From: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
To: Mike Rapoport <rppt@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Larsson <andreas@gaisler.com>,
Borislav Petkov <bp@alien8.de>, Brian Cain <bcain@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"David S. Miller" <davem@davemloft.net>,
Dave Hansen <dave.hansen@linux.intel.com>,
David Hildenbrand <david@kernel.org>,
Dinh Nguyen <dinguyen@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Guo Ren <guoren@kernel.org>, Helge Deller <deller@gmx.de>,
Huacai Chen <chenhuacai@kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Johannes Berg <johannes@sipsolutions.net>,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Magnus Lindholm <linmag7@gmail.com>,
Matt Turner <mattst88@gmail.com>,
Max Filippov <jcmvbkbc@gmail.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Michal Hocko <mhocko@suse.com>, Michal Simek <monstr@monstr.eu>,
Palmer Dabbelt <palmer@dabbelt.com>,
Richard Weinberger <richard@nod.at>,
Russell King <linux@armlinux.org.uk>,
Stafford Horne <shorne@gmail.com>,
Suren Baghdasaryan <surenb@google.com>,
Thomas Gleixner <tglx@kernel.org>,
Vineet Gupta <vgupta@kernel.org>,
Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>,
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: Re: [PATCH mm-unstable] arch, mm: consolidate empty_zero_page
Date: Sat, 24 Jan 2026 11:15:47 +0100 [thread overview]
Message-ID: <02784e9a-d934-44c3-ae24-a83a1bcf678d@kernel.org> (raw)
In-Reply-To: <20260124095628.668870-1-rppt@kernel.org>
Le 24/01/2026 à 10:56, Mike Rapoport a écrit :
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
>
> Reduce 22 declarations of empty_zero_page to 3 and 23 declarations of
> ZERO_PAGE() to 4.
>
> Every architecture defines empty_zero_page that way or another, but for the
> most of them it is always a page aligned page in BSS and most definitions
> of ZERO_PAGE do virt_to_page(empty_zero_page).
>
> Move Linus vetted x86 definition of empty_zero_page and ZERO_PAGE() to the
> core MM and drop these definitions in architectures that do not implement
> colored zero page (MIPS and s390).
>
> ZERO_PAGE() remains a macro because turning it to a wrapper for a static
> inline causes severe pain in header dependencies.
>
> For the most part the change is mechanical, with these being noteworthy:
>
> * alpha: aliased empty_zero_page with ZERO_PGE that was also used for boot
> parameters. Switching to a generic empty_zero_page removes the aliasing
> and keeps ZERO_PGE for boot parameters only
> * arm64: uses __pa_symbol() in ZERO_PAGE() so that definition of
> ZERO_PAGE() is kept intact.
> * m68k/parisc/sparc64/um: allocated empty_zero_page from memblock,
> although they do not support zero page coloring and having it in BSS
> will work fine.
> * sh: used empty_zero_page for boot parameters at the very early boot.
> Rename the parameters page to boot_params_page and let sh use the generic
> empty_zero_page.
> * hexagon: had an amusing comment about empty_zero_page
>
> /* A handy thing to have if one has the RAM. Declared in head.S */
>
> that unfortunately had to go :)
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
> arch/alpha/include/asm/pgtable.h | 6 ------
> arch/arc/include/asm/pgtable.h | 3 ---
> arch/arc/mm/init.c | 2 --
> arch/arm/include/asm/pgtable.h | 9 ---------
> arch/arm/mm/mmu.c | 7 -------
> arch/arm/mm/nommu.c | 7 -------
> arch/arm64/include/asm/pgtable.h | 1 -
> arch/arm64/mm/mmu.c | 7 -------
> arch/csky/include/asm/pgtable.h | 3 ---
> arch/csky/mm/init.c | 3 ---
> arch/hexagon/include/asm/pgtable.h | 6 ------
> arch/hexagon/kernel/head.S | 5 -----
> arch/hexagon/kernel/hexagon_ksyms.c | 1 -
> arch/loongarch/include/asm/pgtable.h | 9 ---------
> arch/loongarch/mm/init.c | 3 ---
> arch/m68k/include/asm/pgtable_mm.h | 9 ---------
> arch/m68k/include/asm/pgtable_no.h | 7 -------
> arch/m68k/mm/init.c | 9 ---------
> arch/m68k/mm/mcfmmu.c | 2 --
> arch/m68k/mm/motorola.c | 6 ------
> arch/m68k/mm/sun3mmu.c | 2 --
> arch/microblaze/include/asm/pgtable.h | 10 ----------
> arch/microblaze/kernel/head.S | 4 ----
> arch/microblaze/kernel/microblaze_ksyms.c | 2 --
> arch/nios2/include/asm/pgtable.h | 7 -------
> arch/nios2/kernel/head.S | 10 ----------
> arch/nios2/kernel/nios2_ksyms.c | 1 -
> arch/openrisc/include/asm/pgtable.h | 4 ----
> arch/openrisc/kernel/head.S | 3 ---
> arch/openrisc/kernel/or32_ksyms.c | 1 -
> arch/openrisc/mm/init.c | 3 ---
> arch/parisc/include/asm/pgtable.h | 11 -----------
> arch/parisc/mm/init.c | 6 ------
> arch/powerpc/include/asm/pgtable.h | 6 ------
> arch/powerpc/mm/mem.c | 3 ---
For powerpc:
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
> arch/riscv/include/asm/pgtable.h | 7 -------
> arch/riscv/mm/init.c | 4 ----
> arch/sh/include/asm/pgtable.h | 8 --------
> arch/sh/include/asm/setup.h | 3 ++-
> arch/sh/kernel/head_32.S | 4 ++--
> arch/sh/kernel/sh_ksyms_32.c | 1 -
> arch/sh/mm/init.c | 1 -
> arch/sparc/include/asm/pgtable_32.h | 8 --------
> arch/sparc/include/asm/pgtable_64.h | 3 ---
> arch/sparc/include/asm/setup.h | 2 --
> arch/sparc/kernel/head_32.S | 7 -------
> arch/sparc/mm/init_32.c | 4 ----
> arch/sparc/mm/init_64.c | 15 ---------------
> arch/um/include/asm/pgtable.h | 9 ---------
> arch/um/include/shared/kern_util.h | 1 -
> arch/um/kernel/mem.c | 16 ----------------
> arch/um/kernel/um_arch.c | 1 -
> arch/x86/include/asm/pgtable.h | 8 --------
> arch/x86/kernel/head_32.S | 4 ----
> arch/x86/kernel/head_64.S | 7 -------
> arch/xtensa/include/asm/pgtable.h | 4 ----
> arch/xtensa/kernel/head.S | 3 ---
> arch/xtensa/kernel/xtensa_ksyms.c | 2 --
> include/linux/pgtable.h | 8 ++++++++
> mm/mm_init.c | 9 +++++++++
> 60 files changed, 21 insertions(+), 296 deletions(-)
>
next prev parent reply other threads:[~2026-01-24 10:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-24 9:56 Mike Rapoport
2026-01-24 10:15 ` Christophe Leroy (CS GROUP) [this message]
2026-01-27 16:02 ` Andreas Larsson
2026-01-27 18:11 ` Mike Rapoport
2026-02-03 10:17 ` Andreas Larsson
2026-02-07 10:36 ` Mike Rapoport
2026-02-09 8:41 ` Andreas Larsson
2026-02-04 20:47 ` David Hildenbrand (arm)
2026-02-07 2:13 ` Helge Deller
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