LXR linux/kernel/trace/trace

   1/*
   2 * Common header file for probe-based Dynamic events.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public License
  14 * along with this program; if not, write to the Free Software
  15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16 *
  17 * This code was copied from kernel/trace/trace_kprobe.h written by
  18 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
  19 *
  20 * Updates to make this generic:
  21 * Copyright (C) IBM Corporation, 2010-2011
  22 * Author:     Srikar Dronamraju
  23 */
  24
  25#include <linux/seq_file.h>
  26#include <linux/slab.h>
  27#include <linux/smp.h>
  28#include <linux/tracefs.h>
  29#include <linux/types.h>
  30#include <linux/string.h>
  31#include <linux/ctype.h>
  32#include <linux/ptrace.h>
  33#include <linux/perf_event.h>
  34#include <linux/kprobes.h>
  35#include <linux/stringify.h>
  36#include <linux/limits.h>
  37#include <linux/uaccess.h>
  38#include <asm/bitsperlong.h>
  39
  40#include "trace.h"
  41#include "trace_output.h"
  42
  43#define MAX_TRACE_ARGS          128
  44#define MAX_ARGSTR_LEN          63
  45#define MAX_EVENT_NAME_LEN      64
  46#define MAX_STRING_SIZE         PATH_MAX
  47
  48/* Reserved field names */
  49#define FIELD_STRING_IP         "__probe_ip"
  50#define FIELD_STRING_RETIP      "__probe_ret_ip"
  51#define FIELD_STRING_FUNC       "__probe_func"
  52
  53#undef DEFINE_FIELD
  54#define DEFINE_FIELD(type, item, name, is_signed)                       \
  55        do {                                                            \
  56                ret = trace_define_field(event_call, #type, name,       \
  57                                         offsetof(typeof(field), item), \
  58                                         sizeof(field.item), is_signed, \
  59                                         FILTER_OTHER);                 \
  60                if (ret)                                                \
  61                        return ret;                                     \
  62        } while (0)
  63
  64
  65/* Flags for trace_probe */
  66#define TP_FLAG_TRACE           1
  67#define TP_FLAG_PROFILE         2
  68#define TP_FLAG_REGISTERED      4
  69
  70
  71/* data_rloc: data relative location, compatible with u32 */
  72#define make_data_rloc(len, roffs)      \
  73        (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
  74#define get_rloc_len(dl)                ((u32)(dl) >> 16)
  75#define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
  76
  77/*
  78 * Convert data_rloc to data_loc:
  79 *  data_rloc stores the offset from data_rloc itself, but data_loc
  80 *  stores the offset from event entry.
  81 */
  82#define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
  83
  84static nokprobe_inline void *get_rloc_data(u32 *dl)
  85{
  86        return (u8 *)dl + get_rloc_offs(*dl);
  87}
  88
  89/* For data_loc conversion */
  90static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
  91{
  92        return (u8 *)ent + get_rloc_offs(*dl);
  93}
  94
  95/* Data fetch function type */
  96typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
  97/* Printing function type */
  98typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
  99
 100/* Fetch types */
 101enum {
 102        FETCH_MTD_reg = 0,
 103        FETCH_MTD_stack,
 104        FETCH_MTD_retval,
 105        FETCH_MTD_memory,
 106        FETCH_MTD_symbol,
 107        FETCH_MTD_deref,
 108        FETCH_MTD_bitfield,
 109        FETCH_MTD_file_offset,
 110        FETCH_MTD_END,
 111};
 112
 113/* Fetch type information table */
 114struct fetch_type {
 115        const char              *name;          /* Name of type */
 116        size_t                  size;           /* Byte size of type */
 117        int                     is_signed;      /* Signed flag */
 118        print_type_func_t       print;          /* Print functions */
 119        const char              *fmt;           /* Fromat string */
 120        const char              *fmttype;       /* Name in format file */
 121        /* Fetch functions */
 122        fetch_func_t            fetch[FETCH_MTD_END];
 123};
 124
 125struct fetch_param {
 126        fetch_func_t            fn;
 127        void                    *data;
 128};
 129
 130/* For defining macros, define string/string_size types */
 131typedef u32 string;
 132typedef u32 string_size;
 133
 134#define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
 135#define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
 136
 137/* Printing  in basic type function template */
 138#define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
 139int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 140                                void *data, void *ent);                 \
 141extern const char PRINT_TYPE_FMT_NAME(type)[]
 142
 143DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
 144DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
 145DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
 146DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
 147DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
 148DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
 149DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
 150DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
 151DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 152
 153#define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 154
 155/* Declare macro for basic types */
 156#define DECLARE_FETCH_FUNC(method, type)                                \
 157extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
 158                                          void *data, void *dest)
 159
 160#define DECLARE_BASIC_FETCH_FUNCS(method)       \
 161DECLARE_FETCH_FUNC(method, u8);                 \
 162DECLARE_FETCH_FUNC(method, u16);                \
 163DECLARE_FETCH_FUNC(method, u32);                \
 164DECLARE_FETCH_FUNC(method, u64)
 165
 166DECLARE_BASIC_FETCH_FUNCS(reg);
 167#define fetch_reg_string                        NULL
 168#define fetch_reg_string_size                   NULL
 169
 170DECLARE_BASIC_FETCH_FUNCS(retval);
 171#define fetch_retval_string                     NULL
 172#define fetch_retval_string_size                NULL
 173
 174DECLARE_BASIC_FETCH_FUNCS(symbol);
 175DECLARE_FETCH_FUNC(symbol, string);
 176DECLARE_FETCH_FUNC(symbol, string_size);
 177
 178DECLARE_BASIC_FETCH_FUNCS(deref);
 179DECLARE_FETCH_FUNC(deref, string);
 180DECLARE_FETCH_FUNC(deref, string_size);
 181
 182DECLARE_BASIC_FETCH_FUNCS(bitfield);
 183#define fetch_bitfield_string                   NULL
 184#define fetch_bitfield_string_size              NULL
 185
 186/*
 187 * Define macro for basic types - we don't need to define s* types, because
 188 * we have to care only about bitwidth at recording time.
 189 */
 190#define DEFINE_BASIC_FETCH_FUNCS(method) \
 191DEFINE_FETCH_##method(u8)               \
 192DEFINE_FETCH_##method(u16)              \
 193DEFINE_FETCH_##method(u32)              \
 194DEFINE_FETCH_##method(u64)
 195
 196/* Default (unsigned long) fetch type */
 197#define __DEFAULT_FETCH_TYPE(t) u##t
 198#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 199#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 200#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 201
 202#define ASSIGN_FETCH_FUNC(method, type) \
 203        [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 204
 205#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 206        {.name = _name,                         \
 207         .size = _size,                                 \
 208         .is_signed = sign,                             \
 209         .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 210         .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 211         .fmttype = _fmttype,                           \
 212         .fetch = {                                     \
 213ASSIGN_FETCH_FUNC(reg, ftype),                          \
 214ASSIGN_FETCH_FUNC(stack, ftype),                        \
 215ASSIGN_FETCH_FUNC(retval, ftype),                       \
 216ASSIGN_FETCH_FUNC(memory, ftype),                       \
 217ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 218ASSIGN_FETCH_FUNC(deref, ftype),                        \
 219ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 220ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
 221          }                                             \
 222        }
 223
 224#define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 225        __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 226
 227#define ASSIGN_FETCH_TYPE_END {}
 228
 229#define FETCH_TYPE_STRING       0
 230#define FETCH_TYPE_STRSIZE      1
 231
 232#ifdef CONFIG_KPROBE_EVENT
 233struct symbol_cache;
 234unsigned long update_symbol_cache(struct symbol_cache *sc);
 235void free_symbol_cache(struct symbol_cache *sc);
 236struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
 237#else
 238/* uprobes do not support symbol fetch methods */
 239#define fetch_symbol_u8                 NULL
 240#define fetch_symbol_u16                NULL
 241#define fetch_symbol_u32                NULL
 242#define fetch_symbol_u64                NULL
 243#define fetch_symbol_string             NULL
 244#define fetch_symbol_string_size        NULL
 245
 246struct symbol_cache {
 247};
 248static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
 249{
 250        return 0;
 251}
 252
 253static inline void __used free_symbol_cache(struct symbol_cache *sc)
 254{
 255}
 256
 257static inline struct symbol_cache * __used
 258alloc_symbol_cache(const char *sym, long offset)
 259{
 260        return NULL;
 261}
 262#endif /* CONFIG_KPROBE_EVENT */
 263
 264struct probe_arg {
 265        struct fetch_param      fetch;
 266        struct fetch_param      fetch_size;
 267        unsigned int            offset; /* Offset from argument entry */
 268        const char              *name;  /* Name of this argument */
 269        const char              *comm;  /* Command of this argument */
 270        const struct fetch_type *type;  /* Type of this argument */
 271};
 272
 273struct trace_probe {
 274        unsigned int                    flags;  /* For TP_FLAG_* */
 275        struct trace_event_class        class;
 276        struct trace_event_call         call;
 277        struct list_head                files;
 278        ssize_t                         size;   /* trace entry size */
 279        unsigned int                    nr_args;
 280        struct probe_arg                args[];
 281};
 282
 283struct event_file_link {
 284        struct trace_event_file         *file;
 285        struct list_head                list;
 286};
 287
 288static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 289{
 290        return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 291}
 292
 293static inline bool trace_probe_is_registered(struct trace_probe *tp)
 294{
 295        return !!(tp->flags & TP_FLAG_REGISTERED);
 296}
 297
 298static nokprobe_inline void call_fetch(struct fetch_param *fprm,
 299                                 struct pt_regs *regs, void *dest)
 300{
 301        return fprm->fn(regs, fprm->data, dest);
 302}
 303
 304/* Check the name is good for event/group/fields */
 305static inline bool is_good_name(const char *name)
 306{
 307        if (!isalpha(*name) && *name != '_')
 308                return false;
 309        while (*++name != '\0') {
 310                if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 311                        return false;
 312        }
 313        return true;
 314}
 315
 316static inline struct event_file_link *
 317find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
 318{
 319        struct event_file_link *link;
 320
 321        list_for_each_entry(link, &tp->files, list)
 322                if (link->file == file)
 323                        return link;
 324
 325        return NULL;
 326}
 327
 328extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 329                   struct probe_arg *parg, bool is_return, bool is_kprobe,
 330                   const struct fetch_type *ftbl);
 331
 332extern int traceprobe_conflict_field_name(const char *name,
 333                               struct probe_arg *args, int narg);
 334
 335extern void traceprobe_update_arg(struct probe_arg *arg);
 336extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 337
 338extern int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset);
 339
 340extern ssize_t traceprobe_probes_write(struct file *file,
 341                const char __user *buffer, size_t count, loff_t *ppos,
 342                int (*createfn)(int, char**));
 343
 344extern int traceprobe_command(const char *buf, int (*createfn)(int, char**));
 345
 346/* Sum up total data length for dynamic arraies (strings) */
 347static nokprobe_inline int
 348__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 349{
 350        int i, ret = 0;
 351        u32 len;
 352
 353        for (i = 0; i < tp->nr_args; i++)
 354                if (unlikely(tp->args[i].fetch_size.fn)) {
 355                        call_fetch(&tp->args[i].fetch_size, regs, &len);
 356                        ret += len;
 357                }
 358
 359        return ret;
 360}
 361
 362/* Store the value of each argument */
 363static nokprobe_inline void
 364store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 365                 u8 *data, int maxlen)
 366{
 367        int i;
 368        u32 end = tp->size;
 369        u32 *dl;        /* Data (relative) location */
 370
 371        for (i = 0; i < tp->nr_args; i++) {
 372                if (unlikely(tp->args[i].fetch_size.fn)) {
 373                        /*
 374                         * First, we set the relative location and
 375                         * maximum data length to *dl
 376                         */
 377                        dl = (u32 *)(data + tp->args[i].offset);
 378                        *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
 379                        /* Then try to fetch string or dynamic array data */
 380                        call_fetch(&tp->args[i].fetch, regs, dl);
 381                        /* Reduce maximum length */
 382                        end += get_rloc_len(*dl);
 383                        maxlen -= get_rloc_len(*dl);
 384                        /* Trick here, convert data_rloc to data_loc */
 385                        *dl = convert_rloc_to_loc(*dl,
 386                                 ent_size + tp->args[i].offset);
 387                } else
 388                        /* Just fetching data normally */
 389                        call_fetch(&tp->args[i].fetch, regs,
 390                                   data + tp->args[i].offset);
 391        }
 392}
 393
 394extern int set_print_fmt(struct trace_probe *tp, bool is_return);
 395