Commit 7ecb344a authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
Browse files

[S390] Improve notify_page_fault implementation. 



notify_page_fault does a preempt_disable/preempt_enable for each
fault generated by a kernel access to user space. If kprobes
is not active that is unnecessary since the interrupts are not
reenabled yet. To play safe repeat the kprobe_running check after
preempt_disable().

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent b11b5334

arch/s390/mm/fault.c

+4 −10
Original line number Original line Diff line number Diff line
@@ -52,11 +52,11 @@ 
extern int sysctl_userprocess_debug;

extern int sysctl_userprocess_debug;

#endif

#endif





#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs)

static inline int notify_page_fault(struct pt_regs *regs, long err)

{

{

	int ret = 0;

	int ret = 0;





#ifdef CONFIG_KPROBES

	/* kprobe_running() needs smp_processor_id() */

	/* kprobe_running() needs smp_processor_id() */

	if (!user_mode(regs)) {

	if (!user_mode(regs)) {

		preempt_disable();

		preempt_disable();
@@ -64,15 +64,9 @@ static inline int notify_page_fault(struct pt_regs *regs, long err) 
			ret = 1;

			ret = 1;

		preempt_enable();

		preempt_enable();

	}

	}



#endif

	return ret;

	return ret;

}

}

#else

static inline int notify_page_fault(struct pt_regs *regs, long err)

{

	return 0;

}

#endif









/*

/*
@@ -274,7 +268,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write, 
	int si_code;

	int si_code;

	int fault;

	int fault;





	if (notify_page_fault(regs, error_code))

	if (notify_page_fault(regs))

		return;

		return;





	tsk = current;

	tsk = current;