From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753198AbeFDNnD (ORCPT ); Mon, 4 Jun 2018 09:43:03 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:48708 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752774AbeFDNnC (ORCPT ); Mon, 4 Jun 2018 09:43:02 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5E70B60224 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=cpandya@codeaurora.org Subject: Re: [PATCH v12 5/5] arm64: Allow huge io mappings again To: Will Deacon Cc: catalin.marinas@arm.com, mark.rutland@arm.com, akpm@linux-foundation.org, toshi.kani@hpe.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <1527856758-27169-1-git-send-email-cpandya@codeaurora.org> <1527856758-27169-6-git-send-email-cpandya@codeaurora.org> <20180604121452.GK9482@arm.com> From: Chintan Pandya Message-ID: Date: Mon, 4 Jun 2018 19:12:57 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180604121452.GK9482@arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/4/2018 5:44 PM, Will Deacon wrote: > On Fri, Jun 01, 2018 at 06:09:18PM +0530, Chintan Pandya wrote: >> Huge mappings have had stability issues due to stale >> TLB entry and memory leak issues. Since, those are >> addressed in this series of patches, it is now safe >> to allow huge mappings. >> >> Signed-off-by: Chintan Pandya >> --- >> arch/arm64/mm/mmu.c | 18 ++---------------- >> 1 file changed, 2 insertions(+), 16 deletions(-) >> >> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c >> index 6e7e16c..c65abc4 100644 >> --- a/arch/arm64/mm/mmu.c >> +++ b/arch/arm64/mm/mmu.c >> @@ -934,15 +934,8 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) >> { >> pgprot_t sect_prot = __pgprot(PUD_TYPE_SECT | >> pgprot_val(mk_sect_prot(prot))); >> - pud_t new_pud = pfn_pud(__phys_to_pfn(phys), sect_prot); >> - >> - /* Only allow permission changes for now */ >> - if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), >> - pud_val(new_pud))) >> - return 0; > > Do you actually need to remove these checks? If we're doing > break-before-make properly, then the check won't fire but it would be > good to keep it there so we can catch misuse of these in future. > > In other words, can we drop this patch? Yes, we don't need this patch as BBM is happening before this. I missed that. I'll remove this patch in v13. > > Will > Chintan -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project