cregit-Linux how code gets into the kernel

Release 4.7 kernel/trace/trace_probe.h

Directory: kernel/trace
/*
 * 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); }

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

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/* 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 /* 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; }

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static inline void __used free_symbol_cache(struct symbol_cache *sc) { }

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static inline struct symbol_cache * __used alloc_symbol_cache(const char *sym, long offset) { return NULL; }

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#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)); }

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

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

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

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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; }

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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; }

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/* 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); } }

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

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masami hiramatsumasami hiramatsu60.42%15.56%
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Directory: kernel/trace
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