LXR linux/kernel/trace/trace

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Common header file for probe-based Dynamic events.
   4 *
   5 * This code was copied from kernel/trace/trace_kprobe.h written by
   6 * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7 *
   8 * Updates to make this generic:
   9 * Copyright (C) IBM Corporation, 2010-2011
  10 * Author:     Srikar Dronamraju
  11 */
  12
  13#include <linux/seq_file.h>
  14#include <linux/slab.h>
  15#include <linux/smp.h>
  16#include <linux/tracefs.h>
  17#include <linux/types.h>
  18#include <linux/string.h>
  19#include <linux/ctype.h>
  20#include <linux/ptrace.h>
  21#include <linux/perf_event.h>
  22#include <linux/kprobes.h>
  23#include <linux/stringify.h>
  24#include <linux/limits.h>
  25#include <linux/uaccess.h>
  26#include <asm/bitsperlong.h>
  27
  28#include "trace.h"
  29#include "trace_output.h"
  30
  31#define MAX_TRACE_ARGS          128
  32#define MAX_ARGSTR_LEN          63
  33#define MAX_STRING_SIZE         PATH_MAX
  34
  35/* Reserved field names */
  36#define FIELD_STRING_IP         "__probe_ip"
  37#define FIELD_STRING_RETIP      "__probe_ret_ip"
  38#define FIELD_STRING_FUNC       "__probe_func"
  39
  40#undef DEFINE_FIELD
  41#define DEFINE_FIELD(type, item, name, is_signed)                       \
  42        do {                                                            \
  43                ret = trace_define_field(event_call, #type, name,       \
  44                                         offsetof(typeof(field), item), \
  45                                         sizeof(field.item), is_signed, \
  46                                         FILTER_OTHER);                 \
  47                if (ret)                                                \
  48                        return ret;                                     \
  49        } while (0)
  50
  51
  52/* Flags for trace_probe */
  53#define TP_FLAG_TRACE           1
  54#define TP_FLAG_PROFILE         2
  55#define TP_FLAG_REGISTERED      4
  56
  57
  58/* data_rloc: data relative location, compatible with u32 */
  59#define make_data_rloc(len, roffs)      \
  60        (((u32)(len) << 16) | ((u32)(roffs) & 0xffff))
  61#define get_rloc_len(dl)                ((u32)(dl) >> 16)
  62#define get_rloc_offs(dl)               ((u32)(dl) & 0xffff)
  63
  64/*
  65 * Convert data_rloc to data_loc:
  66 *  data_rloc stores the offset from data_rloc itself, but data_loc
  67 *  stores the offset from event entry.
  68 */
  69#define convert_rloc_to_loc(dl, offs)   ((u32)(dl) + (offs))
  70
  71static nokprobe_inline void *get_rloc_data(u32 *dl)
  72{
  73        return (u8 *)dl + get_rloc_offs(*dl);
  74}
  75
  76/* For data_loc conversion */
  77static nokprobe_inline void *get_loc_data(u32 *dl, void *ent)
  78{
  79        return (u8 *)ent + get_rloc_offs(*dl);
  80}
  81
  82/* Data fetch function type */
  83typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
  84/* Printing function type */
  85typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *, void *);
  86
  87/* Fetch types */
  88enum {
  89        FETCH_MTD_reg = 0,
  90        FETCH_MTD_stack,
  91        FETCH_MTD_retval,
  92        FETCH_MTD_comm,
  93        FETCH_MTD_memory,
  94        FETCH_MTD_symbol,
  95        FETCH_MTD_deref,
  96        FETCH_MTD_bitfield,
  97        FETCH_MTD_file_offset,
  98        FETCH_MTD_END,
  99};
 100
 101/* Fetch type information table */
 102struct fetch_type {
 103        const char              *name;          /* Name of type */
 104        size_t                  size;           /* Byte size of type */
 105        int                     is_signed;      /* Signed flag */
 106        print_type_func_t       print;          /* Print functions */
 107        const char              *fmt;           /* Fromat string */
 108        const char              *fmttype;       /* Name in format file */
 109        /* Fetch functions */
 110        fetch_func_t            fetch[FETCH_MTD_END];
 111};
 112
 113struct fetch_param {
 114        fetch_func_t            fn;
 115        void                    *data;
 116};
 117
 118/* For defining macros, define string/string_size types */
 119typedef u32 string;
 120typedef u32 string_size;
 121
 122#define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
 123#define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
 124
 125/* Printing  in basic type function template */
 126#define DECLARE_BASIC_PRINT_TYPE_FUNC(type)                             \
 127int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name,   \
 128                                void *data, void *ent);                 \
 129extern const char PRINT_TYPE_FMT_NAME(type)[]
 130
 131DECLARE_BASIC_PRINT_TYPE_FUNC(u8);
 132DECLARE_BASIC_PRINT_TYPE_FUNC(u16);
 133DECLARE_BASIC_PRINT_TYPE_FUNC(u32);
 134DECLARE_BASIC_PRINT_TYPE_FUNC(u64);
 135DECLARE_BASIC_PRINT_TYPE_FUNC(s8);
 136DECLARE_BASIC_PRINT_TYPE_FUNC(s16);
 137DECLARE_BASIC_PRINT_TYPE_FUNC(s32);
 138DECLARE_BASIC_PRINT_TYPE_FUNC(s64);
 139DECLARE_BASIC_PRINT_TYPE_FUNC(x8);
 140DECLARE_BASIC_PRINT_TYPE_FUNC(x16);
 141DECLARE_BASIC_PRINT_TYPE_FUNC(x32);
 142DECLARE_BASIC_PRINT_TYPE_FUNC(x64);
 143
 144DECLARE_BASIC_PRINT_TYPE_FUNC(string);
 145
 146#define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
 147
 148/* Declare macro for basic types */
 149#define DECLARE_FETCH_FUNC(method, type)                                \
 150extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs,         \
 151                                          void *data, void *dest)
 152
 153#define DECLARE_BASIC_FETCH_FUNCS(method)       \
 154DECLARE_FETCH_FUNC(method, u8);                 \
 155DECLARE_FETCH_FUNC(method, u16);                \
 156DECLARE_FETCH_FUNC(method, u32);                \
 157DECLARE_FETCH_FUNC(method, u64)
 158
 159DECLARE_BASIC_FETCH_FUNCS(reg);
 160#define fetch_reg_string                        NULL
 161#define fetch_reg_string_size                   NULL
 162
 163DECLARE_BASIC_FETCH_FUNCS(retval);
 164#define fetch_retval_string                     NULL
 165#define fetch_retval_string_size                NULL
 166
 167DECLARE_BASIC_FETCH_FUNCS(symbol);
 168DECLARE_FETCH_FUNC(symbol, string);
 169DECLARE_FETCH_FUNC(symbol, string_size);
 170
 171DECLARE_BASIC_FETCH_FUNCS(deref);
 172DECLARE_FETCH_FUNC(deref, string);
 173DECLARE_FETCH_FUNC(deref, string_size);
 174
 175DECLARE_BASIC_FETCH_FUNCS(bitfield);
 176#define fetch_bitfield_string                   NULL
 177#define fetch_bitfield_string_size              NULL
 178
 179/* comm only makes sense as a string */
 180#define fetch_comm_u8           NULL
 181#define fetch_comm_u16          NULL
 182#define fetch_comm_u32          NULL
 183#define fetch_comm_u64          NULL
 184DECLARE_FETCH_FUNC(comm, string);
 185DECLARE_FETCH_FUNC(comm, string_size);
 186
 187/*
 188 * Define macro for basic types - we don't need to define s* types, because
 189 * we have to care only about bitwidth at recording time.
 190 */
 191#define DEFINE_BASIC_FETCH_FUNCS(method) \
 192DEFINE_FETCH_##method(u8)               \
 193DEFINE_FETCH_##method(u16)              \
 194DEFINE_FETCH_##method(u32)              \
 195DEFINE_FETCH_##method(u64)
 196
 197/* Default (unsigned long) fetch type */
 198#define __DEFAULT_FETCH_TYPE(t) x##t
 199#define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 200#define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 201#define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 202
 203#define ASSIGN_FETCH_FUNC(method, type) \
 204        [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 205
 206#define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 207        {.name = _name,                         \
 208         .size = _size,                                 \
 209         .is_signed = sign,                             \
 210         .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 211         .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 212         .fmttype = _fmttype,                           \
 213         .fetch = {                                     \
 214ASSIGN_FETCH_FUNC(reg, ftype),                          \
 215ASSIGN_FETCH_FUNC(stack, ftype),                        \
 216ASSIGN_FETCH_FUNC(retval, ftype),                       \
 217ASSIGN_FETCH_FUNC(comm, ftype),                         \
 218ASSIGN_FETCH_FUNC(memory, ftype),                       \
 219ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 220ASSIGN_FETCH_FUNC(deref, ftype),                        \
 221ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 222ASSIGN_FETCH_FUNC(file_offset, ftype),                  \
 223          }                                             \
 224        }
 225
 226#define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 227        __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 228
 229/* If ptype is an alias of atype, use this macro (show atype in format) */
 230#define ASSIGN_FETCH_TYPE_ALIAS(ptype, atype, ftype, sign)              \
 231        __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #atype)
 232
 233#define ASSIGN_FETCH_TYPE_END {}
 234
 235#define FETCH_TYPE_STRING       0
 236#define FETCH_TYPE_STRSIZE      1
 237
 238#ifdef CONFIG_KPROBE_EVENTS
 239struct symbol_cache;
 240unsigned long update_symbol_cache(struct symbol_cache *sc);
 241void free_symbol_cache(struct symbol_cache *sc);
 242struct symbol_cache *alloc_symbol_cache(const char *sym, long offset);
 243bool trace_kprobe_on_func_entry(struct trace_event_call *call);
 244bool trace_kprobe_error_injectable(struct trace_event_call *call);
 245#else
 246/* uprobes do not support symbol fetch methods */
 247#define fetch_symbol_u8                 NULL
 248#define fetch_symbol_u16                NULL
 249#define fetch_symbol_u32                NULL
 250#define fetch_symbol_u64                NULL
 251#define fetch_symbol_string             NULL
 252#define fetch_symbol_string_size        NULL
 253
 254struct symbol_cache {
 255};
 256static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc)
 257{
 258        return 0;
 259}
 260
 261static inline void __used free_symbol_cache(struct symbol_cache *sc)
 262{
 263}
 264
 265static inline struct symbol_cache * __used
 266alloc_symbol_cache(const char *sym, long offset)
 267{
 268        return NULL;
 269}
 270
 271static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 272{
 273        return false;
 274}
 275
 276static inline bool trace_kprobe_error_injectable(struct trace_event_call *call)
 277{
 278        return false;
 279}
 280#endif /* CONFIG_KPROBE_EVENTS */
 281
 282struct probe_arg {
 283        struct fetch_param      fetch;
 284        struct fetch_param      fetch_size;
 285        unsigned int            offset; /* Offset from argument entry */
 286        const char              *name;  /* Name of this argument */
 287        const char              *comm;  /* Command of this argument */
 288        const struct fetch_type *type;  /* Type of this argument */
 289};
 290
 291struct trace_probe {
 292        unsigned int                    flags;  /* For TP_FLAG_* */
 293        struct trace_event_class        class;
 294        struct trace_event_call         call;
 295        struct list_head                files;
 296        ssize_t                         size;   /* trace entry size */
 297        unsigned int                    nr_args;
 298        struct probe_arg                args[];
 299};
 300
 301struct event_file_link {
 302        struct trace_event_file         *file;
 303        struct list_head                list;
 304};
 305
 306static inline bool trace_probe_is_enabled(struct trace_probe *tp)
 307{
 308        return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
 309}
 310
 311static inline bool trace_probe_is_registered(struct trace_probe *tp)
 312{
 313        return !!(tp->flags & TP_FLAG_REGISTERED);
 314}
 315
 316static nokprobe_inline void call_fetch(struct fetch_param *fprm,
 317                                 struct pt_regs *regs, void *dest)
 318{
 319        return fprm->fn(regs, fprm->data, dest);
 320}
 321
 322/* Check the name is good for event/group/fields */
 323static inline bool is_good_name(const char *name)
 324{
 325        if (!isalpha(*name) && *name != '_')
 326                return false;
 327        while (*++name != '\0') {
 328                if (!isalpha(*name) && !isdigit(*name) && *name != '_')
 329                        return false;
 330        }
 331        return true;
 332}
 333
 334static inline struct event_file_link *
 335find_event_file_link(struct trace_probe *tp, struct trace_event_file *file)
 336{
 337        struct event_file_link *link;
 338
 339        list_for_each_entry(link, &tp->files, list)
 340                if (link->file == file)
 341                        return link;
 342
 343        return NULL;
 344}
 345
 346extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 347                   struct probe_arg *parg, bool is_return, bool is_kprobe,
 348                   const struct fetch_type *ftbl);
 349
 350extern int traceprobe_conflict_field_name(const char *name,
 351                               struct probe_arg *args, int narg);
 352
 353extern void traceprobe_update_arg(struct probe_arg *arg);
 354extern void traceprobe_free_probe_arg(struct probe_arg *arg);
 355
 356extern int traceprobe_split_symbol_offset(char *symbol, long *offset);
 357
 358/* Sum up total data length for dynamic arraies (strings) */
 359static nokprobe_inline int
 360__get_data_size(struct trace_probe *tp, struct pt_regs *regs)
 361{
 362        int i, ret = 0;
 363        u32 len;
 364
 365        for (i = 0; i < tp->nr_args; i++)
 366                if (unlikely(tp->args[i].fetch_size.fn)) {
 367                        call_fetch(&tp->args[i].fetch_size, regs, &len);
 368                        ret += len;
 369                }
 370
 371        return ret;
 372}
 373
 374/* Store the value of each argument */
 375static nokprobe_inline void
 376store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs,
 377                 u8 *data, int maxlen)
 378{
 379        int i;
 380        u32 end = tp->size;
 381        u32 *dl;        /* Data (relative) location */
 382
 383        for (i = 0; i < tp->nr_args; i++) {
 384                if (unlikely(tp->args[i].fetch_size.fn)) {
 385                        /*
 386                         * First, we set the relative location and
 387                         * maximum data length to *dl
 388                         */
 389                        dl = (u32 *)(data + tp->args[i].offset);
 390                        *dl = make_data_rloc(maxlen, end - tp->args[i].offset);
 391                        /* Then try to fetch string or dynamic array data */
 392                        call_fetch(&tp->args[i].fetch, regs, dl);
 393                        /* Reduce maximum length */
 394                        end += get_rloc_len(*dl);
 395                        maxlen -= get_rloc_len(*dl);
 396                        /* Trick here, convert data_rloc to data_loc */
 397                        *dl = convert_rloc_to_loc(*dl,
 398                                 ent_size + tp->args[i].offset);
 399                } else
 400                        /* Just fetching data normally */
 401                        call_fetch(&tp->args[i].fetch, regs,
 402                                   data + tp->args[i].offset);
 403        }
 404}
 405
 406extern int set_print_fmt(struct trace_probe *tp, bool is_return);
 407
 408#ifdef CONFIG_PERF_EVENTS
 409extern struct trace_event_call *
 410create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
 411                          bool is_return);
 412extern void destroy_local_trace_kprobe(struct trace_event_call *event_call);
 413
 414extern struct trace_event_call *
 415create_local_trace_uprobe(char *name, unsigned long offs, bool is_return);
 416extern void destroy_local_trace_uprobe(struct trace_event_call *event_call);
 417#endif
 418