From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 564F8C4320A for ; Fri, 13 Aug 2021 07:16:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EA9E26103A for ; Fri, 13 Aug 2021 07:16:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EA9E26103A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 8C5B78D0001; Fri, 13 Aug 2021 03:16:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 875146B0071; Fri, 13 Aug 2021 03:16:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 763438D0001; Fri, 13 Aug 2021 03:16:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0127.hostedemail.com [216.40.44.127]) by kanga.kvack.org (Postfix) with ESMTP id 5A0A06B006C for ; Fri, 13 Aug 2021 03:16:10 -0400 (EDT) Received: from smtpin32.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id F20811801B60C for ; Fri, 13 Aug 2021 07:16:09 +0000 (UTC) X-FDA: 78469198458.32.6CFD73A Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf30.hostedemail.com (Postfix) with ESMTP id 553A6E00E612 for ; Fri, 13 Aug 2021 07:16:09 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5F8C81FB; Fri, 13 Aug 2021 00:16:08 -0700 (PDT) Received: from [10.163.69.16] (unknown [10.163.69.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 24C0D3F718; Fri, 13 Aug 2021 00:16:04 -0700 (PDT) Subject: Re: [RFC V2 01/10] mm/mmap: Dynamically initialize protection_map[] From: Anshuman Khandual To: Catalin Marinas Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, suzuki.poulose@arm.com, mark.rutland@arm.com, will@kernel.org, maz@kernel.org, james.morse@arm.com, steven.price@arm.com References: <1627281445-12445-1-git-send-email-anshuman.khandual@arm.com> <1627281445-12445-2-git-send-email-anshuman.khandual@arm.com> <20210805170318.GB6719@arm.com> Message-ID: <4bbe8b21-cc19-81ac-b53f-8e418a164e1b@arm.com> Date: Fri, 13 Aug 2021 12:46:57 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 553A6E00E612 Authentication-Results: imf30.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf30.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com X-Rspamd-Server: rspam04 X-Stat-Signature: adthstct4whifwhhgbeequjfimrbrnef X-HE-Tag: 1628838969-553026 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 8/12/21 2:45 PM, Anshuman Khandual wrote: > > > On 8/5/21 10:33 PM, Catalin Marinas wrote: >> On Mon, Jul 26, 2021 at 12:07:16PM +0530, Anshuman Khandual wrote: >>> The protection_map[] elements (__PXXX and __SXXX) might sometimes contain >>> runtime variables in certain platforms like arm64 preventing a successful >>> build because of the current static initialization. So it just defers the >>> initialization until mmmap_init() via a new helper init_protection_map(). >>> >>> Signed-off-by: Anshuman Khandual >>> --- >>> mm/mmap.c | 26 ++++++++++++++++++++++---- >>> 1 file changed, 22 insertions(+), 4 deletions(-) >>> >>> diff --git a/mm/mmap.c b/mm/mmap.c >>> index ca54d36..a95b078 100644 >>> --- a/mm/mmap.c >>> +++ b/mm/mmap.c >>> @@ -100,10 +100,7 @@ static void unmap_region(struct mm_struct *mm, >>> * w: (no) no >>> * x: (yes) yes >>> */ >>> -pgprot_t protection_map[16] __ro_after_init = { >>> - __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, >>> - __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 >>> -}; >>> +pgprot_t protection_map[16] __ro_after_init; >> >> Mips, x86, sparc, arm32, m68k all adjust protection_map[] during boot. >> Could we do something similar here and avoid changing the generic code? > > If __P[000..111] and __S[000..111] be made dummy values (e.g 0 or something > standard prot temporarily), hence the compilation problem could be avoided. > Later in the platform code, protection_map[] could be adjusted with actual > prot values which would involve variable. > Following change seems to work without any problem. Using __pgprot(0) as an temporary protection value should be okay, as vm_get_page_prot() which uses protection_map[] should never be called before mem_init() ? arch/arm64/include/asm/pgtable-prot.h | 34 +++++++++++++++++----------------- arch/arm64/mm/init.c | 22 ++++++++++++++++++++++ 2 files changed, 39 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 7032f04..539503a 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -88,23 +88,23 @@ extern bool arm64_use_ng_mappings; #define PAGE_READONLY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN) #define PAGE_EXECONLY __pgprot(_PAGE_DEFAULT | PTE_RDONLY | PTE_NG | PTE_PXN) -#define __P000 PAGE_NONE -#define __P001 PAGE_READONLY -#define __P010 PAGE_READONLY -#define __P011 PAGE_READONLY -#define __P100 PAGE_EXECONLY -#define __P101 PAGE_READONLY_EXEC -#define __P110 PAGE_READONLY_EXEC -#define __P111 PAGE_READONLY_EXEC - -#define __S000 PAGE_NONE -#define __S001 PAGE_READONLY -#define __S010 PAGE_SHARED -#define __S011 PAGE_SHARED -#define __S100 PAGE_EXECONLY -#define __S101 PAGE_READONLY_EXEC -#define __S110 PAGE_SHARED_EXEC -#define __S111 PAGE_SHARED_EXEC +#define __P000 __pgprot(0) +#define __P001 __pgprot(0) +#define __P010 __pgprot(0) +#define __P011 __pgprot(0) +#define __P100 __pgprot(0) +#define __P101 __pgprot(0) +#define __P110 __pgprot(0) +#define __P111 __pgprot(0) + +#define __S000 __pgprot(0) +#define __S001 __pgprot(0) +#define __S010 __pgprot(0) +#define __S011 __pgprot(0) +#define __S100 __pgprot(0) +#define __S101 __pgprot(0) +#define __S110 __pgprot(0) +#define __S111 __pgprot(0) #endif /* __ASSEMBLY__ */ diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 8490ed2..51662b3 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -448,6 +448,27 @@ void __init bootmem_init(void) memblock_dump_all(); } +static void init_protection_map(void) +{ + protection_map[0] = PAGE_NONE; + protection_map[1] = PAGE_READONLY; + protection_map[2] = PAGE_READONLY; + protection_map[3] = PAGE_READONLY; + protection_map[4] = PAGE_READONLY; + protection_map[5] = PAGE_READONLY_EXEC; + protection_map[6] = PAGE_READONLY_EXEC; + protection_map[7] = PAGE_READONLY_EXEC; + + protection_map[8] = PAGE_NONE; + protection_map[9] = PAGE_READONLY; + protection_map[10] = PAGE_SHARED; + protection_map[11] = PAGE_SHARED; + protection_map[12] = PAGE_EXECONLY; + protection_map[13] = PAGE_READONLY_EXEC; + protection_map[14] = PAGE_SHARED_EXEC; + protection_map[15] = PAGE_SHARED_EXEC; +} + /* * mem_init() marks the free areas in the mem_map and tells us how much memory * is free. This is done after various parts of the system have claimed their @@ -489,6 +510,7 @@ void __init mem_init(void) */ sysctl_overcommit_memory = OVERCOMMIT_ALWAYS; } + init_protection_map(); } void free_initmem(void) -- 2.7.4