Commit 9f90b997 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Paul Mackerras
Browse files

[POWERPC] Minor fault path optimization 



Call the kprobes pagefault handler directly instead of going through
the complex notifier chain.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent eb609e52

arch/powerpc/kernel/kprobes.c

+1 −9
Original line number Diff line number Diff line
@@ -410,7 +410,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs) 
	return 1;

}



static int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)

int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)

{

	struct kprobe *cur = kprobe_running();

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -495,14 +495,6 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self, 
		if (post_kprobe_handler(args->regs))

			ret = NOTIFY_STOP;

		break;

	case DIE_PAGE_FAULT:

		/* kprobe_running() needs smp_processor_id() */

		preempt_disable();

		if (kprobe_running() &&

		    kprobe_fault_handler(args->regs, args->trapnr))

			ret = NOTIFY_STOP;

		preempt_enable();

		break;

	default:

		break;

	}

arch/powerpc/mm/fault.c

+15 −27
Original line number Diff line number Diff line
@@ -39,37 +39,26 @@ 
#include <asm/kdebug.h>

#include <asm/siginfo.h>



#ifdef CONFIG_KPROBES

ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);



/* Hook to register for page fault notifications */

int register_page_fault_notifier(struct notifier_block *nb)

{

	return atomic_notifier_chain_register(&notify_page_fault_chain, nb);

}



int unregister_page_fault_notifier(struct notifier_block *nb)

#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs)

{

	return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);

	int ret = 0;



	/* kprobe_running() needs smp_processor_id() */

	if (!user_mode(regs)) {

		preempt_disable();

		if (kprobe_running() && kprobe_fault_handler(regs, 11))

			ret = 1;

		preempt_enable();

	}



static inline int notify_page_fault(enum die_val val, const char *str,

			struct pt_regs *regs, long err, int trap, int sig)

{

	struct die_args args = {

		.regs = regs,

		.str = str,

		.err = err,

		.trapnr = trap,

		.signr = sig

	};

	return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);

	return ret;

}

#else

static inline int notify_page_fault(enum die_val val, const char *str,

			struct pt_regs *regs, long err, int trap, int sig)

static inline int notify_page_fault(struct pt_regs *regs)

{

	return NOTIFY_DONE;

	return 0;

}

#endif
@@ -175,8 +164,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
	is_write = error_code & ESR_DST;

#endif /* CONFIG_4xx || CONFIG_BOOKE */



	if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, error_code,

				11, SIGSEGV) == NOTIFY_STOP)

	if (notify_page_fault(regs))

		return 0;



	if (trap == 0x300) {

include/asm-powerpc/kdebug.h

+14 −3
Original line number Diff line number Diff line
@@ -18,8 +18,20 @@ struct die_args { 


extern int register_die_notifier(struct notifier_block *);

extern int unregister_die_notifier(struct notifier_block *);

extern int register_page_fault_notifier(struct notifier_block *);

extern int unregister_page_fault_notifier(struct notifier_block *);



/*

 * These are only here because kprobes.c wants them to implement a

 * blatant layering violation.  Will hopefully go away soon once all

 * architectures are updated.

 */

static inline int register_page_fault_notifier(struct notifier_block *nb)

{

	return 0;

}

static inline int unregister_page_fault_notifier(struct notifier_block *nb)

{

	return 0;

}

extern struct atomic_notifier_head powerpc_die_chain;



/* Grossly misnamed. */
@@ -29,7 +41,6 @@ enum die_val { 
	DIE_DABR_MATCH,

	DIE_BPT,

	DIE_SSTEP,

	DIE_PAGE_FAULT,

};



static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)

include/asm-powerpc/kprobes.h

+1 −0
Original line number Diff line number Diff line
@@ -116,5 +116,6 @@ struct kprobe_ctlblk { 


extern int kprobe_exceptions_notify(struct notifier_block *self,

					unsigned long val, void *data);

extern int kprobe_fault_handler(struct pt_regs *regs, int trapnr);

#endif /* __KERNEL__ */

#endif	/* _ASM_POWERPC_KPROBES_H */