Commit ee08c6ec authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar

tracing/ftrace: syscall tracing infrastructure, basics

Provide basic callbacks to do syscall tracing.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1236401580-5758-2-git-send-email-fweisbec@gmail.com>
[ simplified it to a trace_printk() for now. ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 4c6ed8f4
......@@ -503,4 +503,25 @@ static inline void trace_hw_branch_oops(void) {}
#endif /* CONFIG_HW_BRANCH_TRACER */
/*
* A syscall entry in the ftrace syscalls array.
*
* @syscall_nr: syscall number
*/
struct syscall_trace_entry {
int syscall_nr;
};
#ifdef CONFIG_FTRACE_SYSCALLS
extern void start_ftrace_syscalls(void);
extern void stop_ftrace_syscalls(void);
extern void ftrace_syscall_enter(struct pt_regs *regs);
extern void ftrace_syscall_exit(struct pt_regs *regs);
#else
static inline void start_ftrace_syscalls(void) { }
static inline void stop_ftrace_syscalls(void) { }
static inline void ftrace_syscall_enter(struct pt_regs *regs) { }
static inline void ftrace_syscall_exit(struct pt_regs *regs) { }
#endif
#endif /* _LINUX_FTRACE_H */
......@@ -34,6 +34,9 @@ config HAVE_FTRACE_MCOUNT_RECORD
config HAVE_HW_BRANCH_TRACER
bool
config HAVE_FTRACE_SYSCALLS
bool
config TRACER_MAX_TRACE
bool
......@@ -175,6 +178,13 @@ config EVENT_TRACER
allowing the user to pick and choose which trace point they
want to trace.
config FTRACE_SYSCALLS
bool "Trace syscalls"
depends on HAVE_FTRACE_SYSCALLS
select TRACING
help
Basic tracer to catch the syscall entry and exit events.
config BOOT_TRACER
bool "Trace boot initcalls"
select TRACING
......
......@@ -43,5 +43,6 @@ obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o
obj-$(CONFIG_EVENT_TRACER) += trace_events.o
obj-$(CONFIG_EVENT_TRACER) += events.o
obj-$(CONFIG_EVENT_TRACER) += trace_export.o
obj-$(CONFIG_FTRACE_SYSCALLS) += trace_syscalls.o
libftrace-y := ftrace.o
......@@ -30,6 +30,8 @@ enum trace_type {
TRACE_GRAPH_ENT,
TRACE_USER_STACK,
TRACE_HW_BRANCHES,
TRACE_SYSCALL_ENTER,
TRACE_SYSCALL_EXIT,
TRACE_KMEM_ALLOC,
TRACE_KMEM_FREE,
TRACE_POWER,
......
#include <linux/ftrace.h>
#include <linux/kernel.h>
#include <asm/syscall.h>
#include "trace_output.h"
#include "trace.h"
static atomic_t refcount;
void start_ftrace_syscalls(void)
{
unsigned long flags;
struct task_struct *g, *t;
if (atomic_inc_return(&refcount) != 1)
goto out;
read_lock_irqsave(&tasklist_lock, flags);
do_each_thread(g, t) {
set_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
} while_each_thread(g, t);
read_unlock_irqrestore(&tasklist_lock, flags);
out:
atomic_dec(&refcount);
}
void stop_ftrace_syscalls(void)
{
unsigned long flags;
struct task_struct *g, *t;
if (atomic_dec_return(&refcount))
goto out;
read_lock_irqsave(&tasklist_lock, flags);
do_each_thread(g, t) {
clear_tsk_thread_flag(t, TIF_SYSCALL_FTRACE);
} while_each_thread(g, t);
read_unlock_irqrestore(&tasklist_lock, flags);
out:
atomic_inc(&refcount);
}
void ftrace_syscall_enter(struct pt_regs *regs)
{
int syscall_nr;
syscall_nr = syscall_get_nr(current, regs);
trace_printk("syscall %d enter\n", syscall_nr);
}
void ftrace_syscall_exit(struct pt_regs *regs)
{
int syscall_nr;
syscall_nr = syscall_get_nr(current, regs);
trace_printk("syscall %d exit\n", syscall_nr);
}
static int init_syscall_tracer(struct trace_array *tr)
{
start_ftrace_syscalls();
return 0;
}
static void reset_syscall_tracer(struct trace_array *tr)
{
stop_ftrace_syscalls();
}
static struct trace_event syscall_enter_event = {
.type = TRACE_SYSCALL_ENTER,
};
static struct trace_event syscall_exit_event = {
.type = TRACE_SYSCALL_EXIT,
};
static struct tracer syscall_tracer __read_mostly = {
.name = "syscall",
.init = init_syscall_tracer,
.reset = reset_syscall_tracer
};
__init int register_ftrace_syscalls(void)
{
int ret;
ret = register_ftrace_event(&syscall_enter_event);
if (!ret) {
printk(KERN_WARNING "event %d failed to register\n",
syscall_enter_event.type);
WARN_ON_ONCE(1);
}
ret = register_ftrace_event(&syscall_exit_event);
if (!ret) {
printk(KERN_WARNING "event %d failed to register\n",
syscall_exit_event.type);
WARN_ON_ONCE(1);
}
return register_tracer(&syscall_tracer);
}
device_initcall(register_ftrace_syscalls);
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