trace_kprobe.c 48.1 KB
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/*
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 * Kprobes-based tracing events
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 *
 * Created by Masami Hiramatsu <mhiramat@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/debugfs.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/ptrace.h>
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#include <linux/perf_event.h>
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#include <linux/stringify.h>
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#include <linux/limits.h>
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#include <asm/bitsperlong.h>
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#include "trace.h"
#include "trace_output.h"

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#define MAX_TRACE_ARGS 128
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#define MAX_ARGSTR_LEN 63
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#define MAX_EVENT_NAME_LEN 64
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#define MAX_STRING_SIZE PATH_MAX
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#define KPROBE_EVENT_SYSTEM "kprobes"
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/* Reserved field names */
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#define FIELD_STRING_IP "__probe_ip"
#define FIELD_STRING_RETIP "__probe_ret_ip"
#define FIELD_STRING_FUNC "__probe_func"
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const char *reserved_field_names[] = {
	"common_type",
	"common_flags",
	"common_preempt_count",
	"common_pid",
	"common_tgid",
	"common_lock_depth",
	FIELD_STRING_IP,
	FIELD_STRING_RETIP,
	FIELD_STRING_FUNC,
};

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/* Printing function type */
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typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *,
				 void *);
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#define PRINT_TYPE_FUNC_NAME(type)	print_type_##type
#define PRINT_TYPE_FMT_NAME(type)	print_type_format_##type

/* Printing  in basic type function template */
#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)			\
static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,	\
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						const char *name,	\
						void *data, void *ent)\
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{									\
	return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
}									\
static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;

DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)

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/* data_rloc: data relative location, compatible with u32 */
#define make_data_rloc(len, roffs)	\
	(((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
#define get_rloc_len(dl)	((u32)(dl) >> 16)
#define get_rloc_offs(dl)	((u32)(dl) & 0xffff)

static inline void *get_rloc_data(u32 *dl)
{
	return (u8 *)dl + get_rloc_offs(*dl);
}

/* For data_loc conversion */
static inline void *get_loc_data(u32 *dl, void *ent)
{
	return (u8 *)ent + get_rloc_offs(*dl);
}

/*
 * Convert data_rloc to data_loc:
 *  data_rloc stores the offset from data_rloc itself, but data_loc
 *  stores the offset from event entry.
 */
#define convert_rloc_to_loc(dl, offs)	((u32)(dl) + (offs))

/* For defining macros, define string/string_size types */
typedef u32 string;
typedef u32 string_size;

/* Print type function for string type */
static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
						  const char *name,
						  void *data, void *ent)
{
	int len = *(u32 *)data >> 16;

	if (!len)
		return trace_seq_printf(s, " %s=(fault)", name);
	else
		return trace_seq_printf(s, " %s=\"%s\"", name,
					(const char *)get_loc_data(data, ent));
}
static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";

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/* Data fetch function type */
typedef	void (*fetch_func_t)(struct pt_regs *, void *, void *);

struct fetch_param {
	fetch_func_t	fn;
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	void *data;
};

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static __kprobes void call_fetch(struct fetch_param *fprm,
				 struct pt_regs *regs, void *dest)
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{
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	return fprm->fn(regs, fprm->data, dest);
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}

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#define FETCH_FUNC_NAME(method, type)	fetch_##method##_##type
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/*
 * Define macro for basic types - we don't need to define s* types, because
 * we have to care only about bitwidth at recording time.
 */
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#define DEFINE_BASIC_FETCH_FUNCS(method) \
DEFINE_FETCH_##method(u8)		\
DEFINE_FETCH_##method(u16)		\
DEFINE_FETCH_##method(u32)		\
DEFINE_FETCH_##method(u64)

#define CHECK_FETCH_FUNCS(method, fn)			\
	(((FETCH_FUNC_NAME(method, u8) == fn) ||	\
	  (FETCH_FUNC_NAME(method, u16) == fn) ||	\
	  (FETCH_FUNC_NAME(method, u32) == fn) ||	\
	  (FETCH_FUNC_NAME(method, u64) == fn) ||	\
	  (FETCH_FUNC_NAME(method, string) == fn) ||	\
	  (FETCH_FUNC_NAME(method, string_size) == fn)) \
	 && (fn != NULL))
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/* Data fetch function templates */
#define DEFINE_FETCH_reg(type)						\
static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,	\
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					void *offset, void *dest)	\
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{									\
	*(type *)dest = (type)regs_get_register(regs,			\
				(unsigned int)((unsigned long)offset));	\
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}
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DEFINE_BASIC_FETCH_FUNCS(reg)
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/* No string on the register */
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL
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#define DEFINE_FETCH_stack(type)					\
static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
					  void *offset, void *dest)	\
{									\
	*(type *)dest = (type)regs_get_kernel_stack_nth(regs,		\
				(unsigned int)((unsigned long)offset));	\
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}
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DEFINE_BASIC_FETCH_FUNCS(stack)
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/* No string on the stack entry */
#define fetch_stack_string NULL
#define fetch_stack_string_size NULL
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#define DEFINE_FETCH_retval(type)					\
static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
					  void *dummy, void *dest)	\
{									\
	*(type *)dest = (type)regs_return_value(regs);			\
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}
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DEFINE_BASIC_FETCH_FUNCS(retval)
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/* No string on the retval */
#define fetch_retval_string NULL
#define fetch_retval_string_size NULL
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#define DEFINE_FETCH_memory(type)					\
static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
					  void *addr, void *dest)	\
{									\
	type retval;							\
	if (probe_kernel_address(addr, retval))				\
		*(type *)dest = 0;					\
	else								\
		*(type *)dest = retval;					\
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}
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DEFINE_BASIC_FETCH_FUNCS(memory)
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/*
 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 * length and relative data location.
 */
static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
						      void *addr, void *dest)
{
	long ret;
	int maxlen = get_rloc_len(*(u32 *)dest);
	u8 *dst = get_rloc_data(dest);
	u8 *src = addr;
	mm_segment_t old_fs = get_fs();
	if (!maxlen)
		return;
	/*
	 * Try to get string again, since the string can be changed while
	 * probing.
	 */
	set_fs(KERNEL_DS);
	pagefault_disable();
	do
		ret = __copy_from_user_inatomic(dst++, src++, 1);
	while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
	dst[-1] = '\0';
	pagefault_enable();
	set_fs(old_fs);

	if (ret < 0) {	/* Failed to fetch string */
		((u8 *)get_rloc_data(dest))[0] = '\0';
		*(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
	} else
		*(u32 *)dest = make_data_rloc(src - (u8 *)addr,
					      get_rloc_offs(*(u32 *)dest));
}
/* Return the length of string -- including null terminal byte */
static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
							void *addr, void *dest)
{
	int ret, len = 0;
	u8 c;
	mm_segment_t old_fs = get_fs();

	set_fs(KERNEL_DS);
	pagefault_disable();
	do {
		ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
		len++;
	} while (c && ret == 0 && len < MAX_STRING_SIZE);
	pagefault_enable();
	set_fs(old_fs);

	if (ret < 0)	/* Failed to check the length */
		*(u32 *)dest = 0;
	else
		*(u32 *)dest = len;
}
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/* Memory fetching by symbol */
struct symbol_cache {
	char *symbol;
	long offset;
	unsigned long addr;
};

static unsigned long update_symbol_cache(struct symbol_cache *sc)
{
	sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
	if (sc->addr)
		sc->addr += sc->offset;
	return sc->addr;
}

static void free_symbol_cache(struct symbol_cache *sc)
{
	kfree(sc->symbol);
	kfree(sc);
}

static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
{
	struct symbol_cache *sc;

	if (!sym || strlen(sym) == 0)
		return NULL;
	sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
	if (!sc)
		return NULL;

	sc->symbol = kstrdup(sym, GFP_KERNEL);
	if (!sc->symbol) {
		kfree(sc);
		return NULL;
	}
	sc->offset = offset;

	update_symbol_cache(sc);
	return sc;
}

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#define DEFINE_FETCH_symbol(type)					\
static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
					  void *data, void *dest)	\
{									\
	struct symbol_cache *sc = data;					\
	if (sc->addr)							\
		fetch_memory_##type(regs, (void *)sc->addr, dest);	\
	else								\
		*(type *)dest = 0;					\
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}
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DEFINE_BASIC_FETCH_FUNCS(symbol)
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DEFINE_FETCH_symbol(string)
DEFINE_FETCH_symbol(string_size)
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/* Dereference memory access function */
struct deref_fetch_param {
	struct fetch_param orig;
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	long offset;
};

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#define DEFINE_FETCH_deref(type)					\
static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
					    void *data, void *dest)	\
{									\
	struct deref_fetch_param *dprm = data;				\
	unsigned long addr;						\
	call_fetch(&dprm->orig, regs, &addr);				\
	if (addr) {							\
		addr += dprm->offset;					\
		fetch_memory_##type(regs, (void *)addr, dest);		\
	} else								\
		*(type *)dest = 0;					\
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}
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DEFINE_BASIC_FETCH_FUNCS(deref)
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DEFINE_FETCH_deref(string)
DEFINE_FETCH_deref(string_size)
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static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
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{
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	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
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		free_deref_fetch_param(data->orig.data);
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	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
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		free_symbol_cache(data->orig.data);
	kfree(data);
}

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/* Bitfield fetch function */
struct bitfield_fetch_param {
	struct fetch_param orig;
	unsigned char hi_shift;
	unsigned char low_shift;
};

#define DEFINE_FETCH_bitfield(type)					\
static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
					    void *data, void *dest)	\
{									\
	struct bitfield_fetch_param *bprm = data;			\
	type buf = 0;							\
	call_fetch(&bprm->orig, regs, &buf);				\
	if (buf) {							\
		buf <<= bprm->hi_shift;					\
		buf >>= bprm->low_shift;				\
	}								\
	*(type *)dest = buf;						\
}
DEFINE_BASIC_FETCH_FUNCS(bitfield)
#define fetch_bitfield_string NULL
#define fetch_bitfield_string_size NULL

static __kprobes void
free_bitfield_fetch_param(struct bitfield_fetch_param *data)
{
	/*
	 * Don't check the bitfield itself, because this must be the
	 * last fetch function.
	 */
	if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
		free_deref_fetch_param(data->orig.data);
	else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
		free_symbol_cache(data->orig.data);
	kfree(data);
}
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/* Default (unsigned long) fetch type */
#define __DEFAULT_FETCH_TYPE(t) u##t
#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)

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/* Fetch types */
enum {
	FETCH_MTD_reg = 0,
	FETCH_MTD_stack,
	FETCH_MTD_retval,
	FETCH_MTD_memory,
	FETCH_MTD_symbol,
	FETCH_MTD_deref,
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	FETCH_MTD_bitfield,
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	FETCH_MTD_END,
};

#define ASSIGN_FETCH_FUNC(method, type)	\
	[FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)

#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype)	\
	{.name = _name,				\
	 .size = _size,					\
	 .is_signed = sign,				\
	 .print = PRINT_TYPE_FUNC_NAME(ptype),		\
	 .fmt = PRINT_TYPE_FMT_NAME(ptype),		\
	 .fmttype = _fmttype,				\
	 .fetch = {					\
ASSIGN_FETCH_FUNC(reg, ftype),				\
ASSIGN_FETCH_FUNC(stack, ftype),			\
ASSIGN_FETCH_FUNC(retval, ftype),			\
ASSIGN_FETCH_FUNC(memory, ftype),			\
ASSIGN_FETCH_FUNC(symbol, ftype),			\
ASSIGN_FETCH_FUNC(deref, ftype),			\
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ASSIGN_FETCH_FUNC(bitfield, ftype),			\
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	  }						\
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	}

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#define ASSIGN_FETCH_TYPE(ptype, ftype, sign)			\
	__ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)

#define FETCH_TYPE_STRING 0
#define FETCH_TYPE_STRSIZE 1

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/* Fetch type information table */
static const struct fetch_type {
	const char	*name;		/* Name of type */
	size_t		size;		/* Byte size of type */
	int		is_signed;	/* Signed flag */
	print_type_func_t	print;	/* Print functions */
	const char	*fmt;		/* Fromat string */
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	const char	*fmttype;	/* Name in format file */
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	/* Fetch functions */
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	fetch_func_t	fetch[FETCH_MTD_END];
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} fetch_type_table[] = {
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	/* Special types */
	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
					sizeof(u32), 1, "__data_loc char[]"),
	[FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
					string_size, sizeof(u32), 0, "u32"),
	/* Basic types */
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	ASSIGN_FETCH_TYPE(u8,  u8,  0),
	ASSIGN_FETCH_TYPE(u16, u16, 0),
	ASSIGN_FETCH_TYPE(u32, u32, 0),
	ASSIGN_FETCH_TYPE(u64, u64, 0),
	ASSIGN_FETCH_TYPE(s8,  u8,  1),
	ASSIGN_FETCH_TYPE(s16, u16, 1),
	ASSIGN_FETCH_TYPE(s32, u32, 1),
	ASSIGN_FETCH_TYPE(s64, u64, 1),
};

static const struct fetch_type *find_fetch_type(const char *type)
{
	int i;

	if (!type)
		type = DEFAULT_FETCH_TYPE_STR;

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	/* Special case: bitfield */
	if (*type == 'b') {
		unsigned long bs;
		type = strchr(type, '/');
		if (!type)
			goto fail;
		type++;
		if (strict_strtoul(type, 0, &bs))
			goto fail;
		switch (bs) {
		case 8:
			return find_fetch_type("u8");
		case 16:
			return find_fetch_type("u16");
		case 32:
			return find_fetch_type("u32");
		case 64:
			return find_fetch_type("u64");
		default:
			goto fail;
		}
	}

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	for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
		if (strcmp(type, fetch_type_table[i].name) == 0)
			return &fetch_type_table[i];
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fail:
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	return NULL;
}

/* Special function : only accept unsigned long */
static __kprobes void fetch_stack_address(struct pt_regs *regs,
					  void *dummy, void *dest)
{
	*(unsigned long *)dest = kernel_stack_pointer(regs);
}

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static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
					    fetch_func_t orig_fn)
{
	int i;

	if (type != &fetch_type_table[FETCH_TYPE_STRING])
		return NULL;	/* Only string type needs size function */
	for (i = 0; i < FETCH_MTD_END; i++)
		if (type->fetch[i] == orig_fn)
			return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];

	WARN_ON(1);	/* This should not happen */
	return NULL;
}

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/**
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 * Kprobe event core functions
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 */

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struct probe_arg {
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	struct fetch_param	fetch;
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	struct fetch_param	fetch_size;
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	unsigned int		offset;	/* Offset from argument entry */
	const char		*name;	/* Name of this argument */
	const char		*comm;	/* Command of this argument */
	const struct fetch_type	*type;	/* Type of this argument */
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};

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/* Flags for trace_probe */
#define TP_FLAG_TRACE	1
#define TP_FLAG_PROFILE	2

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struct trace_probe {
	struct list_head	list;
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	struct kretprobe	rp;	/* Use rp.kp for kprobe use */
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	unsigned long 		nhit;
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	unsigned int		flags;	/* For TP_FLAG_* */
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	const char		*symbol;	/* symbol name */
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	struct ftrace_event_class	class;
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	struct ftrace_event_call	call;
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	ssize_t			size;		/* trace entry size */
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	unsigned int		nr_args;
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	struct probe_arg	args[];
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};

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#define SIZEOF_TRACE_PROBE(n)			\
	(offsetof(struct trace_probe, args) +	\
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	(sizeof(struct probe_arg) * (n)))
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static __kprobes int probe_is_return(struct trace_probe *tp)
{
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	return tp->rp.handler != NULL;
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}

static __kprobes const char *probe_symbol(struct trace_probe *tp)
{
	return tp->symbol ? tp->symbol : "unknown";
}

static int register_probe_event(struct trace_probe *tp);
static void unregister_probe_event(struct trace_probe *tp);

static DEFINE_MUTEX(probe_lock);
static LIST_HEAD(probe_list);

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static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
static int kretprobe_dispatcher(struct kretprobe_instance *ri,
				struct pt_regs *regs);

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/* Check the name is good for event/group/fields */
static int is_good_name(const char *name)
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{
	if (!isalpha(*name) && *name != '_')
		return 0;
	while (*++name != '\0') {
		if (!isalpha(*name) && !isdigit(*name) && *name != '_')
			return 0;
	}
	return 1;
}

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/*
 * Allocate new trace_probe and initialize it (including kprobes).
 */
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static struct trace_probe *alloc_trace_probe(const char *group,
					     const char *event,
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					     void *addr,
					     const char *symbol,
					     unsigned long offs,
					     int nargs, int is_return)
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{
	struct trace_probe *tp;
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	int ret = -ENOMEM;
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	tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
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	if (!tp)
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		return ERR_PTR(ret);
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	if (symbol) {
		tp->symbol = kstrdup(symbol, GFP_KERNEL);
		if (!tp->symbol)
			goto error;
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		tp->rp.kp.symbol_name = tp->symbol;
		tp->rp.kp.offset = offs;
	} else
		tp->rp.kp.addr = addr;

	if (is_return)
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		tp->rp.handler = kretprobe_dispatcher;
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	else
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		tp->rp.kp.pre_handler = kprobe_dispatcher;
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	if (!event || !is_good_name(event)) {
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		ret = -EINVAL;
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		goto error;
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	}

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	tp->call.class = &tp->class;
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	tp->call.name = kstrdup(event, GFP_KERNEL);
	if (!tp->call.name)
		goto error;
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	if (!group || !is_good_name(group)) {
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		ret = -EINVAL;
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		goto error;
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	}

637 638
	tp->class.system = kstrdup(group, GFP_KERNEL);
	if (!tp->class.system)
639 640
		goto error;

641 642 643
	INIT_LIST_HEAD(&tp->list);
	return tp;
error:
644
	kfree(tp->call.name);
645 646
	kfree(tp->symbol);
	kfree(tp);
647
	return ERR_PTR(ret);
648 649
}

650 651
static void free_probe_arg(struct probe_arg *arg)
{
652 653 654
	if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
		free_bitfield_fetch_param(arg->fetch.data);
	else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
655
		free_deref_fetch_param(arg->fetch.data);
656
	else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
657 658
		free_symbol_cache(arg->fetch.data);
	kfree(arg->name);
659
	kfree(arg->comm);
660 661
}

662 663 664 665 666
static void free_trace_probe(struct trace_probe *tp)
{
	int i;

	for (i = 0; i < tp->nr_args; i++)
667
		free_probe_arg(&tp->args[i]);
668

669
	kfree(tp->call.class->system);
670 671 672 673 674
	kfree(tp->call.name);
	kfree(tp->symbol);
	kfree(tp);
}

675 676
static struct trace_probe *find_probe_event(const char *event,
					    const char *group)
677 678 679 680
{
	struct trace_probe *tp;

	list_for_each_entry(tp, &probe_list, list)
681
		if (strcmp(tp->call.name, event) == 0 &&
682
		    strcmp(tp->call.class->system, group) == 0)
683 684 685 686
			return tp;
	return NULL;
}

687 688
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
static void unregister_trace_probe(struct trace_probe *tp)
689 690 691 692
{
	if (probe_is_return(tp))
		unregister_kretprobe(&tp->rp);
	else
693
		unregister_kprobe(&tp->rp.kp);
694
	list_del(&tp->list);
695
	unregister_probe_event(tp);
696 697 698 699 700 701 702 703 704 705
}

/* Register a trace_probe and probe_event */
static int register_trace_probe(struct trace_probe *tp)
{
	struct trace_probe *old_tp;
	int ret;

	mutex_lock(&probe_lock);

706
	/* register as an event */
707
	old_tp = find_probe_event(tp->call.name, tp->call.class->system);
708 709 710 711 712 713 714
	if (old_tp) {
		/* delete old event */
		unregister_trace_probe(old_tp);
		free_trace_probe(old_tp);
	}
	ret = register_probe_event(tp);
	if (ret) {
P
Paul Bolle 已提交
715
		pr_warning("Failed to register probe event(%d)\n", ret);
716 717 718
		goto end;
	}

719
	tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
720 721 722
	if (probe_is_return(tp))
		ret = register_kretprobe(&tp->rp);
	else
723
		ret = register_kprobe(&tp->rp.kp);
724 725 726 727 728 729

	if (ret) {
		pr_warning("Could not insert probe(%d)\n", ret);
		if (ret == -EILSEQ) {
			pr_warning("Probing address(0x%p) is not an "
				   "instruction boundary.\n",
730
				   tp->rp.kp.addr);
731 732
			ret = -EINVAL;
		}
733 734 735
		unregister_probe_event(tp);
	} else
		list_add_tail(&tp->list, &probe_list);
736 737 738 739 740 741
end:
	mutex_unlock(&probe_lock);
	return ret;
}

/* Split symbol and offset. */
742
static int split_symbol_offset(char *symbol, unsigned long *offset)
743 744 745 746 747 748 749 750 751 752
{
	char *tmp;
	int ret;

	if (!offset)
		return -EINVAL;

	tmp = strchr(symbol, '+');
	if (tmp) {
		/* skip sign because strict_strtol doesn't accept '+' */
753
		ret = strict_strtoul(tmp + 1, 0, offset);
754 755 756 757 758 759 760 761 762 763 764
		if (ret)
			return ret;
		*tmp = '\0';
	} else
		*offset = 0;
	return 0;
}

#define PARAM_MAX_ARGS 16
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))

765 766
static int parse_probe_vars(char *arg, const struct fetch_type *t,
			    struct fetch_param *f, int is_return)
767 768 769 770
{
	int ret = 0;
	unsigned long param;

771
	if (strcmp(arg, "retval") == 0) {
772
		if (is_return)
773
			f->fn = t->fetch[FETCH_MTD_retval];
774
		else
775
			ret = -EINVAL;
776 777
	} else if (strncmp(arg, "stack", 5) == 0) {
		if (arg[5] == '\0') {
778 779 780 781
			if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
				f->fn = fetch_stack_address;
			else
				ret = -EINVAL;
782 783
		} else if (isdigit(arg[5])) {
			ret = strict_strtoul(arg + 5, 10, &param);
784 785 786
			if (ret || param > PARAM_MAX_STACK)
				ret = -EINVAL;
			else {
787
				f->fn = t->fetch[FETCH_MTD_stack];
788
				f->data = (void *)param;
789
			}
790 791 792
		} else
			ret = -EINVAL;
	} else
793 794 795 796
		ret = -EINVAL;
	return ret;
}

797
/* Recursive argument parser */
798 799
static int __parse_probe_arg(char *arg, const struct fetch_type *t,
			     struct fetch_param *f, int is_return)
800 801 802 803 804 805 806 807
{
	int ret = 0;
	unsigned long param;
	long offset;
	char *tmp;

	switch (arg[0]) {
	case '$':
808
		ret = parse_probe_vars(arg + 1, t, f, is_return);
809 810 811 812
		break;
	case '%':	/* named register */
		ret = regs_query_register_offset(arg + 1);
		if (ret >= 0) {
813
			f->fn = t->fetch[FETCH_MTD_reg];
814
			f->data = (void *)(unsigned long)ret;
815 816 817
			ret = 0;
		}
		break;
818 819 820 821 822
	case '@':	/* memory or symbol */
		if (isdigit(arg[1])) {
			ret = strict_strtoul(arg + 1, 0, &param);
			if (ret)
				break;
823
			f->fn = t->fetch[FETCH_MTD_memory];
824
			f->data = (void *)param;
825 826 827 828
		} else {
			ret = split_symbol_offset(arg + 1, &offset);
			if (ret)
				break;
829 830
			f->data = alloc_symbol_cache(arg + 1, offset);
			if (f->data)
831
				f->fn = t->fetch[FETCH_MTD_symbol];
832 833
		}
		break;
834
	case '+':	/* deref memory */
835
		arg++;	/* Skip '+', because strict_strtol() rejects it. */
836 837
	case '-':
		tmp = strchr(arg, '(');
838
		if (!tmp)
839 840
			break;
		*tmp = '\0';
841
		ret = strict_strtol(arg, 0, &offset);
842 843 844 845 846
		if (ret)
			break;
		arg = tmp + 1;
		tmp = strrchr(arg, ')');
		if (tmp) {
847 848
			struct deref_fetch_param *dprm;
			const struct fetch_type *t2 = find_fetch_type(NULL);
849
			*tmp = '\0';
850 851 852
			dprm = kzalloc(sizeof(struct deref_fetch_param),
				       GFP_KERNEL);
			if (!dprm)
853
				return -ENOMEM;
854 855 856
			dprm->offset = offset;
			ret = __parse_probe_arg(arg, t2, &dprm->orig,
						is_return);
857
			if (ret)
858
				kfree(dprm);
859
			else {
860
				f->fn = t->fetch[FETCH_MTD_deref];
861
				f->data = (void *)dprm;
862
			}
863
		}
864 865
		break;
	}
866 867 868
	if (!ret && !f->fn) {	/* Parsed, but do not find fetch method */
		pr_info("%s type has no corresponding fetch method.\n",
			t->name);
869
		ret = -EINVAL;
870
	}
871 872 873
	return ret;
}

874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
#define BYTES_TO_BITS(nb)	((BITS_PER_LONG * (nb)) / sizeof(long))

/* Bitfield type needs to be parsed into a fetch function */
static int __parse_bitfield_probe_arg(const char *bf,
				      const struct fetch_type *t,
				      struct fetch_param *f)
{
	struct bitfield_fetch_param *bprm;
	unsigned long bw, bo;
	char *tail;

	if (*bf != 'b')
		return 0;

	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
	if (!bprm)
		return -ENOMEM;
	bprm->orig = *f;
	f->fn = t->fetch[FETCH_MTD_bitfield];
	f->data = (void *)bprm;

	bw = simple_strtoul(bf + 1, &tail, 0);	/* Use simple one */
	if (bw == 0 || *tail != '@')
		return -EINVAL;

	bf = tail + 1;
	bo = simple_strtoul(bf, &tail, 0);
	if (tail == bf || *tail != '/')
		return -EINVAL;

	bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
	bprm->low_shift = bprm->hi_shift + bo;
	return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
}

909
/* String length checking wrapper */
910 911
static int parse_probe_arg(char *arg, struct trace_probe *tp,
			   struct probe_arg *parg, int is_return)
912
{
913
	const char *t;
914
	int ret;
915

916 917 918 919
	if (strlen(arg) > MAX_ARGSTR_LEN) {
		pr_info("Argument is too long.: %s\n",  arg);
		return -ENOSPC;
	}
920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936
	parg->comm = kstrdup(arg, GFP_KERNEL);
	if (!parg->comm) {
		pr_info("Failed to allocate memory for command '%s'.\n", arg);
		return -ENOMEM;
	}
	t = strchr(parg->comm, ':');
	if (t) {
		arg[t - parg->comm] = '\0';
		t++;
	}
	parg->type = find_fetch_type(t);
	if (!parg->type) {
		pr_info("Unsupported type: %s\n", t);
		return -EINVAL;
	}
	parg->offset = tp->size;
	tp->size += parg->type->size;
937
	ret = __parse_probe_arg(arg, parg->type, &parg->fetch, is_return);
938 939
	if (ret >= 0)
		ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
940 941 942 943 944 945
	if (ret >= 0) {
		parg->fetch_size.fn = get_fetch_size_function(parg->type,
							      parg->fetch.fn);
		parg->fetch_size.data = parg->fetch.data;
	}
	return ret;
946 947
}

948 949 950 951 952 953 954 955 956 957 958 959 960 961
/* Return 1 if name is reserved or already used by another argument */
static int conflict_field_name(const char *name,
			       struct probe_arg *args, int narg)
{
	int i;
	for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
		if (strcmp(reserved_field_names[i], name) == 0)
			return 1;
	for (i = 0; i < narg; i++)
		if (strcmp(args[i].name, name) == 0)
			return 1;
	return 0;
}

962 963 964 965
static int create_trace_probe(int argc, char **argv)
{
	/*
	 * Argument syntax:
966 967
	 *  - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
	 *  - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
968
	 * Fetch args:
969 970 971
	 *  $retval	: fetch return value
	 *  $stack	: fetch stack address
	 *  $stackN	: fetch Nth of stack (N:0-)
972 973 974
	 *  @ADDR	: fetch memory at ADDR (ADDR should be in kernel)
	 *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
	 *  %REG	: fetch register REG
975
	 * Dereferencing memory fetch:
976
	 *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
977 978
	 * Alias name of args:
	 *  NAME=FETCHARG : set NAME as alias of FETCHARG.
979 980
	 * Type of args:
	 *  FETCHARG:TYPE : use TYPE instead of unsigned long.
981 982 983
	 */
	struct trace_probe *tp;
	int i, ret = 0;
984
	int is_return = 0, is_delete = 0;
985
	char *symbol = NULL, *event = NULL, *group = NULL;
986
	char *arg;
987
	unsigned long offset = 0;
988
	void *addr = NULL;
989
	char buf[MAX_EVENT_NAME_LEN];
990

991
	/* argc must be >= 1 */
992 993 994 995
	if (argv[0][0] == 'p')
		is_return = 0;
	else if (argv[0][0] == 'r')
		is_return = 1;
996 997
	else if (argv[0][0] == '-')
		is_delete = 1;
998
	else {
999 1000
		pr_info("Probe definition must be started with 'p', 'r' or"
			" '-'.\n");
1001
		return -EINVAL;
1002
	}
1003 1004 1005

	if (argv[0][1] == ':') {
		event = &argv[0][2];
1006 1007 1008 1009 1010
		if (strchr(event, '/')) {
			group = event;
			event = strchr(group, '/') + 1;
			event[-1] = '\0';
			if (strlen(group) == 0) {
1011
				pr_info("Group name is not specified\n");
1012 1013 1014
				return -EINVAL;
			}
		}
1015
		if (strlen(event) == 0) {
1016
			pr_info("Event name is not specified\n");
1017 1018 1019
			return -EINVAL;
		}
	}
1020 1021
	if (!group)
		group = KPROBE_EVENT_SYSTEM;
1022

1023 1024 1025 1026 1027
	if (is_delete) {
		if (!event) {
			pr_info("Delete command needs an event name.\n");
			return -EINVAL;
		}
1028
		mutex_lock(&probe_lock);
1029 1030
		tp = find_probe_event(event, group);
		if (!tp) {
1031
			mutex_unlock(&probe_lock);
1032 1033 1034 1035 1036 1037
			pr_info("Event %s/%s doesn't exist.\n", group, event);
			return -ENOENT;
		}
		/* delete an event */
		unregister_trace_probe(tp);
		free_trace_probe(tp);
1038
		mutex_unlock(&probe_lock);
1039 1040 1041 1042 1043 1044 1045
		return 0;
	}

	if (argc < 2) {
		pr_info("Probe point is not specified.\n");
		return -EINVAL;
	}
1046
	if (isdigit(argv[1][0])) {
1047 1048
		if (is_return) {
			pr_info("Return probe point must be a symbol.\n");
1049
			return -EINVAL;
1050
		}
1051
		/* an address specified */
1052
		ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
1053 1054
		if (ret) {
			pr_info("Failed to parse address.\n");
1055
			return ret;
1056
		}
1057 1058 1059 1060 1061
	} else {
		/* a symbol specified */
		symbol = argv[1];
		/* TODO: support .init module functions */
		ret = split_symbol_offset(symbol, &offset);
1062 1063
		if (ret) {
			pr_info("Failed to parse symbol.\n");
1064
			return ret;
1065 1066 1067
		}
		if (offset && is_return) {
			pr_info("Return probe must be used without offset.\n");
1068
			return -EINVAL;
1069
		}
1070
	}
1071
	argc -= 2; argv += 2;
1072 1073

	/* setup a probe */
1074 1075 1076
	if (!event) {
		/* Make a new event name */
		if (symbol)
1077
			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
1078 1079
				 is_return ? 'r' : 'p', symbol, offset);
		else
1080
			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
1081
				 is_return ? 'r' : 'p', addr);
1082 1083
		event = buf;
	}
1084 1085
	tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
			       is_return);
1086 1087 1088
	if (IS_ERR(tp)) {
		pr_info("Failed to allocate trace_probe.(%d)\n",
			(int)PTR_ERR(tp));
1089
		return PTR_ERR(tp);
1090
	}
1091 1092

	/* parse arguments */
1093 1094
	ret = 0;
	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
1095 1096 1097
		/* Increment count for freeing args in error case */
		tp->nr_args++;

1098 1099
		/* Parse argument name */
		arg = strchr(argv[i], '=');
1100
		if (arg) {
1101
			*arg++ = '\0';
1102 1103
			tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
		} else {
1104
			arg = argv[i];
1105 1106 1107 1108
			/* If argument name is omitted, set "argN" */
			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
			tp->args[i].name = kstrdup(buf, GFP_KERNEL);
		}
1109

1110
		if (!tp->args[i].name) {
1111
			pr_info("Failed to allocate argument[%d] name.\n", i);
1112
			ret = -ENOMEM;
1113 1114
			goto error;
		}
1115 1116 1117 1118 1119 1120 1121

		if (!is_good_name(tp->args[i].name)) {
			pr_info("Invalid argument[%d] name: %s\n",
				i, tp->args[i].name);
			ret = -EINVAL;
			goto error;
		}
1122 1123

		if (conflict_field_name(tp->args[i].name, tp->args, i)) {
1124
			pr_info("Argument[%d] name '%s' conflicts with "
1125 1126 1127 1128
				"another field.\n", i, argv[i]);
			ret = -EINVAL;
			goto error;
		}
1129 1130

		/* Parse fetch argument */
1131
		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
1132
		if (ret) {
1133
			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
1134
			goto error;
1135
		}
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182
	}

	ret = register_trace_probe(tp);
	if (ret)
		goto error;
	return 0;

error:
	free_trace_probe(tp);
	return ret;
}

static void cleanup_all_probes(void)
{
	struct trace_probe *tp;

	mutex_lock(&probe_lock);
	/* TODO: Use batch unregistration */
	while (!list_empty(&probe_list)) {
		tp = list_entry(probe_list.next, struct trace_probe, list);
		unregister_trace_probe(tp);
		free_trace_probe(tp);
	}
	mutex_unlock(&probe_lock);
}


/* Probes listing interfaces */
static void *probes_seq_start(struct seq_file *m, loff_t *pos)
{
	mutex_lock(&probe_lock);
	return seq_list_start(&probe_list, *pos);
}

static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
	return seq_list_next(v, &probe_list, pos);
}

static void probes_seq_stop(struct seq_file *m, void *v)
{
	mutex_unlock(&probe_lock);
}

static int probes_seq_show(struct seq_file *m, void *v)
{
	struct trace_probe *tp = v;
1183
	int i;
1184 1185

	seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
1186
	seq_printf(m, ":%s/%s", tp->call.class->system, tp->call.name);
1187

1188 1189 1190
	if (!tp->symbol)
		seq_printf(m, " 0x%p", tp->rp.kp.addr);
	else if (tp->rp.kp.offset)
1191
		seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
1192
	else
1193
		seq_printf(m, " %s", probe_symbol(tp));
1194

1195 1196
	for (i = 0; i < tp->nr_args; i++)
		seq_printf(m, " %s=%s", tp->args[i].name, tp->args[i].comm);
1197
	seq_printf(m, "\n");
1198

1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233
	return 0;
}

static const struct seq_operations probes_seq_op = {
	.start  = probes_seq_start,
	.next   = probes_seq_next,
	.stop   = probes_seq_stop,
	.show   = probes_seq_show
};

static int probes_open(struct inode *inode, struct file *file)
{
	if ((file->f_mode & FMODE_WRITE) &&
	    (file->f_flags & O_TRUNC))
		cleanup_all_probes();

	return seq_open(file, &probes_seq_op);
}

static int command_trace_probe(const char *buf)
{
	char **argv;
	int argc = 0, ret = 0;

	argv = argv_split(GFP_KERNEL, buf, &argc);
	if (!argv)
		return -ENOMEM;

	if (argc)
		ret = create_trace_probe(argc, argv);

	argv_free(argv);
	return ret;
}

1234
#define WRITE_BUFSIZE 4096
1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292

static ssize_t probes_write(struct file *file, const char __user *buffer,
			    size_t count, loff_t *ppos)
{
	char *kbuf, *tmp;
	int ret;
	size_t done;
	size_t size;

	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
	if (!kbuf)
		return -ENOMEM;

	ret = done = 0;
	while (done < count) {
		size = count - done;
		if (size >= WRITE_BUFSIZE)
			size = WRITE_BUFSIZE - 1;
		if (copy_from_user(kbuf, buffer + done, size)) {
			ret = -EFAULT;
			goto out;
		}
		kbuf[size] = '\0';
		tmp = strchr(kbuf, '\n');
		if (tmp) {
			*tmp = '\0';
			size = tmp - kbuf + 1;
		} else if (done + size < count) {
			pr_warning("Line length is too long: "
				   "Should be less than %d.", WRITE_BUFSIZE);
			ret = -EINVAL;
			goto out;
		}
		done += size;
		/* Remove comments */
		tmp = strchr(kbuf, '#');
		if (tmp)
			*tmp = '\0';

		ret = command_trace_probe(kbuf);
		if (ret)
			goto out;
	}
	ret = done;
out:
	kfree(kbuf);
	return ret;
}

static const struct file_operations kprobe_events_ops = {
	.owner          = THIS_MODULE,
	.open           = probes_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release        = seq_release,
	.write		= probes_write,
};

1293 1294 1295 1296 1297 1298
/* Probes profiling interfaces */
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
	struct trace_probe *tp = v;

	seq_printf(m, "  %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
1299
		   tp->rp.kp.nmissed);
1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323

	return 0;
}

static const struct seq_operations profile_seq_op = {
	.start  = probes_seq_start,
	.next   = probes_seq_next,
	.stop   = probes_seq_stop,
	.show   = probes_profile_seq_show
};

static int profile_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &profile_seq_op);
}

static const struct file_operations kprobe_profile_ops = {
	.owner          = THIS_MODULE,
	.open           = profile_open,
	.read           = seq_read,
	.llseek         = seq_lseek,
	.release        = seq_release,
};

1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
/* Sum up total data length for dynamic arraies (strings) */
static __kprobes int __get_data_size(struct trace_probe *tp,
				     struct pt_regs *regs)
{
	int i, ret = 0;
	u32 len;

	for (i = 0; i < tp->nr_args; i++)
		if (unlikely(tp->args[i].fetch_size.fn)) {
			call_fetch(&tp->args[i].fetch_size, regs, &len);
			ret += len;
		}

	return ret;
}

/* Store the value of each argument */
static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
				       struct pt_regs *regs,
				       u8 *data, int maxlen)
{
	int i;
	u32 end = tp->size;
	u32 *dl;	/* Data (relative) location */

	for (i = 0; i < tp->nr_args; i++) {
		if (unlikely(tp->args[i].fetch_size.fn)) {
			/*
			 * First, we set the relative location and
			 * maximum data length to *dl
			 */
			dl = (u32 *)(data + tp->args[i].offset);
			*dl = make_data_rloc(maxlen, end - tp->args[i].offset);
			/* Then try to fetch string or dynamic array data */
			call_fetch(&tp->args[i].fetch, regs, dl);
			/* Reduce maximum length */
			end += get_rloc_len(*dl);
			maxlen -= get_rloc_len(*dl);
			/* Trick here, convert data_rloc to data_loc */
			*dl = convert_rloc_to_loc(*dl,
				 ent_size + tp->args[i].offset);
		} else
			/* Just fetching data normally */
			call_fetch(&tp->args[i].fetch, regs,
				   data + tp->args[i].offset);
	}
}

1372
/* Kprobe handler */
1373
static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
1374
{
1375
	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1376
	struct kprobe_trace_entry_head *entry;
1377
	struct ring_buffer_event *event;
1378
	struct ring_buffer *buffer;
1379
	int size, dsize, pc;
1380
	unsigned long irq_flags;
1381
	struct ftrace_event_call *call = &tp->call;
1382

1383 1384
	tp->nhit++;

1385 1386 1387
	local_save_flags(irq_flags);
	pc = preempt_count();

1388 1389
	dsize = __get_data_size(tp, regs);
	size = sizeof(*entry) + tp->size + dsize;
1390

1391 1392
	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
						  size, irq_flags, pc);
1393
	if (!event)
1394
		return;
1395 1396 1397

	entry = ring_buffer_event_data(event);
	entry->ip = (unsigned long)kp->addr;
1398
	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1399

1400 1401
	if (!filter_current_check_discard(buffer, call, entry, event))
		trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1402 1403 1404
}

/* Kretprobe handler */
1405
static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
1406 1407 1408
					  struct pt_regs *regs)
{
	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
1409
	struct kretprobe_trace_entry_head *entry;
1410
	struct ring_buffer_event *event;
1411
	struct ring_buffer *buffer;
1412
	int size, pc, dsize;
1413
	unsigned long irq_flags;
1414
	struct ftrace_event_call *call = &tp->call;
1415 1416 1417 1418

	local_save_flags(irq_flags);
	pc = preempt_count();

1419 1420
	dsize = __get_data_size(tp, regs);
	size = sizeof(*entry) + tp->size + dsize;
1421

1422 1423
	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
						  size, irq_flags, pc);
1424
	if (!event)
1425
		return;
1426 1427

	entry = ring_buffer_event_data(event);
1428
	entry->func = (unsigned long)tp->rp.kp.addr;
1429
	entry->ret_ip = (unsigned long)ri->ret_addr;
1430
	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1431

1432 1433
	if (!filter_current_check_discard(buffer, call, entry, event))
		trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
1434 1435 1436 1437
}

/* Event entry printers */
enum print_line_t
1438 1439
print_kprobe_event(struct trace_iterator *iter, int flags,
		   struct trace_event *event)
1440
{
1441
	struct kprobe_trace_entry_head *field;
1442
	struct trace_seq *s = &iter->seq;
1443
	struct trace_probe *tp;
1444
	u8 *data;
1445 1446
	int i;

1447
	field = (struct kprobe_trace_entry_head *)iter->ent;
1448
	tp = container_of(event, struct trace_probe, call.event);
1449

1450 1451 1452
	if (!trace_seq_printf(s, "%s: (", tp->call.name))
		goto partial;

1453 1454 1455
	if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
		goto partial;

1456
	if (!trace_seq_puts(s, ")"))
1457 1458
		goto partial;

1459 1460 1461
	data = (u8 *)&field[1];
	for (i = 0; i < tp->nr_args; i++)
		if (!tp->args[i].type->print(s, tp->args[i].name,
1462
					     data + tp->args[i].offset, field))
1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473
			goto partial;

	if (!trace_seq_puts(s, "\n"))
		goto partial;

	return TRACE_TYPE_HANDLED;
partial:
	return TRACE_TYPE_PARTIAL_LINE;
}

enum print_line_t
1474 1475
print_kretprobe_event(struct trace_iterator *iter, int flags,
		      struct trace_event *event)
1476
{
1477
	struct kretprobe_trace_entry_head *field;
1478
	struct trace_seq *s = &iter->seq;
1479
	struct trace_probe *tp;
1480
	u8 *data;
1481 1482
	int i;

1483
	field = (struct kretprobe_trace_entry_head *)iter->ent;
1484
	tp = container_of(event, struct trace_probe, call.event);
1485

1486 1487 1488
	if (!trace_seq_printf(s, "%s: (", tp->call.name))
		goto partial;

1489 1490 1491 1492 1493 1494 1495 1496 1497
	if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
		goto partial;

	if (!trace_seq_puts(s, " <- "))
		goto partial;

	if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
		goto partial;

1498
	if (!trace_seq_puts(s, ")"))
1499 1500
		goto partial;

1501 1502 1503
	data = (u8 *)&field[1];
	for (i = 0; i < tp->nr_args; i++)
		if (!tp->args[i].type->print(s, tp->args[i].name,
1504
					     data + tp->args[i].offset, field))
1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518
			goto partial;

	if (!trace_seq_puts(s, "\n"))
		goto partial;

	return TRACE_TYPE_HANDLED;
partial:
	return TRACE_TYPE_PARTIAL_LINE;
}

static int probe_event_enable(struct ftrace_event_call *call)
{
	struct trace_probe *tp = (struct trace_probe *)call->data;

1519 1520
	tp->flags |= TP_FLAG_TRACE;
	if (probe_is_return(tp))
1521
		return enable_kretprobe(&tp->rp);
1522
	else
1523
		return enable_kprobe(&tp->rp.kp);
1524 1525 1526 1527 1528 1529
}

static void probe_event_disable(struct ftrace_event_call *call)
{
	struct trace_probe *tp = (struct trace_probe *)call->data;

1530 1531 1532 1533 1534 1535 1536
	tp->flags &= ~TP_FLAG_TRACE;
	if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
		if (probe_is_return(tp))
			disable_kretprobe(&tp->rp);
		else
			disable_kprobe(&tp->rp.kp);
	}
1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552
}

#undef DEFINE_FIELD
#define DEFINE_FIELD(type, item, name, is_signed)			\
	do {								\
		ret = trace_define_field(event_call, #type, name,	\
					 offsetof(typeof(field), item),	\
					 sizeof(field.item), is_signed, \
					 FILTER_OTHER);			\
		if (ret)						\
			return ret;					\
	} while (0)

static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
{
	int ret, i;
1553
	struct kprobe_trace_entry_head field;
1554 1555
	struct trace_probe *tp = (struct trace_probe *)event_call->data;

1556
	DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1557
	/* Set argument names as fields */
1558
	for (i = 0; i < tp->nr_args; i++) {
1559
		ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1560 1561 1562 1563 1564 1565 1566 1567
					 tp->args[i].name,
					 sizeof(field) + tp->args[i].offset,
					 tp->args[i].type->size,
					 tp->args[i].type->is_signed,
					 FILTER_OTHER);
		if (ret)
			return ret;
	}
1568 1569 1570 1571 1572 1573
	return 0;
}

static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
{
	int ret, i;
1574
	struct kretprobe_trace_entry_head field;
1575 1576
	struct trace_probe *tp = (struct trace_probe *)event_call->data;

1577 1578
	DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
	DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1579
	/* Set argument names as fields */
1580
	for (i = 0; i < tp->nr_args; i++) {
1581
		ret = trace_define_field(event_call, tp->args[i].type->fmttype,
1582 1583 1584 1585 1586 1587 1588 1589
					 tp->args[i].name,
					 sizeof(field) + tp->args[i].offset,
					 tp->args[i].type->size,
					 tp->args[i].type->is_signed,
					 FILTER_OTHER);
		if (ret)
			return ret;
	}
1590 1591 1592
	return 0;
}

1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613
static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
{
	int i;
	int pos = 0;

	const char *fmt, *arg;

	if (!probe_is_return(tp)) {
		fmt = "(%lx)";
		arg = "REC->" FIELD_STRING_IP;
	} else {
		fmt = "(%lx <- %lx)";
		arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
	}

	/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)

	pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);

	for (i = 0; i < tp->nr_args; i++) {
1614 1615
		pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
				tp->args[i].name, tp->args[i].type->fmt);
1616 1617 1618 1619 1620
	}

	pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);

	for (i = 0; i < tp->nr_args; i++) {
1621 1622 1623 1624 1625 1626 1627
		if (strcmp(tp->args[i].type->name, "string") == 0)
			pos += snprintf(buf + pos, LEN_OR_ZERO,
					", __get_str(%s)",
					tp->args[i].name);
		else
			pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
					tp->args[i].name);
1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653
	}

#undef LEN_OR_ZERO

	/* return the length of print_fmt */
	return pos;
}

static int set_print_fmt(struct trace_probe *tp)
{
	int len;
	char *print_fmt;

	/* First: called with 0 length to calculate the needed length */
	len = __set_print_fmt(tp, NULL, 0);
	print_fmt = kmalloc(len + 1, GFP_KERNEL);
	if (!print_fmt)
		return -ENOMEM;

	/* Second: actually write the @print_fmt */
	__set_print_fmt(tp, print_fmt, len + 1);
	tp->call.print_fmt = print_fmt;

	return 0;
}

1654
#ifdef CONFIG_PERF_EVENTS
1655 1656

/* Kprobe profile handler */
1657
static __kprobes void kprobe_perf_func(struct kprobe *kp,
1658 1659 1660 1661
					 struct pt_regs *regs)
{
	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
	struct ftrace_event_call *call = &tp->call;
1662
	struct kprobe_trace_entry_head *entry;
1663
	struct hlist_head *head;
1664
	int size, __size, dsize;
1665
	int rctx;
1666

1667 1668
	dsize = __get_data_size(tp, regs);
	__size = sizeof(*entry) + tp->size + dsize;
1669 1670
	size = ALIGN(__size + sizeof(u32), sizeof(u64));
	size -= sizeof(u32);
1671
	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1672
		     "profile buffer not large enough"))
1673
		return;
1674

S
Steven Rostedt 已提交
1675
	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1676
	if (!entry)
1677
		return;
1678 1679

	entry->ip = (unsigned long)kp->addr;
1680 1681
	memset(&entry[1], 0, dsize);
	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1682

1683
	head = this_cpu_ptr(call->perf_events);
1684
	perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
1685 1686 1687
}

/* Kretprobe profile handler */
1688
static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
1689 1690 1691 1692
					    struct pt_regs *regs)
{
	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
	struct ftrace_event_call *call = &tp->call;
1693
	struct kretprobe_trace_entry_head *entry;
1694
	struct hlist_head *head;
1695
	int size, __size, dsize;
1696
	int rctx;
1697

1698 1699
	dsize = __get_data_size(tp, regs);
	__size = sizeof(*entry) + tp->size + dsize;
1700 1701
	size = ALIGN(__size + sizeof(u32), sizeof(u64));
	size -= sizeof(u32);
1702
	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
1703
		     "profile buffer not large enough"))
1704
		return;
1705

S
Steven Rostedt 已提交
1706
	entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
1707
	if (!entry)
1708
		return;
1709

1710 1711
	entry->func = (unsigned long)tp->rp.kp.addr;
	entry->ret_ip = (unsigned long)ri->ret_addr;
1712
	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
1713

1714
	head = this_cpu_ptr(call->perf_events);
1715
	perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
1716 1717
}

1718
static int probe_perf_enable(struct ftrace_event_call *call)
1719 1720 1721
{
	struct trace_probe *tp = (struct trace_probe *)call->data;

1722
	tp->flags |= TP_FLAG_PROFILE;
1723

1724
	if (probe_is_return(tp))
1725
		return enable_kretprobe(&tp->rp);
1726
	else
1727 1728 1729
		return enable_kprobe(&tp->rp.kp);
}

1730
static void probe_perf_disable(struct ftrace_event_call *call)
1731
{
1732 1733
	struct trace_probe *tp = (struct trace_probe *)call->data;

1734
	tp->flags &= ~TP_FLAG_PROFILE;
1735

1736
	if (!(tp->flags & TP_FLAG_TRACE)) {
1737 1738 1739 1740 1741
		if (probe_is_return(tp))
			disable_kretprobe(&tp->rp);
		else
			disable_kprobe(&tp->rp.kp);
	}
1742
}
1743
#endif	/* CONFIG_PERF_EVENTS */
1744

1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764
static __kprobes
int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
{
	switch (type) {
	case TRACE_REG_REGISTER:
		return probe_event_enable(event);
	case TRACE_REG_UNREGISTER:
		probe_event_disable(event);
		return 0;

#ifdef CONFIG_PERF_EVENTS
	case TRACE_REG_PERF_REGISTER:
		return probe_perf_enable(event);
	case TRACE_REG_PERF_UNREGISTER:
		probe_perf_disable(event);
		return 0;
#endif
	}
	return 0;
}
1765 1766 1767 1768 1769

static __kprobes
int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
{
	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
1770

1771 1772
	if (tp->flags & TP_FLAG_TRACE)
		kprobe_trace_func(kp, regs);
1773
#ifdef CONFIG_PERF_EVENTS
1774
	if (tp->flags & TP_FLAG_PROFILE)
1775
		kprobe_perf_func(kp, regs);
1776
#endif
1777 1778 1779 1780 1781 1782 1783 1784 1785 1786
	return 0;	/* We don't tweek kernel, so just return 0 */
}

static __kprobes
int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
{
	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);

	if (tp->flags & TP_FLAG_TRACE)
		kretprobe_trace_func(ri, regs);
1787
#ifdef CONFIG_PERF_EVENTS
1788
	if (tp->flags & TP_FLAG_PROFILE)
1789
		kretprobe_perf_func(ri, regs);
1790
#endif
1791 1792
	return 0;	/* We don't tweek kernel, so just return 0 */
}
1793

1794 1795 1796 1797 1798 1799 1800 1801
static struct trace_event_functions kretprobe_funcs = {
	.trace		= print_kretprobe_event
};

static struct trace_event_functions kprobe_funcs = {
	.trace		= print_kprobe_event
};

1802 1803 1804 1805 1806 1807
static int register_probe_event(struct trace_probe *tp)
{
	struct ftrace_event_call *call = &tp->call;
	int ret;

	/* Initialize ftrace_event_call */
1808
	INIT_LIST_HEAD(&call->class->fields);
1809
	if (probe_is_return(tp)) {
1810
		call->event.funcs = &kretprobe_funcs;
1811
		call->class->define_fields = kretprobe_event_define_fields;
1812
	} else {
1813
		call->event.funcs = &kprobe_funcs;
1814
		call->class->define_fields = kprobe_event_define_fields;
1815
	}
1816 1817
	if (set_print_fmt(tp) < 0)
		return -ENOMEM;
1818 1819
	ret = register_ftrace_event(&call->event);
	if (!ret) {
1820
		kfree(call->print_fmt);
1821
		return -ENODEV;
1822
	}
1823
	call->flags = 0;
1824
	call->class->reg = kprobe_register;
1825 1826
	call->data = tp;
	ret = trace_add_event_call(call);
1827
	if (ret) {
1828
		pr_info("Failed to register kprobe event: %s\n", call->name);
1829
		kfree(call->print_fmt);
1830
		unregister_ftrace_event(&call->event);
1831
	}
1832 1833 1834 1835 1836
	return ret;
}

static void unregister_probe_event(struct trace_probe *tp)
{
1837
	/* tp->event is unregistered in trace_remove_event_call() */
1838
	trace_remove_event_call(&tp->call);
1839
	kfree(tp->call.print_fmt);
1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
}

/* Make a debugfs interface for controling probe points */
static __init int init_kprobe_trace(void)
{
	struct dentry *d_tracer;
	struct dentry *entry;

	d_tracer = tracing_init_dentry();
	if (!d_tracer)
		return 0;

	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
				    NULL, &kprobe_events_ops);

1855
	/* Event list interface */
1856 1857 1858
	if (!entry)
		pr_warning("Could not create debugfs "
			   "'kprobe_events' entry\n");
1859 1860 1861 1862 1863 1864 1865 1866

	/* Profile interface */
	entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
				    NULL, &kprobe_profile_ops);

	if (!entry)
		pr_warning("Could not create debugfs "
			   "'kprobe_profile' entry\n");
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	return 0;
}
fs_initcall(init_kprobe_trace);


#ifdef CONFIG_FTRACE_STARTUP_TEST

static int kprobe_trace_selftest_target(int a1, int a2, int a3,
					int a4, int a5, int a6)
{
	return a1 + a2 + a3 + a4 + a5 + a6;
}

static __init int kprobe_trace_self_tests_init(void)
{
1882
	int ret, warn = 0;
1883
	int (*target)(int, int, int, int, int, int);
1884
	struct trace_probe *tp;
1885 1886 1887 1888 1889 1890

	target = kprobe_trace_selftest_target;

	pr_info("Testing kprobe tracing: ");

	ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903
				  "$stack $stack0 +0($stack)");
	if (WARN_ON_ONCE(ret)) {
		pr_warning("error on probing function entry.\n");
		warn++;
	} else {
		/* Enable trace point */
		tp = find_probe_event("testprobe", KPROBE_EVENT_SYSTEM);
		if (WARN_ON_ONCE(tp == NULL)) {
			pr_warning("error on getting new probe.\n");
			warn++;
		} else
			probe_event_enable(&tp->call);
	}
1904 1905

	ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
1906
				  "$retval");
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	if (WARN_ON_ONCE(ret)) {
		pr_warning("error on probing function return.\n");
		warn++;
	} else {
		/* Enable trace point */
		tp = find_probe_event("testprobe2", KPROBE_EVENT_SYSTEM);
		if (WARN_ON_ONCE(tp == NULL)) {
			pr_warning("error on getting new probe.\n");
			warn++;
		} else
			probe_event_enable(&tp->call);
	}

	if (warn)
		goto end;
1922 1923 1924

	ret = target(1, 2, 3, 4, 5, 6);

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	ret = command_trace_probe("-:testprobe");
	if (WARN_ON_ONCE(ret)) {
		pr_warning("error on deleting a probe.\n");
		warn++;
	}

	ret = command_trace_probe("-:testprobe2");
	if (WARN_ON_ONCE(ret)) {
		pr_warning("error on deleting a probe.\n");
		warn++;
	}
1936

1937 1938 1939 1940 1941 1942
end:
	cleanup_all_probes();
	if (warn)
		pr_cont("NG: Some tests are failed. Please check them.\n");
	else
		pr_cont("OK\n");
1943 1944 1945 1946 1947 1948
	return 0;
}

late_initcall(kprobe_trace_self_tests_init);

#endif