Commit 608566b4 authored by Harvey Harrison's avatar Harvey Harrison Committed by Ingo Molnar
Browse files

x86: do_page_fault small unification 



Copy the prefetch of map_sem from X86_64 and move the check
notify_page_fault (soon to be kprobe_handle_fault) out of
the unlikely if() statement.

This makes the X86_32|64 pagefault handlers closer to each
other.

Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent f2857ce9

arch/x86/mm/fault_32.c

+7 −9
Original line number Diff line number Diff line
@@ -295,13 +295,18 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
	 */

	trace_hardirqs_fixup();



	tsk = current;

	mm = tsk->mm;

	prefetchw(&mm->mmap_sem);



	/* get the address */

	address = read_cr2();



	tsk = current;



	si_code = SEGV_MAPERR;



	if (notify_page_fault(regs))

		return;



	/*

	 * We fault-in kernel-space virtual memory on-demand. The

	 * 'reference' page table is init_mm.pgd.
@@ -319,8 +324,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
		if (!(error_code & (PF_RSVD|PF_USER|PF_PROT)) &&

		    vmalloc_fault(address) >= 0)

			return;

		if (notify_page_fault(regs))

			return;

		/*

		 * Don't take the mm semaphore here. If we fixup a prefetch

		 * fault we could otherwise deadlock.
@@ -328,16 +331,11 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
		goto bad_area_nosemaphore;

	}



	if (notify_page_fault(regs))

		return;



	/* It's safe to allow irq's after cr2 has been saved and the vmalloc

	   fault has been handled. */

	if (regs->flags & (X86_EFLAGS_IF|VM_MASK))

		local_irq_enable();



	mm = tsk->mm;



	/*

	 * If we're in an interrupt, have no user context or are running in an

	 * atomic region then we must not take the fault.

arch/x86/mm/fault_64.c

+2 −5
Original line number Diff line number Diff line
@@ -355,6 +355,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 


	si_code = SEGV_MAPERR;



	if (notify_page_fault(regs))

		return;



	/*

	 * We fault-in kernel-space virtual memory on-demand. The
@@ -380,8 +382,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
			if (vmalloc_fault(address) >= 0)

				return;

		}

		if (notify_page_fault(regs))

			return;

		/*

		 * Don't take the mm semaphore here. If we fixup a prefetch

		 * fault we could otherwise deadlock.
@@ -389,9 +389,6 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
		goto bad_area_nosemaphore;

	}



	if (notify_page_fault(regs))

		return;



	if (likely(regs->flags & X86_EFLAGS_IF))

		local_irq_enable();

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