From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA83C606A8BA for ; Thu, 12 Nov 2026 11:26:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=q7eksHZD; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=JETWMfWj DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=FD/V4+e8O0iqTKVI3Ylc4RORwqMbtboEEa/TKhMeE7M=; b=q7eksHZDwt0tMF 3+ArH/sgzy2o1ZDM5iMt1w2zjBswwFQ7HPiF1oZTW3pSbpQ82aA/RGcurmMKQo90/miTi6mgz8Wnm h13V9v5cI6ZZnR5Apu2caYeDZsIfxD1y/ghWWSPBXp5Lh/YQedQXmLvQFt1FobgcORAHWaucSf4Qj Hf6SZEcJPdXxc8B5nKgaSpCLFH79iUNMRfZvVcawJdjocW7E13CnEsBJNp9JhqY6W6FZukXWZEn94 2ugErz5ZmEs2R0AfvbVln+5PsEZf0fjwmGxqsXh2MWjYZxSuecuzFvxGH7V9lZSEUYMSTAejUp9db GY5jw3uVDrhqgx48iy3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRSwU-00000009gkY-2jCW; Thu, 12 Nov 2026 11:26:10 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRSwH-00000009gfJ-3oSA for linux-arm-kernel@lists.infradead.org; Thu, 12 Nov 2026 11:25:58 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1D21247A1E; Thu, 12 Nov 2026 11:25:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 662A91F00A05; Thu, 12 Nov 2026 11:25:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794482757; bh=FD/V4+e8O0iqTKVI3Ylc4RORwqMbtboEEa/TKhMeE7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=JETWMfWjkKeINJWiPkhAD/QsItp30dH2rFFfUxvvsc0JyhM1taj1AERUtJ/N3Cjs3 AwYVFzZ/m6zQ7KYBU+YiTIl9hTHpftthT74h5Nr4oeuYEHYYSiIf3AXVs+RKZKKHrV mIOmMwkG2K3nP1x7rGrbfTQKpZOVBqfxi9f/LcxqS5J0K6eBwmu7A8mogUZQyc4cgy znPGEVxp9AgLlfDVNExZSLItcLclY123hZKVh9JoHVE3H6OQiccRm+Ibc4Tk7V2+rw AM4h3/ZJfG+Yk80QegP3t50LRsE3vQEfEM9YcerbVpZJF++E9cU7QgrbnSemDfJFmG qhJVBLKkuZ+CQ== From: Arnd Bergmann To: linux-mm@kvack.org Cc: Arnd Bergmann , Andrew Morton , Andreas Larsson , "Christophe Leroy (CS GROUP)" , Dave Hansen , "David Hildenbrand (Arm)" , Jason Gunthorpe , Linus Walleij , "Lorenzo Stoakes (ARM)" , Matthew Wilcox , Malin Jonsson , Richard Weinberger , Russell King , linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: [PATCH v2 3/6] ARM: drop CONFIG_HIGHPTE support Date: Thu, 12 Nov 2026 12:25:25 +0100 Message-ID: <20261112112528.1116405-4-arnd@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261112112528.1116405-1-arnd@kernel.org> References: <20261112112528.1116405-1-arnd@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 From: Arnd Bergmann CONFIG_HIGHPTE was added in linux-2.6.32, a few years before 64-bit support. At the time it made sense, as the CONFIG_ARM_LPAE option allowed systems with 16GB of memory that made lowmem a particularly scarce resource, and the HIGHPTE implementation gave feature parity with 32-bit x86 and frv machines. Since Arm is the last architecture remaining that uses this, and almost no 32-bit machines support more than 4GB of RAM, the cost of continuing to maintain HIGHPTE seems unjustified, so remove it here to allow simplifying the generic page table handling. Link: https://lore.kernel.org/lkml/20241204103042.1904639-8-arnd@kernel.org/T/#u Signed-off-by: Arnd Bergmann --- I sent a patch to drop HIGHPTE support on x86 today, see https://lore.kernel.org/lkml/20241210144945.2325330-9-arnd@kernel.org/T/#u If that one gets merged, we can merge this one instead of the one that makes HIGHPTE depend on !PREEMPT_RT, but if we decide against the x86 change, then we probably don't want this one either. Signed-off-by: Arnd Bergmann --- arch/arm/Kconfig | 11 ----------- arch/arm/include/asm/pgalloc.h | 8 +------- 2 files changed, 1 insertion(+), 18 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index fd01ccab9c12..fc66d52d847e 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1225,17 +1225,6 @@ config HIGHMEM If unsure, say n. -config HIGHPTE - bool "Allocate 2nd-level pagetables from highmem" if EXPERT - depends on HIGHMEM && !PREEMPT_RT - default y - help - The VM uses one page of physical memory for each page table. - For systems with a lot of processes, this can use a lot of - precious low memory, eventually leading to low memory being - consumed by page tables. Setting this option will allow - user-space 2nd level page tables to reside in high memory. - config ARM_PAN bool "Enable privileged no-access" depends on MMU diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h index a17f01235c29..ef6cb3e6d179 100644 --- a/arch/arm/include/asm/pgalloc.h +++ b/arch/arm/include/asm/pgalloc.h @@ -85,18 +85,12 @@ pte_alloc_one_kernel(struct mm_struct *mm) return pte; } -#ifdef CONFIG_HIGHPTE -#define PGTABLE_HIGHMEM __GFP_HIGHMEM -#else -#define PGTABLE_HIGHMEM 0 -#endif - static inline pgtable_t pte_alloc_one(struct mm_struct *mm) { struct page *pte; - pte = __pte_alloc_one(mm, GFP_PGTABLE_USER | PGTABLE_HIGHMEM); + pte = __pte_alloc_one(mm, GFP_PGTABLE_USER); if (!pte) return NULL; if (!PageHighMem(pte)) -- 2.53.0