linux/kernel/trace/trace_syscalls.c

632 lines
15 KiB
C

#include <trace/syscall.h>
#include <trace/events/syscalls.h>
#include <linux/kernel.h>
#include <linux/ftrace.h>
#include <linux/perf_event.h>
#include <asm/syscall.h>
#include "trace_output.h"
#include "trace.h"
static DEFINE_MUTEX(syscall_trace_lock);
static int sys_refcount_enter;
static int sys_refcount_exit;
static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
extern unsigned long __start_syscalls_metadata[];
extern unsigned long __stop_syscalls_metadata[];
static struct syscall_metadata **syscalls_metadata;
static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
{
struct syscall_metadata *start;
struct syscall_metadata *stop;
char str[KSYM_SYMBOL_LEN];
start = (struct syscall_metadata *)__start_syscalls_metadata;
stop = (struct syscall_metadata *)__stop_syscalls_metadata;
kallsyms_lookup(syscall, NULL, NULL, NULL, str);
for ( ; start < stop; start++) {
/*
* Only compare after the "sys" prefix. Archs that use
* syscall wrappers may have syscalls symbols aliases prefixed
* with "SyS" instead of "sys", leading to an unwanted
* mismatch.
*/
if (start->name && !strcmp(start->name + 3, str + 3))
return start;
}
return NULL;
}
static struct syscall_metadata *syscall_nr_to_meta(int nr)
{
if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
return NULL;
return syscalls_metadata[nr];
}
enum print_line_t
print_syscall_enter(struct trace_iterator *iter, int flags)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *ent = iter->ent;
struct syscall_trace_enter *trace;
struct syscall_metadata *entry;
int i, ret, syscall;
trace = (typeof(trace))ent;
syscall = trace->nr;
entry = syscall_nr_to_meta(syscall);
if (!entry)
goto end;
if (entry->enter_event->id != ent->type) {
WARN_ON_ONCE(1);
goto end;
}
ret = trace_seq_printf(s, "%s(", entry->name);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
for (i = 0; i < entry->nb_args; i++) {
/* parameter types */
if (trace_flags & TRACE_ITER_VERBOSE) {
ret = trace_seq_printf(s, "%s ", entry->types[i]);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* parameter values */
ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
trace->args[i],
i == entry->nb_args - 1 ? "" : ", ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_putc(s, ')');
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
end:
ret = trace_seq_putc(s, '\n');
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
enum print_line_t
print_syscall_exit(struct trace_iterator *iter, int flags)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *ent = iter->ent;
struct syscall_trace_exit *trace;
int syscall;
struct syscall_metadata *entry;
int ret;
trace = (typeof(trace))ent;
syscall = trace->nr;
entry = syscall_nr_to_meta(syscall);
if (!entry) {
trace_seq_printf(s, "\n");
return TRACE_TYPE_HANDLED;
}
if (entry->exit_event->id != ent->type) {
WARN_ON_ONCE(1);
return TRACE_TYPE_UNHANDLED;
}
ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
trace->ret);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
extern char *__bad_type_size(void);
#define SYSCALL_FIELD(type, name) \
sizeof(type) != sizeof(trace.name) ? \
__bad_type_size() : \
#type, #name, offsetof(typeof(trace), name), \
sizeof(trace.name), is_signed_type(type)
int syscall_enter_format(struct ftrace_event_call *call, struct trace_seq *s)
{
int i;
int ret;
struct syscall_metadata *entry = call->data;
struct syscall_trace_enter trace;
int offset = offsetof(struct syscall_trace_enter, args);
ret = trace_seq_printf(s, "\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
"\tsigned:%u;\n",
SYSCALL_FIELD(int, nr));
if (!ret)
return 0;
for (i = 0; i < entry->nb_args; i++) {
ret = trace_seq_printf(s, "\tfield:%s %s;", entry->types[i],
entry->args[i]);
if (!ret)
return 0;
ret = trace_seq_printf(s, "\toffset:%d;\tsize:%zu;"
"\tsigned:%u;\n", offset,
sizeof(unsigned long),
is_signed_type(unsigned long));
if (!ret)
return 0;
offset += sizeof(unsigned long);
}
trace_seq_puts(s, "\nprint fmt: \"");
for (i = 0; i < entry->nb_args; i++) {
ret = trace_seq_printf(s, "%s: 0x%%0%zulx%s", entry->args[i],
sizeof(unsigned long),
i == entry->nb_args - 1 ? "" : ", ");
if (!ret)
return 0;
}
trace_seq_putc(s, '"');
for (i = 0; i < entry->nb_args; i++) {
ret = trace_seq_printf(s, ", ((unsigned long)(REC->%s))",
entry->args[i]);
if (!ret)
return 0;
}
return trace_seq_putc(s, '\n');
}
int syscall_exit_format(struct ftrace_event_call *call, struct trace_seq *s)
{
int ret;
struct syscall_trace_exit trace;
ret = trace_seq_printf(s,
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
"\tsigned:%u;\n"
"\tfield:%s %s;\toffset:%zu;\tsize:%zu;"
"\tsigned:%u;\n",
SYSCALL_FIELD(int, nr),
SYSCALL_FIELD(long, ret));
if (!ret)
return 0;
return trace_seq_printf(s, "\nprint fmt: \"0x%%lx\", REC->ret\n");
}
int syscall_enter_define_fields(struct ftrace_event_call *call)
{
struct syscall_trace_enter trace;
struct syscall_metadata *meta = call->data;
int ret;
int i;
int offset = offsetof(typeof(trace), args);
ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
if (ret)
return ret;
for (i = 0; i < meta->nb_args; i++) {
ret = trace_define_field(call, meta->types[i],
meta->args[i], offset,
sizeof(unsigned long), 0,
FILTER_OTHER);
offset += sizeof(unsigned long);
}
return ret;
}
int syscall_exit_define_fields(struct ftrace_event_call *call)
{
struct syscall_trace_exit trace;
int ret;
ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
if (ret)
return ret;
ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
FILTER_OTHER);
return ret;
}
void ftrace_syscall_enter(struct pt_regs *regs, long id)
{
struct syscall_trace_enter *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int size;
int syscall_nr;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
return;
if (!test_bit(syscall_nr, enabled_enter_syscalls))
return;
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
event = trace_current_buffer_lock_reserve(&buffer,
sys_data->enter_event->id, size, 0, 0);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
if (!filter_current_check_discard(buffer, sys_data->enter_event,
entry, event))
trace_current_buffer_unlock_commit(buffer, event, 0, 0);
}
void ftrace_syscall_exit(struct pt_regs *regs, long ret)
{
struct syscall_trace_exit *entry;
struct syscall_metadata *sys_data;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
int syscall_nr;
syscall_nr = syscall_get_nr(current, regs);
if (syscall_nr < 0)
return;
if (!test_bit(syscall_nr, enabled_exit_syscalls))
return;
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
event = trace_current_buffer_lock_reserve(&buffer,
sys_data->exit_event->id, sizeof(*entry), 0, 0);
if (!event)
return;
entry = ring_buffer_event_data(event);
entry->nr = syscall_nr;
entry->ret = syscall_get_return_value(current, regs);
if (!filter_current_check_discard(buffer, sys_data->exit_event,
entry, event))
trace_current_buffer_unlock_commit(buffer, event, 0, 0);
}
int reg_event_syscall_enter(struct ftrace_event_call *call)
{
int ret = 0;
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
if (num < 0 || num >= NR_syscalls)
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!sys_refcount_enter)
ret = register_trace_sys_enter(ftrace_syscall_enter);
if (!ret) {
set_bit(num, enabled_enter_syscalls);
sys_refcount_enter++;
}
mutex_unlock(&syscall_trace_lock);
return ret;
}
void unreg_event_syscall_enter(struct ftrace_event_call *call)
{
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
if (num < 0 || num >= NR_syscalls)
return;
mutex_lock(&syscall_trace_lock);
sys_refcount_enter--;
clear_bit(num, enabled_enter_syscalls);
if (!sys_refcount_enter)
unregister_trace_sys_enter(ftrace_syscall_enter);
mutex_unlock(&syscall_trace_lock);
}
int reg_event_syscall_exit(struct ftrace_event_call *call)
{
int ret = 0;
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
if (num < 0 || num >= NR_syscalls)
return -ENOSYS;
mutex_lock(&syscall_trace_lock);
if (!sys_refcount_exit)
ret = register_trace_sys_exit(ftrace_syscall_exit);
if (!ret) {
set_bit(num, enabled_exit_syscalls);
sys_refcount_exit++;
}
mutex_unlock(&syscall_trace_lock);
return ret;
}
void unreg_event_syscall_exit(struct ftrace_event_call *call)
{
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
if (num < 0 || num >= NR_syscalls)
return;
mutex_lock(&syscall_trace_lock);
sys_refcount_exit--;
clear_bit(num, enabled_exit_syscalls);
if (!sys_refcount_exit)
unregister_trace_sys_exit(ftrace_syscall_exit);
mutex_unlock(&syscall_trace_lock);
}
int init_syscall_trace(struct ftrace_event_call *call)
{
int id;
id = register_ftrace_event(call->event);
if (!id)
return -ENODEV;
call->id = id;
INIT_LIST_HEAD(&call->fields);
return 0;
}
int __init init_ftrace_syscalls(void)
{
struct syscall_metadata *meta;
unsigned long addr;
int i;
syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
NR_syscalls, GFP_KERNEL);
if (!syscalls_metadata) {
WARN_ON(1);
return -ENOMEM;
}
for (i = 0; i < NR_syscalls; i++) {
addr = arch_syscall_addr(i);
meta = find_syscall_meta(addr);
if (!meta)
continue;
meta->syscall_nr = i;
syscalls_metadata[i] = meta;
}
return 0;
}
core_initcall(init_ftrace_syscalls);
#ifdef CONFIG_EVENT_PROFILE
static DECLARE_BITMAP(enabled_prof_enter_syscalls, NR_syscalls);
static DECLARE_BITMAP(enabled_prof_exit_syscalls, NR_syscalls);
static int sys_prof_refcount_enter;
static int sys_prof_refcount_exit;
static void prof_syscall_enter(struct pt_regs *regs, long id)
{
struct syscall_metadata *sys_data;
struct syscall_trace_enter *rec;
unsigned long flags;
char *trace_buf;
char *raw_data;
int syscall_nr;
int rctx;
int size;
int cpu;
syscall_nr = syscall_get_nr(current, regs);
if (!test_bit(syscall_nr, enabled_prof_enter_syscalls))
return;
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
/* get the size after alignment with the u32 buffer size field */
size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
size = ALIGN(size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
"profile buffer not large enough"))
return;
/* Protect the per cpu buffer, begin the rcu read side */
local_irq_save(flags);
rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
goto end_recursion;
cpu = smp_processor_id();
trace_buf = rcu_dereference(perf_trace_buf);
if (!trace_buf)
goto end;
raw_data = per_cpu_ptr(trace_buf, cpu);
/* zero the dead bytes from align to not leak stack to user */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
rec = (struct syscall_trace_enter *) raw_data;
tracing_generic_entry_update(&rec->ent, 0, 0);
rec->ent.type = sys_data->enter_event->id;
rec->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
perf_tp_event(sys_data->enter_event->id, 0, 1, rec, size);
end:
perf_swevent_put_recursion_context(rctx);
end_recursion:
local_irq_restore(flags);
}
int prof_sysenter_enable(struct ftrace_event_call *call)
{
int ret = 0;
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
mutex_lock(&syscall_trace_lock);
if (!sys_prof_refcount_enter)
ret = register_trace_sys_enter(prof_syscall_enter);
if (ret) {
pr_info("event trace: Could not activate"
"syscall entry trace point");
} else {
set_bit(num, enabled_prof_enter_syscalls);
sys_prof_refcount_enter++;
}
mutex_unlock(&syscall_trace_lock);
return ret;
}
void prof_sysenter_disable(struct ftrace_event_call *call)
{
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
mutex_lock(&syscall_trace_lock);
sys_prof_refcount_enter--;
clear_bit(num, enabled_prof_enter_syscalls);
if (!sys_prof_refcount_enter)
unregister_trace_sys_enter(prof_syscall_enter);
mutex_unlock(&syscall_trace_lock);
}
static void prof_syscall_exit(struct pt_regs *regs, long ret)
{
struct syscall_metadata *sys_data;
struct syscall_trace_exit *rec;
unsigned long flags;
int syscall_nr;
char *trace_buf;
char *raw_data;
int rctx;
int size;
int cpu;
syscall_nr = syscall_get_nr(current, regs);
if (!test_bit(syscall_nr, enabled_prof_exit_syscalls))
return;
sys_data = syscall_nr_to_meta(syscall_nr);
if (!sys_data)
return;
/* We can probably do that at build time */
size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
/*
* Impossible, but be paranoid with the future
* How to put this check outside runtime?
*/
if (WARN_ONCE(size > FTRACE_MAX_PROFILE_SIZE,
"exit event has grown above profile buffer size"))
return;
/* Protect the per cpu buffer, begin the rcu read side */
local_irq_save(flags);
rctx = perf_swevent_get_recursion_context();
if (rctx < 0)
goto end_recursion;
cpu = smp_processor_id();
trace_buf = rcu_dereference(perf_trace_buf);
if (!trace_buf)
goto end;
raw_data = per_cpu_ptr(trace_buf, cpu);
/* zero the dead bytes from align to not leak stack to user */
*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
rec = (struct syscall_trace_exit *)raw_data;
tracing_generic_entry_update(&rec->ent, 0, 0);
rec->ent.type = sys_data->exit_event->id;
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);
perf_tp_event(sys_data->exit_event->id, 0, 1, rec, size);
end:
perf_swevent_put_recursion_context(rctx);
end_recursion:
local_irq_restore(flags);
}
int prof_sysexit_enable(struct ftrace_event_call *call)
{
int ret = 0;
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
mutex_lock(&syscall_trace_lock);
if (!sys_prof_refcount_exit)
ret = register_trace_sys_exit(prof_syscall_exit);
if (ret) {
pr_info("event trace: Could not activate"
"syscall entry trace point");
} else {
set_bit(num, enabled_prof_exit_syscalls);
sys_prof_refcount_exit++;
}
mutex_unlock(&syscall_trace_lock);
return ret;
}
void prof_sysexit_disable(struct ftrace_event_call *call)
{
int num;
num = ((struct syscall_metadata *)call->data)->syscall_nr;
mutex_lock(&syscall_trace_lock);
sys_prof_refcount_exit--;
clear_bit(num, enabled_prof_exit_syscalls);
if (!sys_prof_refcount_exit)
unregister_trace_sys_exit(prof_syscall_exit);
mutex_unlock(&syscall_trace_lock);
}
#endif