype), \
424	ASSIGN_FETCH_FUNC(memory, ftype), \
425	ASSIGN_FETCH_FUNC(symbol, ftype), \
426	ASSIGN_FETCH_FUNC(deref, ftype), \
427	ASSIGN_FETCH_FUNC(bitfield, ftype), \
428	} \
429	}
430
431	#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
432	__ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
433
434	#define FETCH_TYPE_STRING 0
435	#define FETCH_TYPE_STRSIZE 1
436
437	/* Fetch type information table */
438	static const struct fetch_type {
439	const char name; / Name of type */
440	size_t size; /* Byte size of type */
441	int is_signed; /* Signed flag */
442	print_type_func_t print; /* Print functions */
443	const char fmt; / Fromat string */
444	const char fmttype; / Name in format file */
445	/* Fetch functions */
446	fetch_func_t fetch[FETCH_MTD_END];
447	} fetch_type_table[] = {
448	/* Special types */
449	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
450	sizeof(u32), 1, "__data_loc char[]"),
451	[FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
452	string_size, sizeof(u32), 0, "u32"),
453	/* Basic types */
454	ASSIGN_FETCH_TYPE(u8, u8, 0),
455	ASSIGN_FETCH_TYPE(u16, u16, 0),
456	ASSIGN_FETCH_TYPE(u32, u32, 0),
457	ASSIGN_FETCH_TYPE(u64, u64, 0),
458	ASSIGN_FETCH_TYPE(s8, u8, 1),
459	ASSIGN_FETCH_TYPE(s16, u16, 1),
460	ASSIGN_FETCH_TYPE(s32, u32, 1),
461	ASSIGN_FETCH_TYPE(s64, u64, 1),
462	};
463
464	static const struct fetch_type find_fetch_type(const char type)
465	{
466	int i;
467
468	if (!type)
469	type = DEFAULT_FETCH_TYPE_STR;
470
471	/* Special case: bitfield */
472	if (*type == 'b') {
473	unsigned long bs;
474	type = strchr(type, '/');
475	if (!type)
476	goto fail;
477	type++;
478	if (strict_strtoul(type, 0, &bs))
479	goto fail;
480	switch (bs) {
481	case 8:
482	return find_fetch_type("u8");
483	case 16:
484	return find_fetch_type("u16");
485	case 32:
486	return find_fetch_type("u32");
487	case 64:
488	return find_fetch_type("u64");
489	default:
490	goto fail;
491	}
492	}
493
494	for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
495	if (strcmp(type, fetch_type_table[i].name) == 0)
496	return &fetch_type_table[i];
497	fail:
498	return NULL;
499	}
500
501	/* Special function : only accept unsigned long */
502	static __kprobes void fetch_stack_address(struct pt_regs *regs,
503	void dummy, void dest)
504	{
505	(unsigned long )dest = kernel_stack_pointer(regs);
506	}
507
508	static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
509	fetch_func_t orig_fn)
510	{
511	int i;
512
513	if (type != &fetch_type_table[FETCH_TYPE_STRING])
514	return NULL; /* Only string type needs size function */
515	for (i = 0; i < FETCH_MTD_END; i++)
516	if (type->fetch[i] == orig_fn)
517	return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
518
519	WARN_ON(1); /* This should not happen */
520	return NULL;
521	}
522
523	/**
524	* Kprobe event core functions
525	*/
526
527	struct probe_arg {
528	struct fetch_param fetch;
529	struct fetch_param fetch_size;
530	unsigned int offset; /* Offset from argument entry */
531	const char name; / Name of this argument */
532	const char comm; / Command of this argument */
533	const struct fetch_type type; / Type of this argument */
534	};
535
536	/* Flags for trace_probe */
537	#define TP_FLAG_TRACE 1
538	#define TP_FLAG_PROFILE 2
539
540	struct trace_probe {
541	struct list_head list;
542	struct kretprobe rp; /* Use rp.kp for kprobe use */
543	unsigned long nhit;
544	unsigned int flags; /* For TP_FLAG_* */
545	const char symbol; / symbol name */
546	struct ftrace_event_class class;
547	struct ftrace_event_call call;
548	ssize_t size; /* trace entry size */
549	unsigned int nr_args;
550	struct probe_arg args[];
551	};
552
553	#define SIZEOF_TRACE_PROBE(n) \
554	(offsetof(struct trace_probe, args) + \
555	(sizeof(struct probe_arg) * (n)))
556
557
558	static __kprobes int probe_is_return(struct trace_probe *tp)
559	{
560	return tp->rp.handler != NULL;
561	}
562
563	static __kprobes const char probe_symbol(struct trace_probe tp)
564	{
565	return tp->symbol ? tp->symbol : "unknown";
566	}
567
568	static int register_probe_event(struct trace_probe *tp);
569	static void unregister_probe_event(struct trace_probe *tp);
570
571	static DEFINE_MUTEX(probe_lock);
572	static LIST_HEAD(probe_list);
573
574	static int kprobe_dispatcher(struct kprobe kp, struct pt_regs regs);
575	static int kretprobe_dispatcher(struct kretprobe_instance *ri,
576	struct pt_regs *regs);
577
578	/* Check the name is good for event/group/fields */
579	static int is_good_name(const char *name)
580	{
581	if (!isalpha(name) && name != '_')
582	return 0;
583	while (*++name != '\0') {
584	if (!isalpha(name) && !isdigit(name) && *name != '_')
585	return 0;
586	}
587	return 1;
588	}
589
590	/*
591	* Allocate new trace_probe and initialize it (including kprobes).
592	*/
593	static struct trace_probe alloc_trace_probe(const char group,
594	const char *event,
595	void *addr,
596	const char *symbol,
597	unsigned long offs,
598	int nargs, int is_return)
599	{
600	struct trace_probe *tp;
601	int ret = -ENOMEM;
602
603	tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
604	if (!tp)
605	return ERR_PTR(ret);
606
607	if (symbol) {
608	tp->symbol = kstrdup(symbol, GFP_KERNEL);
609	if (!tp->symbol)
610	goto error;
611	tp->rp.kp.symbol_name = tp->symbol;
612	tp->rp.kp.offset = offs;
613	} else
614	tp->rp.kp.addr = addr;
615
616	if (is_return)
617	tp->rp.handler = kretprobe_dispatcher;
618	else
619	tp->rp.kp.pre_handler = kprobe_dispatcher;
620
621	if (!event \|\| !is_good_name(event)) {
622	ret = -EINVAL;
623	goto error;
624	}
625
626	tp->call.class = &tp->class;
627	tp->call.name = kstrdup(event, GFP_KERNEL);
628	if (!tp->call.name)
629	goto error;
630
631	if (!group \|\| !is_good_name(group)) {
632	ret = -EINVAL;
633	goto error;
634	}
635
636	tp->class.system = kstrdup(group, GFP_KERNEL);
637	if (!tp->class.system)
638	goto error;
639
640	INIT_LIST_HEAD(&tp->list);
641	return tp;
642	error:
643	kfree(tp->call.name);
644	kfree(tp->symbol);
645	kfree(tp);
646	return ERR_PTR(ret);
647	}
648
649	static void free_probe_arg(struct probe_arg *arg)
650	{
651	if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
652	free_bitfield_fetch_param(arg->fetch.data);
653	else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
654	free_deref_fetch_param(arg->fetch.data);
655	else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
656	free_symbol_cache(arg->fetch.data);
657	kfree(arg->name);
658	kfree(arg->comm);
659	}
660
661	static void free_trace_probe(struct trace_probe *tp)
662	{
663	int i;
664
665	for (i = 0; i < tp->nr_args; i++)
666	free_probe_arg(&tp->args[i]);
667
668	kfree(tp->call.class->system);
669	kfree(tp->call.name);
670	kfree(tp->symbol);
671	kfree(tp);
672	}
673
674	static struct trace_probe find_probe_event(const char event,
675	const char *group)
676	{
677	struct trace_probe *tp;
678
679	list_for_each_entry(tp, &probe_list, list)
680	if (strcmp(tp->call.name, event) == 0 &&
681	strcmp(tp->call.class->system, group) == 0)
682	return tp;
683	return NULL;
684	}
685
686	/* Unregister a trace_probe and probe_event: call with locking probe_lock */
687	static void unregister_trace_probe(struct trace_probe *tp)
688	{
689	if (probe_is_return(tp))
690	unregister_kretprobe(&tp->rp);
691	else
692	unregister_kprobe(&tp->rp.kp);
693	list_del(&tp->list);
694	unregister_probe_event(tp);
695	}
696
697	/* Register a trace_probe and probe_event */
698	static int register_trace_probe(struct trace_probe *tp)
699	{
700	struct trace_probe *old_tp;
701	int ret;
702
703	mutex_lock(&probe_lock);
704
705	/* register as an event */
706	old_tp = find_probe_event(tp->call.name, tp->call.class->system);
707	if (old_tp) {
708	/* delete old event */
709	unregister_trace_probe(old_tp);
710	free_trace_probe(old_tp);
711	}
712	ret = register_probe_event(tp);
713	if (ret) {
714	pr_warning("Failed to register probe event(%d)\n", ret);
715	goto end;
716	}
717
718	tp->rp.kp.flags \|= KPROBE_FLAG_DISABLED;
719	if (probe_is_return(tp))
720	ret = register_kretprobe(&tp->rp);
721	else
722	ret = register_kprobe(&tp->rp.kp);
723
724	if (ret) {
725	pr_warning("Could not insert probe(%d)\n", ret);
726	if (ret == -EILSEQ) {
727	pr_warning("Probing address(0x%p) is not an "
728	"instruction boundary.\n",
729	tp->rp.kp.addr);
730	ret = -EINVAL;
731	}
732	unregister_probe_event(tp);
733	} else
734	list_add_tail(&tp->list, &probe_list);
735	end:
736	mutex_unlock(&probe_lock);
737	return ret;
738	}
739
740	/* Split symbol and offset. */
741	static int split_symbol_offset(char symbol, unsigned long offset)
742	{
743	char *tmp;
744	int ret;
745
746	if (!offset)
747	return -EINVAL;
748
749	tmp = strchr(symbol, '+');
750	if (tmp) {
751	/* skip sign because strict_strtol doesn't accept '+' */
752	ret = strict_strtoul(tmp + 1, 0, offset);
753	if (ret)
754	return ret;
755	*tmp = '\0';
756	} else
757	*offset = 0;
758	return 0;
759	}
760
761	#define PARAM_MAX_ARGS 16
762	#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
763
764	static int parse_probe_vars(char arg, const struct fetch_type t,
765	struct fetch_param *f, int is_return)
766	{
767	int ret = 0;
768	unsigned long param;
769
770	if (strcmp(arg, "retval") == 0) {
771	if (is_return)
772	f->fn = t->fetch[FETCH_MTD_retval];
773	else
774	ret = -EINVAL;
775	} else if (strncmp(arg, "stack", 5) == 0) {
776	if (arg[5] == '\0') {
777	if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
778	f->fn = fetch_stack_address;
779	else
780	ret = -EINVAL;
781	} else if (isdigit(arg[5])) {
782	ret = strict_strtoul(arg + 5, 10, &param);
783	if (ret \|\| param > PARAM_MAX_STACK)
784	ret = -EINVAL;
785	else {
786	f->fn = t->fetch[FETCH_MTD_stack];
787	f->data = (void *)param;
788	}
789	} else
790	ret = -EINVAL;
791	} else
792	ret = -EINVAL;
793	return ret;
794	}
795
796	/* Recursive argument parser */
797	static int __parse_probe_arg(char arg, const struct fetch_type t,
798	struct fetch_param *f, int is_return)
799	{
800	int ret = 0;
801	unsigned long param;
802	long offset;
803	char *tmp;
804
805	switch (arg[0]) {
806	case '$':
807	ret = parse_probe_vars(arg + 1, t, f, is_return);
808	break;
809	case '%': /* named register */
810	ret = regs_query_register_offset(arg + 1);
811	if (ret >= 0) {
812	f->fn = t->fetch[FETCH_MTD_reg];
813	f->data = (void *)(unsigned long)ret;
814	ret = 0;
815	}
816	break;
817	case '@': /* memory or symbol */
818	if (isdigit(arg[1])) {
819	ret = strict_strtoul(arg + 1, 0, &param);
820	if (ret)
821	break;
822	f->fn = t->fetch[FETCH_MTD_memory];
823	f->data = (void *)param;
824	} else {
825	ret = split_symbol_offset(arg + 1, &offset);
826	if (ret)
827	break;
828	f->data = alloc_symbol_cache(arg + 1, offset);
829	if (f->data)
830	f->fn = t->fetch[FETCH_MTD_symbol];
831	}
832	break;
833	case '+': /* deref memory */
834	arg++; /* Skip '+', because strict_strtol() rejects it. */
835	case '-':
836	tmp = strchr(arg, '(');
837	if (!tmp)
838	break;
839	*tmp = '\0';
840	ret = strict_strtol(arg, 0, &offset);
841	if (ret)
842	break;
843	arg = tmp + 1;
844	tmp = strrchr(arg, ')');
845	if (tmp) {
846	struct deref_fetch_param *dprm;
847	const struct fetch_type *t2 = find_fetch_type(NULL);
848	*tmp = '\0';
849	dprm = kzalloc(sizeof(struct deref_fetch_param),
850	GFP_KERNEL);
851	if (!dprm)
852	return -ENOMEM;
853	dprm->offset = offset;
854	ret = __parse_probe_arg(arg, t2, &dprm->orig,
855	is_return);
856	if (ret)
857	kfree(dprm);
858	else {
859	f->fn = t->fetch[FETCH_MTD_deref];
860	f->data = (void *)dprm;
861	}
862	}
863	break;
864	}
865	if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
866	pr_info("%s type has no corresponding fetch method.\n",
867	t->name);
868	ret = -EINVAL;
869	}
870	return ret;
871	}
872
873	#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
874
875	/* Bitfield type needs to be parsed into a fetch function */
876	static int __parse_bitfield_probe_arg(const char *bf,
877	const struct fetch_type *t,
878	struct fetch_param *f)
879	{
880	struct bitfield_fetch_param *bprm;
881	unsigned long bw, bo;
882	char *tail;
883
884	if (*bf != 'b')
885	return 0;
886
887	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
888	if (!bprm)
889	return -ENOMEM;
890	bprm->orig = *f;
891	f->fn = t->fetch[FETCH_MTD_bitfield];
892	f->data = (void *)bprm;
893
894	bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
895	if (bw == 0 \|\| *tail != '@')
896	return -EINVAL;
897
898	bf = tail + 1;
899	bo = simple_strtoul(bf, &tail, 0);
900	if (tail == bf \|\| *tail != '/')
901	return -EINVAL;
902
903	bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
904	bprm->low_shift = bprm->hi_shift + bo;
905	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
906	}
907
908	/* String length checking wrapper */
909	static int parse_probe_arg(char arg, struct trace_probe tp,
910	struct probe_arg *parg, int is_return)
911	{
912	const char *t;
913	int ret;
914
915	if (strlen(arg) > MAX_ARGSTR_LEN) {
916	pr_info("Argument is too long.: %s\n", arg);
917	return -ENOSPC;
918	}
919	parg->comm = kstrdup(arg, GFP_KERNEL);
920	if (!parg->comm) {
921	pr_info("Failed to allocate memory for command '%s'.\n", arg);
922	return -ENOMEM;
923	}
924	t = strchr(parg->comm, ':');
925	if (t) {
926	arg[t - parg->comm] = '\0';
927	t++;
928	}
929	parg->type = find_fetch_type(t);
930	if (!parg->type) {
931	pr_info("Unsupported type: %s\n", t);
932	return -EINVAL;
933	}
934	parg->offset = tp->size;
935	tp->size += parg->type->size;
936	ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
937	if (ret >= 0 && t != NULL)
938	ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
939	if (ret >= 0) {
940	parg->fetch_size.fn = get_fetch_size_function(parg->type,
941	parg->fetch.fn);
942	parg->fetch_size.data = parg->fetch.data;
943	}
944	return ret;
945	}
946
947	/* Return 1 if name is reserved or already used by another argument */
948	static int conflict_field_name(const char *name,
949	struct probe_arg *args, int narg)
950	{
951	int i;
952	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
953	if (strcmp(reserved_field_names[i], name) == 0)
954	return 1;
955	for (i = 0; i < narg; i++)
956	if (strcmp(args[i].name, name) == 0)
957	return 1;
958	return 0;
959	}
960
961	static int create_trace_probe(int argc, char **argv)
962	{
963	/*
964	* Argument syntax:
965	* - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]\|KADDR [FETCHARGS]
966	* - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
967	* Fetch args:
968	* $retval : fetch return value
969	* $stack : fetch stack address
970	* $stackN : fetch Nth of stack (N:0-)
971	* @ADDR : fetch memory at ADDR (ADDR should be in kernel)
972	* @SYM[+\|-offs] : fetch memory at SYM +\|- offs (SYM is a data symbol)
973	* %REG : fetch register REG
974	* Dereferencing memory fetch:
975	* +\|-offs(ARG) : fetch memory at ARG +\|- offs address.
976	* Alias name of args:
977	* NAME=FETCHARG : set NAME as alias of FETCHARG.
978	* Type of args:
979	* FETCHARG:TYPE : use TYPE instead of unsigned long.
980	*/
981	struct trace_probe *tp;
982	int i, ret = 0;
983	int is_return = 0, is_delete = 0;
984	char symbol = NULL, event = NULL, *group = NULL;
985	char *arg;
986	unsigned long offset = 0;
987	void *addr = NULL;
988	char buf[MAX_EVENT_NAME_LEN];
989
990	/* argc must be >= 1 */
991	if (argv[0][0] == 'p')
992	is_return = 0;
993	else if (argv[0][0] == 'r')
994	is_return = 1;
995	else if (argv[0][0] == '-')
996	is_delete = 1;
997	else {
998	pr_info("Probe definition must be started with 'p', 'r' or"
999	" '-'.\n");
1000	return -EINVAL;
1001	}
1002
1003	if (argv[0][1] == ':') {
1004	event = &argv[0][2];
1005	if (strchr(event, '/')) {
1006	group = event;
1007	event = strchr(group, '/') + 1;
1008	event[-1] = '\0';
1009	if (strlen(group) == 0) {
1010	pr_info("Group name is not specified\n");
1011	return -EINVAL;
1012	}
1013	}
1014	if (strlen(event) == 0) {
1015	pr_info("Event name is not specified\n");
1016	return -EINVAL;
1017	}
1018	}
1019	if (!group)
1020	group = KPROBE_EVENT_SYSTEM;
1021
1022	if (is_delete) {
1023	if (!event) {
1024	pr_info("Delete command needs an event name.\n");
1025	return -EINVAL;
1026	}
1027	mutex_lock(&probe_lock);
1028	tp = find_probe_event(event, group);
1029	if (!tp) {
1030	mutex_unlock(&probe_lock);
1031	pr_info("Event %s/%s doesn't exist.\n", group, event);
1032	return -ENOENT;
1033	}
1034	/* delete an event */
1035	unregister_trace_probe(tp);
1036	free_trace_probe(tp);
1037	mutex_unlock(&probe_lock);
1038	return 0;
1039	}
1040
1041	if (argc < 2) {
1042	pr_info("Probe point is not specified.\n");
1043	return -EINVAL;
1044	}
1045	if (isdigit(argv[1][0])) {
1046	if (is_return) {
1047	pr_info("Return probe point must be a symbol.\n");
1048	return -EINVAL;
1049	}
1050	/* an address specified */
1051	ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1052	if (ret) {
1053	pr_info("Failed to parse address.\n");
1054	return ret;
1055	}
1056	} else {
1057	/* a symbol specified */
1058	symbol = argv[1];
1059	/* TODO: support .init module functions */
1060	ret = split_symbol_offset(symbol, &offset);
1061	if (ret) {
1062	pr_info("Failed to parse symbol.\n");
1063	return ret;
1064	}
1065	if (offset && is_return) {
1066	pr_info("Return probe must be used without offset.\n");
1067	return -EINVAL;
1068	}
1069	}
1070	argc -= 2; argv += 2;
1071
1072	/* setup a probe */
1073	if (!event) {
1074	/* Make a new event name */
1075	if (symbol)
1076	snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1077	is_return ? 'r' : 'p', symbol, offset);
1078	else
1079	snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1080	is_return ? 'r' : 'p', addr);
1081	event = buf;
1082	}
1083	tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
1084	is_return);
1085	if (IS_ERR(tp)) {
1086	pr_info("Failed to allocate trace_probe.(%d)\n",
1087	(int)PTR_ERR(tp));
1088	return PTR_ERR(tp);
1089	}
1090
1091	/* parse arguments */
1092	ret = 0;
1093	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1094	/* Increment count for freeing args in error case */
1095	tp->nr_args++;
1096
1097	/* Parse argument name */
1098	arg = strchr(argv[i], '=');
1099	if (arg) {
1100	*arg++ = '\0';
1101	tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
1102	} else {
1103	arg = argv[i];
1104	/* If argument name is omitted, set "argN" */
1105	snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
1106	tp->args[i].name = kstrdup(buf, GFP_KERNEL);
1107	}
1108
1109	if (!tp->args[i].name) {
1110	pr_info("Failed to allocate argument[%d] name.\n", i);
1111	ret = -ENOMEM;
1112	goto error;
1113	}
1114
1115	if (!is_good_name(tp->args[i].name)) {
1116	pr_info("Invalid argument[%d] name: %s\n",
1117	i, tp->args[i].name);
1118	ret = -EINVAL;
1119	goto error;
1120	}
1121
1122	if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1123	pr_info("Argument[%d] name '%s' conflicts with "
1124	"another field.\n", i, argv[i]);
1125	ret = -EINVAL;
1126	goto error;
1127	}
1128
1129	/* Parse fetch argument */
1130	ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1131	if (ret) {
1132	pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1133	goto error;
1134	}
1135	}
1136
1137	ret = register_trace_probe(tp);
1138	if (ret)
1139	goto error;
1140	return 0;
1141
1142	error:
1143	free_trace_probe(tp);
1144	return ret;
1145	}
1146
1147	static void cleanup_all_probes(void)
1148	{
1149	struct trace_probe *tp;
1150
1151	mutex_lock(&probe_lock);
1152	/* TODO: Use batch unregistration */
1153	while (!list_empty(&probe_list)) {
1154	tp = list_entry(probe_list.next, struct trace_probe, list);
1155	unregister_trace_probe(tp);
1156	free_trace_probe(tp);
1157	}
1158	mutex_unlock(&probe_lock);
1159	}
1160
1161
1162	/* Probes listing interfaces */
1163	static void probes_seq_start(struct seq_file m, loff_t *pos)
1164	{
1165	mutex_lock(&probe_lock);
1166	return seq_list_start(&probe_list, *pos);
1167	}
1168
1169	static void probes_seq_next(struct seq_file m, void v, loff_t pos)
1170	{
1171	return seq_list_next(v, &probe_list, pos);
1172	}
1173
1174	static void probes_seq_stop(struct seq_file m, void v)
1175	{
1176	mutex_unlock(&probe_lock);
1177	}
1178
1179	static int probes_seq_show(struct seq_file m, void v)
1180	{
1181	struct trace_probe *tp = v;
1182	int i;
1183
1184	seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
1185	seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1186
1187	if (!tp->symbol)
1188	seq_printf(m, " 0x%p", tp->rp.kp.addr);
1189	else if (tp->rp.kp.offset)
1190	seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
1191	else
1192	seq_printf(m, " %s", probe_symbol(tp));
1193
1194	for (i = 0; i < tp->nr_args; i++)
1195	seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1196	seq_printf(m, "\n");
1197
1198	return 0;
1199	}
1200
1201	static const struct seq_operations probes_seq_op = {
1202	.start = probes_seq_start,
1203	.next = probes_seq_next,
1204	.stop = probes_seq_stop,
1205	.show = probes_seq_show
1206	};
1207
1208	static int probes_open(struct inode inode, struct file file)
1209	{
1210	if ((file->f_mode & FMODE_WRITE) &&
1211	(file->f_flags & O_TRUNC))
1212	cleanup_all_probes();
1213
1214	return seq_open(file, &probes_seq_op);
1215	}
1216
1217	static int command_trace_probe(const char *buf)
1218	{
1219	char **argv;
1220	int argc = 0, ret = 0;
1221
1222	argv = argv_split(GFP_KERNEL, buf, &argc);
1223	if (!argv)
1224	return -ENOMEM;
1225
1226	if (argc)
1227	ret = create_trace_probe(argc, argv);
1228
1229	argv_free(argv);
1230	return ret;
1231	}
1232
1233	#define WRITE_BUFSIZE 4096
1234
1235	static ssize_t probes_write(struct file file, const char __user buffer,
1236	size_t count, loff_t *ppos)
1237	{
1238	char kbuf, tmp;
1239	int ret;
1240	size_t done;
1241	size_t size;
1242
1243	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
1244	if (!kbuf)
1245	return -ENOMEM;
1246
1247	ret = done = 0;
1248	while (done < count) {
1249	size = count - done;
1250	if (size >= WRITE_BUFSIZE)
1251	size = WRITE_BUFSIZE - 1;
1252	if (copy_from_user(kbuf, buffer + done, size)) {
1253	ret = -EFAULT;
1254	goto out;
1255	}
1256	kbuf[size] = '\0';
1257	tmp = strchr(kbuf, '\n');
1258	if (tmp) {
1259	*tmp = '\0';
1260	size = tmp - kbuf + 1;
1261	} else if (done + size < count) {
1262	pr_warning("Line length is too long: "
1263	"Should be less than %d.", WRITE_BUFSIZE);
1264	ret = -EINVAL;
1265	goto out;
1266	}
1267	done += size;
1268	/* Remove comments */
1269	tmp = strchr(kbuf, '#');
1270	if (tmp)
1271	*tmp = '\0';
1272
1273	ret = command_trace_probe(kbuf);
1274	if (ret)
1275	goto out;
1276	}
1277	ret = done;
1278	out:
1279	kfree(kbuf);
1280	return ret;
1281	}
1282
1283	static const struct file_operations kprobe_events_ops = {
1284	.owner = THIS_MODULE,
1285	.open = probes_open,
1286	.read = seq_read,
1287	.llseek = seq_lseek,
1288	.release = seq_release,
1289	.write = probes_write,
1290	};
1291
1292	/* Probes profiling interfaces */
1293	static int probes_profile_seq_show(struct seq_file m, void v)
1294	{
1295	struct trace_probe *tp = v;
1296
1297	seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1298	tp->rp.kp.nmissed);
1299
1300	return 0;
1301	}
1302
1303	static const struct seq_operations profile_seq_op = {
1304	.start = probes_seq_start,
1305	.next = probes_seq_next,
1306	.stop = probes_seq_stop,
1307	.show = probes_profile_seq_show
1308	};
1309
1310	static int profile_open(struct inode inode, struct file file)
1311	{
1312	return seq_open(file, &profile_seq_op);
1313	}
1314
1315	static const struct file_operations kprobe_profile_ops = {
1316	.owner = THIS_MODULE,
1317	.open = profile_open,
1318	.read = seq_read,
1319	.llseek = seq_lseek,
1320	.release = seq_release,
1321	};
1322
1323	/* Sum up total data length for dynamic arraies (strings) */
1324	static __kprobes int __get_data_size(struct trace_probe *tp,
1325	struct pt_regs *regs)
1326	{
1327	int i, ret = 0;
1328	u32 len;
1329
1330	for (i = 0; i < tp->nr_args; i++)
1331	if (unlikely(tp->args[i].fetch_size.fn)) {
1332	call_fetch(&tp->args[i].fetch_size, regs, &len);
1333	ret += len;
1334	}
1335
1336	return ret;
1337	}
1338
1339	/* Store the value of each argument */
1340	static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
1341	struct pt_regs *regs,
1342	u8 *data, int maxlen)
1343	{
1344	int i;
1345	u32 end = tp->size;
1346	u32 dl; / Data (relative) location */
1347
1348	for (i = 0; i < tp->nr_args; i++) {
1349	if (unlikely(tp->args[i].fetch_size.fn)) {
1350	/*
1351	* First, we set the relative location and
1352	* maximum data length to *dl
1353	*/
1354	dl = (u32 *)(data + tp->args[i].offset);
1355	*dl = make_data_rloc(maxlen, end - tp->args[i].offset);
1356	/* Then try to fetch string or dynamic array data */
1357	call_fetch(&tp->args[i].fetch, regs, dl);
1358	/* Reduce maximum length */
1359	end += get_rloc_len(*dl);
1360	maxlen -= get_rloc_len(*dl);
1361	/* Trick here, convert data_rloc to data_loc */
1362	dl = convert_rloc_to_loc(dl,
1363	ent_size + tp->args[i].offset);
1364	} else
1365	/* Just fetching data normally */
1366	call_fetch(&tp->args[i].fetch, regs,
1367	data + tp->args[i].offset);
1368	}
1369	}
1370
1371	/* Kprobe handler */
1372	static __kprobes void kprobe_trace_func(struct kprobe kp, struct pt_regs regs)
1373	{
1374	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1375	struct kprobe_trace_entry_head *entry;
1376	struct ring_buffer_event *event;
1377	struct ring_buffer *buffer;
1378	int size, dsize, pc;
1379	unsigned long irq_flags;
1380	struct ftrace_event_call *call = &tp->call;
1381
1382	tp->nhit++;
1383
1384	local_save_flags(irq_flags);
1385	pc = preempt_count();
1386
1387	dsize = __get_data_size(tp, regs);
1388	size = sizeof(*entry) + tp->size + dsize;
1389
1390	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1391	size, irq_flags, pc);
1392	if (!event)
1393	return;
1394
1395	entry = ring_buffer_event_data(event);
1396	entry->ip = (unsigned long)kp->addr;
1397	store_trace_args(sizeof(entry), tp, regs, (u8 )&entry[1], dsize);
1398
1399	if (!filter_current_check_discard(buffer, call, entry, event))
1400	trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1401	}
1402
1403	/* Kretprobe handler */
1404	static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1405	struct pt_regs *regs)
1406	{
1407	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1408	struct kretprobe_trace_entry_head *entry;
1409	struct ring_buffer_event *event;
1410	struct ring_buffer *buffer;
1411	int size, pc, dsize;
1412	unsigned long irq_flags;
1413	struct ftrace_event_call *call = &tp->call;
1414
1415	local_save_flags(irq_flags);
1416	pc = preempt_count();
1417
1418	dsize = __get_data_size(tp, regs);
1419	size = sizeof(*entry) + tp->size + dsize;
1420
1421	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
1422	size, irq_flags, pc);
1423	if (!event)
1424	return;
1425
1426	entry = ring_buffer_event_data(event);
1427	entry->func = (unsigned long)tp->rp.kp.addr;
1428	entry->ret_ip = (unsigned long)ri->ret_addr;
1429	store_trace_args(sizeof(entry), tp, regs, (u8 )&entry[1], dsize);
1430
1431	if (!filter_current_check_discard(buffer, call, entry, event))
1432	trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1433	}
1434
1435	/* Event entry printers */
1436	enum print_line_t
1437	print_kprobe_event(struct trace_iterator *iter, int flags,
1438	struct trace_event *event)
1439	{
1440	struct kprobe_trace_entry_head *field;
1441	struct trace_seq *s = &iter->seq;
1442	struct trace_probe *tp;
1443	u8 *data;
1444	int i;
1445
1446	field = (struct kprobe_trace_entry_head *)iter->ent;
1447	tp = container_of(event, struct trace_probe, call.event);
1448
1449	if (!trace_seq_printf(s, "%s: (", tp->call.name))
1450	goto partial;
1451
1452	if (!seq_print_ip_sym(s, field->ip, flags \| TRACE_ITER_SYM_OFFSET))
1453	goto partial;
1454
1455	if (!trace_seq_puts(s, ")"))
1456	goto partial;
1457
1458	data = (u8 *)&field[1];
1459	for (i = 0; i < tp->nr_args; i++)
1460	if (!tp->args[i].type->print(s, tp->args[i].name,
1461	data + tp->args[i].offset, field))
1462	goto partial;
1463
1464	if (!trace_seq_puts(s, "\n"))
1465	goto partial;
1466
1467	return TRACE_TYPE_HANDLED;
1468	partial:
1469	return TRACE_TYPE_PARTIAL_LINE;
1470	}
1471
1472	enum print_line_t
1473	print_kretprobe_event(struct trace_iterator *iter, int flags,
1474	struct trace_event *event)
1475	{
1476	struct kretprobe_trace_entry_head *field;
1477	struct trace_seq *s = &iter->seq;
1478	struct trace_probe *tp;
1479	u8 *data;
1480	int i;
1481
1482	field = (struct kretprobe_trace_entry_head *)iter->ent;
1483	tp = container_of(event, struct trace_probe, call.event);
1484
1485	if (!trace_seq_printf(s, "%s: (", tp->call.name))
1486	goto partial;
1487
1488	if (!seq_print_ip_sym(s, field->ret_ip, flags \| TRACE_ITER_SYM_OFFSET))
1489	goto partial;
1490
1491	if (!trace_seq_puts(s, " <- "))
1492	goto partial;
1493
1494	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1495	goto partial;
1496
1497	if (!trace_seq_puts(s, ")"))
1498	goto partial;
1499
1500	data = (u8 *)&field[1];
1501	for (i = 0; i < tp->nr_args; i++)
1502	if (!tp->args[i].type->print(s, tp->args[i].name,
1503	data + tp->args[i].offset, field))
1504	goto partial;
1505
1506	if (!trace_seq_puts(s, "\n"))
1507	goto partial;
1508
1509	return TRACE_TYPE_HANDLED;
1510	partial:
1511	return TRACE_TYPE_PARTIAL_LINE;
1512	}
1513
1514	static int probe_event_enable(struct ftrace_event_call *call)
1515	{
1516	struct trace_probe tp = (struct trace_probe )call->data;
1517
1518	tp->flags \|= TP_FLAG_TRACE;
1519	if (probe_is_return(tp))
1520	return enable_kretprobe(&tp->rp);
1521	else
1522	return enable_kprobe(&tp->rp.kp);
1523	}
1524
1525	static void probe_event_disable(struct ftrace_event_call *call)
1526	{
1527	struct trace_probe tp = (struct trace_probe )call->data;
1528
1529	tp->flags &= ~TP_FLAG_TRACE;
1530	if (!(tp->flags & (TP_FLAG_TRACE \| TP_FLAG_PROFILE))) {
1531	if (probe_is_return(tp))
1532	disable_kretprobe(&tp->rp);
1533	else
1534	disable_kprobe(&tp->rp.kp);
1535	}
1536	}
1537
1538	#undef DEFINE_FIELD
1539	#define DEFINE_FIELD(type, item, name, is_signed) \
1540	do { \
1541	ret = trace_define_field(event_call, #type, name, \
1542	offsetof(typeof(field), item), \
1543	sizeof(field.item), is_signed, \
1544	FILTER_OTHER); \
1545	if (ret) \
1546	return ret; \
1547	} while (0)
1548
1549	static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
1550	{
1551	int ret, i;
1552	struct kprobe_trace_entry_head field;
1553	struct trace_probe tp = (struct trace_probe )event_call->data;
1554
1555	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1556	/* Set argument names as fields */
1557	for (i = 0; i < tp->nr_args; i++) {
1558	ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1559	tp->args[i].name,
1560	sizeof(field) + tp->args[i].offset,
1561	tp->args[i].type->size,
1562	tp->args[i].type->is_signed,
1563	FILTER_OTHER);
1564	if (ret)
1565	return ret;
1566	}
1567	return 0;
1568	}
1569
1570	static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
1571	{
1572	int ret, i;
1573	struct kretprobe_trace_entry_head field;
1574	struct trace_probe tp = (struct trace_probe )event_call->data;
1575
1576	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1577	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1578	/* Set argument names as fields */
1579	for (i = 0; i < tp->nr_args; i++) {
1580	ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1581	tp->args[i].name,
1582	sizeof(field) + tp->args[i].offset,
1583	tp->args[i].type->size,
1584	tp->args[i].type->is_signed,
1585	FILTER_OTHER);
1586	if (ret)
1587	return ret;
1588	}
1589	return 0;
1590	}
1591
1592	static int __set_print_fmt(struct trace_probe tp, char buf, int len)
1593	{
1594	int i;
1595	int pos = 0;
1596
1597	const char fmt, arg;
1598
1599	if (!probe_is_return(tp)) {
1600	fmt = "(%lx)";
1601	arg = "REC->" FIELD_STRING_IP;
1602	} else {
1603	fmt = "(%lx <- %lx)";
1604	arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
1605	}
1606
1607	/* When len=0, we just calculate the needed length */
1608	#define LEN_OR_ZERO (len ? len - pos : 0)
1609
1610	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
1611
1612	for (i = 0; i < tp->nr_args; i++) {
1613	pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
1614	tp->args[i].name, tp->args[i].type->fmt);
1615	}
1616
1617	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
1618
1619	for (i = 0; i < tp->nr_args; i++) {
1620	if (strcmp(tp->args[i].type->name, "string") == 0)
1621	pos += snprintf(buf + pos, LEN_OR_ZERO,
1622	", __get_str(%s)",
1623	tp->args[i].name);
1624	else
1625	pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
1626	tp->args[i].name);
1627	}
1628
1629	#undef LEN_OR_ZERO
1630
1631	/* return the length of print_fmt */
1632	return pos;
1633	}
1634
1635	static int set_print_fmt(struct trace_probe *tp)
1636	{
1637	int len;
1638	char *print_fmt;
1639
1640	/* First: called with 0 length to calculate the needed length */
1641	len = __set_print_fmt(tp, NULL, 0);
1642	print_fmt = kmalloc(len + 1, GFP_KERNEL);
1643	if (!print_fmt)
1644	return -ENOMEM;
1645
1646	/* Second: actually write the @print_fmt */
1647	__set_print_fmt(tp, print_fmt, len + 1);
1648	tp->call.print_fmt = print_fmt;
1649
1650	return 0;
1651	}
1652
1653	#ifdef CONFIG_PERF_EVENTS
1654
1655	/* Kprobe profile handler */
1656	static __kprobes void kprobe_perf_func(struct kprobe *kp,
1657	struct pt_regs *regs)
1658	{
1659	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1660	struct ftrace_event_call *call = &tp->call;
1661	struct kprobe_trace_entry_head *entry;
1662	struct hlist_head *head;
1663	int size, __size, dsize;
1664	int rctx;
1665
1666	dsize = __get_data_size(tp, regs);
1667	__size = sizeof(*entry) + tp->size + dsize;
1668	size = ALIGN(__size + sizeof(u32), sizeof(u64));
1669	size -= sizeof(u32);
1670	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1671	"profile buffer not large enough"))
1672	return;
1673
1674	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1675	if (!entry)
1676	return;
1677
1678	entry->ip = (unsigned long)kp->addr;
1679	memset(&entry[1], 0, dsize);
1680	store_trace_args(sizeof(entry), tp, regs, (u8 )&entry[1], dsize);
1681
1682	head = this_cpu_ptr(call->perf_events);
1683	perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1684	}
1685
1686	/* Kretprobe profile handler */
1687	static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1688	struct pt_regs *regs)
1689	{
1690	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1691	struct ftrace_event_call *call = &tp->call;
1692	struct kretprobe_trace_entry_head *entry;
1693	struct hlist_head *head;
1694	int size, __size, dsize;
1695	int rctx;
1696
1697	dsize = __get_data_size(tp, regs);
1698	__size = sizeof(*entry) + tp->size + dsize;
1699	size = ALIGN(__size + sizeof(u32), sizeof(u64));
1700	size -= sizeof(u32);
1701	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1702	"profile buffer not large enough"))
1703	return;
1704
1705	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1706	if (!entry)
1707	return;
1708
1709	entry->func = (unsigned long)tp->rp.kp.addr;
1710	entry->ret_ip = (unsigned long)ri->ret_addr;
1711	store_trace_args(sizeof(entry), tp, regs, (u8 )&entry[1], dsize);
1712
1713	head = this_cpu_ptr(call->perf_events);
1714	perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1715	}
1716
1717	static int probe_perf_enable(struct ftrace_event_call *call)
1718	{
1719	struct trace_probe tp = (struct trace_probe )call->data;
1720
1721	tp->flags \|= TP_FLAG_PROFILE;
1722
1723	if (probe_is_return(tp))
1724	return enable_kretprobe(&tp->rp);
1725	else
1726	return enable_kprobe(&tp->rp.kp);
1727	}
1728
1729	static void probe_perf_disable(struct ftrace_event_call *call)
1730	{
1731	struct trace_probe tp = (struct trace_probe )call->data;
1732
1733	tp->flags &= ~TP_FLAG_PROFILE;
1734
1735	if (!(tp->flags & TP_FLAG_TRACE)) {
1736	if (probe_is_return(tp))
1737	disable_kretprobe(&tp->rp);
1738	else
1739	disable_kprobe(&tp->rp.kp);
1740	}
1741	}
1742	#endif /* CONFIG_PERF_EVENTS */
1743
1744	static __kprobes
1745	int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
1746	{
1747	switch (type) {
1748	case TRACE_REG_REGISTER:
1749	return probe_event_enable(event);
1750	case TRACE_REG_UNREGISTER:
1751	probe_event_disable(event);
1752	return 0;
1753
1754	#ifdef CONFIG_PERF_EVENTS
1755	case TRACE_REG_PERF_REGISTER:
1756	return probe_perf_enable(event);
1757	case TRACE_REG_PERF_UNREGISTER:
1758	probe_perf_disable(event);
1759	return 0;
1760	#endif
1761	}
1762	return 0;
1763	}
1764
1765	static __kprobes
1766	int kprobe_dispatcher(struct kprobe kp, struct pt_regs regs)
1767	{
1768	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1769
1770	if (tp->flags & TP_FLAG_TRACE)
1771	kprobe_trace_func(kp, regs);
1772	#ifdef CONFIG_PERF_EVENTS
1773	if (tp->flags & TP_FLAG_PROFILE)
1774	kprobe_perf_func(kp, regs);
1775	#endif
1776	return 0; /* We don't tweek kernel, so just return 0 */
1777	}
1778
1779	static __kprobes
1780	int kretprobe_dispatcher(struct kretprobe_instance ri, struct pt_regs regs)
1781	{
1782	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1783
1784	if (tp->flags & TP_FLAG_TRACE)
1785	kretprobe_trace_func(ri, regs);
1786	#ifdef CONFIG_PERF_EVENTS
1787	if (tp->flags & TP_FLAG_PROFILE)
1788	kretprobe_perf_func(ri, regs);
1789	#endif
1790	return 0; /* We don't tweek kernel, so just return 0 */
1791	}
1792
1793	static struct trace_event_functions kretprobe_funcs = {
1794	.trace = print_kretprobe_event
1795	};
1796
1797	static struct trace_event_functions kprobe_funcs = {
1798	.trace = print_kprobe_event
1799	};
1800
1801	static int register_probe_event(struct trace_probe *tp)
1802	{
1803	struct ftrace_event_call *call = &tp->call;
1804	int ret;
1805
1806	/* Initialize ftrace_event_call */
1807	INIT_LIST_HEAD(&call->class->fields);
1808	if (probe_is_return(tp)) {
1809	call->event.funcs = &kretprobe_funcs;
1810	call->class->define_fields = kretprobe_event_define_fields;
1811	} else {
1812	call->event.funcs = &kprobe_funcs;
1813	call->class->define_fields = kprobe_event_define_fields;
1814	}
1815	if (set_print_fmt(tp) < 0)
1816	return -ENOMEM;
1817	ret = register_ftrace_event(&call->event);
1818	if (!ret) {
1819	kfree(call->print_fmt);
1820	return -ENODEV;
1821	}
1822	call->flags = 0;
1823	call->class->reg = kprobe_register;
1824	call->data = tp;
1825	ret = trace_add_event_call(call);
1826	if (ret) {
1827	pr_info("Failed to register kprobe event: %s\n", call->name);
1828	kfree(call->print_fmt);
1829	unregister_ftrace_event(&call->event);
1830	}
1831	return ret;
1832	}
1833
1834	static void unregister_probe_event(struct trace_probe *tp)
1835	{
1836	/* tp->event is unregistered in trace_remove_event_call() */
1837	trace_remove_event_call(&tp->call);
1838	kfree(tp->call.print_fmt);
1839	}
1840
1841	/* Make a debugfs interface for controlling probe points */
1842	static __init int init_kprobe_trace(void)
1843	{
1844	struct dentry *d_tracer;
1845	struct dentry *entry;
1846
1847	d_tracer = tracing_init_dentry();
1848	if (!d_tracer)
1849	return 0;
1850
1851	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
1852	NULL, &kprobe_events_ops);
1853
1854	/* Event list interface */
1855	if (!entry)
1856	pr_warning("Could not create debugfs "
1857	"'kprobe_events' entry\n");
1858
1859	/* Profile interface */
1860	entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
1861	NULL, &kprobe_profile_ops);
1862
1863	if (!entry)
1864	pr_warning("Could not create debugfs "
1865	"'kprobe_profile' entry\n");
1866	return 0;
1867	}
1868	fs_initcall(init_kprobe_trace);
1869
1870
1871	#ifdef CONFIG_FTRACE_STARTUP_TEST
1872
1873	/*
1874	* The "__used" keeps gcc from removing the function symbol
1875	* from the kallsyms table.
1876	*/
1877	static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
1878	int a4, int a5, int a6)
1879	{
1880	return a1 + a2 + a3 + a4 + a5 + a6;
1881	}
1882
1883	static __init int kprobe_trace_self_tests_init(void)
1884	{
1885	int ret, warn = 0;
1886	int (*target)(int, int, int, int, int, int);
1887	struct trace_probe *tp;
1888
1889	target = kprobe_trace_selftest_target;
1890
1891	pr_info("Testing kprobe tracing: ");
1892
1893	ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1894	"$stack $stack0 +0($stack)");
1895	if (WARN_ON_ONCE(ret)) {
1896	pr_warning("error on probing function entry.\n");
1897	warn++;
1898	} else {
1899	/* Enable trace point */
1900	tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
1901	if (WARN_ON_ONCE(tp == NULL)) {
1902	pr_warning("error on getting new probe.\n");
1903	warn++;
1904	} else
1905	probe_event_enable(&tp->call);
1906	}
1907
1908	ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1909	"$retval");
1910	if (WARN_ON_ONCE(ret)) {
1911	pr_warning("error on probing function return.\n");
1912	warn++;
1913	} else {
1914	/* Enable trace point */
1915	tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
1916	if (WARN_ON_ONCE(tp == NULL)) {
1917	pr_warning("error on getting new probe.\n");
1918	warn++;
1919	} else
1920	probe_event_enable(&tp->call);
1921	}
1922
1923	if (warn)
1924	goto end;
1925
1926	ret = target(1, 2, 3, 4, 5, 6);
1927
1928	ret = command_trace_probe("-:testprobe");
1929	if (WARN_ON_ONCE(ret)) {
1930	pr_warning("error on deleting a probe.\n");
1931	warn++;
1932	}
1933
1934	ret = command_trace_probe("-:testprobe2");
1935	if (WARN_ON_ONCE(ret)) {
1936	pr_warning("error on deleting a probe.\n");
1937	warn++;
1938	}
1939
1940	end:
1941	cleanup_all_probes();
1942	if (warn)
1943	pr_cont("NG: Some tests are failed. Please check them.\n");
1944	else
1945	pr_cont("OK\n");
1946	return 0;
1947	}
1948
1949	late_initcall(kprobe_trace_self_tests_init);
1950
1951	#endif
1952

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jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9

Kernel

Kernel Git Source Tree

Root/kernel/trace/trace_kprobe.c

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