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=-7.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED 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 6C502C04AB6 for ; Tue, 28 May 2019 08:10:17 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 424DE20717 for ; Tue, 28 May 2019 08:10:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="gWNOFekv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 424DE20717 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zQxFgX2Lh/kCNgbcYcg4cjKeAoh7+fk83fSbx5+9awg=; b=gWNOFekvXDtl1V 2u0r8CPnNP3X1BC2c11Vft7aTEEQA9FT6vTfs9E+q+Ay0vlp5Bfa/BSfPlWzPupIXZkkLNrjWEoAj 9uFIUspUdkJG9RBn9/JxD9WWNnAyZqM+Hgdu2gvakyf9FaWPFRmvscUSxkZALz0sl6RZYldT2ZfNc YJllZrqxaKPZQsDZr8RQJFDAu4z1CygtSPvJKsRIYCUeoMjEAGhloaldQ1sBEpkZw2Xjze6KY+Bp0 fttKYJUopjIz0bz9sZqi4oyTAfnzZqNg3VEjF4rIJ4jzuofKuiOCiGPxyl79GrDak04wL5lsQztbD U4CwXA01zQ85zw8uVrhg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hVXBW-00058E-A3; Tue, 28 May 2019 08:10:14 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hVXBS-00057j-7e for linux-arm-kernel@lists.infradead.org; Tue, 28 May 2019 08:10:11 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9A0FE341; Tue, 28 May 2019 01:10:09 -0700 (PDT) Received: from [10.162.40.141] (p8cg001049571a15.blr.arm.com [10.162.40.141]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1111E3F5AF; Tue, 28 May 2019 01:10:04 -0700 (PDT) Subject: Re: [PATCH 2/4] arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP To: Ard Biesheuvel , linux-arm-kernel@lists.infradead.org References: <20190523102256.29168-1-ard.biesheuvel@arm.com> <20190523102256.29168-3-ard.biesheuvel@arm.com> From: Anshuman Khandual Message-ID: Date: Tue, 28 May 2019 13:40:16 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190523102256.29168-3-ard.biesheuvel@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190528_011010_289392_49F29177 X-CRM114-Status: GOOD ( 25.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, marc.zyngier@arm.com, Will Deacon , linux-kernel@vger.kernel.org, Peter Zijlstra , Nadav Amit , Masami Hiramatsu , James Morse , Andrew Morton , Rick Edgecombe Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 05/23/2019 03:52 PM, Ard Biesheuvel wrote: > Wire up the special helper functions to manipulate aliases of vmalloc > regions in the linear map. IMHO the commit message here could be bit more descriptive because of the amount of changes this patch brings in. > > Signed-off-by: Ard Biesheuvel > --- > arch/arm64/Kconfig | 1 + > arch/arm64/include/asm/cacheflush.h | 3 ++ > arch/arm64/mm/pageattr.c | 48 ++++++++++++++++---- > mm/vmalloc.c | 11 ----- > 4 files changed, 44 insertions(+), 19 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index ca9c175fb949..4ab32180eabd 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -26,6 +26,7 @@ config ARM64 > select ARCH_HAS_MEMBARRIER_SYNC_CORE > select ARCH_HAS_PTE_SPECIAL > select ARCH_HAS_SETUP_DMA_OPS > + select ARCH_HAS_SET_DIRECT_MAP > select ARCH_HAS_SET_MEMORY > select ARCH_HAS_STRICT_KERNEL_RWX > select ARCH_HAS_STRICT_MODULE_RWX > diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h > index 19844211a4e6..b9ee5510067f 100644 > --- a/arch/arm64/include/asm/cacheflush.h > +++ b/arch/arm64/include/asm/cacheflush.h > @@ -187,4 +187,7 @@ static inline void flush_cache_vunmap(unsigned long start, unsigned long end) > > int set_memory_valid(unsigned long addr, int numpages, int enable); > > +int set_direct_map_invalid_noflush(struct page *page); > +int set_direct_map_default_noflush(struct page *page); > + > #endif > diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c > index 6cd645edcf35..9c6b9039ec8f 100644 > --- a/arch/arm64/mm/pageattr.c > +++ b/arch/arm64/mm/pageattr.c > @@ -159,17 +159,48 @@ int set_memory_valid(unsigned long addr, int numpages, int enable) > __pgprot(PTE_VALID)); > } > > -#ifdef CONFIG_DEBUG_PAGEALLOC > +int set_direct_map_invalid_noflush(struct page *page) > +{ > + struct page_change_data data = { > + .set_mask = __pgprot(0), > + .clear_mask = __pgprot(PTE_VALID), > + }; > + > + if (!rodata_full) > + return 0; Why rodata_full needs to be probed here ? Should not we still require the following transition even if rodata_full is not enabled. Just wondering whether we can use VM_FLUSH_RESET_PERMS feature without these required transitions. /* * Set direct map to something invalid so that it won't be cached if * there are any accesses after the TLB flush, then flush the TLB and * reset the direct map permissions to the default. */ set_area_direct_map(area, set_direct_map_invalid_noflush); _vm_unmap_aliases(start, end, 1); set_area_direct_map(area, set_direct_map_default_noflush); > + > + return apply_to_page_range(&init_mm, > + (unsigned long)page_address(page), > + PAGE_SIZE, change_page_range, &data); > +} > + > +int set_direct_map_default_noflush(struct page *page) > +{ > + struct page_change_data data = { > + .set_mask = __pgprot(PTE_VALID | PTE_WRITE), > + .clear_mask = __pgprot(PTE_RDONLY), Replace __pgprot(PTE_VALID | PTE_WRITE) with PAGE_KERNEL instead ! > + }; > + > + if (!rodata_full) > + return 0; > + > + return apply_to_page_range(&init_mm, > + (unsigned long)page_address(page), > + PAGE_SIZE, change_page_range, &data); > +} > + IIUC set_direct_map_invalid_noflush() and set_direct_map_default_noflush() should set *appropriate* permissions as seen fit from platform perspective to implement this transition. In here set_direct_map_invalid_noflush() makes the entry invalid preventing further MMU walks (hence new TLB entries). set_direct_map_default_noflush() makes it a valid write entry. Though it looks similar to PAGE_KERNEL which is the default permission for linear mapping on arm64 via __map_memblock(). Should not PAGE_KERNEL be used explicitly as suggested above. > void __kernel_map_pages(struct page *page, int numpages, int enable) > { > + if (!debug_pagealloc_enabled() && !rodata_full) > + return; > + I guess this is not related to CONFIG_ARCH_HAS_SET_DIRECT_MAP here and should be a fix or an enhancement to CONFIG_DEBUG_PAGEALLOC implementation. Just curious, !rodata_full check here to ensure that linear mapping does not have block or contig mappings and should be backed by regular pages only ? > set_memory_valid((unsigned long)page_address(page), numpages, enable); > } > -#ifdef CONFIG_HIBERNATION > + > /* > - * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function > - * is used to determine if a linear map page has been marked as not-valid by > - * CONFIG_DEBUG_PAGEALLOC. Walk the page table and check the PTE_VALID bit. > - * This is based on kern_addr_valid(), which almost does what we need. > + * This function is used to determine if a linear map page has been marked as > + * not-valid. Walk the page table and check the PTE_VALID bit. This is based > + * on kern_addr_valid(), which almost does what we need. > * > * Because this is only called on the kernel linear map, p?d_sect() implies > * p?d_present(). When debug_pagealloc is enabled, sections mappings are > @@ -183,6 +214,9 @@ bool kernel_page_present(struct page *page) > pte_t *ptep; > unsigned long addr = (unsigned long)page_address(page); > > + if (!debug_pagealloc_enabled() && !rodata_full) > + return true; > + Ditto, not related to CONFIG_ARCH_HAS_SET_DIRECT_MAP. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel