From 842915f56667f9eebd85932f08c79565148c26d6 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 12 Feb 2015 14:58:25 -0800 Subject: 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: Mel Gorman Acked-by: Aneesh Kumar K.V Tested-by: Sasha Levin Cc: Benjamin Herrenschmidt Cc: Dave Jones Cc: Hugh Dickins Cc: Ingo Molnar Cc: Kirill Shutemov Cc: Linus Torvalds Cc: Paul Mackerras Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/mm/copro_fault.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/mm/copro_fault.c') diff --git a/arch/powerpc/mm/copro_fault.c b/arch/powerpc/mm/copro_fault.c index 1b5305d4bdab..f031a47d7701 100644 --- a/arch/powerpc/mm/copro_fault.c +++ b/arch/powerpc/mm/copro_fault.c @@ -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; -- cgit v1.2.1