linux/kernel/trace/trace_probe.h

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/*
* 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/tracefs.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))
static nokprobe_inline void *get_rloc_data(u32 *dl)
{
return (u8 *)dl + get_rloc_offs(*dl);
}
/* For data_loc conversion */
static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
{
return (u8 *)ent + get_rloc_offs(*dl);
}
/* 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_file_offset,
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;
};
/* For defining macros, define string/string_size types */
typedef u32 string;
typedef u32 string_size;
#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 DECLARE_BASIC_PRINT_TYPE_FUNC(type) \
int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
void *data, void *ent); \
extern const char PRINT_TYPE_FMT_NAME(type)[]
DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
DECLARE_BASIC_PRINT_TYPE_FUNC(string);
#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
/* Declare macro for basic types */
#define DECLARE_FETCH_FUNC(method, type) \
extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs, \
void *data, void *dest)
#define DECLARE_BASIC_FETCH_FUNCS(method) \
DECLARE_FETCH_FUNC(method, u8); \
DECLARE_FETCH_FUNC(method, u16); \
DECLARE_FETCH_FUNC(method, u32); \
DECLARE_FETCH_FUNC(method, u64)
DECLARE_BASIC_FETCH_FUNCS(reg);
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL
DECLARE_BASIC_FETCH_FUNCS(retval);
#define fetch_retval_string NULL
#define fetch_retval_string_size NULL
DECLARE_BASIC_FETCH_FUNCS(symbol);
DECLARE_FETCH_FUNC(symbol, string);
DECLARE_FETCH_FUNC(symbol, string_size);
DECLARE_BASIC_FETCH_FUNCS(deref);
DECLARE_FETCH_FUNC(deref, string);
DECLARE_FETCH_FUNC(deref, string_size);
DECLARE_BASIC_FETCH_FUNCS(bitfield);
#define fetch_bitfield_string NULL
#define fetch_bitfield_string_size NULL
/*
* Define macro for basic types - we don't need to define s* types, because
* we have to care only about bitwidth at recording time.
*/
#define DEFINE_BASIC_FETCH_FUNCS(method) \
DEFINE_FETCH_##method(u8) \
DEFINE_FETCH_##method(u16) \
DEFINE_FETCH_##method(u32) \
DEFINE_FETCH_##method(u64)
/* 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)
#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), \
ASSIGN_FETCH_FUNC(bitfield, ftype), \
ASSIGN_FETCH_FUNC(file_offset, ftype), \
} \
}
#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
__ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
#define ASSIGN_FETCH_TYPE_END {}
#define FETCH_TYPE_STRING 0
#define FETCH_TYPE_STRSIZE 1
#ifdef CONFIG_KPROBE_EVENT
struct symbol_cache;
unsigned long update_symbol_cache(struct symbol_cache *sc);
void free_symbol_cache(struct symbol_cache *sc);
struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
#else
tracing/probes: Fix build break on !CONFIG_KPROBE_EVENT When kprobe-based dynamic event tracer is not enabled, it caused following build error: kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8dd): undefined reference to `fetch_symbol_u8' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8e9): undefined reference to `fetch_symbol_u16' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c8f5): undefined reference to `fetch_symbol_u32' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c901): undefined reference to `fetch_symbol_u64' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c909): undefined reference to `fetch_symbol_string' kernel/built-in.o: In function `traceprobe_update_arg': (.text+0x10c913): undefined reference to `fetch_symbol_string_size' ... It was due to the fetch methods are referred from CHECK_FETCH_FUNCS macro and since it was only defined in trace_kprobe.c. Move NULL definition of such fetch functions to the header file. Note, it also requires CONFIG_BRANCH_PROFILING enabled to trigger this failure as well. This is because the "fetch_symbol_*" variables are referenced in a "else if" statement that will only call update_symbol_cache(), which is a static inline stub function when CONFIG_KPROBE_EVENT is not enabled. gcc is smart enough to optimize this "else if" out and that also removes the code that references the undefined variables. But when BRANCH_PROFILING is enabled, it fools gcc into keeping the if statement around and thus references the undefined symbols and fails to build. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-01-03 13:12:46 +08:00
/* uprobes do not support symbol fetch methods */
#define fetch_symbol_u8 NULL
#define fetch_symbol_u16 NULL
#define fetch_symbol_u32 NULL
#define fetch_symbol_u64 NULL
#define fetch_symbol_string NULL
#define fetch_symbol_string_size NULL
struct symbol_cache {
};
static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
{
return 0;
}
static inline void __used free_symbol_cache(struct symbol_cache *sc)
{
}
static inline struct symbol_cache * __used
alloc_symbol_cache(const char *sym, long offset)
{
return NULL;
}
#endif /* CONFIG_KPROBE_EVENT */
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 trace_event_class class;
struct trace_event_call call;
struct list_head files;
ssize_t size; /* trace entry size */
unsigned int nr_args;
struct probe_arg args[];
};
struct event_file_link {
struct trace_event_file *file;
struct list_head list;
};
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 nokprobe_inline 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;
}
static inline struct event_file_link *
find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
{
struct event_file_link *link;
list_for_each_entry(link, &tp->files, list)
if (link->file == file)
return link;
return NULL;
}
extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
struct probe_arg *parg, bool is_return, bool is_kprobe,
const struct fetch_type *ftbl);
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 nokprobe_inline 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 nokprobe_inline 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);