From 842915f56667f9eebd85932f08c79565148c26d6 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 12 Feb 2015 14:58:25 -0800 Subject: [PATCH] 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 ++++++-- arch/powerpc/mm/fault.c | 20 +++++++++----------- 2 files changed, 15 insertions(+), 13 deletions(-) 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; diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index f38327b95f76..b396868d2aa7 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -389,17 +389,6 @@ good_area: #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 @@ good_area: (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 @@ good_area: } else { if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) goto bad_area; + WARN_ON_ONCE(error_code & DSISR_PROTFAULT); } /* -- 2.20.1