Commit b98cca44 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Linus Torvalds
Browse files

mm, kprobes: generalize and rename notify_page_fault() as kprobe_page_fault() 

Architectures which support kprobes have very similar boilerplate around
calling kprobe_fault_handler().  Use a helper function in kprobes.h to
unify them, based on the x86 code.

This changes the behaviour for other architectures when preemption is
enabled.  Previously, they would have disabled preemption while calling
the kprobe handler.  However, preemption would be disabled if this fault
was due to a kprobe, so we know the fault was not due to a kprobe
handler and can simply return failure.

This behaviour was introduced in commit a980c0ef ("x86/kprobes:
Refactor kprobes_fault() like kprobe_exceptions_notify()")

[anshuman.khandual@arm.com: export kprobe_fault_handler()]
  Link: http://lkml.kernel.org/r/1561133358-8876-1-git-send-email-anshuman.khandual@arm.com
Link: http://lkml.kernel.org/r/1560420444-25737-1-git-send-email-anshuman.khandual@arm.com


Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 92bae787

arch/arm/mm/fault.c

+1 −23
Original line number Diff line number Diff line
@@ -27,28 +27,6 @@ 


#ifdef CONFIG_MMU



#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)

{

	int ret = 0;



	if (!user_mode(regs)) {

		/* kprobe_running() needs smp_processor_id() */

		preempt_disable();

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

			ret = 1;

		preempt_enable();

	}



	return ret;

}

#else

static inline int notify_page_fault(struct pt_regs *regs, unsigned int fsr)

{

	return 0;

}

#endif



/*

 * This is useful to dump out the page tables associated with

 * 'addr' in mm 'mm'.
@@ -265,7 +243,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) 
	vm_fault_t fault;

	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;



	if (notify_page_fault(regs, fsr))

	if (kprobe_page_fault(regs, fsr))

		return 0;



	tsk = current;

arch/arm64/mm/fault.c

+1 −23
Original line number Diff line number Diff line
@@ -59,28 +59,6 @@ static inline const struct fault_info *esr_to_debug_fault_info(unsigned int esr) 
	return debug_fault_info + DBG_ESR_EVT(esr);

}



#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)

{

	int ret = 0;



	/* kprobe_running() needs smp_processor_id() */

	if (!user_mode(regs)) {

		preempt_disable();

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

			ret = 1;

		preempt_enable();

	}



	return ret;

}

#else

static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)

{

	return 0;

}

#endif



static void data_abort_decode(unsigned int esr)

{

	pr_alert("Data abort info:\n");
@@ -434,7 +412,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, 
	unsigned long vm_flags = VM_READ | VM_WRITE;

	unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;



	if (notify_page_fault(regs, esr))

	if (kprobe_page_fault(regs, esr))

		return 0;



	/*

arch/ia64/mm/fault.c

+1 −23
Original line number Diff line number Diff line
@@ -21,28 +21,6 @@ 


extern int die(char *, struct pt_regs *, long);



#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs, int trap)

{

	int ret = 0;



	if (!user_mode(regs)) {

		/* kprobe_running() needs smp_processor_id() */

		preempt_disable();

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

			ret = 1;

		preempt_enable();

	}



	return ret;

}

#else

static inline int notify_page_fault(struct pt_regs *regs, int trap)

{

	return 0;

}

#endif



/*

 * Return TRUE if ADDRESS points at a page in the kernel's mapped segment

 * (inside region 5, on ia64) and that page is present.
@@ -116,7 +94,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re 
	/*

	 * This is to handle the kprobes on user space access instructions

	 */

	if (notify_page_fault(regs, TRAP_BRKPT))

	if (kprobe_page_fault(regs, TRAP_BRKPT))

		return;



	if (user_mode(regs))

arch/mips/include/asm/kprobes.h

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ do { \ 
#define kretprobe_blacklist_size 0



void arch_remove_kprobe(struct kprobe *p);

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



/* Architecture specific copy of original instruction*/

struct arch_specific_insn {

arch/mips/kernel/kprobes.c

+1 −1
Original line number Diff line number Diff line
@@ -398,7 +398,7 @@ out: 
	return 1;

}



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

int kprobe_fault_handler(struct pt_regs *regs, int trapnr)

{

	struct kprobe *cur = kprobe_running();

	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

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