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Commit 842915f5 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

ppc64: add paranoid warnings for unexpected DSISR_PROTFAULT 



ppc64 should not be depending on DSISR_PROTFAULT and it's unexpected if
they are triggered.  This patch adds warnings just in case they are being
accidentally depended upon.

Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
Acked-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Tested-by: default avatarSasha Levin <sasha.levin@oracle.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8a0516ed

arch/powerpc/mm/copro_fault.c

+6 −2
Original line number Diff line number Diff line
@@ -64,10 +64,14 @@ int copro_handle_mm_fault(struct mm_struct *mm, unsigned long ea, 
		if (!(vma->vm_flags & VM_WRITE))

			goto out_unlock;

	} else {

		if (dsisr & DSISR_PROTFAULT)

			goto out_unlock;

		if (!(vma->vm_flags & (VM_READ | VM_EXEC)))

			goto out_unlock;

		/*

		 * protfault should only happen due to us

		 * mapping a region readonly temporarily. PROT_NONE

		 * is also covered by the VMA check above.

		 */

		WARN_ON_ONCE(dsisr & DSISR_PROTFAULT);

	}



	ret = 0;

arch/powerpc/mm/fault.c

+9 −11
Original line number Diff line number Diff line
@@ -389,17 +389,6 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
#endif /* CONFIG_8xx */



	if (is_exec) {

#ifdef CONFIG_PPC_STD_MMU

		/* Protection fault on exec go straight to failure on

		 * Hash based MMUs as they either don't support per-page

		 * execute permission, or if they do, it's handled already

		 * at the hash level. This test would probably have to

		 * be removed if we change the way this works to make hash

		 * processors use the same I/D cache coherency mechanism

		 * as embedded.

		 */

#endif /* CONFIG_PPC_STD_MMU */



		/*

		 * Allow execution from readable areas if the MMU does not

		 * provide separate controls over reading and executing.
@@ -414,6 +403,14 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
		    (cpu_has_feature(CPU_FTR_NOEXECUTE) ||

		     !(vma->vm_flags & (VM_READ | VM_WRITE))))

			goto bad_area;

#ifdef CONFIG_PPC_STD_MMU

		/*

		 * protfault should only happen due to us

		 * mapping a region readonly temporarily. PROT_NONE

		 * is also covered by the VMA check above.

		 */

		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);

#endif /* CONFIG_PPC_STD_MMU */

	/* a write */

	} else if (is_write) {

		if (!(vma->vm_flags & VM_WRITE))
@@ -423,6 +420,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address, 
	} else {

		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))

			goto bad_area;

		WARN_ON_ONCE(error_code & DSISR_PROTFAULT);

	}



	/*