linux/arch/um/include/asm
Mike Rapoport (Microsoft) 6215d9f447 arch, mm: consolidate empty_zero_page
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/um: allocated empty_zero_page from memblock,
  although they do not support zero page coloring and having it in BSS
  will work fine.
* sparc64 can have empty_zero_page in BSS rather allocate it, but it
  can't use virt_to_page() for BSS. Keep it's definition of ZERO_PAGE()
  but instead of allocating it, make mem_map_zero point to
  empty_zero_page.
* 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 :)

Link: https://lkml.kernel.org/r/20260211103141.3215197-4-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Helge Deller <deller@gmx.de>		[parisc]
Tested-by: Helge Deller <deller@gmx.de>		[parisc]
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Magnus Lindholm <linmag7@gmail.com>	[alpha]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>	[nios2]
Acked-by: Andreas Larsson <andreas@gaisler.com>	[sparc]
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-04-05 13:53:01 -07:00
..
fpu um: Include linux/types.h in asm/fpu/api.h 2025-05-07 16:45:40 +08:00
archrandom.h random: handle archrandom with multiple longs 2022-07-25 13:26:14 +02:00
asm-prototypes.h um: Add cmpxchg8b_emu and checksum functions to asm-prototypes.h 2025-05-05 10:22:07 +02:00
bpf_perf_event.h um: don't generate asm/bpf_perf_event.h 2024-07-10 14:23:30 +02:00
cache.h
cacheflush.h um: implement flush_cache_vmap/flush_cache_vunmap 2021-06-17 22:04:40 +02:00
common.lds.S UML: add support for KASAN under x86_64 2022-07-17 23:35:22 +02:00
cpufeature.h um: Replace __ASSEMBLY__ with __ASSEMBLER__ in the usermode headers 2025-07-22 17:12:45 +02:00
current.h um: Add initial SMP support 2025-10-27 16:41:15 +01:00
delay.h um: fix ndelay/udelay defines 2021-12-21 21:13:43 +01:00
dma.h
futex.h um: add a UML specific futex implementation 2021-06-17 22:01:45 +02:00
hardirq.h um: Add initial SMP support 2025-10-27 16:41:15 +01:00
io.h um: add PCI over virtio emulation driver 2021-06-17 21:45:43 +02:00
irq.h um: Track userspace children dying in SECCOMP mode 2025-06-02 15:17:19 +02:00
irqflags.h um: Turn signals_* into thread-local variables 2025-10-27 16:41:15 +01:00
kasan.h um: Disable KASAN_INLINE when STATIC_LINK is selected 2025-12-01 11:54:50 +01:00
Kbuild x86/asm: Remove ANNOTATE_DATA_SPECIAL usage 2025-12-03 16:53:19 +01:00
kvm_para.h
mmu_context.h um: Stop tracking virtual CPUs via mm_cpumask() 2025-09-10 14:23:53 +02:00
mmu.h um: Add initial SMP support 2025-10-27 16:41:15 +01:00
msi.h um: add PCI over virtio emulation driver 2021-06-17 21:45:43 +02:00
page.h treewide: provide a generic clear_user_page() variant 2026-01-20 19:24:39 -08:00
pci.h PCI/MSI: Get rid of PCI_MSI_IRQ_DOMAIN 2022-11-17 15:15:19 +01:00
pgalloc.h mm: pgtable: convert some architectures to use tlb_remove_ptdesc() 2025-04-01 15:17:13 -07:00
pgtable-2level.h um: remove custom definition of mk_pte() 2025-05-11 17:48:03 -07:00
pgtable-4level.h um: remove custom definition of mk_pte() 2025-05-11 17:48:03 -07:00
pgtable.h arch, mm: consolidate empty_zero_page 2026-04-05 13:53:01 -07:00
processor-generic.h um: Remove unused ipi_pipe field from cpuinfo_um 2025-09-10 14:23:58 +02:00
ptrace-generic.h um: Replace __ASSEMBLY__ with __ASSEMBLER__ in the usermode headers 2025-07-22 17:12:45 +02:00
sections.h
setup.h
smp.h um: Add initial SMP support 2025-10-27 16:41:15 +01:00
stacktrace.h
syscall-generic.h syscall.h: introduce syscall_set_nr() 2025-05-11 17:48:15 -07:00
thread_info.h um: Replace __ASSEMBLY__ with __ASSEMBLER__ in the usermode headers 2025-07-22 17:12:45 +02:00
timex.h um: use fallback for random_get_entropy() instead of zero 2022-05-13 23:59:23 +02:00
tlb.h um: implement flush_cache_vmap/flush_cache_vunmap 2021-06-17 22:04:40 +02:00
tlbflush.h um: Abandon the _PAGE_NEWPROT bit 2024-10-23 09:52:49 +02:00
uaccess.h um: Remove __access_ok_vsyscall() 2025-11-06 13:02:34 +01:00
unwind.h
vmalloc.h mm/vmalloc: Add empty <asm/vmalloc.h> headers and use them from <linux/vmalloc.h> 2019-12-10 10:12:55 +01:00
vmlinux.lds.h
xor.h um: Remove straying parenthesis 2022-07-17 23:24:20 +02:00