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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 51763C2A062 for ; Sun, 4 Jan 2026 12:02:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8856D6B0092; Sun, 4 Jan 2026 07:02:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 832D46B0093; Sun, 4 Jan 2026 07:02:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6E08B6B0095; Sun, 4 Jan 2026 07:02:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 5BFAF6B0092 for ; Sun, 4 Jan 2026 07:02:07 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id B457414090D for ; Sun, 4 Jan 2026 12:02:06 +0000 (UTC) X-FDA: 84294143052.04.90E5D82 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf11.hostedemail.com (Postfix) with ESMTP id 0C6F140002 for ; Sun, 4 Jan 2026 12:02:04 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=INT0kxBN; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf11.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1767528125; a=rsa-sha256; cv=none; b=6FkZyWX9f3D4v1RnbQsZzq2kliJAEF2USGm6vxfHC8YQjJzJ+lWEAAVl9my9HxCNO+f3zH P0FmJQek5Y8FtUeWi2cyKRg4Rvfd9jPslPpyQ3p6CQ7To7UkM0mLylAGYSRkdjNOpXtpyv 5FcExuMGvNy3kL4XEOMa893asK655B4= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=INT0kxBN; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf11.hostedemail.com: domain of rppt@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767528125; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1CFQ5srPeWoqo1JSWCS2nyReDQiTWkIfIDjv/mL7ZvY=; b=qDEwYW1Oalyk5CurhZ0V3lIA/enoDwAscONE5ggkHP9kVp+cn3V/C7yY4fzGJmOpYsPW3O jQfA0dmssYsO0d90r/LgRkG68tZfwZoMi03WgnTOPN/m+hTpgnTd2SsBqd1hboYbsPAHFY 5gwnkVQCEzF+9gioTdxGdZmS4miW0UM= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id B443941990; Sun, 4 Jan 2026 12:02:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBEE4C4CEF7; Sun, 4 Jan 2026 12:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767528123; bh=4sa1iSi4oDg5XKMoz/YTQfrnb1djTAsHN5WmWDd4u+I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=INT0kxBNHgbBEXAA8WBKHyCuHkaVMGgpladnOebfsTa2yzQEYV4mt1yJlN1PwnUNz G4VwNDd1qyIbSlxRqbG31MW/aCW0NgYeMa2AQOcXg9gdLQ2vLQ8cpLRs/OvRLxPgLM zrYw+rbOt3/ZgtPyhC+4awQoJA3/jIoNRc6jn+AQvMSMdpvmZk0yDmwOEIirlcn6Fk MRm98b/tsfvPN/LkKJNqg07jtHRl5wM8VTQcUWaDc+iUxs0zzTGNhqOtNPkcd9CZqU 27IV33yAMIJYJGbt3gk6IFngZkbX6GD6/FqDbQgyLW1/3NDufvpgxz5xhJM1ESJUtq 0kvgqRIhU453Q== Date: Sun, 4 Jan 2026 14:01:40 +0200 From: Mike Rapoport To: Klara Modin , Andrew Morton Cc: Alex Shi , Alexander Gordeev , Andreas Larsson , Borislav Petkov , Brian Cain , "Christophe Leroy (CS GROUP)" , Catalin Marinas , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Heiko Carstens , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , Jonathan Corbet , "Liam R. Howlett" , Lorenzo Stoakes , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Muchun Song , Oscar Salvador , Palmer Dabbelt , Pratyush Yadav , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vineet Gupta , Vlastimil Babka , Will Deacon , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-cxl@vger.kernel.org, linux-doc@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org Subject: [PATCH 3.5] arm: make initialization of zero page independent of the memory map (was Re: [PATCH v2 22/28] arch, mm: consolidate initialization of nodes, zones and memory map) Message-ID: References: <20260102070005.65328-1-rppt@kernel.org> <20260102070005.65328-23-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 0C6F140002 X-Stat-Signature: aqeeoo9p5gyrbwwp36wjmk948i9ryicd X-Rspam-User: X-HE-Tag: 1767528124-53429 X-HE-Meta: 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 y9o8Pit3 ofJkjmX9FCcfTTv0s/RX+knlZNJgfhrZlR4OB/3mJsfTwrSpIrIlHxpvkRYZteeNzo7Zqdhk9IN8ev9L9GAQnkbYiJd6LSKufdqt1B5PaJOTClO/ZBeUMTFCI1943sDuwqo9StEF+hzXs6Ia4ClZh0ZiMV60hWzSZdkH0XDi38dORfucF4qlZbaUYjU4FJR11iS5WiVymC5NAby40PXA5TckK1HebenP9bqd+8Yt2Y5PzJAoifEnewFamq1Uec9Q2QRRW0xg8yZcQr83rMhPxP///OWZhIYFTqex46ZZenkj2xyDMFXFw6uElISAn+6KtYfUTWqpLReaarUs= 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: List-Subscribe: List-Unsubscribe: Andrew, Can you please stick this between patch 3 (arm: introduce arch_zone_limits_init()) and patch 4 (arm64: introduce arch_zone_limits_init())? >From 35d016bbf5da7c08cc5c5547c85558fc50cb63aa Mon Sep 17 00:00:00 2001 From: Klara Modin Date: Sat, 3 Jan 2026 20:40:09 +0200 Subject: [PATCH] arm: make initialization of zero page independent of the memory map Unlike most architectures, arm keeps a struct page pointer to the empty_zero_page and to initialize it requires conversion of a virtual address to page which makes it necessary to have memory map initialized before creating the empty_zero_page. Make empty_zero_page a stataic array in BSS to decouple it's initialization from the initialization of the memory map. This also aligns arm with vast majorty of architectures. Signed-off-by: Klara Modin Signed-off-by: Mike Rapoport (Microsoft) --- arch/arm/include/asm/pgtable.h | 4 ++-- arch/arm/mm/mmu.c | 10 +--------- arch/arm/mm/nommu.c | 10 +--------- 3 files changed, 4 insertions(+), 20 deletions(-) diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h index 86378eec7757..6fa9acd6a7f5 100644 --- a/arch/arm/include/asm/pgtable.h +++ b/arch/arm/include/asm/pgtable.h @@ -15,8 +15,8 @@ * ZERO_PAGE is a global shared page that is always zero: used * for zero-mapped memory areas etc.. */ -extern struct page *empty_zero_page; -#define ZERO_PAGE(vaddr) (empty_zero_page) +extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; +#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page)) #endif #include diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 8bac96e205ac..518def8314e7 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -45,7 +45,7 @@ extern unsigned long __atags_pointer; * empty_zero_page is a special page that is used for * zero-initialized data and COW. */ -struct page *empty_zero_page; +unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; EXPORT_SYMBOL(empty_zero_page); /* @@ -1754,8 +1754,6 @@ static void __init early_fixmap_shutdown(void) */ void __init paging_init(const struct machine_desc *mdesc) { - void *zero_page; - #ifdef CONFIG_XIP_KERNEL /* Store the kernel RW RAM region start/end in these variables */ kernel_sec_start = CONFIG_PHYS_OFFSET & SECTION_MASK; @@ -1781,13 +1779,7 @@ void __init paging_init(const struct machine_desc *mdesc) top_pmd = pmd_off_k(0xffff0000); - /* allocate the zero page. */ - zero_page = early_alloc(PAGE_SIZE); - bootmem_init(); - - empty_zero_page = virt_to_page(zero_page); - __flush_dcache_folio(NULL, page_folio(empty_zero_page)); } void __init early_mm_init(const struct machine_desc *mdesc) diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c index d638cc87807e..7e42d8accec6 100644 --- a/arch/arm/mm/nommu.c +++ b/arch/arm/mm/nommu.c @@ -31,7 +31,7 @@ unsigned long vectors_base; * empty_zero_page is a special page that is used for * zero-initialized data and COW. */ -struct page *empty_zero_page; +unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; EXPORT_SYMBOL(empty_zero_page); #ifdef CONFIG_ARM_MPU @@ -156,18 +156,10 @@ void __init adjust_lowmem_bounds(void) */ void __init paging_init(const struct machine_desc *mdesc) { - void *zero_page; - early_trap_init((void *)vectors_base); mpu_setup(); - /* allocate the zero page. */ - zero_page = (void *)memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE); - bootmem_init(); - - empty_zero_page = virt_to_page(zero_page); - flush_dcache_page(empty_zero_page); } /* -- 2.51.0