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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 70B94C4363A for ; Thu, 8 Oct 2020 15:37:42 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 EED4620658 for ; Thu, 8 Oct 2020 15:37:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ekwuYC+S"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="MrUumqcn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EED4620658 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=eaCHcDZAcCj50xlqmr9MG6i/m1jJ5bB3lAUPbyGYVsU=; b=ekwuYC+SMygaVqCUhjkCZNAWCs EsIgzFQVdbPp+pM6fT72JGnWPl2RZoMsLlChhOX7/T+CA6KK3j3eyOCptRoV+2QwYWZoXu069EaoY Y8wXOhyTDwNLsn0ma7nVLes34fxM/GZ912NVOTiPsyuM0f/rDKBL5eVo2VZcZYmcr9OX7Bs0IIsNm L0HZakpsRIC5en0wxaL9Hnh4kuV4pXrLqdeu3I11nTMt/RmClG+2K85GcRn3KkX0RWOxkRiWdGoRq MsBkreXt/X36jc/WV65RQTp86qz/Y6Zj/HXeyGBU267HSUToAreo86BeYZvmcExN597xk3a8AXzfB 9JhhztGg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQXxp-0008L2-M1; Thu, 08 Oct 2020 15:36:17 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQXxi-0008Ia-KL for linux-arm-kernel@lists.infradead.org; Thu, 08 Oct 2020 15:36:12 +0000 Received: from e123331-lin.nice.arm.com (lfbn-nic-1-188-42.w2-15.abo.wanadoo.fr [2.15.37.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 882D821924; Thu, 8 Oct 2020 15:36:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602171369; bh=j8m05cRIu7pFP3AuxppbdKLRVwGCUV5/KOffZzv+RgI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MrUumqcnWUzIg7DYKtMcSuURIuhLdZKCkX3R6aDGHUYswCLTPySdtHRoaT4nHLoM4 Q1SfEyrWChIhsjaj4WVINU+6THMM47P/uDiohquMhtWLmbo2JwcEi7TU3TE6+pvYSa BkSzBiCpdD7XE2eBpjbW9L975v9NMcs7WnbFn6VI= From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/4] arm64: mm: use single quantity to represent the PA to VA translation Date: Thu, 8 Oct 2020 17:35:59 +0200 Message-Id: <20201008153602.9467-2-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201008153602.9467-1-ardb@kernel.org> References: <20201008153602.9467-1-ardb@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201008_113610_821666_87A56CA3 X-CRM114-Status: GOOD ( 23.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, Anshuman Khandual , will@kernel.org, Ard Biesheuvel , Steve Capper MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On arm64, the global variable memstart_addr represents the physical address of PAGE_OFFSET, and so physical to virtual translations or vice versa used to come down to simple additions or subtractions involving the values of PAGE_OFFSET and memstart_addr. When support for 52-bit virtual addressing was introduced, we had to deal with PAGE_OFFSET potentially being outside of the region that can be covered by the virtual range (as the 52-bit VA capable build needs to be able to run on systems that are only 48-bit VA capable), and for this reason, another translation was introduced, and recorded in the global variable physvirt_offset. However, if we go back to the original definition of memstart_addr, i.e., the physical address of PAGE_OFFSET, it turns out that there is no need for two separate translations: instead, we can simply subtract the size of the unaddressable VA space from memstart_addr to make the available physical memory appear in the 48-bit addressable VA region. This simplifies things, but also fixes a bug on KASLR builds, which may update memstart_addr later on in arm64_memblock_init(), but fails to update vmemmap and physvirt_offset accordingly. Fixes: 5383cc6efed13 ("arm64: mm: Introduce vabits_actual") Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/memory.h | 5 ++-- arch/arm64/include/asm/pgtable.h | 4 +-- arch/arm64/mm/init.c | 30 +++++++------------- 3 files changed, 14 insertions(+), 25 deletions(-) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index afa722504bfd..1ded73189874 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -164,7 +164,6 @@ extern u64 vabits_actual; #define PAGE_END (_PAGE_END(vabits_actual)) -extern s64 physvirt_offset; extern s64 memstart_addr; /* PHYS_OFFSET - the physical address of the start of memory. */ #define PHYS_OFFSET ({ VM_BUG_ON(memstart_addr & 1); memstart_addr; }) @@ -240,7 +239,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) */ #define __is_lm_address(addr) (!(((u64)addr) & BIT(vabits_actual - 1))) -#define __lm_to_phys(addr) (((addr) + physvirt_offset)) +#define __lm_to_phys(addr) (((addr) & ~PAGE_OFFSET) + PHYS_OFFSET) #define __kimg_to_phys(addr) ((addr) - kimage_voffset) #define __virt_to_phys_nodebug(x) ({ \ @@ -258,7 +257,7 @@ extern phys_addr_t __phys_addr_symbol(unsigned long x); #define __phys_addr_symbol(x) __pa_symbol_nodebug(x) #endif /* CONFIG_DEBUG_VIRTUAL */ -#define __phys_to_virt(x) ((unsigned long)((x) - physvirt_offset)) +#define __phys_to_virt(x) ((unsigned long)((x) - PHYS_OFFSET) | PAGE_OFFSET) #define __phys_to_kimg(x) ((unsigned long)((x) + kimage_voffset)) /* diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index d5d3fbe73953..88233d42d9c2 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -23,6 +23,8 @@ #define VMALLOC_START (MODULES_END) #define VMALLOC_END (- PUD_SIZE - VMEMMAP_SIZE - SZ_64K) +#define vmemmap ((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT)) + #define FIRST_USER_ADDRESS 0UL #ifndef __ASSEMBLY__ @@ -33,8 +35,6 @@ #include #include -extern struct page *vmemmap; - extern void __pte_error(const char *file, int line, unsigned long val); extern void __pmd_error(const char *file, int line, unsigned long val); extern void __pud_error(const char *file, int line, unsigned long val); diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 481d22c32a2e..324f0e0894f6 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -54,12 +54,6 @@ s64 memstart_addr __ro_after_init = -1; EXPORT_SYMBOL(memstart_addr); -s64 physvirt_offset __ro_after_init; -EXPORT_SYMBOL(physvirt_offset); - -struct page *vmemmap __ro_after_init; -EXPORT_SYMBOL(vmemmap); - /* * We create both ZONE_DMA and ZONE_DMA32. ZONE_DMA covers the first 1G of * memory as some devices, namely the Raspberry Pi 4, have peripherals with @@ -290,20 +284,6 @@ void __init arm64_memblock_init(void) memstart_addr = round_down(memblock_start_of_DRAM(), ARM64_MEMSTART_ALIGN); - physvirt_offset = PHYS_OFFSET - PAGE_OFFSET; - - vmemmap = ((struct page *)VMEMMAP_START - (memstart_addr >> PAGE_SHIFT)); - - /* - * If we are running with a 52-bit kernel VA config on a system that - * does not support it, we have to offset our vmemmap and physvirt_offset - * s.t. we avoid the 52-bit portion of the direct linear map - */ - if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52)) { - vmemmap += (_PAGE_OFFSET(48) - _PAGE_OFFSET(52)) >> PAGE_SHIFT; - physvirt_offset = PHYS_OFFSET - _PAGE_OFFSET(48); - } - /* * Remove the memory that we will not be able to cover with the * linear mapping. Take care not to clip the kernel which may be @@ -318,6 +298,16 @@ void __init arm64_memblock_init(void) memblock_remove(0, memstart_addr); } + /* + * If we are running with a 52-bit kernel VA config on a system that + * does not support it, we have to place the available physical + * memory in the 48-bit addressable part of the linear region, i.e., + * we have to move it upward. Since memstart_addr represents the + * physical address of PAGE_OFFSET, we have to *subtract* from it. + */ + if (IS_ENABLED(CONFIG_ARM64_VA_BITS_52) && (vabits_actual != 52)) + memstart_addr -= _PAGE_OFFSET(48) - _PAGE_OFFSET(52); + /* * Apply the memory limit if it was set. Since the kernel may be loaded * high up in memory, add back the kernel region that must be accessible -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel