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mirrored from https://android.googlesource.com/kernel/common.git
/
trace_kprobe.c
2127 lines (1843 loc) · 52.9 KB
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trace_kprobe.c
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/*
* Kprobes-based tracing events
*
* Created by Masami Hiramatsu <mhiramat@redhat.com>
*
* 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
*/
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#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/stringify.h>
#include <linux/limits.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
#define KPROBE_EVENT_SYSTEM "kprobes"
/* Reserved field names */
#define FIELD_STRING_IP "__probe_ip"
#define FIELD_STRING_RETIP "__probe_ret_ip"
#define FIELD_STRING_FUNC "__probe_func"
const char *reserved_field_names[] = {
"common_type",
"common_flags",
"common_preempt_count",
"common_pid",
"common_tgid",
FIELD_STRING_IP,
FIELD_STRING_RETIP,
FIELD_STRING_FUNC,
};
/* Printing function type */
typedef int (*print_type_func_t)(struct trace_seq *, const char *, void *,
void *);
#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 DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast) \
static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, \
const char *name, \
void *data, void *ent)\
{ \
return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
} \
static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
/* 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)
static inline void *get_rloc_data(u32 *dl)
{
return (u8 *)dl + get_rloc_offs(*dl);
}
/* For data_loc conversion */
static inline void *get_loc_data(u32 *dl, void *ent)
{
return (u8 *)ent + get_rloc_offs(*dl);
}
/*
* 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))
/* For defining macros, define string/string_size types */
typedef u32 string;
typedef u32 string_size;
/* Print type function for string type */
static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
const char *name,
void *data, void *ent)
{
int len = *(u32 *)data >> 16;
if (!len)
return trace_seq_printf(s, " %s=(fault)", name);
else
return trace_seq_printf(s, " %s=\"%s\"", name,
(const char *)get_loc_data(data, ent));
}
static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
/* Data fetch function type */
typedef void (*fetch_func_t)(struct pt_regs *, void *, void *);
struct fetch_param {
fetch_func_t fn;
void *data;
};
static __kprobes void call_fetch(struct fetch_param *fprm,
struct pt_regs *regs, void *dest)
{
return fprm->fn(regs, fprm->data, dest);
}
#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type
/*
* 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)
#define CHECK_FETCH_FUNCS(method, fn) \
(((FETCH_FUNC_NAME(method, u8) == fn) || \
(FETCH_FUNC_NAME(method, u16) == fn) || \
(FETCH_FUNC_NAME(method, u32) == fn) || \
(FETCH_FUNC_NAME(method, u64) == fn) || \
(FETCH_FUNC_NAME(method, string) == fn) || \
(FETCH_FUNC_NAME(method, string_size) == fn)) \
&& (fn != NULL))
/* Data fetch function templates */
#define DEFINE_FETCH_reg(type) \
static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, \
void *offset, void *dest) \
{ \
*(type *)dest = (type)regs_get_register(regs, \
(unsigned int)((unsigned long)offset)); \
}
DEFINE_BASIC_FETCH_FUNCS(reg)
/* No string on the register */
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL
#define DEFINE_FETCH_stack(type) \
static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
void *offset, void *dest) \
{ \
*(type *)dest = (type)regs_get_kernel_stack_nth(regs, \
(unsigned int)((unsigned long)offset)); \
}
DEFINE_BASIC_FETCH_FUNCS(stack)
/* No string on the stack entry */
#define fetch_stack_string NULL
#define fetch_stack_string_size NULL
#define DEFINE_FETCH_retval(type) \
static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
void *dummy, void *dest) \
{ \
*(type *)dest = (type)regs_return_value(regs); \
}
DEFINE_BASIC_FETCH_FUNCS(retval)
/* No string on the retval */
#define fetch_retval_string NULL
#define fetch_retval_string_size NULL
#define DEFINE_FETCH_memory(type) \
static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
void *addr, void *dest) \
{ \
type retval; \
if (probe_kernel_address(addr, retval)) \
*(type *)dest = 0; \
else \
*(type *)dest = retval; \
}
DEFINE_BASIC_FETCH_FUNCS(memory)
/*
* Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
* length and relative data location.
*/
static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
void *addr, void *dest)
{
long ret;
int maxlen = get_rloc_len(*(u32 *)dest);
u8 *dst = get_rloc_data(dest);
u8 *src = addr;
mm_segment_t old_fs = get_fs();
if (!maxlen)
return;
/*
* Try to get string again, since the string can be changed while
* probing.
*/
set_fs(KERNEL_DS);
pagefault_disable();
do
ret = __copy_from_user_inatomic(dst++, src++, 1);
while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
dst[-1] = '\0';
pagefault_enable();
set_fs(old_fs);
if (ret < 0) { /* Failed to fetch string */
((u8 *)get_rloc_data(dest))[0] = '\0';
*(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
} else
*(u32 *)dest = make_data_rloc(src - (u8 *)addr,
get_rloc_offs(*(u32 *)dest));
}
/* Return the length of string -- including null terminal byte */
static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
void *addr, void *dest)
{
int ret, len = 0;
u8 c;
mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
pagefault_disable();
do {
ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
len++;
} while (c && ret == 0 && len < MAX_STRING_SIZE);
pagefault_enable();
set_fs(old_fs);
if (ret < 0) /* Failed to check the length */
*(u32 *)dest = 0;
else
*(u32 *)dest = len;
}
/* Memory fetching by symbol */
struct symbol_cache {
char *symbol;
long offset;
unsigned long addr;
};
static unsigned long update_symbol_cache(struct symbol_cache *sc)
{
sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
if (sc->addr)
sc->addr += sc->offset;
return sc->addr;
}
static void free_symbol_cache(struct symbol_cache *sc)
{
kfree(sc->symbol);
kfree(sc);
}
static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
{
struct symbol_cache *sc;
if (!sym || strlen(sym) == 0)
return NULL;
sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
if (!sc)
return NULL;
sc->symbol = kstrdup(sym, GFP_KERNEL);
if (!sc->symbol) {
kfree(sc);
return NULL;
}
sc->offset = offset;
update_symbol_cache(sc);
return sc;
}
#define DEFINE_FETCH_symbol(type) \
static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
void *data, void *dest) \
{ \
struct symbol_cache *sc = data; \
if (sc->addr) \
fetch_memory_##type(regs, (void *)sc->addr, dest); \
else \
*(type *)dest = 0; \
}
DEFINE_BASIC_FETCH_FUNCS(symbol)
DEFINE_FETCH_symbol(string)
DEFINE_FETCH_symbol(string_size)
/* Dereference memory access function */
struct deref_fetch_param {
struct fetch_param orig;
long offset;
};
#define DEFINE_FETCH_deref(type) \
static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
void *data, void *dest) \
{ \
struct deref_fetch_param *dprm = data; \
unsigned long addr; \
call_fetch(&dprm->orig, regs, &addr); \
if (addr) { \
addr += dprm->offset; \
fetch_memory_##type(regs, (void *)addr, dest); \
} else \
*(type *)dest = 0; \
}
DEFINE_BASIC_FETCH_FUNCS(deref)
DEFINE_FETCH_deref(string)
DEFINE_FETCH_deref(string_size)
static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
{
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
update_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
update_symbol_cache(data->orig.data);
}
static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
{
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
free_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
free_symbol_cache(data->orig.data);
kfree(data);
}
/* Bitfield fetch function */
struct bitfield_fetch_param {
struct fetch_param orig;
unsigned char hi_shift;
unsigned char low_shift;
};
#define DEFINE_FETCH_bitfield(type) \
static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
void *data, void *dest) \
{ \
struct bitfield_fetch_param *bprm = data; \
type buf = 0; \
call_fetch(&bprm->orig, regs, &buf); \
if (buf) { \
buf <<= bprm->hi_shift; \
buf >>= bprm->low_shift; \
} \
*(type *)dest = buf; \
}
DEFINE_BASIC_FETCH_FUNCS(bitfield)
#define fetch_bitfield_string NULL
#define fetch_bitfield_string_size NULL
static __kprobes void
update_bitfield_fetch_param(struct bitfield_fetch_param *data)
{
/*
* Don't check the bitfield itself, because this must be the
* last fetch function.
*/
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
update_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
update_symbol_cache(data->orig.data);
}
static __kprobes void
free_bitfield_fetch_param(struct bitfield_fetch_param *data)
{
/*
* Don't check the bitfield itself, because this must be the
* last fetch function.
*/
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
free_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
free_symbol_cache(data->orig.data);
kfree(data);
}
/* 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)
/* 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,
};
#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), \
} \
}
#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \
__ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
#define FETCH_TYPE_STRING 0
#define FETCH_TYPE_STRSIZE 1
/* Fetch type information table */
static const 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];
} fetch_type_table[] = {
/* Special types */
[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
sizeof(u32), 1, "__data_loc char[]"),
[FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
string_size, sizeof(u32), 0, "u32"),
/* Basic types */
ASSIGN_FETCH_TYPE(u8, u8, 0),
ASSIGN_FETCH_TYPE(u16, u16, 0),
ASSIGN_FETCH_TYPE(u32, u32, 0),
ASSIGN_FETCH_TYPE(u64, u64, 0),
ASSIGN_FETCH_TYPE(s8, u8, 1),
ASSIGN_FETCH_TYPE(s16, u16, 1),
ASSIGN_FETCH_TYPE(s32, u32, 1),
ASSIGN_FETCH_TYPE(s64, u64, 1),
};
static const struct fetch_type *find_fetch_type(const char *type)
{
int i;
if (!type)
type = DEFAULT_FETCH_TYPE_STR;
/* Special case: bitfield */
if (*type == 'b') {
unsigned long bs;
type = strchr(type, '/');
if (!type)
goto fail;
type++;
if (strict_strtoul(type, 0, &bs))
goto fail;
switch (bs) {
case 8:
return find_fetch_type("u8");
case 16:
return find_fetch_type("u16");
case 32:
return find_fetch_type("u32");
case 64:
return find_fetch_type("u64");
default:
goto fail;
}
}
for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
if (strcmp(type, fetch_type_table[i].name) == 0)
return &fetch_type_table[i];
fail:
return NULL;
}
/* Special function : only accept unsigned long */
static __kprobes void fetch_stack_address(struct pt_regs *regs,
void *dummy, void *dest)
{
*(unsigned long *)dest = kernel_stack_pointer(regs);
}
static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
fetch_func_t orig_fn)
{
int i;
if (type != &fetch_type_table[FETCH_TYPE_STRING])
return NULL; /* Only string type needs size function */
for (i = 0; i < FETCH_MTD_END; i++)
if (type->fetch[i] == orig_fn)
return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
WARN_ON(1); /* This should not happen */
return NULL;
}
/**
* Kprobe event core functions
*/
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 */
};
/* Flags for trace_probe */
#define TP_FLAG_TRACE 1
#define TP_FLAG_PROFILE 2
#define TP_FLAG_REGISTERED 4
struct trace_probe {
struct list_head list;
struct kretprobe rp; /* Use rp.kp for kprobe use */
unsigned long nhit;
unsigned int flags; /* For TP_FLAG_* */
const char *symbol; /* symbol name */
struct ftrace_event_class class;
struct ftrace_event_call call;
ssize_t size; /* trace entry size */
unsigned int nr_args;
struct probe_arg args[];
};
#define SIZEOF_TRACE_PROBE(n) \
(offsetof(struct trace_probe, args) + \
(sizeof(struct probe_arg) * (n)))
static __kprobes int trace_probe_is_return(struct trace_probe *tp)
{
return tp->rp.handler != NULL;
}
static __kprobes const char *trace_probe_symbol(struct trace_probe *tp)
{
return tp->symbol ? tp->symbol : "unknown";
}
static __kprobes unsigned long trace_probe_offset(struct trace_probe *tp)
{
return tp->rp.kp.offset;
}
static __kprobes bool trace_probe_is_enabled(struct trace_probe *tp)
{
return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
}
static __kprobes bool trace_probe_is_registered(struct trace_probe *tp)
{
return !!(tp->flags & TP_FLAG_REGISTERED);
}
static __kprobes bool trace_probe_has_gone(struct trace_probe *tp)
{
return !!(kprobe_gone(&tp->rp.kp));
}
static __kprobes bool trace_probe_within_module(struct trace_probe *tp,
struct module *mod)
{
int len = strlen(mod->name);
const char *name = trace_probe_symbol(tp);
return strncmp(mod->name, name, len) == 0 && name[len] == ':';
}
static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
{
return !!strchr(trace_probe_symbol(tp), ':');
}
static int register_probe_event(struct trace_probe *tp);
static void unregister_probe_event(struct trace_probe *tp);
static DEFINE_MUTEX(probe_lock);
static LIST_HEAD(probe_list);
static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
static int kretprobe_dispatcher(struct kretprobe_instance *ri,
struct pt_regs *regs);
/* Check the name is good for event/group/fields */
static 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;
}
/*
* Allocate new trace_probe and initialize it (including kprobes).
*/
static struct trace_probe *alloc_trace_probe(const char *group,
const char *event,
void *addr,
const char *symbol,
unsigned long offs,
int nargs, int is_return)
{
struct trace_probe *tp;
int ret = -ENOMEM;
tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
if (!tp)
return ERR_PTR(ret);
if (symbol) {
tp->symbol = kstrdup(symbol, GFP_KERNEL);
if (!tp->symbol)
goto error;
tp->rp.kp.symbol_name = tp->symbol;
tp->rp.kp.offset = offs;
} else
tp->rp.kp.addr = addr;
if (is_return)
tp->rp.handler = kretprobe_dispatcher;
else
tp->rp.kp.pre_handler = kprobe_dispatcher;
if (!event || !is_good_name(event)) {
ret = -EINVAL;
goto error;
}
tp->call.class = &tp->class;
tp->call.name = kstrdup(event, GFP_KERNEL);
if (!tp->call.name)
goto error;
if (!group || !is_good_name(group)) {
ret = -EINVAL;
goto error;
}
tp->class.system = kstrdup(group, GFP_KERNEL);
if (!tp->class.system)
goto error;
INIT_LIST_HEAD(&tp->list);
return tp;
error:
kfree(tp->call.name);
kfree(tp->symbol);
kfree(tp);
return ERR_PTR(ret);
}
static void update_probe_arg(struct probe_arg *arg)
{
if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
update_bitfield_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
update_deref_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
update_symbol_cache(arg->fetch.data);
}
static void free_probe_arg(struct probe_arg *arg)
{
if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
free_bitfield_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
free_deref_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
free_symbol_cache(arg->fetch.data);
kfree(arg->name);
kfree(arg->comm);
}
static void free_trace_probe(struct trace_probe *tp)
{
int i;
for (i = 0; i < tp->nr_args; i++)
free_probe_arg(&tp->args[i]);
kfree(tp->call.class->system);
kfree(tp->call.name);
kfree(tp->symbol);
kfree(tp);
}
static struct trace_probe *find_trace_probe(const char *event,
const char *group)
{
struct trace_probe *tp;
list_for_each_entry(tp, &probe_list, list)
if (strcmp(tp->call.name, event) == 0 &&
strcmp(tp->call.class->system, group) == 0)
return tp;
return NULL;
}
/* Enable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
static int enable_trace_probe(struct trace_probe *tp, int flag)
{
int ret = 0;
tp->flags |= flag;
if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
!trace_probe_has_gone(tp)) {
if (trace_probe_is_return(tp))
ret = enable_kretprobe(&tp->rp);
else
ret = enable_kprobe(&tp->rp.kp);
}
return ret;
}
/* Disable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
static void disable_trace_probe(struct trace_probe *tp, int flag)
{
tp->flags &= ~flag;
if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
if (trace_probe_is_return(tp))
disable_kretprobe(&tp->rp);
else
disable_kprobe(&tp->rp.kp);
}
}
/* Internal register function - just handle k*probes and flags */
static int __register_trace_probe(struct trace_probe *tp)
{
int i, ret;
if (trace_probe_is_registered(tp))
return -EINVAL;
for (i = 0; i < tp->nr_args; i++)
update_probe_arg(&tp->args[i]);
/* Set/clear disabled flag according to tp->flag */
if (trace_probe_is_enabled(tp))
tp->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
else
tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
if (trace_probe_is_return(tp))
ret = register_kretprobe(&tp->rp);
else
ret = register_kprobe(&tp->rp.kp);
if (ret == 0)
tp->flags |= TP_FLAG_REGISTERED;
else {
pr_warning("Could not insert probe at %s+%lu: %d\n",
trace_probe_symbol(tp), trace_probe_offset(tp), ret);
if (ret == -ENOENT && trace_probe_is_on_module(tp)) {
pr_warning("This probe might be able to register after"
"target module is loaded. Continue.\n");
ret = 0;
} else if (ret == -EILSEQ) {
pr_warning("Probing address(0x%p) is not an "
"instruction boundary.\n",
tp->rp.kp.addr);
ret = -EINVAL;
}
}
return ret;
}
/* Internal unregister function - just handle k*probes and flags */
static void __unregister_trace_probe(struct trace_probe *tp)
{
if (trace_probe_is_registered(tp)) {
if (trace_probe_is_return(tp))
unregister_kretprobe(&tp->rp);
else
unregister_kprobe(&tp->rp.kp);
tp->flags &= ~TP_FLAG_REGISTERED;
/* Cleanup kprobe for reuse */
if (tp->rp.kp.symbol_name)
tp->rp.kp.addr = NULL;
}
}
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
static int unregister_trace_probe(struct trace_probe *tp)
{
/* Enabled event can not be unregistered */
if (trace_probe_is_enabled(tp))
return -EBUSY;
__unregister_trace_probe(tp);
list_del(&tp->list);
unregister_probe_event(tp);
return 0;
}
/* Register a trace_probe and probe_event */
static int register_trace_probe(struct trace_probe *tp)
{
struct trace_probe *old_tp;
int ret;
mutex_lock(&probe_lock);
/* Delete old (same name) event if exist */
old_tp = find_trace_probe(tp->call.name, tp->call.class->system);
if (old_tp) {
ret = unregister_trace_probe(old_tp);
if (ret < 0)
goto end;
free_trace_probe(old_tp);
}
/* Register new event */
ret = register_probe_event(tp);
if (ret) {
pr_warning("Failed to register probe event(%d)\n", ret);
goto end;
}
/* Register k*probe */
ret = __register_trace_probe(tp);
if (ret < 0)
unregister_probe_event(tp);
else
list_add_tail(&tp->list, &probe_list);
end:
mutex_unlock(&probe_lock);
return ret;
}
/* Module notifier call back, checking event on the module */
static int trace_probe_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
{
struct module *mod = data;
struct trace_probe *tp;
int ret;
if (val != MODULE_STATE_COMING)
return NOTIFY_DONE;
/* Update probes on coming module */
mutex_lock(&probe_lock);
list_for_each_entry(tp, &probe_list, list) {
if (trace_probe_within_module(tp, mod)) {
/* Don't need to check busy - this should have gone. */
__unregister_trace_probe(tp);
ret = __register_trace_probe(tp);
if (ret)
pr_warning("Failed to re-register probe %s on"
"%s: %d\n",
tp->call.name, mod->name, ret);
}
}
mutex_unlock(&probe_lock);
return NOTIFY_DONE;
}
static struct notifier_block trace_probe_module_nb = {
.notifier_call = trace_probe_module_callback,
.priority = 1 /* Invoked after kprobe module callback */
};
/* Split symbol and offset. */
static int split_symbol_offset(char *symbol, unsigned long *offset)
{
char *tmp;
int ret;
if (!offset)
return -EINVAL;
tmp = strchr(symbol, '+');
if (tmp) {
/* skip sign because strict_strtol doesn't accept '+' */
ret = strict_strtoul(tmp + 1, 0, offset);
if (ret)
return ret;
*tmp = '\0';
} else
*offset = 0;
return 0;
}
#define PARAM_MAX_ARGS 16
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
static int parse_probe_vars(char *arg, const struct fetch_type *t,
struct fetch_param *f, int is_return)
{
int ret = 0;
unsigned long param;
if (strcmp(arg, "retval") == 0) {
if (is_return)
f->fn = t->fetch[FETCH_MTD_retval];
else
ret = -EINVAL;
} else if (strncmp(arg, "stack", 5) == 0) {
if (arg[5] == '\0') {
if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
f->fn = fetch_stack_address;
else
ret = -EINVAL;
} else if (isdigit(arg[5])) {
ret = strict_strtoul(arg + 5, 10, ¶m);
if (ret || param > PARAM_MAX_STACK)
ret = -EINVAL;
else {
f->fn = t->fetch[FETCH_MTD_stack];
f->data = (void *)param;
}
} else
ret = -EINVAL;
} else
ret = -EINVAL;
return ret;
}
/* Recursive argument parser */
static int __parse_probe_arg(char *arg, const struct fetch_type *t,
struct fetch_param *f, int is_return)
{
int ret = 0;
unsigned long param;
long offset;
char *tmp;
switch (arg[0]) {
case '$':
ret = parse_probe_vars(arg + 1, t, f, is_return);
break;
case '%': /* named register */
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
f->fn = t->fetch[FETCH_MTD_reg];
f->data = (void *)(unsigned long)ret;
ret = 0;
}
break;
case '@': /* memory or symbol */
if (isdigit(arg[1])) {