Linux-2.6.33.2/kernel/trace/trace_kprobe.c
/*
* 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 "trace.h"
#include "trace_output.h"
#define MAX_TRACE_ARGS 128
#define MAX_ARGSTR_LEN 63
#define MAX_EVENT_NAME_LEN 64
#define KPROBE_EVENT_SYSTEM "kprobes"
/* Reserved field names */
#define FIELD_STRING_IP "__probe_ip"
#define FIELD_STRING_NARGS "__probe_nargs"
#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",
"common_lock_depth",
FIELD_STRING_IP,
FIELD_STRING_NARGS,
FIELD_STRING_RETIP,
FIELD_STRING_FUNC,
};
struct fetch_func {
unsigned long (*func)(struct pt_regs *, void *);
void *data;
};
static __kprobes unsigned long call_fetch(struct fetch_func *f,
struct pt_regs *regs)
{
return f->func(regs, f->data);
}
/* fetch handlers */
static __kprobes unsigned long fetch_register(struct pt_regs *regs,
void *offset)
{
return regs_get_register(regs, (unsigned int)((unsigned long)offset));
}
static __kprobes unsigned long fetch_stack(struct pt_regs *regs,
void *num)
{
return regs_get_kernel_stack_nth(regs,
(unsigned int)((unsigned long)num));
}
static __kprobes unsigned long fetch_memory(struct pt_regs *regs, void *addr)
{
unsigned long retval;
if (probe_kernel_address(addr, retval))
return 0;
return retval;
}
static __kprobes unsigned long fetch_argument(struct pt_regs *regs, void *num)
{
return regs_get_argument_nth(regs, (unsigned int)((unsigned long)num));
}
static __kprobes unsigned long fetch_retvalue(struct pt_regs *regs,
void *dummy)
{
return regs_return_value(regs);
}
static __kprobes unsigned long fetch_stack_address(struct pt_regs *regs,
void *dummy)
{
return kernel_stack_pointer(regs);
}
/* 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;
}
static __kprobes unsigned long fetch_symbol(struct pt_regs *regs, void *data)
{
struct symbol_cache *sc = data;
if (sc->addr)
return fetch_memory(regs, (void *)sc->addr);
else
return 0;
}
/* Special indirect memory access interface */
struct indirect_fetch_data {
struct fetch_func orig;
long offset;
};
static __kprobes unsigned long fetch_indirect(struct pt_regs *regs, void *data)
{
struct indirect_fetch_data *ind = data;
unsigned long addr;
addr = call_fetch(&ind->orig, regs);
if (addr) {
addr += ind->offset;
return fetch_memory(regs, (void *)addr);
} else
return 0;
}
static __kprobes void free_indirect_fetch_data(struct indirect_fetch_data *data)
{
if (data->orig.func == fetch_indirect)
free_indirect_fetch_data(data->orig.data);
else if (data->orig.func == fetch_symbol)
free_symbol_cache(data->orig.data);
kfree(data);
}
/**
* Kprobe event core functions
*/
struct probe_arg {
struct fetch_func fetch;
const char *name;
};
/* Flags for trace_probe */
#define TP_FLAG_TRACE 1
#define TP_FLAG_PROFILE 2
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_call call;
struct trace_event event;
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 probe_is_return(struct trace_probe *tp)
{
return tp->rp.handler != NULL;
}
static __kprobes const char *probe_symbol(struct trace_probe *tp)
{
return tp->symbol ? tp->symbol : "unknown";
}
static int probe_arg_string(char *buf, size_t n, struct fetch_func *ff)
{
int ret = -EINVAL;
if (ff->func == fetch_argument)
ret = snprintf(buf, n, "$arg%lu", (unsigned long)ff->data);
else if (ff->func == fetch_register) {
const char *name;
name = regs_query_register_name((unsigned int)((long)ff->data));
ret = snprintf(buf, n, "%%%s", name);
} else if (ff->func == fetch_stack)
ret = snprintf(buf, n, "$stack%lu", (unsigned long)ff->data);
else if (ff->func == fetch_memory)
ret = snprintf(buf, n, "@0x%p", ff->data);
else if (ff->func == fetch_symbol) {
struct symbol_cache *sc = ff->data;
if (sc->offset)
ret = snprintf(buf, n, "@%s%+ld", sc->symbol,
sc->offset);
else
ret = snprintf(buf, n, "@%s", sc->symbol);
} else if (ff->func == fetch_retvalue)
ret = snprintf(buf, n, "$retval");
else if (ff->func == fetch_stack_address)
ret = snprintf(buf, n, "$stack");
else if (ff->func == fetch_indirect) {
struct indirect_fetch_data *id = ff->data;
size_t l = 0;
ret = snprintf(buf, n, "%+ld(", id->offset);
if (ret >= n)
goto end;
l += ret;
ret = probe_arg_string(buf + l, n - l, &id->orig);
if (ret < 0)
goto end;
l += ret;
ret = snprintf(buf + l, n - l, ")");
ret += l;
}
end:
if (ret >= n)
return -ENOSPC;
return ret;
}
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 */
static int check_event_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 || !check_event_name(event)) {
ret = -EINVAL;
goto error;
}
tp->call.name = kstrdup(event, GFP_KERNEL);
if (!tp->call.name)
goto error;
if (!group || !check_event_name(group)) {
ret = -EINVAL;
goto error;
}
tp->call.system = kstrdup(group, GFP_KERNEL);
if (!tp->call.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 free_probe_arg(struct probe_arg *arg)
{
if (arg->fetch.func == fetch_symbol)
free_symbol_cache(arg->fetch.data);
else if (arg->fetch.func == fetch_indirect)
free_indirect_fetch_data(arg->fetch.data);
kfree(arg->name);
}
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.system);
kfree(tp->call.name);
kfree(tp->symbol);
kfree(tp);
}
static struct trace_probe *find_probe_event(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.system, group) == 0)
return tp;
return NULL;
}
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
static void unregister_trace_probe(struct trace_probe *tp)
{
if (probe_is_return(tp))
unregister_kretprobe(&tp->rp);
else
unregister_kprobe(&tp->rp.kp);
list_del(&tp->list);
unregister_probe_event(tp);
}
/* 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);
/* register as an event */
old_tp = find_probe_event(tp->call.name, tp->call.system);
if (old_tp) {
/* delete old event */
unregister_trace_probe(old_tp);
free_trace_probe(old_tp);
}
ret = register_probe_event(tp);
if (ret) {
pr_warning("Faild to register probe event(%d)\n", ret);
goto end;
}
tp->rp.kp.flags |= KPROBE_FLAG_DISABLED;
if (probe_is_return(tp))
ret = register_kretprobe(&tp->rp);
else
ret = register_kprobe(&tp->rp.kp);
if (ret) {
pr_warning("Could not insert probe(%d)\n", ret);
if (ret == -EILSEQ) {
pr_warning("Probing address(0x%p) is not an "
"instruction boundary.\n",
tp->rp.kp.addr);
ret = -EINVAL;
}
unregister_probe_event(tp);
} else
list_add_tail(&tp->list, &probe_list);
end:
mutex_unlock(&probe_lock);
return ret;
}
/* 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, struct fetch_func *ff, int is_return)
{
int ret = 0;
unsigned long param;
if (strcmp(arg, "retval") == 0) {
if (is_return) {
ff->func = fetch_retvalue;
ff->data = NULL;
} else
ret = -EINVAL;
} else if (strncmp(arg, "stack", 5) == 0) {
if (arg[5] == '\0') {
ff->func = fetch_stack_address;
ff->data = NULL;
} else if (isdigit(arg[5])) {
ret = strict_strtoul(arg + 5, 10, ¶m);
if (ret || param > PARAM_MAX_STACK)
ret = -EINVAL;
else {
ff->func = fetch_stack;
ff->data = (void *)param;
}
} else
ret = -EINVAL;
} else if (strncmp(arg, "arg", 3) == 0 && isdigit(arg[3])) {
ret = strict_strtoul(arg + 3, 10, ¶m);
if (ret || param > PARAM_MAX_ARGS)
ret = -EINVAL;
else {
ff->func = fetch_argument;
ff->data = (void *)param;
}
} else
ret = -EINVAL;
return ret;
}
/* Recursive argument parser */
static int __parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
{
int ret = 0;
unsigned long param;
long offset;
char *tmp;
switch (arg[0]) {
case '$':
ret = parse_probe_vars(arg + 1, ff, is_return);
break;
case '%': /* named register */
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
ff->func = fetch_register;
ff->data = (void *)(unsigned long)ret;
ret = 0;
}
break;
case '@': /* memory or symbol */
if (isdigit(arg[1])) {
ret = strict_strtoul(arg + 1, 0, ¶m);
if (ret)
break;
ff->func = fetch_memory;
ff->data = (void *)param;
} else {
ret = split_symbol_offset(arg + 1, &offset);
if (ret)
break;
ff->data = alloc_symbol_cache(arg + 1, offset);
if (ff->data)
ff->func = fetch_symbol;
else
ret = -EINVAL;
}
break;
case '+': /* indirect memory */
case '-':
tmp = strchr(arg, '(');
if (!tmp) {
ret = -EINVAL;
break;
}
*tmp = '\0';
ret = strict_strtol(arg + 1, 0, &offset);
if (ret)
break;
if (arg[0] == '-')
offset = -offset;
arg = tmp + 1;
tmp = strrchr(arg, ')');
if (tmp) {
struct indirect_fetch_data *id;
*tmp = '\0';
id = kzalloc(sizeof(struct indirect_fetch_data),
GFP_KERNEL);
if (!id)
return -ENOMEM;
id->offset = offset;
ret = __parse_probe_arg(arg, &id->orig, is_return);
if (ret)
kfree(id);
else {
ff->func = fetch_indirect;
ff->data = (void *)id;
}
} else
ret = -EINVAL;
break;
default:
/* TODO: support custom handler */
ret = -EINVAL;
}
return ret;
}
/* String length checking wrapper */
static int parse_probe_arg(char *arg, struct fetch_func *ff, int is_return)
{
if (strlen(arg) > MAX_ARGSTR_LEN) {
pr_info("Argument is too long.: %s\n", arg);
return -ENOSPC;
}
return __parse_probe_arg(arg, ff, is_return);
}
/* Return 1 if name is reserved or already used by another argument */
static int conflict_field_name(const char *name,
struct probe_arg *args, int narg)
{
int i;
for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
if (strcmp(reserved_field_names[i], name) == 0)
return 1;
for (i = 0; i < narg; i++)
if (strcmp(args[i].name, name) == 0)
return 1;
return 0;
}
static int create_trace_probe(int argc, char **argv)
{
/*
* Argument syntax:
* - Add kprobe: p[:[GRP/]EVENT] KSYM[+OFFS]|KADDR [FETCHARGS]
* - Add kretprobe: r[:[GRP/]EVENT] KSYM[+0] [FETCHARGS]
* Fetch args:
* $argN : fetch Nth of function argument. (N:0-)
* $retval : fetch return value
* $stack : fetch stack address
* $stackN : fetch Nth of stack (N:0-)
* @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
* Indirect memory fetch:
* +|-offs(ARG) : fetch memory at ARG +|- offs address.
* Alias name of args:
* NAME=FETCHARG : set NAME as alias of FETCHARG.
*/
struct trace_probe *tp;
int i, ret = 0;
int is_return = 0, is_delete = 0;
char *symbol = NULL, *event = NULL, *arg = NULL, *group = NULL;
unsigned long offset = 0;
void *addr = NULL;
char buf[MAX_EVENT_NAME_LEN];
/* argc must be >= 1 */
if (argv[0][0] == 'p')
is_return = 0;
else if (argv[0][0] == 'r')
is_return = 1;
else if (argv[0][0] == '-')
is_delete = 1;
else {
pr_info("Probe definition must be started with 'p', 'r' or"
" '-'.\n");
return -EINVAL;
}
if (argv[0][1] == ':') {
event = &argv[0][2];
if (strchr(event, '/')) {
group = event;
event = strchr(group, '/') + 1;
event[-1] = '\0';
if (strlen(group) == 0) {
pr_info("Group name is not specifiled\n");
return -EINVAL;
}
}
if (strlen(event) == 0) {
pr_info("Event name is not specifiled\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;
}
tp = find_probe_event(event, group);
if (!tp) {
pr_info("Event %s/%s doesn't exist.\n", group, event);
return -ENOENT;
}
/* delete an event */
unregister_trace_probe(tp);
free_trace_probe(tp);
return 0;
}
if (argc < 2) {
pr_info("Probe point is not specified.\n");
return -EINVAL;
}
if (isdigit(argv[1][0])) {
if (is_return) {
pr_info("Return probe point must be a symbol.\n");
return -EINVAL;
}
/* an address specified */
ret = strict_strtoul(&argv[1][0], 0, (unsigned long *)&addr);
if (ret) {
pr_info("Failed to parse address.\n");
return ret;
}
} else {
/* a symbol specified */
symbol = argv[1];
/* TODO: support .init module functions */
ret = split_symbol_offset(symbol, &offset);
if (ret) {
pr_info("Failed to parse symbol.\n");
return ret;
}
if (offset && is_return) {
pr_info("Return probe must be used without offset.\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);
event = buf;
}
tp = alloc_trace_probe(group, event, addr, symbol, offset, argc,
is_return);
if (IS_ERR(tp)) {
pr_info("Failed to allocate trace_probe.(%d)\n",
(int)PTR_ERR(tp));
return PTR_ERR(tp);
}
/* parse arguments */
ret = 0;
for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
/* Parse argument name */
arg = strchr(argv[i], '=');
if (arg)
*arg++ = '\0';
else
arg = argv[i];
if (conflict_field_name(argv[i], tp->args, i)) {
pr_info("Argument%d name '%s' conflicts with "
"another field.\n", i, argv[i]);
ret = -EINVAL;
goto error;
}
tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
if (!tp->args[i].name) {
pr_info("Failed to allocate argument%d name '%s'.\n",
i, argv[i]);
ret = -ENOMEM;
goto error;
}
/* Parse fetch argument */
ret = parse_probe_arg(arg, &tp->args[i].fetch, is_return);
if (ret) {
pr_info("Parse error at argument%d. (%d)\n", i, ret);
kfree(tp->args[i].name);
goto error;
}
tp->nr_args++;
}
ret = register_trace_probe(tp);
if (ret)
goto error;
return 0;
error:
free_trace_probe(tp);
return ret;
}
static void cleanup_all_probes(void)
{
struct trace_probe *tp;
mutex_lock(&probe_lock);
/* TODO: Use batch unregistration */
while (!list_empty(&probe_list)) {
tp = list_entry(probe_list.next, struct trace_probe, list);
unregister_trace_probe(tp);
free_trace_probe(tp);
}
mutex_unlock(&probe_lock);
}
/* 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_probe *tp = v;
int i, ret;
char buf[MAX_ARGSTR_LEN + 1];
seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
seq_printf(m, ":%s/%s", tp->call.system, tp->call.name);
if (!tp->symbol)
seq_printf(m, " 0x%p", tp->rp.kp.addr);
else if (tp->rp.kp.offset)
seq_printf(m, " %s+%u", probe_symbol(tp), tp->rp.kp.offset);
else
seq_printf(m, " %s", probe_symbol(tp));
for (i = 0; i < tp->nr_args; i++) {
ret = probe_arg_string(buf, MAX_ARGSTR_LEN, &tp->args[i].fetch);
if (ret < 0) {
pr_warning("Argument%d decoding error(%d).\n", i, ret);
return ret;
}
seq_printf(m, " %s=%s", tp->args[i].name, buf);
}
seq_printf(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)
{
if ((file->f_mode & FMODE_WRITE) &&
(file->f_flags & O_TRUNC))
cleanup_all_probes();
return seq_open(file, &probes_seq_op);
}
static int command_trace_probe(const char *buf)
{
char **argv;
int argc = 0, ret = 0;
argv = argv_split(GFP_KERNEL, buf, &argc);
if (!argv)
return -ENOMEM;
if (argc)
ret = create_trace_probe(argc, argv);
argv_free(argv);
return ret;
}
#define WRITE_BUFSIZE 128
static ssize_t probes_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
char *kbuf, *tmp;
int ret;
size_t done;
size_t size;
kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
ret = done = 0;
while (done < count) {
size = count - done;
if (size >= WRITE_BUFSIZE)
size = WRITE_BUFSIZE - 1;
if (copy_from_user(kbuf, buffer + done, size)) {
ret = -EFAULT;
goto out;
}
kbuf[size] = '\0';
tmp = strchr(kbuf, '\n');
if (tmp) {
*tmp = '\0';
size = tmp - kbuf + 1;
} else if (done + size < count) {
pr_warning("Line length is too long: "
"Should be less than %d.", WRITE_BUFSIZE);
ret = -EINVAL;
goto out;
}
done += size;
/* Remove comments */
tmp = strchr(kbuf, '#');
if (tmp)
*tmp = '\0';
ret = command_trace_probe(kbuf);
if (ret)
goto out;
}
ret = done;
out:
kfree(kbuf);
return ret;
}
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_probe *tp = v;
seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
tp->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 __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
{
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct kprobe_trace_entry *entry;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int size, i, pc;
unsigned long irq_flags;
struct ftrace_event_call *call = &tp->call;
tp->nhit++;
local_save_flags(irq_flags);
pc = preempt_count();
size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
irq_flags, pc);
if (!event)
return 0;
entry = ring_buffer_event_data(event);
entry->nargs = tp->nr_args;
entry->ip = (unsigned long)kp->addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
if (!filter_current_check_discard(buffer, call, entry, event))
trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
return 0;
}
/* Kretprobe handler */
static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
struct kretprobe_trace_entry *entry;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int size, i, pc;
unsigned long irq_flags;
struct ftrace_event_call *call = &tp->call;
local_save_flags(irq_flags);
pc = preempt_count();
size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
event = trace_current_buffer_lock_reserve(&buffer, call->id, size,
irq_flags, pc);
if (!event)
return 0;
entry = ring_buffer_event_data(event);
entry->nargs = tp->nr_args;
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
if (!filter_current_check_discard(buffer, call, entry, event))
trace_nowake_buffer_unlock_commit(buffer, event, irq_flags, pc);
return 0;
}
/* Event entry printers */
enum print_line_t
print_kprobe_event(struct trace_iterator *iter, int flags)
{
struct kprobe_trace_entry *field;
struct trace_seq *s = &iter->seq;
struct trace_event *event;
struct trace_probe *tp;
int i;
field = (struct kprobe_trace_entry *)iter->ent;
event = ftrace_find_event(field->ent.type);
tp = container_of(event, struct trace_probe, event);
if (!trace_seq_printf(s, "%s: (", tp->call.name))
goto partial;
if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
goto partial;
if (!trace_seq_puts(s, ")"))
goto partial;
for (i = 0; i < field->nargs; i++)
if (!trace_seq_printf(s, " %s=%lx",
tp->args[i].name, field->args[i]))
goto partial;
if (!trace_seq_puts(s, "\n"))
goto partial;
return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
enum print_line_t
print_kretprobe_event(struct trace_iterator *iter, int flags)
{
struct kretprobe_trace_entry *field;
struct trace_seq *s = &iter->seq;
struct trace_event *event;
struct trace_probe *tp;
int i;
field = (struct kretprobe_trace_entry *)iter->ent;
event = ftrace_find_event(field->ent.type);
tp = container_of(event, struct trace_probe, event);
if (!trace_seq_printf(s, "%s: (", tp->call.name))
goto partial;
if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
goto partial;
if (!trace_seq_puts(s, " <- "))
goto partial;
if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
goto partial;
if (!trace_seq_puts(s, ")"))
goto partial;
for (i = 0; i < field->nargs; i++)
if (!trace_seq_printf(s, " %s=%lx",
tp->args[i].name, field->args[i]))
goto partial;
if (!trace_seq_puts(s, "\n"))
goto partial;
return TRACE_TYPE_HANDLED;
partial:
return TRACE_TYPE_PARTIAL_LINE;
}
static int probe_event_enable(struct ftrace_event_call *call)
{
struct trace_probe *tp = (struct trace_probe *)call->data;
tp->flags |= TP_FLAG_TRACE;
if (probe_is_return(tp))
return enable_kretprobe(&tp->rp);
else
return enable_kprobe(&tp->rp.kp);
}
static void probe_event_disable(struct ftrace_event_call *call)
{
struct trace_probe *tp = (struct trace_probe *)call->data;
tp->flags &= ~TP_FLAG_TRACE;
if (!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE))) {
if (probe_is_return(tp))
disable_kretprobe(&tp->rp);
else
disable_kprobe(&tp->rp.kp);
}
}
static int probe_event_raw_init(struct ftrace_event_call *event_call)
{
INIT_LIST_HEAD(&event_call->fields);
return 0;
}
#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)
static int kprobe_event_define_fields(struct ftrace_event_call *event_call)
{
int ret, i;
struct kprobe_trace_entry field;
struct trace_probe *tp = (struct trace_probe *)event_call->data;
DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
return 0;
}
static int kretprobe_event_define_fields(struct ftrace_event_call *event_call)
{
int ret, i;
struct kretprobe_trace_entry field;
struct trace_probe *tp = (struct trace_probe *)event_call->data;
DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
DEFINE_FIELD(int, nargs, FIELD_STRING_NARGS, 1);
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++)
DEFINE_FIELD(unsigned long, args[i], tp->args[i].name, 0);
return 0;
}
static int __probe_event_show_format(struct trace_seq *s,
struct trace_probe *tp, const char *fmt,
const char *arg)
{
int i;
/* Show format */
if (!trace_seq_printf(s, "\nprint fmt: \"%s", fmt))
return 0;
for (i = 0; i < tp->nr_args; i++)
if (!trace_seq_printf(s, " %s=%%lx", tp->args[i].name))
return 0;
if (!trace_seq_printf(s, "\", %s", arg))
return 0;
for (i = 0; i < tp->nr_args; i++)
if (!trace_seq_printf(s, ", REC->%s", tp->args[i].name))
return 0;
return trace_seq_puts(s, "\n");
}
#undef SHOW_FIELD
#define SHOW_FIELD(type, item, name) \
do { \
ret = trace_seq_printf(s, "\tfield:" #type " %s;\t" \
"offset:%u;\tsize:%u;\tsigned:%d;\n", name,\
(unsigned int)offsetof(typeof(field), item),\
(unsigned int)sizeof(type), \
is_signed_type(type)); \
if (!ret) \
return 0; \
} while (0)
static int kprobe_event_show_format(struct ftrace_event_call *call,
struct trace_seq *s)
{
struct kprobe_trace_entry field __attribute__((unused));
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;
SHOW_FIELD(unsigned long, ip, FIELD_STRING_IP);
SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
/* Show fields */
for (i = 0; i < tp->nr_args; i++)
SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
trace_seq_puts(s, "\n");
return __probe_event_show_format(s, tp, "(%lx)",
"REC->" FIELD_STRING_IP);
}
static int kretprobe_event_show_format(struct ftrace_event_call *call,
struct trace_seq *s)
{
struct kretprobe_trace_entry field __attribute__((unused));
int ret, i;
struct trace_probe *tp = (struct trace_probe *)call->data;
SHOW_FIELD(unsigned long, func, FIELD_STRING_FUNC);
SHOW_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP);
SHOW_FIELD(int, nargs, FIELD_STRING_NARGS);
/* Show fields */
for (i = 0; i < tp->nr_args; i++)
SHOW_FIELD(unsigned long, args[i], tp->args[i].name);
trace_seq_puts(s, "\n");
return __probe_event_show_format(s, tp, "(%lx <- %lx)",
"REC->" FIELD_STRING_FUNC
", REC->" FIELD_STRING_RETIP);
}
#ifdef CONFIG_EVENT_PROFILE
/* Kprobe profile handler */
static __kprobes int kprobe_profile_func(struct kprobe *kp,
struct pt_regs *regs)
{
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct ftrace_event_call *call = &tp->call;
struct kprobe_trace_entry *entry;
struct trace_entry *ent;
int size, __size, i, pc, __cpu;
unsigned long irq_flags;
char *trace_buf;
char *raw_data;
int rctx;
pc = preempt_count();
__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
"profile buffer not large enough"))
return 0;
/*
* Protect the non nmi buffer
* This also protects the rcu read side
*/
local_irq_save(irq_flags);
rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
goto end_recursion;
__cpu = smp_processor_id();
if (in_nmi())
trace_buf = rcu_dereference(perf_trace_buf_nmi);
else
trace_buf = rcu_dereference(perf_trace_buf);
if (!trace_buf)
goto end;
raw_data = per_cpu_ptr(trace_buf, __cpu);
/* Zero dead bytes from alignment to avoid buffer leak to userspace */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
entry = (struct kprobe_trace_entry *)raw_data;
ent = &entry->ent;
tracing_generic_entry_update(ent, irq_flags, pc);
ent->type = call->id;
entry->nargs = tp->nr_args;
entry->ip = (unsigned long)kp->addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
perf_tp_event(call->id, entry->ip, 1, entry, size);
end:
perf_swevent_put_recursion_context(rctx);
end_recursion:
local_irq_restore(irq_flags);
return 0;
}
/* Kretprobe profile handler */
static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
struct ftrace_event_call *call = &tp->call;
struct kretprobe_trace_entry *entry;
struct trace_entry *ent;
int size, __size, i, pc, __cpu;
unsigned long irq_flags;
char *trace_buf;
char *raw_data;
int rctx;
pc = preempt_count();
__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
"profile buffer not large enough"))
return 0;
/*
* Protect the non nmi buffer
* This also protects the rcu read side
*/
local_irq_save(irq_flags);
rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
goto end_recursion;
__cpu = smp_processor_id();
if (in_nmi())
trace_buf = rcu_dereference(perf_trace_buf_nmi);
else
trace_buf = rcu_dereference(perf_trace_buf);
if (!trace_buf)
goto end;
raw_data = per_cpu_ptr(trace_buf, __cpu);
/* Zero dead bytes from alignment to avoid buffer leak to userspace */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
entry = (struct kretprobe_trace_entry *)raw_data;
ent = &entry->ent;
tracing_generic_entry_update(ent, irq_flags, pc);
ent->type = call->id;
entry->nargs = tp->nr_args;
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
for (i = 0; i < tp->nr_args; i++)
entry->args[i] = call_fetch(&tp->args[i].fetch, regs);
perf_tp_event(call->id, entry->ret_ip, 1, entry, size);
end:
perf_swevent_put_recursion_context(rctx);
end_recursion:
local_irq_restore(irq_flags);
return 0;
}
static int probe_profile_enable(struct ftrace_event_call *call)
{
struct trace_probe *tp = (struct trace_probe *)call->data;
tp->flags |= TP_FLAG_PROFILE;
if (probe_is_return(tp))
return enable_kretprobe(&tp->rp);
else
return enable_kprobe(&tp->rp.kp);
}
static void probe_profile_disable(struct ftrace_event_call *call)
{
struct trace_probe *tp = (struct trace_probe *)call->data;
tp->flags &= ~TP_FLAG_PROFILE;
if (!(tp->flags & TP_FLAG_TRACE)) {
if (probe_is_return(tp))
disable_kretprobe(&tp->rp);
else
disable_kprobe(&tp->rp.kp);
}
}
#endif /* CONFIG_EVENT_PROFILE */
static __kprobes
int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
{
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
if (tp->flags & TP_FLAG_TRACE)
kprobe_trace_func(kp, regs);
#ifdef CONFIG_EVENT_PROFILE
if (tp->flags & TP_FLAG_PROFILE)
kprobe_profile_func(kp, regs);
#endif /* CONFIG_EVENT_PROFILE */
return 0; /* We don't tweek kernel, so just return 0 */
}
static __kprobes
int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
{
struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
if (tp->flags & TP_FLAG_TRACE)
kretprobe_trace_func(ri, regs);
#ifdef CONFIG_EVENT_PROFILE
if (tp->flags & TP_FLAG_PROFILE)
kretprobe_profile_func(ri, regs);
#endif /* CONFIG_EVENT_PROFILE */
return 0; /* We don't tweek kernel, so just return 0 */
}
static int register_probe_event(struct trace_probe *tp)
{
struct ftrace_event_call *call = &tp->call;
int ret;
/* Initialize ftrace_event_call */
if (probe_is_return(tp)) {
tp->event.trace = print_kretprobe_event;
call->raw_init = probe_event_raw_init;
call->show_format = kretprobe_event_show_format;
call->define_fields = kretprobe_event_define_fields;
} else {
tp->event.trace = print_kprobe_event;
call->raw_init = probe_event_raw_init;
call->show_format = kprobe_event_show_format;
call->define_fields = kprobe_event_define_fields;
}
call->event = &tp->event;
call->id = register_ftrace_event(&tp->event);
if (!call->id)
return -ENODEV;
call->enabled = 0;
call->regfunc = probe_event_enable;
call->unregfunc = probe_event_disable;
#ifdef CONFIG_EVENT_PROFILE
call->profile_enable = probe_profile_enable;
call->profile_disable = probe_profile_disable;
#endif
call->data = tp;
ret = trace_add_event_call(call);
if (ret) {
pr_info("Failed to register kprobe event: %s\n", call->name);
unregister_ftrace_event(&tp->event);
}
return ret;
}
static void unregister_probe_event(struct trace_probe *tp)
{
/* tp->event is unregistered in trace_remove_event_call() */
trace_remove_event_call(&tp->call);
}
/* Make a debugfs interface for controling probe points */
static __init int init_kprobe_trace(void)
{
struct dentry *d_tracer;
struct dentry *entry;
d_tracer = tracing_init_dentry();
if (!d_tracer)
return 0;
entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
NULL, &kprobe_events_ops);
/* Event list interface */
if (!entry)
pr_warning("Could not create debugfs "
"'kprobe_events' entry\n");
/* Profile interface */
entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
NULL, &kprobe_profile_ops);
if (!entry)
pr_warning("Could not create debugfs "
"'kprobe_profile' entry\n");
return 0;
}
fs_initcall(init_kprobe_trace);
#ifdef CONFIG_FTRACE_STARTUP_TEST
static int kprobe_trace_selftest_target(int a1, int a2, int a3,
int a4, int a5, int a6)
{
return a1 + a2 + a3 + a4 + a5 + a6;
}
static __init int kprobe_trace_self_tests_init(void)
{
int ret;
int (*target)(int, int, int, int, int, int);
target = kprobe_trace_selftest_target;
pr_info("Testing kprobe tracing: ");
ret = command_trace_probe("p:testprobe kprobe_trace_selftest_target "
"$arg1 $arg2 $arg3 $arg4 $stack $stack0");
if (WARN_ON_ONCE(ret))
pr_warning("error enabling function entry\n");
ret = command_trace_probe("r:testprobe2 kprobe_trace_selftest_target "
"$retval");
if (WARN_ON_ONCE(ret))
pr_warning("error enabling function return\n");
ret = target(1, 2, 3, 4, 5, 6);
cleanup_all_probes();
pr_cont("OK\n");
return 0;
}
late_initcall(kprobe_trace_self_tests_init);
#endif