OpenCloudOS-Kernel/kernel/trace/trace_probe.h

/*
 * Common header file for probe-based Dynamic events.
 *
 * 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
 *
 * This code was copied from kernel/trace/trace_kprobe.h written by
 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 *
 * Updates to make this generic:
 * Copyright (C) IBM Corporation, 2010-2011
 * Author:     Srikar Dronamraju
 */

#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>
#include <linux/perf_event.h>
#include <linux/kprobes.h>
#include <linux/stringify.h>
#include <linux/limits.h>
#include <linux/uaccess.h>
#include <asm/bitsperlong.h>

#include "trace.h"
#include "trace_output.h"

#define MAX_TRACE_ARGS		128
#define MAX_ARGSTR_LEN		63
#define MAX_EVENT_NAME_LEN	64
#define MAX_STRING_SIZE		PATH_MAX

/* Reserved field names */
#define FIELD_STRING_IP		"__probe_ip"
#define FIELD_STRING_RETIP	"__probe_ret_ip"
#define FIELD_STRING_FUNC	"__probe_func"

#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)


/* Flags for trace_probe */
#define TP_FLAG_TRACE		1
#define TP_FLAG_PROFILE		2
#define TP_FLAG_REGISTERED	4


/* 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)

/*
 * 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))

/* Data fetch function type */
typedef	void (*fetch_func_t)(struct pt_regs *, void *, void *);
/* Printing function type */
typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);

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

/* Fetch type information table */
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 */
	const char		*fmttype;	/* Name in format file */
	/* Fetch functions */
	fetch_func_t		fetch[FETCH_MTD_END];
};

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

struct probe_arg {
	struct fetch_param	fetch;
	struct fetch_param	fetch_size;
	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 */
};

struct trace_probe {
	unsigned int			flags;	/* For TP_FLAG_* */
	struct ftrace_event_class	class;
	struct ftrace_event_call	call;
	struct list_head 		files;
	ssize_t				size;	/* trace entry size */
	unsigned int			nr_args;
	struct probe_arg		args[];
};

static inline bool trace_probe_is_enabled(struct trace_probe *tp)
{
	return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
}

static inline bool trace_probe_is_registered(struct trace_probe *tp)
{
	return !!(tp->flags & TP_FLAG_REGISTERED);
}

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

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

extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
		   struct probe_arg *parg, bool is_return, bool is_kprobe);

extern int traceprobe_conflict_field_name(const char *name,
			       struct probe_arg *args, int narg);

extern void traceprobe_update_arg(struct probe_arg *arg);
extern void traceprobe_free_probe_arg(struct probe_arg *arg);

extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);

extern ssize_t traceprobe_probes_write(struct file *file,
		const char __user *buffer, size_t count, loff_t *ppos,
		int (*createfn)(int, char**));

extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));

/* Sum up total data length for dynamic arraies (strings) */
static inline __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 inline __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);
	}
}

extern int set_print_fmt(struct trace_probe *tp, bool is_return);