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trace_kprobe.c
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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
*/
#define pr_fmt(fmt) "trace_kprobe: " fmt
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/rculist.h>
#include "trace_probe.h"
#define KPROBE_EVENT_SYSTEM "kprobes"
#define KRETPROBE_MAXACTIVE_MAX 4096
/**
* Kprobe event core functions
*/
struct trace_kprobe {
struct list_head list;
struct kretprobe rp; /* Use rp.kp for kprobe use */
unsigned long __percpu *nhit;
const char *symbol; /* symbol name */
struct trace_probe tp;
};
#define SIZEOF_TRACE_KPROBE(n) \
(offsetof(struct trace_kprobe, tp.args) + \
(sizeof(struct probe_arg) * (n)))
static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
{
return tk->rp.handler != NULL;
}
static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
{
return tk->symbol ? tk->symbol : "unknown";
}
static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
{
return tk->rp.kp.offset;
}
static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
{
return !!(kprobe_gone(&tk->rp.kp));
}
static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
struct module *mod)
{
int len = strlen(mod->name);
const char *name = trace_kprobe_symbol(tk);
return strncmp(mod->name, name, len) == 0 && name[len] == ':';
}
static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk)
{
return !!strchr(trace_kprobe_symbol(tk), ':');
}
static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
{
unsigned long nhit = 0;
int cpu;
for_each_possible_cpu(cpu)
nhit += *per_cpu_ptr(tk->nhit, cpu);
return nhit;
}
static int register_kprobe_event(struct trace_kprobe *tk);
static int unregister_kprobe_event(struct trace_kprobe *tk);
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);
/* Memory fetching by symbol */
struct symbol_cache {
char *symbol;
long offset;
unsigned long addr;
};
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;
}
void free_symbol_cache(struct symbol_cache *sc)
{
kfree(sc->symbol);
kfree(sc);
}
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;
}
/*
* Kprobes-specific fetch functions
*/
#define DEFINE_FETCH_stack(type) \
static 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)); \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type));
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_memory(type) \
static 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; \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type));
DEFINE_BASIC_FETCH_FUNCS(memory)
/*
* Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
* length and relative data location.
*/
static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
void *addr, void *dest)
{
int maxlen = get_rloc_len(*(u32 *)dest);
u8 *dst = get_rloc_data(dest);
long ret;
if (!maxlen)
return;
/*
* Try to get string again, since the string can be changed while
* probing.
*/
ret = strncpy_from_unsafe(dst, addr, maxlen);
if (ret < 0) { /* Failed to fetch string */
dst[0] = '\0';
*(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
} else {
*(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
}
}
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string));
/* Return the length of string -- including null terminal byte */
static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
void *addr, void *dest)
{
mm_segment_t old_fs;
int ret, len = 0;
u8 c;
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;
}
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size));
#define DEFINE_FETCH_symbol(type) \
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; \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type));
DEFINE_BASIC_FETCH_FUNCS(symbol)
DEFINE_FETCH_symbol(string)
DEFINE_FETCH_symbol(string_size)
/* kprobes don't support file_offset fetch methods */
#define fetch_file_offset_u8 NULL
#define fetch_file_offset_u16 NULL
#define fetch_file_offset_u32 NULL
#define fetch_file_offset_u64 NULL
#define fetch_file_offset_string NULL
#define fetch_file_offset_string_size NULL
/* Fetch type information table */
static const struct fetch_type kprobes_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),
ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0),
ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
ASSIGN_FETCH_TYPE_END
};
/*
* Allocate new trace_probe and initialize it (including kprobes).
*/
static struct trace_kprobe *alloc_trace_kprobe(const char *group,
const char *event,
void *addr,
const char *symbol,
unsigned long offs,
int maxactive,
int nargs, bool is_return)
{
struct trace_kprobe *tk;
int ret = -ENOMEM;
tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
if (!tk)
return ERR_PTR(ret);
tk->nhit = alloc_percpu(unsigned long);
if (!tk->nhit)
goto error;
if (symbol) {
tk->symbol = kstrdup(symbol, GFP_KERNEL);
if (!tk->symbol)
goto error;
tk->rp.kp.symbol_name = tk->symbol;
tk->rp.kp.offset = offs;
} else
tk->rp.kp.addr = addr;
if (is_return)
tk->rp.handler = kretprobe_dispatcher;
else
tk->rp.kp.pre_handler = kprobe_dispatcher;
tk->rp.maxactive = maxactive;
if (!event || !is_good_name(event)) {
ret = -EINVAL;
goto error;
}
tk->tp.call.class = &tk->tp.class;
tk->tp.call.name = kstrdup(event, GFP_KERNEL);
if (!tk->tp.call.name)
goto error;
if (!group || !is_good_name(group)) {
ret = -EINVAL;
goto error;
}
tk->tp.class.system = kstrdup(group, GFP_KERNEL);
if (!tk->tp.class.system)
goto error;
INIT_LIST_HEAD(&tk->list);
INIT_LIST_HEAD(&tk->tp.files);
return tk;
error:
kfree(tk->tp.call.name);
kfree(tk->symbol);
free_percpu(tk->nhit);
kfree(tk);
return ERR_PTR(ret);
}
static void free_trace_kprobe(struct trace_kprobe *tk)
{
int i;
for (i = 0; i < tk->tp.nr_args; i++)
traceprobe_free_probe_arg(&tk->tp.args[i]);
kfree(tk->tp.call.class->system);
kfree(tk->tp.call.name);
kfree(tk->symbol);
free_percpu(tk->nhit);
kfree(tk);
}
static struct trace_kprobe *find_trace_kprobe(const char *event,
const char *group)
{
struct trace_kprobe *tk;
list_for_each_entry(tk, &probe_list, list)
if (strcmp(trace_event_name(&tk->tp.call), event) == 0 &&
strcmp(tk->tp.call.class->system, group) == 0)
return tk;
return NULL;
}
/*
* Enable trace_probe
* if the file is NULL, enable "perf" handler, or enable "trace" handler.
*/
static int
enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
int ret = 0;
if (file) {
struct event_file_link *link;
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link) {
ret = -ENOMEM;
goto out;
}
link->file = file;
list_add_tail_rcu(&link->list, &tk->tp.files);
tk->tp.flags |= TP_FLAG_TRACE;
} else
tk->tp.flags |= TP_FLAG_PROFILE;
if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) {
if (trace_kprobe_is_return(tk))
ret = enable_kretprobe(&tk->rp);
else
ret = enable_kprobe(&tk->rp.kp);
}
out:
return ret;
}
/*
* Disable trace_probe
* if the file is NULL, disable "perf" handler, or disable "trace" handler.
*/
static int
disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
{
struct event_file_link *link = NULL;
int wait = 0;
int ret = 0;
if (file) {
link = find_event_file_link(&tk->tp, file);
if (!link) {
ret = -EINVAL;
goto out;
}
list_del_rcu(&link->list);
wait = 1;
if (!list_empty(&tk->tp.files))
goto out;
tk->tp.flags &= ~TP_FLAG_TRACE;
} else
tk->tp.flags &= ~TP_FLAG_PROFILE;
if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) {
if (trace_kprobe_is_return(tk))
disable_kretprobe(&tk->rp);
else
disable_kprobe(&tk->rp.kp);
wait = 1;
}
out:
if (wait) {
/*
* Synchronize with kprobe_trace_func/kretprobe_trace_func
* to ensure disabled (all running handlers are finished).
* This is not only for kfree(), but also the caller,
* trace_remove_event_call() supposes it for releasing
* event_call related objects, which will be accessed in
* the kprobe_trace_func/kretprobe_trace_func.
*/
synchronize_sched();
kfree(link); /* Ignored if link == NULL */
}
return ret;
}
/* Internal register function - just handle k*probes and flags */
static int __register_trace_kprobe(struct trace_kprobe *tk)
{
int i, ret;
if (trace_probe_is_registered(&tk->tp))
return -EINVAL;
for (i = 0; i < tk->tp.nr_args; i++)
traceprobe_update_arg(&tk->tp.args[i]);
/* Set/clear disabled flag according to tp->flag */
if (trace_probe_is_enabled(&tk->tp))
tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
else
tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
if (trace_kprobe_is_return(tk))
ret = register_kretprobe(&tk->rp);
else
ret = register_kprobe(&tk->rp.kp);
if (ret == 0)
tk->tp.flags |= TP_FLAG_REGISTERED;
else {
pr_warn("Could not insert probe at %s+%lu: %d\n",
trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret);
if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) {
pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
ret = 0;
} else if (ret == -EILSEQ) {
pr_warn("Probing address(0x%p) is not an instruction boundary.\n",
tk->rp.kp.addr);
ret = -EINVAL;
}
}
return ret;
}
/* Internal unregister function - just handle k*probes and flags */
static void __unregister_trace_kprobe(struct trace_kprobe *tk)
{
if (trace_probe_is_registered(&tk->tp)) {
if (trace_kprobe_is_return(tk))
unregister_kretprobe(&tk->rp);
else
unregister_kprobe(&tk->rp.kp);
tk->tp.flags &= ~TP_FLAG_REGISTERED;
/* Cleanup kprobe for reuse */
if (tk->rp.kp.symbol_name)
tk->rp.kp.addr = NULL;
}
}
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
static int unregister_trace_kprobe(struct trace_kprobe *tk)
{
/* Enabled event can not be unregistered */
if (trace_probe_is_enabled(&tk->tp))
return -EBUSY;
/* Will fail if probe is being used by ftrace or perf */
if (unregister_kprobe_event(tk))
return -EBUSY;
__unregister_trace_kprobe(tk);
list_del(&tk->list);
return 0;
}
/* Register a trace_probe and probe_event */
static int register_trace_kprobe(struct trace_kprobe *tk)
{
struct trace_kprobe *old_tk;
int ret;
mutex_lock(&probe_lock);
/* Delete old (same name) event if exist */
old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call),
tk->tp.call.class->system);
if (old_tk) {
ret = unregister_trace_kprobe(old_tk);
if (ret < 0)
goto end;
free_trace_kprobe(old_tk);
}
/* Register new event */
ret = register_kprobe_event(tk);
if (ret) {
pr_warn("Failed to register probe event(%d)\n", ret);
goto end;
}
/* Register k*probe */
ret = __register_trace_kprobe(tk);
if (ret < 0)
unregister_kprobe_event(tk);
else
list_add_tail(&tk->list, &probe_list);
end:
mutex_unlock(&probe_lock);
return ret;
}
/* Module notifier call back, checking event on the module */
static int trace_kprobe_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
{
struct module *mod = data;
struct trace_kprobe *tk;
int ret;
if (val != MODULE_STATE_COMING)
return NOTIFY_DONE;
/* Update probes on coming module */
mutex_lock(&probe_lock);
list_for_each_entry(tk, &probe_list, list) {
if (trace_kprobe_within_module(tk, mod)) {
/* Don't need to check busy - this should have gone. */
__unregister_trace_kprobe(tk);
ret = __register_trace_kprobe(tk);
if (ret)
pr_warn("Failed to re-register probe %s on %s: %d\n",
trace_event_name(&tk->tp.call),
mod->name, ret);
}
}
mutex_unlock(&probe_lock);
return NOTIFY_DONE;
}
static struct notifier_block trace_kprobe_module_nb = {
.notifier_call = trace_kprobe_module_callback,
.priority = 1 /* Invoked after kprobe module callback */
};
/* Convert certain expected symbols into '_' when generating event names */
static inline void sanitize_event_name(char *name)
{
while (*name++ != '\0')
if (*name == ':' || *name == '.')
*name = '_';
}
static int create_trace_kprobe(int argc, char **argv)
{
/*
* Argument syntax:
* - Add kprobe:
* p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
* - Add kretprobe:
* r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
* Fetch args:
* $retval : fetch return value
* $stack : fetch stack address
* $stackN : fetch Nth of stack (N:0-)
* $comm : fetch current task comm
* @ADDR : fetch memory at ADDR (ADDR should be in kernel)
* @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
* %REG : fetch register REG
* Dereferencing memory fetch:
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
* Alias name of args:
* NAME=FETCHARG : set NAME as alias of FETCHARG.
* Type of args:
* FETCHARG:TYPE : use TYPE instead of unsigned long.
*/
struct trace_kprobe *tk;
int i, ret = 0;
bool is_return = false, is_delete = false;
char *symbol = NULL, *event = NULL, *group = NULL;
int maxactive = 0;
char *arg;
unsigned long offset = 0;
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];
/* argc must be >= 1 */
if (argv[0][0] == 'p')
is_return = false;
else if (argv[0][0] == 'r')
is_return = true;
else if (argv[0][0] == '-')
is_delete = true;
else {
pr_info("Probe definition must be started with 'p', 'r' or"
" '-'.\n");
return -EINVAL;
}
event = strchr(&argv[0][1], ':');
if (event) {
event[0] = '\0';
event++;
}
if (is_return && isdigit(argv[0][1])) {
ret = kstrtouint(&argv[0][1], 0, &maxactive);
if (ret) {
pr_info("Failed to parse maxactive.\n");
return ret;
}
/* kretprobes instances are iterated over via a list. The
* maximum should stay reasonable.
*/
if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
pr_info("Maxactive is too big (%d > %d).\n",
maxactive, KRETPROBE_MAXACTIVE_MAX);
return -E2BIG;
}
}
if (event) {
if (strchr(event, '/')) {
group = event;
event = strchr(group, '/') + 1;
event[-1] = '\0';
if (strlen(group) == 0) {
pr_info("Group name is not specified\n");
return -EINVAL;
}
}
if (strlen(event) == 0) {
pr_info("Event name is not specified\n");
return -EINVAL;
}
}
if (!group)
group = KPROBE_EVENT_SYSTEM;
if (is_delete) {
if (!event) {
pr_info("Delete command needs an event name.\n");
return -EINVAL;
}
mutex_lock(&probe_lock);
tk = find_trace_kprobe(event, group);
if (!tk) {
mutex_unlock(&probe_lock);
pr_info("Event %s/%s doesn't exist.\n", group, event);
return -ENOENT;
}
/* delete an event */
ret = unregister_trace_kprobe(tk);
if (ret == 0)
free_trace_kprobe(tk);
mutex_unlock(&probe_lock);
return ret;
}
if (argc < 2) {
pr_info("Probe point is not specified.\n");
return -EINVAL;
}
/* try to parse an address. if that fails, try to read the
* input as a symbol. */
if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
/* a symbol specified */
symbol = argv[1];
/* TODO: support .init module functions */
ret = traceprobe_split_symbol_offset(symbol, &offset);
if (ret) {
pr_info("Failed to parse either an address or a symbol.\n");
return ret;
}
if (offset && is_return &&
!kprobe_on_func_entry(NULL, symbol, offset)) {
pr_info("Given offset is not valid for return probe.\n");
return -EINVAL;
}
}
argc -= 2; argv += 2;
/* setup a probe */
if (!event) {
/* Make a new event name */
if (symbol)
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
is_return ? 'r' : 'p', symbol, offset);
else
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
is_return ? 'r' : 'p', addr);
sanitize_event_name(buf);
event = buf;
}
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
argc, is_return);
if (IS_ERR(tk)) {
pr_info("Failed to allocate trace_probe.(%d)\n",
(int)PTR_ERR(tk));
return PTR_ERR(tk);
}
/* parse arguments */
ret = 0;
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
struct probe_arg *parg = &tk->tp.args[i];
/* Increment count for freeing args in error case */
tk->tp.nr_args++;
/* Parse argument name */
arg = strchr(argv[i], '=');
if (arg) {
*arg++ = '\0';
parg->name = kstrdup(argv[i], GFP_KERNEL);
} else {
arg = argv[i];
/* If argument name is omitted, set "argN" */
snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
parg->name = kstrdup(buf, GFP_KERNEL);
}
if (!parg->name) {
pr_info("Failed to allocate argument[%d] name.\n", i);
ret = -ENOMEM;
goto error;
}
if (!is_good_name(parg->name)) {
pr_info("Invalid argument[%d] name: %s\n",
i, parg->name);
ret = -EINVAL;
goto error;
}
if (traceprobe_conflict_field_name(parg->name,
tk->tp.args, i)) {
pr_info("Argument[%d] name '%s' conflicts with "
"another field.\n", i, argv[i]);
ret = -EINVAL;
goto error;
}
/* Parse fetch argument */
ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg,
is_return, true,
kprobes_fetch_type_table);
if (ret) {
pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
goto error;
}
}
ret = register_trace_kprobe(tk);
if (ret)
goto error;
return 0;
error:
free_trace_kprobe(tk);
return ret;
}
static int release_all_trace_kprobes(void)
{
struct trace_kprobe *tk;
int ret = 0;
mutex_lock(&probe_lock);
/* Ensure no probe is in use. */
list_for_each_entry(tk, &probe_list, list)
if (trace_probe_is_enabled(&tk->tp)) {
ret = -EBUSY;
goto end;
}
/* TODO: Use batch unregistration */
while (!list_empty(&probe_list)) {
tk = list_entry(probe_list.next, struct trace_kprobe, list);
ret = unregister_trace_kprobe(tk);
if (ret)
goto end;
free_trace_kprobe(tk);
}
end:
mutex_unlock(&probe_lock);
return ret;
}
/* Probes listing interfaces */
static void *probes_seq_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&probe_lock);
return seq_list_start(&probe_list, *pos);
}
static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
return seq_list_next(v, &probe_list, pos);
}
static void probes_seq_stop(struct seq_file *m, void *v)
{
mutex_unlock(&probe_lock);
}
static int probes_seq_show(struct seq_file *m, void *v)
{
struct trace_kprobe *tk = v;
int i;
seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
seq_printf(m, ":%s/%s", tk->tp.call.class->system,
trace_event_name(&tk->tp.call));
if (!tk->symbol)
seq_printf(m, " 0x%p", tk->rp.kp.addr);
else if (tk->rp.kp.offset)
seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
tk->rp.kp.offset);
else
seq_printf(m, " %s", trace_kprobe_symbol(tk));
for (i = 0; i < tk->tp.nr_args; i++)
seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
seq_putc(m, '\n');
return 0;
}
static const struct seq_operations probes_seq_op = {
.start = probes_seq_start,
.next = probes_seq_next,
.stop = probes_seq_stop,
.show = probes_seq_show
};
static int probes_open(struct inode *inode, struct file *file)
{
int ret;
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
ret = release_all_trace_kprobes();
if (ret < 0)
return ret;
}
return seq_open(file, &probes_seq_op);
}
static ssize_t probes_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
return trace_parse_run_command(file, buffer, count, ppos,
create_trace_kprobe);
}
static const struct file_operations kprobe_events_ops = {
.owner = THIS_MODULE,
.open = probes_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
.write = probes_write,
};
/* Probes profiling interfaces */
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
struct trace_kprobe *tk = v;
seq_printf(m, " %-44s %15lu %15lu\n",
trace_event_name(&tk->tp.call),
trace_kprobe_nhit(tk),
tk->rp.kp.nmissed);
return 0;
}
static const struct seq_operations profile_seq_op = {
.start = probes_seq_start,
.next = probes_seq_next,
.stop = probes_seq_stop,
.show = probes_profile_seq_show
};
static int profile_open(struct inode *inode, struct file *file)
{
return seq_open(file, &profile_seq_op);
}
static const struct file_operations kprobe_profile_ops = {
.owner = THIS_MODULE,
.open = profile_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/* Kprobe handler */
static nokprobe_inline void
__kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
struct trace_event_file *trace_file)
{
struct kprobe_trace_entry_head *entry;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int size, dsize, pc;
unsigned long irq_flags;
struct trace_event_call *call = &tk->tp.call;
WARN_ON(call != trace_file->event_call);
if (trace_trigger_soft_disabled(trace_file))
return;
local_save_flags(irq_flags);
pc = preempt_count();
dsize = __get_data_size(&tk->tp, regs);
size = sizeof(*entry) + tk->tp.size + dsize;
event = trace_event_buffer_lock_reserve(&buffer, trace_file,
call->event.type,
size, irq_flags, pc);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->ip = (unsigned long)tk->rp.kp.addr;
store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize);
event_trigger_unlock_commit_regs(trace_file, buffer, event,
entry, irq_flags, pc, regs);
}
static void
kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
{
struct event_file_link *link;
list_for_each_entry_rcu(link, &tk->tp.files, list)
__kprobe_trace_func(tk, regs, link->file);
}