From patchwork Thu Nov 20 10:19:44 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 412625 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 8E09914017B for ; Thu, 20 Nov 2014 21:23:52 +1100 (AEDT) Received: from ozlabs.org (ozlabs.org [103.22.144.67]) by lists.ozlabs.org (Postfix) with ESMTP id 72EFF1A2B63 for ; Thu, 20 Nov 2014 21:23:52 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) (using TLSv1 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id E4EE81A0A00 for ; Thu, 20 Nov 2014 21:20:01 +1100 (AEDT) Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 55550AD89; Thu, 20 Nov 2014 10:19:59 +0000 (UTC) From: Mel Gorman To: Linux Kernel Subject: [PATCH 04/10] ppc64: Add paranoid warnings for unexpected DSISR_PROTFAULT Date: Thu, 20 Nov 2014 10:19:44 +0000 Message-Id: <1416478790-27522-5-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 2.1.2 In-Reply-To: <1416478790-27522-1-git-send-email-mgorman@suse.de> References: <1416478790-27522-1-git-send-email-mgorman@suse.de> Cc: Rik van Riel , Linus Torvalds , Hugh Dickins , Linux-MM , Ingo Molnar , Paul Mackerras , Aneesh Kumar , Sasha Levin , Dave Jones , LinuxPPC-dev , Kirill Shutemov , Mel Gorman X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 --- 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 5a236f0..0450d68 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 5007497..9d6e0b3 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -396,17 +396,6 @@ 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. @@ -421,6 +410,14 @@ 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)) @@ -430,6 +427,7 @@ good_area: } else { if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) goto bad_area; + WARN_ON_ONCE(error_code & DSISR_PROTFAULT); } /*