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Commit a871bd33 authored by Jason Baron's avatar Jason Baron Committed by Frederic Weisbecker
Browse files

tracing: Add syscall tracepoints 



add two tracepoints in syscall exit and entry path, conditioned on
TIF_SYSCALL_FTRACE. Supports the syscall trace event code.

Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Jiaying Zhang <jiayingz@google.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
parent 63fbdab3

arch/x86/kernel/ptrace.c

+5 −2
Original line number Original line Diff line number Diff line
@@ -37,6 +37,9 @@ 




#include <trace/syscall.h>

#include <trace/syscall.h>





DEFINE_TRACE(syscall_enter);

DEFINE_TRACE(syscall_exit);



#include "tls.h"

#include "tls.h"





enum x86_regset {

enum x86_regset {
@@ -1498,7 +1501,7 @@ asmregparm long syscall_trace_enter(struct pt_regs *regs) 
		ret = -1L;

		ret = -1L;





	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))

	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))

		ftrace_syscall_enter(regs);

		trace_syscall_enter(regs, regs->orig_ax);





	if (unlikely(current->audit_context)) {

	if (unlikely(current->audit_context)) {

		if (IS_IA32)

		if (IS_IA32)
@@ -1524,7 +1527,7 @@ asmregparm void syscall_trace_leave(struct pt_regs *regs) 
		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);

		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);





	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))

	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))

		ftrace_syscall_exit(regs);

		trace_syscall_exit(regs, regs->ax);





	if (test_thread_flag(TIF_SYSCALL_TRACE))

	if (test_thread_flag(TIF_SYSCALL_TRACE))

		tracehook_report_syscall_exit(regs, 0);

		tracehook_report_syscall_exit(regs, 0);

include/trace/syscall.h

+20 −0
Original line number Original line Diff line number Diff line 
#ifndef _TRACE_SYSCALL_H

#ifndef _TRACE_SYSCALL_H

#define _TRACE_SYSCALL_H

#define _TRACE_SYSCALL_H





#include <linux/tracepoint.h>



#include <asm/ptrace.h>

#include <asm/ptrace.h>







extern void syscall_regfunc(void);

extern void syscall_unregfunc(void);



DECLARE_TRACE_WITH_CALLBACK(syscall_enter,

	TP_PROTO(struct pt_regs *regs, long id),

	TP_ARGS(regs, id),

	syscall_regfunc,

	syscall_unregfunc

);



DECLARE_TRACE_WITH_CALLBACK(syscall_exit,

	TP_PROTO(struct pt_regs *regs, long ret),

	TP_ARGS(regs, ret),

	syscall_regfunc,

	syscall_unregfunc

);



/*

/*

 * A syscall entry in the ftrace syscalls array.

 * A syscall entry in the ftrace syscalls array.

 *

 *

kernel/tracepoint.c

+38 −0
Original line number Original line Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/tracepoint.h>

#include <linux/tracepoint.h>

#include <linux/err.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/slab.h>

#include <linux/sched.h>





extern struct tracepoint __start___tracepoints[];

extern struct tracepoint __start___tracepoints[];

extern struct tracepoint __stop___tracepoints[];

extern struct tracepoint __stop___tracepoints[];
@@ -577,3 +578,40 @@ static int init_tracepoints(void) 
__initcall(init_tracepoints);

__initcall(init_tracepoints);





#endif /* CONFIG_MODULES */

#endif /* CONFIG_MODULES */



static DEFINE_MUTEX(regfunc_mutex);

static int sys_tracepoint_refcount;



void syscall_regfunc(void)

{

	unsigned long flags;

	struct task_struct *g, *t;



	mutex_lock(&regfunc_mutex);

	if (!sys_tracepoint_refcount) {

		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);

	}

	sys_tracepoint_refcount++;

	mutex_unlock(&regfunc_mutex);

}



void syscall_unregfunc(void)

{

	unsigned long flags;

	struct task_struct *g, *t;



	mutex_lock(&regfunc_mutex);

	sys_tracepoint_refcount--;

	if (!sys_tracepoint_refcount) {

		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);

	}

	mutex_unlock(&regfunc_mutex);

}