From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1576346FA1; Wed, 11 Feb 2026 10:32:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770805934; cv=none; b=F+G7t1Xe1iDw4AOsrmVM8hbqKlK/Z/UCVHOugCzSFQDc6iJIj22lrrDqjQY8/cBoS1mGnvbeYTOu0KtuN81RNsMJ4W3jPL/vWkvrCrz57MNzVhAJhlKbzj+yGQuhCUe/3ZVjyjmLDOoUZ2Svi45kW07r8Hls4lSZObzJRT5ofa8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770805934; c=relaxed/simple; bh=IrP0HcvbxJyr+QPUUgTWRvTOZExBIyn/P520HSFeTE0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Rdw/2Yz/3Zj4ODbo75y3+TK2sqojW+N/gkOsZprdqu+BGTCDC1ZSzFzEvzrYzJiFxdLnIVkwiJtt/rnvnokvm8qB0l/P2FAVbLBEJ9Ku9MW+qzPKabo+VAGMWFd1rxrWLBpREPOcTaNDW2LWcCmkiKT+CMiL3mJFUEXeDZ/s/rk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TFe7/nLN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TFe7/nLN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7BD6C4CEF7; Wed, 11 Feb 2026 10:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770805934; bh=IrP0HcvbxJyr+QPUUgTWRvTOZExBIyn/P520HSFeTE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TFe7/nLN+rKkMzW67S9vCNdZrax/kPne+WpMF87k95gqGlUzqF+fR5WSEUhJQdT3j pPxb8u1Ax2zDRwbXDSOUkXQnSyyGT9ATA7S3mMXNx2TRCmDY+UML8uqdt2x5uN5KOn Myw0c7iyqZfsQ6nIDluj/Ct6feChieIpAVe31sKpg0gTQ8BQT8IA1FdMJRou60J6Id rBVyOi00C1KINFPks7VJijlaVTWk5jn2wnNxzaifUW5ZIAAy72z1/aL01QcnnfNWRP Oom4Kb7P8HeZb9qPQLur3tBkv0FhMqGVt2yWCiPLRGAsku2RHRh3DuKoejRqRBa2Dx Gdc7juu6vCfng== From: Mike Rapoport To: Andrew Morton Cc: Andreas Larsson , Borislav Petkov , Brian Cain , Catalin Marinas , "Christophe Leroy (CS GROUP)" , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , "Liam R. Howlett" , Lorenzo Stoakes , Madhavan Srinivasan , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Mike Rapoport , Palmer Dabbelt , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Gleixner , Vineet Gupta , Vlastimil Babka , Will Deacon , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org Subject: [PATCH v3 1/4] mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn() Date: Wed, 11 Feb 2026 12:31:38 +0200 Message-ID: <20260211103141.3215197-2-rppt@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260211103141.3215197-1-rppt@kernel.org> References: <20260211103141.3215197-1-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-sh@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Mike Rapoport (Microsoft)" nommu architectures have empty_zero_page and define ZERO_PAGE() and although they don't really use it to populate page tables, there is no reason to hardwire !MMU implementation of is_zero_pfn() and my_zero_pfn() to 0. Drop #ifdef CONFIG_MMU around implementations of is_zero_pfn() and my_zero_pfn() and remove !MMU version. While on it, make zero_pfn __ro_after_init. Signed-off-by: Mike Rapoport (Microsoft) --- include/linux/pgtable.h | 14 +------------- mm/memory.c | 13 ------------- mm/mm_init.c | 10 ++++++++++ 3 files changed, 11 insertions(+), 26 deletions(-) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 827dca25c0bc..08a88b0d56e5 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1882,7 +1882,6 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot) pfnmap_setup_cachemode(pfn, PAGE_SIZE, prot); } -#ifdef CONFIG_MMU #ifdef __HAVE_COLOR_ZERO_PAGE static inline int is_zero_pfn(unsigned long pfn) { @@ -1905,18 +1904,7 @@ static inline unsigned long my_zero_pfn(unsigned long addr) extern unsigned long zero_pfn; return zero_pfn; } -#endif -#else -static inline int is_zero_pfn(unsigned long pfn) -{ - return 0; -} - -static inline unsigned long my_zero_pfn(unsigned long addr) -{ - return 0; -} -#endif /* CONFIG_MMU */ +#endif /* __HAVE_COLOR_ZERO_PAGE */ #ifdef CONFIG_MMU diff --git a/mm/memory.c b/mm/memory.c index 187f16b7e996..51d2018a387a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -162,21 +162,8 @@ static int __init disable_randmaps(char *s) } __setup("norandmaps", disable_randmaps); -unsigned long zero_pfn __read_mostly; -EXPORT_SYMBOL(zero_pfn); - unsigned long highest_memmap_pfn __read_mostly; -/* - * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() - */ -static int __init init_zero_pfn(void) -{ - zero_pfn = page_to_pfn(ZERO_PAGE(0)); - return 0; -} -early_initcall(init_zero_pfn); - void mm_trace_rss_stat(struct mm_struct *mm, int member) { trace_rss_stat(mm, member); diff --git a/mm/mm_init.c b/mm/mm_init.c index 1a29a719af58..dcf9eff34f83 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -53,6 +53,9 @@ EXPORT_SYMBOL(mem_map); void *high_memory; EXPORT_SYMBOL(high_memory); +unsigned long zero_pfn __ro_after_init; +EXPORT_SYMBOL(zero_pfn); + #ifdef CONFIG_DEBUG_MEMORY_INIT int __meminitdata mminit_loglevel; @@ -2667,6 +2670,13 @@ static void __init mem_init_print_info(void) ); } +static int __init init_zero_pfn(void) +{ + zero_pfn = page_to_pfn(ZERO_PAGE(0)); + return 0; +} +early_initcall(init_zero_pfn); + void __init __weak arch_mm_preinit(void) { } -- 2.51.0