[PATCH v3 0/4] arch, mm: consolidate empty_zero_page

STALE169d

Revision v3 of 2 in this series.

18 messages, 8 authors, 2026-04-30 · open the first message on its own page

[PATCH v3 0/4] arch, mm: consolidate empty_zero_page

From: Mike Rapoport <rppt@kernel.org>
Date: 2026-02-11 10:31:58

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

Hi,

These patches cleanup handling of ZERO_PAGE() and zero_pfn.

v3 changes:
* move zero_page_pfn extern declaration back inside the helpers
* add tags, thanks all!

v2: https://lore.kernel.org/all/20260209144058.2092871-1-rppt@kernel.org
* add patches that cleanup zero_pfn code a bit (patches 1,2)
* add a patch that caches struct page for empty_zero_page (patch 4)
* use uint8_t instead of unsigned long for empty_zero_page
* fix sparc64 changes in patch 3

v1: https://lore.kernel.org/all/20260124095628.668870-1-rppt@kernel.org

Mike Rapoport (Microsoft) (4):
  mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()
  mm: rename my_zero_pfn() to zero_pfn()
  arch, mm: consolidate empty_zero_page
  mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()

 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          |  7 ----
 arch/arm64/mm/init.c                      |  5 +++
 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/mips/mm/init.c                       | 11 +-----
 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 --
 arch/riscv/include/asm/pgtable.h          |  7 ----
 arch/riscv/mm/init.c                      |  4 --
 arch/s390/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                   | 24 +++++-------
 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/x86/kvm/mmu/spte.h                   |  2 +-
 arch/xtensa/include/asm/pgtable.h         |  4 --
 arch/xtensa/kernel/head.S                 |  3 --
 arch/xtensa/kernel/xtensa_ksyms.c         |  2 -
 fs/dax.c                                  |  2 +-
 fs/proc/vmcore.c                          |  2 +-
 include/linux/pgtable.h                   | 48 ++++++++++++++---------
 mm/huge_memory.c                          |  2 +-
 mm/memory.c                               | 15 +------
 mm/migrate.c                              |  2 +-
 mm/mm_init.c                              | 28 +++++++++++++
 mm/userfaultfd.c                          |  4 +-
 70 files changed, 86 insertions(+), 354 deletions(-)


base-commit: 50c7f34c5c7403a12003c6759f6f6ca9a5a10872
--
2.51.0

*** BLURB HERE ***

Mike Rapoport (Microsoft) (4):
  mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()
  mm: rename my_zero_pfn() to zero_pfn()
  arch, mm: consolidate empty_zero_page
  mm: cache struct page for empty_zero_page and return it from
    ZERO_PAGE()

 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          |  7 ----
 arch/arm64/mm/init.c                      |  5 +++
 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/mips/mm/init.c                       | 11 +----
 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 --
 arch/riscv/include/asm/pgtable.h          |  7 ----
 arch/riscv/mm/init.c                      |  4 --
 arch/s390/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                   | 24 ++++-------
 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/x86/kvm/mmu/spte.h                   |  2 +-
 arch/xtensa/include/asm/pgtable.h         |  4 --
 arch/xtensa/kernel/head.S                 |  3 --
 arch/xtensa/kernel/xtensa_ksyms.c         |  2 -
 fs/dax.c                                  |  2 +-
 fs/proc/vmcore.c                          |  2 +-
 include/linux/pgtable.h                   | 51 +++++++++++++++--------
 mm/huge_memory.c                          |  2 +-
 mm/memory.c                               | 15 +------
 mm/migrate.c                              |  2 +-
 mm/mm_init.c                              | 28 +++++++++++++
 mm/userfaultfd.c                          |  4 +-
 70 files changed, 89 insertions(+), 354 deletions(-)


base-commit: 50c7f34c5c7403a12003c6759f6f6ca9a5a10872
--
2.51.0

[PATCH v3 1/4] mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()

From: Mike Rapoport <rppt@kernel.org>
Date: 2026-02-11 10:32:14

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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) <rppt@kernel.org>
---
 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

[PATCH v3 2/4] mm: rename my_zero_pfn() to zero_pfn()

From: Mike Rapoport <rppt@kernel.org>
Date: 2026-02-11 10:32:26

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

my_zero_pfn() is a silly name.

Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to
zero_pfn().

While on it, move extern declarations of zero_page_pfn outside the
functions that use it and add a comment about what ZERO_PAGE is.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/x86/kvm/mmu/spte.h |  2 +-
 fs/dax.c                |  2 +-
 fs/proc/vmcore.c        |  2 +-
 include/linux/pgtable.h | 28 ++++++++++++++++++++--------
 mm/huge_memory.c        |  2 +-
 mm/memory.c             |  2 +-
 mm/migrate.c            |  2 +-
 mm/mm_init.c            | 10 +++++-----
 mm/userfaultfd.c        |  4 ++--
 9 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 91ce29fd6f1b..8c0ffa2cded6 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h

@@ -248,7 +248,7 @@ extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
 
 static inline hpa_t kvm_mmu_get_dummy_root(void)
 {
-	return my_zero_pfn(0) << PAGE_SHIFT;
+	return zero_pfn(0) << PAGE_SHIFT;
 }
 
 static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page)

diff --git a/fs/dax.c b/fs/dax.c
index 289e6254aa30..b78cff9c91b3 100644
--- a/fs/dax.c
+++ b/fs/dax.c

@@ -1360,7 +1360,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf,
 {
 	struct inode *inode = iter->inode;
 	unsigned long vaddr = vmf->address;
-	unsigned long pfn = my_zero_pfn(vaddr);
+	unsigned long pfn = zero_pfn(vaddr);
 	vm_fault_t ret;
 
 	*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index f188bd900eb2..44d15436439f 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c

@@ -525,7 +525,7 @@ static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
 {
 	unsigned long map_size;
 	unsigned long pos_start, pos_end, pos;
-	unsigned long zeropage_pfn = my_zero_pfn(0);
+	unsigned long zeropage_pfn = zero_pfn(0);
 	size_t len = 0;
 
 	pos_start = pfn;

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 08a88b0d56e5..9bacf4df9769 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1882,27 +1882,39 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
 	pfnmap_setup_cachemode(pfn, PAGE_SIZE, prot);
 }
 
+/*
+ * ZERO_PAGE() is global shared page(s) that is always zero. It is used for
+ * zero-mapped memory areas, CoW etc.
+ *
+ * On architectures that __HAVE_COLOR_ZERO_PAGE there are several such pages
+ * for different ranges in the virtual address space.
+ *
+ * zero_page_pfn identifies the first (or the only) pfn for these pages.
+ */
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)
 {
-	extern unsigned long zero_pfn;
-	unsigned long offset_from_zero_pfn = pfn - zero_pfn;
+	extern unsigned long zero_page_pfn;
+	unsigned long offset_from_zero_pfn = pfn - zero_page_pfn;
+
 	return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 }
 
-#define my_zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))
+#define zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))
 
 #else
 static inline int is_zero_pfn(unsigned long pfn)
 {
-	extern unsigned long zero_pfn;
-	return pfn == zero_pfn;
+	extern unsigned long zero_page_pfn;
+
+	return pfn == zero_page_pfn;
 }
 
-static inline unsigned long my_zero_pfn(unsigned long addr)
+static inline unsigned long zero_pfn(unsigned long addr)
 {
-	extern unsigned long zero_pfn;
-	return zero_pfn;
+	extern unsigned long zero_page_pfn;
+
+	return zero_page_pfn;
 }
 #endif /* __HAVE_COLOR_ZERO_PAGE */

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 44ff8a648afd..bc15fd152526 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c

@@ -2968,7 +2968,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
 	for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
 		pte_t entry;
 
-		entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot);
+		entry = pfn_pte(zero_pfn(addr), vma->vm_page_prot);
 		entry = pte_mkspecial(entry);
 		if (pmd_uffd_wp(old_pmd))
 			entry = pte_mkuffd_wp(entry);

diff --git a/mm/memory.c b/mm/memory.c
index 51d2018a387a..ae610afa9cea 100644
--- a/mm/memory.c
+++ b/mm/memory.c

@@ -5165,7 +5165,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 	/* Use the zero-page for reads */
 	if (!(vmf->flags & FAULT_FLAG_WRITE) &&
 			!mm_forbids_zeropage(vma->vm_mm)) {
-		entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address),
+		entry = pte_mkspecial(pfn_pte(zero_pfn(vmf->address),
 						vma->vm_page_prot));
 		vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 				vmf->address, &vmf->ptl);

diff --git a/mm/migrate.c b/mm/migrate.c
index 1bf2cf8c44dd..739c4e03769b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c

@@ -321,7 +321,7 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw,
 	if (!pages_identical(page, ZERO_PAGE(0)))
 		return false;
 
-	newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address),
+	newpte = pte_mkspecial(pfn_pte(zero_pfn(pvmw->address),
 					pvmw->vma->vm_page_prot));
 
 	if (pte_swp_soft_dirty(old_pte))

diff --git a/mm/mm_init.c b/mm/mm_init.c
index dcf9eff34f83..a0ca236eb4f5 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -53,8 +53,8 @@ EXPORT_SYMBOL(mem_map);
 void *high_memory;
 EXPORT_SYMBOL(high_memory);
 
-unsigned long zero_pfn __ro_after_init;
-EXPORT_SYMBOL(zero_pfn);
+unsigned long zero_page_pfn __ro_after_init;
+EXPORT_SYMBOL(zero_page_pfn);
 
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

@@ -2670,12 +2670,12 @@ static void __init mem_init_print_info(void)
 		);
 }
 
-static int __init init_zero_pfn(void)
+static int __init init_zero_page_pfn(void)
 {
-	zero_pfn = page_to_pfn(ZERO_PAGE(0));
+	zero_page_pfn = page_to_pfn(ZERO_PAGE(0));
 	return 0;
 }
-early_initcall(init_zero_pfn);
+early_initcall(init_zero_page_pfn);
 
 void __init __weak arch_mm_preinit(void)
 {

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 927086bb4a3c..e19872e51878 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c

@@ -357,7 +357,7 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd,
 	if (mm_forbids_zeropage(dst_vma->vm_mm))
 		return mfill_atomic_pte_zeroed_folio(dst_pmd, dst_vma, dst_addr);
 
-	_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
+	_dst_pte = pte_mkspecial(pfn_pte(zero_pfn(dst_addr),
 					 dst_vma->vm_page_prot));
 	ret = -EAGAIN;
 	dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl);

@@ -1229,7 +1229,7 @@ static int move_zeropage_pte(struct mm_struct *mm,
 		return -EAGAIN;
 	}
 
-	zero_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
+	zero_pte = pte_mkspecial(pfn_pte(zero_pfn(dst_addr),
 					 dst_vma->vm_page_prot));
 	ptep_clear_flush(src_vma, src_addr, src_pte);
 	set_pte_at(mm, dst_addr, dst_pte, zero_pte);

-- 
2.51.0

[PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: Mike Rapoport <rppt@kernel.org>
Date: 2026-02-11 10:32:38

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/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 :)

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>
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 ---
 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/setup.h            |  2 --
 arch/sparc/kernel/head_32.S               |  7 -------
 arch/sparc/mm/init_32.c                   |  4 ----
 arch/sparc/mm/init_64.c                   | 11 ++++-------
 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                   | 10 ++++++++++
 mm/mm_init.c                              |  5 +++++
 59 files changed, 23 insertions(+), 285 deletions(-)

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 90e7a9539102..12a3c5f8ece8 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h

@@ -125,12 +125,6 @@ struct vm_area_struct;
  */
 #define pgprot_noncached(prot)	(prot)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero:  used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	(virt_to_page(ZERO_PGE))
-
 /*
  * On certain platforms whose physical address space can overlap KSEG,
  * namely EV6 and above, we must re-twiddle the physaddr to restore the

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index bd580e2b62d7..0fdaea81b5fa 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h

@@ -21,9 +21,6 @@
 
 #ifndef __ASSEMBLER__
 
-extern char empty_zero_page[PAGE_SIZE];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
 
 /* to cope with aliasing VIPT cache */

diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index a5e92f46e5d1..d6b5c27a0098 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c

@@ -19,8 +19,6 @@
 #include <asm/arcregs.h>
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
-char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
-EXPORT_SYMBOL(empty_zero_page);
 
 static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
 static unsigned long low_mem_sz;

diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 6fa9acd6a7f5..982795cf4563 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h

@@ -10,15 +10,6 @@
 #include <linux/const.h>
 #include <asm/proc-fns.h>
 
-#ifndef __ASSEMBLY__
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-#endif
-
 #include <asm-generic/pgtable-nopud.h>
 
 #ifndef CONFIG_MMU

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 518def8314e7..23b87b5ef7f1 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c

@@ -41,13 +41,6 @@
 
 extern unsigned long __atags_pointer;
 
-/*
- * empty_zero_page is a special page that is used for
- * zero-initialized data and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * The pmd table for the upper-most set of pages.
  */

diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 7e42d8accec6..040ea43cce32 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c

@@ -27,13 +27,6 @@
 
 unsigned long vectors_base;
 
-/*
- * empty_zero_page is a special page that is used for
- * zero-initialized data and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 #ifdef CONFIG_ARM_MPU
 struct mpu_rgn_info mpu_rgn_info;
 #endif

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index d94445b4f3df..63da07398a30 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -110,7 +110,6 @@ static inline void arch_leave_lazy_mmu_mode(void)
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
  */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr)	phys_to_page(__pa_symbol(empty_zero_page))
 
 #define pte_ERROR(e)	\

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a6a00accf4f9..0f6a171faf1f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c

@@ -64,13 +64,6 @@ static bool rodata_is_rw __ro_after_init = true;
  */
 long __section(".mmuoff.data.write") __early_cpu_boot_status;
 
-/*
- * Empty_zero_page is a special page that is used for zero-initialized data
- * and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 static DEFINE_SPINLOCK(swapper_pgdir_lock);
 static DEFINE_MUTEX(fixmap_lock);

diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index d606afbabce1..bafcd5823531 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h

@@ -76,9 +76,6 @@
 #define MAX_SWAPFILES_CHECK() \
 		BUILD_BUG_ON(MAX_SWAPFILES_SHIFT != 5)
 
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern void load_pgd(unsigned long pg_dir);
 extern pte_t invalid_pte_table[PTRS_PER_PTE];

diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index 573da66b2543..fa16015ea1c0 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c

@@ -38,9 +38,6 @@ pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
 pte_t kernel_pte_tables[PTRS_KERN_TABLE] __page_aligned_bss;
 
 EXPORT_SYMBOL(invalid_pte_table);
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-						__page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
 
 void free_initmem(void)
 {

diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index fbf24d1d1ca6..27b269e2870d 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h

@@ -14,9 +14,6 @@
 #include <asm/page.h>
 #include <asm-generic/pgtable-nopmd.h>
 
-/* A handy thing to have if one has the RAM. Declared in head.S */
-extern unsigned long empty_zero_page;
-
 /*
  * The PTE model described here is that of the Hexagon Virtual Machine,
  * which autonomously walks 2-level page tables.  At a lower level, we

@@ -348,9 +345,6 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 	return (unsigned long)__va(pmd_val(pmd) & PAGE_MASK);
 }
 
-/* ZERO_PAGE - returns the globally shared zero page */
-#define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page))
-
 /*
  * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
  * are !pte_none() && !pte_present().

diff --git a/arch/hexagon/kernel/head.S b/arch/hexagon/kernel/head.S
index 0b016308cc79..908ffece9132 100644
--- a/arch/hexagon/kernel/head.S
+++ b/arch/hexagon/kernel/head.S

@@ -216,8 +216,3 @@ __head_s_vaddr_target:
 .p2align PAGE_SHIFT
 ENTRY(external_cmdline_buffer)
         .fill _PAGE_SIZE,1,0
-
-.data
-.p2align PAGE_SHIFT
-ENTRY(empty_zero_page)
-        .fill _PAGE_SIZE,1,0

diff --git a/arch/hexagon/kernel/hexagon_ksyms.c b/arch/hexagon/kernel/hexagon_ksyms.c
index 36a80e31d187..81bc6f81e200 100644
--- a/arch/hexagon/kernel/hexagon_ksyms.c
+++ b/arch/hexagon/kernel/hexagon_ksyms.c

@@ -17,7 +17,6 @@ EXPORT_SYMBOL(raw_copy_to_user);
 EXPORT_SYMBOL(__vmgetie);
 EXPORT_SYMBOL(__vmsetie);
 EXPORT_SYMBOL(__vmyield);
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memset);

diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index c33b3bcb733e..a244de27a03e 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h

@@ -74,15 +74,6 @@
 struct mm_struct;
 struct vm_area_struct;
 
-/*
- * ZERO_PAGE is a global shared page that is always zero; used
- * for zero-mapped memory areas etc..
- */
-
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
-#define ZERO_PAGE(vaddr)	virt_to_page(empty_zero_page)
-
 #ifdef CONFIG_32BIT
 
 #define VMALLOC_START	(vm_map_base + PCI_IOSIZE + (2 * PAGE_SIZE))

diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index c331bf69d2ec..00f3822b6e47 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c

@@ -36,9 +36,6 @@
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 void copy_user_highpage(struct page *to, struct page *from,
 	unsigned long vaddr, struct vm_area_struct *vma)
 {

diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index bba64a9c49ac..7501ff030c63 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h

@@ -110,15 +110,6 @@ extern unsigned long m68k_vmalloc_end;
 #define VMALLOC_END KMAP_START
 #endif
 
-/* zero page used for uninitialized stuff */
-extern void *empty_zero_page;
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern void kernel_set_cachemode(void *addr, unsigned long size, int cmode);
 
 /*

diff --git a/arch/m68k/include/asm/pgtable_no.h b/arch/m68k/include/asm/pgtable_no.h
index 1a86c15b9008..11751807a3f3 100644
--- a/arch/m68k/include/asm/pgtable_no.h
+++ b/arch/m68k/include/asm/pgtable_no.h

@@ -30,13 +30,6 @@
 
 #define swapper_pg_dir ((pgd_t *) 0)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern void *empty_zero_page;
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 /*
  * All 32bit addresses are effectively valid for vmalloc...
  * Sort of meaningless for non-VM targets.

diff --git a/arch/m68k/mm/init.c b/arch/m68k/mm/init.c
index 53b71f786c27..3b88c0dd1616 100644
--- a/arch/m68k/mm/init.c
+++ b/arch/m68k/mm/init.c

@@ -33,13 +33,6 @@
 #include <asm/sections.h>
 #include <asm/tlb.h>
 
-/*
- * ZERO_PAGE is a special page that is used for zero-initialized
- * data and COW.
- */
-void *empty_zero_page;
-EXPORT_SYMBOL(empty_zero_page);
-
 void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
 {
 	max_zone_pfns[ZONE_DMA] = PFN_DOWN(memblock_end_of_DRAM());

@@ -71,8 +64,6 @@ void __init paging_init(void)
 	unsigned long end_mem = memory_end & PAGE_MASK;
 
 	high_memory = (void *) end_mem;
-
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
 }
 
 #endif /* CONFIG_MMU */

diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 3418fd864237..4924f2ff8ef8 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c

@@ -41,8 +41,6 @@ void __init paging_init(void)
 	unsigned long next_pgtable;
 	int i;
 
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	pg_dir = swapper_pg_dir;
 	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 127a3fa69f4c..b30aa69a73a6 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c

@@ -498,12 +498,6 @@ void __init paging_init(void)
 
 	early_memtest(min_addr, max_addr);
 
-	/*
-	 * initialize the bad page table and bad page to point
-	 * to a couple of allocated pages
-	 */
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	/*
 	 * Set up SFC/DFC registers
 	 */

diff --git a/arch/m68k/mm/sun3mmu.c b/arch/m68k/mm/sun3mmu.c
index c801677f7df8..f139cc15753a 100644
--- a/arch/m68k/mm/sun3mmu.c
+++ b/arch/m68k/mm/sun3mmu.c

@@ -43,8 +43,6 @@ void __init paging_init(void)
 	unsigned long bootmem_end;
 	unsigned long size;
 
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	address = PAGE_OFFSET;
 	pg_dir = swapper_pg_dir;
 	memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));

diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 4eb76de6be4a..ea72291de553 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h

@@ -207,16 +207,6 @@ extern pte_t *va_to_pte(unsigned long address);
  * Also, write permissions imply read permissions.
  */
 
-#ifndef __ASSEMBLER__
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[1024];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
-#endif /* __ASSEMBLER__ */
-
 #define pte_none(pte)		((pte_val(pte) & ~_PTE_NONE_MASK) == 0)
 #define pte_present(pte)	(pte_val(pte) & _PAGE_PRESENT)
 #define pte_clear(mm, addr, ptep) \

diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S
index ec2fcb545e64..808019c3b7ac 100644
--- a/arch/microblaze/kernel/head.S
+++ b/arch/microblaze/kernel/head.S

@@ -39,10 +39,6 @@
 #include <asm/processor.h>
 
 .section .data
-.global empty_zero_page
-.align 12
-empty_zero_page:
-	.space	PAGE_SIZE
 .global swapper_pg_dir
 swapper_pg_dir:
 	.space	PAGE_SIZE

diff --git a/arch/microblaze/kernel/microblaze_ksyms.c b/arch/microblaze/kernel/microblaze_ksyms.c
index a8553f54152b..ad7596d7ba07 100644
--- a/arch/microblaze/kernel/microblaze_ksyms.c
+++ b/arch/microblaze/kernel/microblaze_ksyms.c

@@ -33,8 +33,6 @@ EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
 #endif
 
-EXPORT_SYMBOL(empty_zero_page);
-
 EXPORT_SYMBOL(mbc);
 
 extern void __divsi3(void);

diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 844dce55569f..d389aa9ca57c 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h

@@ -65,13 +65,6 @@ struct mm_struct;
 #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];

diff --git a/arch/nios2/kernel/head.S b/arch/nios2/kernel/head.S
index 372ce4a33018..613212e1a63a 100644
--- a/arch/nios2/kernel/head.S
+++ b/arch/nios2/kernel/head.S

@@ -23,16 +23,6 @@
 #include <asm/asm-offsets.h>
 #include <asm/asm-macros.h>
 
-/*
- * ZERO_PAGE is a special page that is used for zero-initialized
- * data and COW.
- */
-.data
-.global empty_zero_page
-.align 12
-empty_zero_page:
-	.space	PAGE_SIZE
-
 /*
  * This global variable is used as an extension to the nios'
  * STATUS register to emulate a user/supervisor mode.

diff --git a/arch/nios2/kernel/nios2_ksyms.c b/arch/nios2/kernel/nios2_ksyms.c
index 54f7b23df1bf..c40aa39e8658 100644
--- a/arch/nios2/kernel/nios2_ksyms.c
+++ b/arch/nios2/kernel/nios2_ksyms.c

@@ -20,7 +20,6 @@ EXPORT_SYMBOL(memmove);
 
 /* memory management */
 
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(flush_icache_range);
 
 /*

diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index b218050e2f6d..6b89996d0b62 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h

@@ -179,10 +179,6 @@ extern void paging_init(void);
 	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
 		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
 
-/* zero page used for uninitialized stuff */
-extern unsigned long empty_zero_page[2048];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #define pte_none(x)	(!pte_val(x))
 #define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
 #define pte_clear(mm, addr, xp)	do { pte_val(*(xp)) = 0; } while (0)

diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S
index bd760066f1cd..45890393947d 100644
--- a/arch/openrisc/kernel/head.S
+++ b/arch/openrisc/kernel/head.S

@@ -1563,9 +1563,6 @@ _string_nl:
  */
 	.section .data,"aw"
 	.align	8192
-	.global  empty_zero_page
-empty_zero_page:
-	.space  8192
 
 	.global  swapper_pg_dir
 swapper_pg_dir:

diff --git a/arch/openrisc/kernel/or32_ksyms.c b/arch/openrisc/kernel/or32_ksyms.c
index 212e5f85004c..84a937a64e2a 100644
--- a/arch/openrisc/kernel/or32_ksyms.c
+++ b/arch/openrisc/kernel/or32_ksyms.c

@@ -40,7 +40,6 @@ DECLARE_EXPORT(__ashldi3);
 DECLARE_EXPORT(__lshrdi3);
 DECLARE_EXPORT(__ucmpdi2);
 
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(__copy_tofrom_user);
 EXPORT_SYMBOL(__clear_user);
 EXPORT_SYMBOL(memset);

diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index 78fb0734cdbc..89d8c6df8855 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c

@@ -188,9 +188,6 @@ void __init mem_init(void)
 {
 	BUG_ON(!mem_map);
 
-	/* clear the zero-page */
-	memset((void *)empty_zero_page, 0, PAGE_SIZE);
-
 	printk("mem_init_done ...........................................\n");
 	mem_init_done = 1;
 	return;

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 2c139a4dbf4b..cbdc01a26ea0 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h

@@ -262,17 +262,6 @@ extern pgd_t swapper_pg_dir[]; /* declared in init_task.c */
 
 extern pte_t pg0[];
 
-/* zero page used for uninitialized stuff */
-
-extern unsigned long *empty_zero_page;
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #define pte_none(x)     (pte_val(x) == 0)
 #define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
 #define pte_user(x)	(pte_val(x) & _PAGE_USER)

diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 6a39e031e5ff..be3380c9bcda 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c

@@ -604,9 +604,6 @@ void __init mem_init(void)
 #endif
 }
 
-unsigned long *empty_zero_page __ro_after_init;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * pagetable_init() sets up the page tables
  *

@@ -639,9 +636,6 @@ static void __init pagetable_init(void)
 			  initrd_end - initrd_start, PAGE_KERNEL, 0);
 	}
 #endif
-
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 }
 
 static void __init gateway_init(void)

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index dcd3a88caaf6..b27d94c06d0e 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h

@@ -76,12 +76,6 @@ static inline const void *pmd_page_vaddr(pmd_t pmd)
 }
 #define pmd_page_vaddr pmd_page_vaddr
 #endif
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 
 extern pgd_t swapper_pg_dir[];

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 3789a51bdaae..85508392a6b6 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -34,9 +34,6 @@
 
 unsigned long long memory_limit __initdata;
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 pgprot_t __phys_mem_access_prot(unsigned long pfn, unsigned long size,
 				pgprot_t vma_prot)
 {

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9ecbf0366719..a6b496f4944f 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h

@@ -1258,13 +1258,6 @@ extern u64 satp_mode;
 void paging_init(void);
 void misc_mem_init(void);
 
-/*
- * ZERO_PAGE is a global shared page that is always zero,
- * used for zero-mapped memory areas, etc.
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 /*
  * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
  * TLB flush will be required as a result of the "set". For example, use

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 848efeb9e163..95ac79c62067 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c

@@ -69,10 +69,6 @@ unsigned long vmemmap_start_pfn __ro_after_init;
 EXPORT_SYMBOL(vmemmap_start_pfn);
 #endif
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-							__page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 extern char _start[];
 void *_dtb_early_va __initdata;
 uintptr_t _dtb_early_pa __initdata;

diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 10fa8f2bb8d1..d5ce0950a323 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h

@@ -20,14 +20,6 @@
 #ifndef __ASSEMBLER__
 #include <asm/addrspace.h>
 #include <asm/fixmap.h>
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #endif /* !__ASSEMBLER__ */
 
 /*

diff --git a/arch/sh/include/asm/setup.h b/arch/sh/include/asm/setup.h
index 84bb23a771f3..63c9efc06348 100644
--- a/arch/sh/include/asm/setup.h
+++ b/arch/sh/include/asm/setup.h

@@ -7,7 +7,8 @@
 /*
  * This is set up by the setup-routine at boot-time
  */
-#define PARAM	((unsigned char *)empty_zero_page)
+extern unsigned char *boot_params_page;
+#define PARAM boot_params_page
 
 #define MOUNT_ROOT_RDONLY (*(unsigned long *) (PARAM+0x000))
 #define RAMDISK_FLAGS (*(unsigned long *) (PARAM+0x004))

diff --git a/arch/sh/kernel/head_32.S b/arch/sh/kernel/head_32.S
index b603b7968b38..0b91bb85d40a 100644
--- a/arch/sh/kernel/head_32.S
+++ b/arch/sh/kernel/head_32.S

@@ -26,7 +26,7 @@
 #endif
 
 	.section	.empty_zero_page, "aw"
-ENTRY(empty_zero_page)
+ENTRY(boot_params_page)
 	.long	1		/* MOUNT_ROOT_RDONLY */
 	.long	0		/* RAMDISK_FLAGS */
 	.long	0x0200		/* ORIG_ROOT_DEV */

@@ -39,7 +39,7 @@ ENTRY(empty_zero_page)
 	.long	0x53453f00 + 29	/* "SE?" = 29 bit */
 #endif
 1:
-	.skip	PAGE_SIZE - empty_zero_page - 1b
+	.skip	PAGE_SIZE - boot_params_page - 1b
 
 	__HEAD

diff --git a/arch/sh/kernel/sh_ksyms_32.c b/arch/sh/kernel/sh_ksyms_32.c
index 5858936cb431..041191002e2e 100644
--- a/arch/sh/kernel/sh_ksyms_32.c
+++ b/arch/sh/kernel/sh_ksyms_32.c

@@ -20,7 +20,6 @@ EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy_generic);
 EXPORT_SYMBOL(copy_page);
 EXPORT_SYMBOL(__clear_user);
-EXPORT_SYMBOL(empty_zero_page);
 #ifdef CONFIG_FLATMEM
 /* need in pfn_valid macro */
 EXPORT_SYMBOL(min_low_pfn);

diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 464a3a63e2fa..4e40d5e96be9 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c

@@ -332,7 +332,6 @@ void __init mem_init(void)
 	cpu_cache_init();
 
 	/* clear the zero-page */
-	memset(empty_zero_page, 0, PAGE_SIZE);
 	__flush_wback_region(empty_zero_page, PAGE_SIZE);
 
 	vsyscall_init();

diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index a9f802d1dd64..f89b1250661d 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h

@@ -71,14 +71,6 @@ extern unsigned long ptr_in_current_pgd;
 extern unsigned long phys_base;
 extern unsigned long pfn_base;
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 /*
  * In general all page table modifications should use the V8 atomic
  * swap instruction.  This insures the mmu and the cpu are in sync

diff --git a/arch/sparc/include/asm/setup.h b/arch/sparc/include/asm/setup.h
index 72205684e51e..21bed5514028 100644
--- a/arch/sparc/include/asm/setup.h
+++ b/arch/sparc/include/asm/setup.h

@@ -17,8 +17,6 @@ extern char reboot_command[];
  */
 extern unsigned char boot_cpu_id;
 
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
 extern int serial_console;
 static inline int con_is_present(void)
 {

diff --git a/arch/sparc/kernel/head_32.S b/arch/sparc/kernel/head_32.S
index 38345460d542..8c320fa25a67 100644
--- a/arch/sparc/kernel/head_32.S
+++ b/arch/sparc/kernel/head_32.S

@@ -57,13 +57,6 @@ sun4e_notsup:
 
 	.align PAGE_SIZE
 
-/* This was the only reasonable way I could think of to properly align
- * these page-table data structures.
- */
-	.globl empty_zero_page
-empty_zero_page:	.skip PAGE_SIZE
-EXPORT_SYMBOL(empty_zero_page)
-
 	.global root_flags
 	.global ram_flags
 	.global root_dev

diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index fdc93dd12c3e..e0e66f91ceeb 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c

@@ -246,10 +246,6 @@ void __init arch_mm_preinit(void)
 		prom_halt();
 	}
 
-
-	/* Saves us work later. */
-	memset((void *)empty_zero_page, 0, PAGE_SIZE);
-
 	i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
 	i += 1;
 	sparc_valid_addr_bitmap = (unsigned long *)

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 4f7bdb18774b..0cc8de2fea90 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c

@@ -2498,6 +2498,9 @@ static void __init register_page_bootmem_info(void)
 }
 void __init mem_init(void)
 {
+	phys_addr_t zero_page_pa = kern_base +
+		((unsigned long)&empty_zero_page[0] - KERNBASE);
+
 	/*
 	 * Must be done after boot memory is put on freelist, because here we
 	 * might set fields in deferred struct pages that have not yet been

@@ -2510,13 +2513,7 @@ void __init mem_init(void)
 	 * Set up the zero page, mark it reserved, so that page count
 	 * is not manipulated when freeing the page from user ptes.
 	 */
-	mem_map_zero = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
-	if (mem_map_zero == NULL) {
-		prom_printf("paging_init: Cannot alloc zero page.\n");
-		prom_halt();
-	}
-	mark_page_reserved(mem_map_zero);
-
+	mem_map_zero = pfn_to_page(PHYS_PFN(zero_page_pa));
 
 	if (tlb_type == cheetah || tlb_type == cheetah_plus)
 		cheetah_ecache_flush_init();

diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 3b42b0f45bf6..19e0608fb649 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h

@@ -34,9 +34,6 @@
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 
-/* zero page used for uninitialized stuff */
-extern unsigned long *empty_zero_page;
-
 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  * current 8MB value just means that there will be a 8MB "hole" after the
  * physical memory until the kernel virtual memory starts.  That means that

@@ -74,12 +71,6 @@ extern unsigned long *empty_zero_page;
  * get..
  */
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr) virt_to_page(empty_zero_page)
-
 #define pte_clear(mm, addr, xp) pte_set_val(*(xp), (phys_t) 0, __pgprot(_PAGE_NEEDSYNC))
 
 #define pmd_none(x)	(!((unsigned long)pmd_val(x) & ~_PAGE_NEEDSYNC))

diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index 38321188c04c..9812efd14ec0 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h

@@ -38,7 +38,6 @@ extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs
 extern void uml_pm_wake(void);
 
 extern int start_uml(void);
-extern void paging_init(void);
 
 extern void uml_cleanup(void);
 extern void do_uml_exitcalls(void);

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 89c8c8b94a79..1eef0e42ef5d 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c

@@ -44,10 +44,6 @@ __section(".kasan_init") __used
 = kasan_init;
 #endif
 
-/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
-unsigned long *empty_zero_page = NULL;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * Initialized during boot, and readonly for initializing page tables
  * afterwards

@@ -65,9 +61,6 @@ void __init arch_mm_preinit(void)
 	/* Safe to call after jump_label_init(). Enables KASAN. */
 	kasan_init_generic();
 
-	/* clear the zero-page */
-	memset(empty_zero_page, 0, PAGE_SIZE);
-
 	/* Map in the area just after the brk now that kmalloc is about
 	 * to be turned on.
 	 */

@@ -89,15 +82,6 @@ void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
 	max_zone_pfns[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT;
 }
 
-void __init paging_init(void)
-{
-	empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
-							       PAGE_SIZE);
-	if (!empty_zero_page)
-		panic("%s: Failed to allocate %lu bytes align=%lx\n",
-		      __func__, PAGE_SIZE, PAGE_SIZE);
-}
-
 /*
  * This can't do anything because nothing in the kernel image can be freed
  * since it's not in kernel physical memory.

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index e2b24e1ecfa6..2141f5f1f5a2 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c

@@ -413,7 +413,6 @@ void __init setup_arch(char **cmdline_p)
 	uml_dtb_init();
 	read_initrd();
 
-	paging_init();
 	strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 	*cmdline_p = command_line;
 	setup_hostinfo(host_info, sizeof host_info);

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1662c5a8f445..54289f4587a4 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h

@@ -47,14 +47,6 @@ void ptdump_walk_user_pgd_level_checkwx(void);
 #define debug_checkwx_user()	do { } while (0)
 #endif
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-	__visible;
-#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
-
 extern spinlock_t pgd_lock;
 extern struct list_head pgd_list;

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 80ef5d386b03..5171cb746444 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S

@@ -441,10 +441,6 @@ initial_pg_fixmap:
 swapper_pg_dir:
 	.fill 1024,4,0
 	.fill PTI_USER_PGD_FILL,4,0
-.globl empty_zero_page
-empty_zero_page:
-	.fill 4096,1,0
-EXPORT_SYMBOL(empty_zero_page)
 
 /*
  * This starts the data section.

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 21816b48537c..cbf7647a25d8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S

@@ -712,10 +712,3 @@ SYM_PIC_ALIAS(phys_base);
 EXPORT_SYMBOL(phys_base)
 
 #include "../xen/xen-head.S"
-
-	__PAGE_ALIGNED_BSS
-SYM_DATA_START_PAGE_ALIGNED(empty_zero_page)
-	.skip PAGE_SIZE
-SYM_DATA_END(empty_zero_page)
-EXPORT_SYMBOL(empty_zero_page)
-

diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 50a136213b2b..61f07d981a94 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h

@@ -209,10 +209,6 @@
 #define pgd_ERROR(e) \
 	printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 
-extern unsigned long empty_zero_page[1024];
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #ifdef CONFIG_MMU
 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
 extern void paging_init(void);

diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 8484294bc623..4b0c5c5e685a 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S

@@ -381,6 +381,3 @@ ENTRY(swapper_pg_dir)
 	.fill	PAGE_SIZE, 1, 0
 END(swapper_pg_dir)
 #endif
-ENTRY(empty_zero_page)
-	.fill	PAGE_SIZE, 1, 0
-END(empty_zero_page)

diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c
index 62d81e76e18e..ced335b4df5f 100644
--- a/arch/xtensa/kernel/xtensa_ksyms.c
+++ b/arch/xtensa/kernel/xtensa_ksyms.c

@@ -15,8 +15,6 @@
 #include <linux/module.h>
 #include <asm/pgtable.h>
 
-EXPORT_SYMBOL(empty_zero_page);
-
 unsigned int __sync_fetch_and_and_4(volatile void *p, unsigned int v)
 {
 	BUG();

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 9bacf4df9769..3d48eea57cd2 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1890,6 +1890,9 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
  * for different ranges in the virtual address space.
  *
  * zero_page_pfn identifies the first (or the only) pfn for these pages.
+ *
+ * For architectures that don't __HAVE_COLOR_ZERO_PAGE the zero page lives in
+ * empty_zero_page in BSS.
  */
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)

@@ -1916,6 +1919,13 @@ static inline unsigned long zero_pfn(unsigned long addr)
 
 	return zero_page_pfn;
 }
+
+extern uint8_t empty_zero_page[PAGE_SIZE];
+
+#ifndef ZERO_PAGE
+#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
+#endif
+
 #endif /* __HAVE_COLOR_ZERO_PAGE */
 
 #ifdef CONFIG_MMU

diff --git a/mm/mm_init.c b/mm/mm_init.c
index a0ca236eb4f5..1eac634ece1a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -56,6 +56,11 @@ EXPORT_SYMBOL(high_memory);
 unsigned long zero_page_pfn __ro_after_init;
 EXPORT_SYMBOL(zero_page_pfn);
 
+#ifndef __HAVE_COLOR_ZERO_PAGE
+uint8_t empty_zero_page[PAGE_SIZE] __page_aligned_bss;
+EXPORT_SYMBOL(empty_zero_page);
+#endif
+
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

-- 
2.51.0

[PATCH v3 4/4] mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()

From: Mike Rapoport <rppt@kernel.org>
Date: 2026-02-11 10:32:50

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

For most architectures every invocation of ZERO_PAGE() does
virt_to_page(empty_zero_page). But empty_zero_page is in BSS and it is
enough to get its struct page once at initialization time and then use
it whenever a zero page should be accessed.

Add yet another __zero_page variable that will be initialized as
virt_to_page(empty_zero_page) for most architectures in a weak
arch_setup_zero_pages() function.

For architectures that use colored zero pages (MIPS and s390) rename their
setup_zero_pages() to arch_setup_zero_pages() and make it global rather
than static.

For architectures that cannot use virt_to_page() for BSS (arm64 and
sparc64) add override of arch_setup_zero_pages().

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/arm64/include/asm/pgtable.h    |  6 ------
 arch/arm64/mm/init.c                |  5 +++++
 arch/mips/mm/init.c                 | 11 +----------
 arch/s390/mm/init.c                 |  4 +---
 arch/sparc/include/asm/pgtable_64.h |  3 ---
 arch/sparc/mm/init_64.c             | 17 +++++++----------
 include/linux/pgtable.h             | 11 ++++++++---
 mm/mm_init.c                        | 21 +++++++++++++++++----
 8 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 63da07398a30..2c1ec7cc8612 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -106,12 +106,6 @@ static inline void arch_leave_lazy_mmu_mode(void)
 #define flush_tlb_fix_spurious_fault_pmd(vma, address, pmdp)	\
 	local_flush_tlb_page_nonotify(vma, address)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	phys_to_page(__pa_symbol(empty_zero_page))
-
 #define pte_ERROR(e)	\
 	pr_err("%s:%d: bad pte %016llx.\n", __FILE__, __LINE__, pte_val(e))

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 96711b8578fd..417ec7efe569 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c

@@ -328,6 +328,11 @@ void __init bootmem_init(void)
 	memblock_dump_all();
 }
 
+void __init arch_setup_zero_pages(void)
+{
+	__zero_page = phys_to_page(__pa_symbol(empty_zero_page));
+}
+
 void __init arch_mm_preinit(void)
 {
 	unsigned int flags = SWIOTLB_VERBOSE;

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 4f6449ad02ca..55b25e85122a 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c

@@ -56,10 +56,7 @@ unsigned long empty_zero_page, zero_page_mask;
 EXPORT_SYMBOL_GPL(empty_zero_page);
 EXPORT_SYMBOL(zero_page_mask);
 
-/*
- * Not static inline because used by IP27 special magic initialization code
- */
-static void __init setup_zero_pages(void)
+void __init arch_setup_zero_pages(void)
 {
 	unsigned int order;

@@ -450,7 +447,6 @@ void __init arch_mm_preinit(void)
 	BUILD_BUG_ON(IS_ENABLED(CONFIG_32BIT) && (PFN_PTE_SHIFT > PAGE_SHIFT));
 
 	maar_init();
-	setup_zero_pages();	/* Setup zeroed pages.  */
 	highmem_init();
 
 #ifdef CONFIG_64BIT

@@ -461,11 +457,6 @@ void __init arch_mm_preinit(void)
 				0x80000000 - 4, KCORE_TEXT);
 #endif
 }
-#else  /* CONFIG_NUMA */
-void __init arch_mm_preinit(void)
-{
-	setup_zero_pages();	/* This comes from node 0 */
-}
 #endif /* !CONFIG_NUMA */
 
 void free_init_pages(const char *what, unsigned long begin, unsigned long end)

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 3c20475cbee2..1f72efc2a579 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c

@@ -69,7 +69,7 @@ unsigned long empty_zero_page, zero_page_mask;
 EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(zero_page_mask);
 
-static void __init setup_zero_pages(void)
+void __init arch_setup_zero_pages(void)
 {
 	unsigned long total_pages = memblock_estimated_nr_free_pages();
 	unsigned int order;

@@ -159,8 +159,6 @@ void __init arch_mm_preinit(void)
 	cpumask_set_cpu(0, mm_cpumask(&init_mm));
 
 	pv_init();
-
-	setup_zero_pages();	/* Setup zeroed pages. */
 }
 
 unsigned long memory_block_size_bytes(void)

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 615f460c50af..74ede706fb32 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h

@@ -210,9 +210,6 @@ extern unsigned long _PAGE_CACHE;
 extern unsigned long pg_iobits;
 extern unsigned long _PAGE_ALL_SZ_BITS;
 
-extern struct page *mem_map_zero;
-#define ZERO_PAGE(vaddr)	(mem_map_zero)
-
 /* PFNs are real physical page numbers.  However, mem_map only begins to record
  * per-page information starting at pfn_base.  This is to handle systems where
  * the first physical page in the machine is at some huge physical address,

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 0cc8de2fea90..707c1df67d79 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c

@@ -177,9 +177,6 @@ extern unsigned long sparc_ramdisk_image64;
 extern unsigned int sparc_ramdisk_image;
 extern unsigned int sparc_ramdisk_size;
 
-struct page *mem_map_zero __read_mostly;
-EXPORT_SYMBOL(mem_map_zero);
-
 unsigned int sparc64_highest_unlocked_tlb_ent __read_mostly;
 
 unsigned long sparc64_kern_pri_context __read_mostly;

@@ -2496,11 +2493,17 @@ static void __init register_page_bootmem_info(void)
 			register_page_bootmem_info_node(NODE_DATA(i));
 #endif
 }
-void __init mem_init(void)
+
+void __init arch_setup_zero_pages(void)
 {
 	phys_addr_t zero_page_pa = kern_base +
 		((unsigned long)&empty_zero_page[0] - KERNBASE);
 
+	__zero_page = phys_to_page(zero_page_pa);
+}
+
+void __init mem_init(void)
+{
 	/*
 	 * Must be done after boot memory is put on freelist, because here we
 	 * might set fields in deferred struct pages that have not yet been

@@ -2509,12 +2512,6 @@ void __init mem_init(void)
 	 */
 	register_page_bootmem_info();
 
-	/*
-	 * Set up the zero page, mark it reserved, so that page count
-	 * is not manipulated when freeing the page from user ptes.
-	 */
-	mem_map_zero = pfn_to_page(PHYS_PFN(zero_page_pa));
-
 	if (tlb_type == cheetah || tlb_type == cheetah_plus)
 		cheetah_ecache_flush_init();
 }

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 3d48eea57cd2..1da21ec62836 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1894,6 +1894,8 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
  * For architectures that don't __HAVE_COLOR_ZERO_PAGE the zero page lives in
  * empty_zero_page in BSS.
  */
+void arch_setup_zero_pages(void);
+
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)
 {

@@ -1921,10 +1923,13 @@ static inline unsigned long zero_pfn(unsigned long addr)
 }
 
 extern uint8_t empty_zero_page[PAGE_SIZE];
+extern struct page *__zero_page;
 
-#ifndef ZERO_PAGE
-#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
-#endif
+static inline struct page *_zero_page(unsigned long addr)
+{
+	return __zero_page;
+}
+#define ZERO_PAGE(vaddr) _zero_page(vaddr)
 
 #endif /* __HAVE_COLOR_ZERO_PAGE */

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 1eac634ece1a..b08608c1b71d 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -59,7 +59,10 @@ EXPORT_SYMBOL(zero_page_pfn);
 #ifndef __HAVE_COLOR_ZERO_PAGE
 uint8_t empty_zero_page[PAGE_SIZE] __page_aligned_bss;
 EXPORT_SYMBOL(empty_zero_page);
-#endif
+
+struct page *__zero_page __ro_after_init;
+EXPORT_SYMBOL(__zero_page);
+#endif /* __HAVE_COLOR_ZERO_PAGE */
 
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

@@ -2675,12 +2678,21 @@ static void __init mem_init_print_info(void)
 		);
 }
 
-static int __init init_zero_page_pfn(void)
+#ifndef __HAVE_COLOR_ZERO_PAGE
+/*
+ * architectures that __HAVE_COLOR_ZERO_PAGE must define this function
+ */
+void __init __weak arch_setup_zero_pages(void)
+{
+	__zero_page = virt_to_page(empty_zero_page);
+}
+#endif
+
+static void __init init_zero_page_pfn(void)
 {
+	arch_setup_zero_pages();
 	zero_page_pfn = page_to_pfn(ZERO_PAGE(0));
-	return 0;
 }
-early_initcall(init_zero_page_pfn);
 
 void __init __weak arch_mm_preinit(void)
 {

@@ -2704,6 +2716,7 @@ void __init mm_core_init_early(void)
 void __init mm_core_init(void)
 {
 	arch_mm_preinit();
+	init_zero_page_pfn();
 
 	/* Initializations relying on SMP setup */
 	BUILD_BUG_ON(MAX_ZONELISTS > 2);

-- 
2.51.0

Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: Magnus Lindholm <linmag7@gmail.com>
Date: 2026-02-11 20:14:33

On Wed, Feb 11, 2026 at 11:32 AM Mike Rapoport [off-list ref] wrote:

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/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 :)

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>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/alpha/include/asm/pgtable.h          |  6 ------

quoted hunk

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 90e7a9539102..12a3c5f8ece8 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h

@@ -125,12 +125,6 @@ struct vm_area_struct;
  */
 #define pgprot_noncached(prot) (prot)

-/*
- * ZERO_PAGE is a global shared page that is always zero:  used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)       (virt_to_page(ZERO_PGE))
-
 /*
  * On certain platforms whose physical address space can overlap KSEG,
  * namely EV6 and above, we must re-twiddle the physaddr to restore the

This looks good from an Alpha perspective

Acked-by: Magnus Lindholm <linmag7@gmail.com>

Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: Dinh Nguyen <dinguyen@kernel.org>
Date: 2026-02-12 05:33:14


On 2/11/26 04:31, Mike Rapoport wrote:

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/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 :)

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>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---

  arch/nios2/include/asm/pgtable.h          |  7 -------
  arch/nios2/kernel/head.S                  | 10 ----------
  arch/nios2/kernel/nios2_ksyms.c           |  1 -

For nios2,

Acked-by: Dinh Nguyen <dinguyen@kernel.org>

Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: Andreas Larsson <andreas@gaisler.com>
Date: 2026-02-12 08:39:33

On 2026-02-11 11:31, Mike Rapoport wrote:

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/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 :)

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>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---

 arch/sparc/include/asm/pgtable_32.h       |  8 --------
 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                   | 11 ++++-------

Acked-by: Andreas Larsson <andreas@gaisler.com> #sparc

Cheers,
Andreas

Re: [PATCH v3 1/4] mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()

From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-02-12 08:58:43

On 2/11/26 11:31, Mike Rapoport wrote:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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) <rppt@kernel.org>
---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v3 2/4] mm: rename my_zero_pfn() to zero_pfn()

From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-02-12 09:01:47

On 2/11/26 11:31, Mike Rapoport wrote:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

my_zero_pfn() is a silly name.

Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to
zero_pfn().

While on it, move extern declarations of zero_page_pfn outside the
functions that use it and add a comment about what ZERO_PAGE is.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-02-12 09:04:22

On 2/11/26 11:31, Mike Rapoport wrote:

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/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 :)

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>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v3 4/4] mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()

From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-02-12 09:09:07

On 2/11/26 11:31, Mike Rapoport wrote:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

For most architectures every invocation of ZERO_PAGE() does
virt_to_page(empty_zero_page). But empty_zero_page is in BSS and it is
enough to get its struct page once at initialization time and then use
it whenever a zero page should be accessed.

Add yet another __zero_page variable that will be initialized as
virt_to_page(empty_zero_page) for most architectures in a weak
arch_setup_zero_pages() function.

For architectures that use colored zero pages (MIPS and s390) rename their
setup_zero_pages() to arch_setup_zero_pages() and make it global rather
than static.

For architectures that cannot use virt_to_page() for BSS (arm64 and
sparc64) add override of arch_setup_zero_pages().

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH v3 2/4] mm: rename my_zero_pfn() to zero_pfn()

From: Vlastimil Babka <hidden>
Date: 2026-02-12 15:28:25

On 2/11/26 11:31, Mike Rapoport wrote:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

my_zero_pfn() is a silly name.

Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to
zero_pfn().

While on it, move extern declarations of zero_page_pfn outside the
functions that use it and add a comment about what ZERO_PAGE is.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Acked-by: Vlastimil Babka <redacted>

Re: [PATCH v3 1/4] mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()

From: Liam R. Howlett <hidden>
Date: 2026-02-12 18:31:53

* Mike Rapoport [off-list ref] [260211 05:32]:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

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) <rppt@kernel.org>

Acked-by: Liam R. Howlett <redacted>

quoted hunk

---
 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

Re: [PATCH v3 2/4] mm: rename my_zero_pfn() to zero_pfn()

From: Liam R. Howlett <hidden>
Date: 2026-02-12 18:34:45

* Mike Rapoport [off-list ref] [260211 05:32]:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

my_zero_pfn() is a silly name.

Rename zero_pfn variable to zero_page_pfn and my_zero_pfn() function to
zero_pfn().

While on it, move extern declarations of zero_page_pfn outside the
functions that use it and add a comment about what ZERO_PAGE is.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Reviewed-by: Liam R. Howlett <redacted>

quoted hunk

---
 arch/x86/kvm/mmu/spte.h |  2 +-
 fs/dax.c                |  2 +-
 fs/proc/vmcore.c        |  2 +-
 include/linux/pgtable.h | 28 ++++++++++++++++++++--------
 mm/huge_memory.c        |  2 +-
 mm/memory.c             |  2 +-
 mm/migrate.c            |  2 +-
 mm/mm_init.c            | 10 +++++-----
 mm/userfaultfd.c        |  4 ++--
 9 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 91ce29fd6f1b..8c0ffa2cded6 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h

@@ -248,7 +248,7 @@ extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
 
 static inline hpa_t kvm_mmu_get_dummy_root(void)
 {
-	return my_zero_pfn(0) << PAGE_SHIFT;
+	return zero_pfn(0) << PAGE_SHIFT;
 }
 
 static inline bool kvm_mmu_is_dummy_root(hpa_t shadow_page)

diff --git a/fs/dax.c b/fs/dax.c
index 289e6254aa30..b78cff9c91b3 100644
--- a/fs/dax.c
+++ b/fs/dax.c

@@ -1360,7 +1360,7 @@ static vm_fault_t dax_load_hole(struct xa_state *xas, struct vm_fault *vmf,
 {
 	struct inode *inode = iter->inode;
 	unsigned long vaddr = vmf->address;
-	unsigned long pfn = my_zero_pfn(vaddr);
+	unsigned long pfn = zero_pfn(vaddr);
 	vm_fault_t ret;
 
 	*entry = dax_insert_entry(xas, vmf, iter, *entry, pfn, DAX_ZERO_PAGE);

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index f188bd900eb2..44d15436439f 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c

@@ -525,7 +525,7 @@ static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
 {
 	unsigned long map_size;
 	unsigned long pos_start, pos_end, pos;
-	unsigned long zeropage_pfn = my_zero_pfn(0);
+	unsigned long zeropage_pfn = zero_pfn(0);
 	size_t len = 0;
 
 	pos_start = pfn;

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 08a88b0d56e5..9bacf4df9769 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1882,27 +1882,39 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
 	pfnmap_setup_cachemode(pfn, PAGE_SIZE, prot);
 }
 
+/*
+ * ZERO_PAGE() is global shared page(s) that is always zero. It is used for
+ * zero-mapped memory areas, CoW etc.
+ *
+ * On architectures that __HAVE_COLOR_ZERO_PAGE there are several such pages
+ * for different ranges in the virtual address space.
+ *
+ * zero_page_pfn identifies the first (or the only) pfn for these pages.
+ */
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)
 {
-	extern unsigned long zero_pfn;
-	unsigned long offset_from_zero_pfn = pfn - zero_pfn;
+	extern unsigned long zero_page_pfn;
+	unsigned long offset_from_zero_pfn = pfn - zero_page_pfn;
+
 	return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT);
 }
 
-#define my_zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))
+#define zero_pfn(addr)	page_to_pfn(ZERO_PAGE(addr))
 
 #else
 static inline int is_zero_pfn(unsigned long pfn)
 {
-	extern unsigned long zero_pfn;
-	return pfn == zero_pfn;
+	extern unsigned long zero_page_pfn;
+
+	return pfn == zero_page_pfn;
 }
 
-static inline unsigned long my_zero_pfn(unsigned long addr)
+static inline unsigned long zero_pfn(unsigned long addr)
 {
-	extern unsigned long zero_pfn;
-	return zero_pfn;
+	extern unsigned long zero_page_pfn;
+
+	return zero_page_pfn;
 }
 #endif /* __HAVE_COLOR_ZERO_PAGE */

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 44ff8a648afd..bc15fd152526 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c

@@ -2968,7 +2968,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
 	for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) {
 		pte_t entry;
 
-		entry = pfn_pte(my_zero_pfn(addr), vma->vm_page_prot);
+		entry = pfn_pte(zero_pfn(addr), vma->vm_page_prot);
 		entry = pte_mkspecial(entry);
 		if (pmd_uffd_wp(old_pmd))
 			entry = pte_mkuffd_wp(entry);

diff --git a/mm/memory.c b/mm/memory.c
index 51d2018a387a..ae610afa9cea 100644
--- a/mm/memory.c
+++ b/mm/memory.c

@@ -5165,7 +5165,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
 	/* Use the zero-page for reads */
 	if (!(vmf->flags & FAULT_FLAG_WRITE) &&
 			!mm_forbids_zeropage(vma->vm_mm)) {
-		entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address),
+		entry = pte_mkspecial(pfn_pte(zero_pfn(vmf->address),
 						vma->vm_page_prot));
 		vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
 				vmf->address, &vmf->ptl);

diff --git a/mm/migrate.c b/mm/migrate.c
index 1bf2cf8c44dd..739c4e03769b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c

@@ -321,7 +321,7 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw,
 	if (!pages_identical(page, ZERO_PAGE(0)))
 		return false;
 
-	newpte = pte_mkspecial(pfn_pte(my_zero_pfn(pvmw->address),
+	newpte = pte_mkspecial(pfn_pte(zero_pfn(pvmw->address),
 					pvmw->vma->vm_page_prot));
 
 	if (pte_swp_soft_dirty(old_pte))

diff --git a/mm/mm_init.c b/mm/mm_init.c
index dcf9eff34f83..a0ca236eb4f5 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -53,8 +53,8 @@ EXPORT_SYMBOL(mem_map);
 void *high_memory;
 EXPORT_SYMBOL(high_memory);
 
-unsigned long zero_pfn __ro_after_init;
-EXPORT_SYMBOL(zero_pfn);
+unsigned long zero_page_pfn __ro_after_init;
+EXPORT_SYMBOL(zero_page_pfn);
 
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

@@ -2670,12 +2670,12 @@ static void __init mem_init_print_info(void)
 		);
 }
 
-static int __init init_zero_pfn(void)
+static int __init init_zero_page_pfn(void)
 {
-	zero_pfn = page_to_pfn(ZERO_PAGE(0));
+	zero_page_pfn = page_to_pfn(ZERO_PAGE(0));
 	return 0;
 }
-early_initcall(init_zero_pfn);
+early_initcall(init_zero_page_pfn);
 
 void __init __weak arch_mm_preinit(void)
 {

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 927086bb4a3c..e19872e51878 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c

@@ -357,7 +357,7 @@ static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd,
 	if (mm_forbids_zeropage(dst_vma->vm_mm))
 		return mfill_atomic_pte_zeroed_folio(dst_pmd, dst_vma, dst_addr);
 
-	_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
+	_dst_pte = pte_mkspecial(pfn_pte(zero_pfn(dst_addr),
 					 dst_vma->vm_page_prot));
 	ret = -EAGAIN;
 	dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl);

@@ -1229,7 +1229,7 @@ static int move_zeropage_pte(struct mm_struct *mm,
 		return -EAGAIN;
 	}
 
-	zero_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
+	zero_pte = pte_mkspecial(pfn_pte(zero_pfn(dst_addr),
 					 dst_vma->vm_page_prot));
 	ptep_clear_flush(src_vma, src_addr, src_pte);
 	set_pte_at(mm, dst_addr, dst_pte, zero_pte);

-- 
2.51.0

Re: [PATCH v3 3/4] arch, mm: consolidate empty_zero_page

From: Liam R. Howlett <hidden>
Date: 2026-02-12 18:39:38

* Mike Rapoport [off-list ref] [260211 05:32]:

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/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 :)

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>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Acked-by: Liam R. Howlett <redacted>

quoted hunk

---
 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 ---
 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/setup.h            |  2 --
 arch/sparc/kernel/head_32.S               |  7 -------
 arch/sparc/mm/init_32.c                   |  4 ----
 arch/sparc/mm/init_64.c                   | 11 ++++-------
 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                   | 10 ++++++++++
 mm/mm_init.c                              |  5 +++++
 59 files changed, 23 insertions(+), 285 deletions(-)

diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
index 90e7a9539102..12a3c5f8ece8 100644
--- a/arch/alpha/include/asm/pgtable.h
+++ b/arch/alpha/include/asm/pgtable.h

@@ -125,12 +125,6 @@ struct vm_area_struct;
  */
 #define pgprot_noncached(prot)	(prot)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero:  used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	(virt_to_page(ZERO_PGE))
-
 /*
  * On certain platforms whose physical address space can overlap KSEG,
  * namely EV6 and above, we must re-twiddle the physaddr to restore the

diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index bd580e2b62d7..0fdaea81b5fa 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h

@@ -21,9 +21,6 @@
 
 #ifndef __ASSEMBLER__
 
-extern char empty_zero_page[PAGE_SIZE];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern pgd_t swapper_pg_dir[] __aligned(PAGE_SIZE);
 
 /* to cope with aliasing VIPT cache */

diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index a5e92f46e5d1..d6b5c27a0098 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c

@@ -19,8 +19,6 @@
 #include <asm/arcregs.h>
 
 pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
-char empty_zero_page[PAGE_SIZE] __aligned(PAGE_SIZE);
-EXPORT_SYMBOL(empty_zero_page);
 
 static const unsigned long low_mem_start = CONFIG_LINUX_RAM_BASE;
 static unsigned long low_mem_sz;

diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index 6fa9acd6a7f5..982795cf4563 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h

@@ -10,15 +10,6 @@
 #include <linux/const.h>
 #include <asm/proc-fns.h>
 
-#ifndef __ASSEMBLY__
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-#endif
-
 #include <asm-generic/pgtable-nopud.h>
 
 #ifndef CONFIG_MMU

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 518def8314e7..23b87b5ef7f1 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c

@@ -41,13 +41,6 @@
 
 extern unsigned long __atags_pointer;
 
-/*
- * empty_zero_page is a special page that is used for
- * zero-initialized data and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * The pmd table for the upper-most set of pages.
  */

diff --git a/arch/arm/mm/nommu.c b/arch/arm/mm/nommu.c
index 7e42d8accec6..040ea43cce32 100644
--- a/arch/arm/mm/nommu.c
+++ b/arch/arm/mm/nommu.c

@@ -27,13 +27,6 @@
 
 unsigned long vectors_base;
 
-/*
- * empty_zero_page is a special page that is used for
- * zero-initialized data and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 #ifdef CONFIG_ARM_MPU
 struct mpu_rgn_info mpu_rgn_info;
 #endif

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index d94445b4f3df..63da07398a30 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -110,7 +110,6 @@ static inline void arch_leave_lazy_mmu_mode(void)
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
  */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr)	phys_to_page(__pa_symbol(empty_zero_page))
 
 #define pte_ERROR(e)	\

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index a6a00accf4f9..0f6a171faf1f 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c

@@ -64,13 +64,6 @@ static bool rodata_is_rw __ro_after_init = true;
  */
 long __section(".mmuoff.data.write") __early_cpu_boot_status;
 
-/*
- * Empty_zero_page is a special page that is used for zero-initialized data
- * and COW.
- */
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 static DEFINE_SPINLOCK(swapper_pgdir_lock);
 static DEFINE_MUTEX(fixmap_lock);

diff --git a/arch/csky/include/asm/pgtable.h b/arch/csky/include/asm/pgtable.h
index d606afbabce1..bafcd5823531 100644
--- a/arch/csky/include/asm/pgtable.h
+++ b/arch/csky/include/asm/pgtable.h

@@ -76,9 +76,6 @@
 #define MAX_SWAPFILES_CHECK() \
 		BUILD_BUG_ON(MAX_SWAPFILES_SHIFT != 5)
 
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern void load_pgd(unsigned long pg_dir);
 extern pte_t invalid_pte_table[PTRS_PER_PTE];

diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index 573da66b2543..fa16015ea1c0 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c

@@ -38,9 +38,6 @@ pte_t invalid_pte_table[PTRS_PER_PTE] __page_aligned_bss;
 pte_t kernel_pte_tables[PTRS_KERN_TABLE] __page_aligned_bss;
 
 EXPORT_SYMBOL(invalid_pte_table);
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-						__page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
 
 void free_initmem(void)
 {

diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index fbf24d1d1ca6..27b269e2870d 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h

@@ -14,9 +14,6 @@
 #include <asm/page.h>
 #include <asm-generic/pgtable-nopmd.h>
 
-/* A handy thing to have if one has the RAM. Declared in head.S */
-extern unsigned long empty_zero_page;
-
 /*
  * The PTE model described here is that of the Hexagon Virtual Machine,
  * which autonomously walks 2-level page tables.  At a lower level, we

@@ -348,9 +345,6 @@ static inline unsigned long pmd_page_vaddr(pmd_t pmd)
 	return (unsigned long)__va(pmd_val(pmd) & PAGE_MASK);
 }
 
-/* ZERO_PAGE - returns the globally shared zero page */
-#define ZERO_PAGE(vaddr) (virt_to_page(&empty_zero_page))
-
 /*
  * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
  * are !pte_none() && !pte_present().

diff --git a/arch/hexagon/kernel/head.S b/arch/hexagon/kernel/head.S
index 0b016308cc79..908ffece9132 100644
--- a/arch/hexagon/kernel/head.S
+++ b/arch/hexagon/kernel/head.S

@@ -216,8 +216,3 @@ __head_s_vaddr_target:
 .p2align PAGE_SHIFT
 ENTRY(external_cmdline_buffer)
         .fill _PAGE_SIZE,1,0
-
-.data
-.p2align PAGE_SHIFT
-ENTRY(empty_zero_page)
-        .fill _PAGE_SIZE,1,0

diff --git a/arch/hexagon/kernel/hexagon_ksyms.c b/arch/hexagon/kernel/hexagon_ksyms.c
index 36a80e31d187..81bc6f81e200 100644
--- a/arch/hexagon/kernel/hexagon_ksyms.c
+++ b/arch/hexagon/kernel/hexagon_ksyms.c

@@ -17,7 +17,6 @@ EXPORT_SYMBOL(raw_copy_to_user);
 EXPORT_SYMBOL(__vmgetie);
 EXPORT_SYMBOL(__vmsetie);
 EXPORT_SYMBOL(__vmyield);
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memset);

diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index c33b3bcb733e..a244de27a03e 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h

@@ -74,15 +74,6 @@
 struct mm_struct;
 struct vm_area_struct;
 
-/*
- * ZERO_PAGE is a global shared page that is always zero; used
- * for zero-mapped memory areas etc..
- */
-
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
-#define ZERO_PAGE(vaddr)	virt_to_page(empty_zero_page)
-
 #ifdef CONFIG_32BIT
 
 #define VMALLOC_START	(vm_map_base + PCI_IOSIZE + (2 * PAGE_SIZE))

diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index c331bf69d2ec..00f3822b6e47 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c

@@ -36,9 +36,6 @@
 #include <asm/pgalloc.h>
 #include <asm/tlb.h>
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 void copy_user_highpage(struct page *to, struct page *from,
 	unsigned long vaddr, struct vm_area_struct *vma)
 {

diff --git a/arch/m68k/include/asm/pgtable_mm.h b/arch/m68k/include/asm/pgtable_mm.h
index bba64a9c49ac..7501ff030c63 100644
--- a/arch/m68k/include/asm/pgtable_mm.h
+++ b/arch/m68k/include/asm/pgtable_mm.h

@@ -110,15 +110,6 @@ extern unsigned long m68k_vmalloc_end;
 #define VMALLOC_END KMAP_START
 #endif
 
-/* zero page used for uninitialized stuff */
-extern void *empty_zero_page;
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern void kernel_set_cachemode(void *addr, unsigned long size, int cmode);
 
 /*

diff --git a/arch/m68k/include/asm/pgtable_no.h b/arch/m68k/include/asm/pgtable_no.h
index 1a86c15b9008..11751807a3f3 100644
--- a/arch/m68k/include/asm/pgtable_no.h
+++ b/arch/m68k/include/asm/pgtable_no.h

@@ -30,13 +30,6 @@
 
 #define swapper_pg_dir ((pgd_t *) 0)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern void *empty_zero_page;
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 /*
  * All 32bit addresses are effectively valid for vmalloc...
  * Sort of meaningless for non-VM targets.

diff --git a/arch/m68k/mm/init.c b/arch/m68k/mm/init.c
index 53b71f786c27..3b88c0dd1616 100644
--- a/arch/m68k/mm/init.c
+++ b/arch/m68k/mm/init.c

@@ -33,13 +33,6 @@
 #include <asm/sections.h>
 #include <asm/tlb.h>
 
-/*
- * ZERO_PAGE is a special page that is used for zero-initialized
- * data and COW.
- */
-void *empty_zero_page;
-EXPORT_SYMBOL(empty_zero_page);
-
 void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
 {
 	max_zone_pfns[ZONE_DMA] = PFN_DOWN(memblock_end_of_DRAM());

@@ -71,8 +64,6 @@ void __init paging_init(void)
 	unsigned long end_mem = memory_end & PAGE_MASK;
 
 	high_memory = (void *) end_mem;
-
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
 }
 
 #endif /* CONFIG_MMU */

diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 3418fd864237..4924f2ff8ef8 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c

@@ -41,8 +41,6 @@ void __init paging_init(void)
 	unsigned long next_pgtable;
 	int i;
 
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	pg_dir = swapper_pg_dir;
 	memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));

diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 127a3fa69f4c..b30aa69a73a6 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c

@@ -498,12 +498,6 @@ void __init paging_init(void)
 
 	early_memtest(min_addr, max_addr);
 
-	/*
-	 * initialize the bad page table and bad page to point
-	 * to a couple of allocated pages
-	 */
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	/*
 	 * Set up SFC/DFC registers
 	 */

diff --git a/arch/m68k/mm/sun3mmu.c b/arch/m68k/mm/sun3mmu.c
index c801677f7df8..f139cc15753a 100644
--- a/arch/m68k/mm/sun3mmu.c
+++ b/arch/m68k/mm/sun3mmu.c

@@ -43,8 +43,6 @@ void __init paging_init(void)
 	unsigned long bootmem_end;
 	unsigned long size;
 
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 	address = PAGE_OFFSET;
 	pg_dir = swapper_pg_dir;
 	memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));

diff --git a/arch/microblaze/include/asm/pgtable.h b/arch/microblaze/include/asm/pgtable.h
index 4eb76de6be4a..ea72291de553 100644
--- a/arch/microblaze/include/asm/pgtable.h
+++ b/arch/microblaze/include/asm/pgtable.h

@@ -207,16 +207,6 @@ extern pte_t *va_to_pte(unsigned long address);
  * Also, write permissions imply read permissions.
  */
 
-#ifndef __ASSEMBLER__
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[1024];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
-#endif /* __ASSEMBLER__ */
-
 #define pte_none(pte)		((pte_val(pte) & ~_PTE_NONE_MASK) == 0)
 #define pte_present(pte)	(pte_val(pte) & _PAGE_PRESENT)
 #define pte_clear(mm, addr, ptep) \

diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S
index ec2fcb545e64..808019c3b7ac 100644
--- a/arch/microblaze/kernel/head.S
+++ b/arch/microblaze/kernel/head.S

@@ -39,10 +39,6 @@
 #include <asm/processor.h>
 
 .section .data
-.global empty_zero_page
-.align 12
-empty_zero_page:
-	.space	PAGE_SIZE
 .global swapper_pg_dir
 swapper_pg_dir:
 	.space	PAGE_SIZE

diff --git a/arch/microblaze/kernel/microblaze_ksyms.c b/arch/microblaze/kernel/microblaze_ksyms.c
index a8553f54152b..ad7596d7ba07 100644
--- a/arch/microblaze/kernel/microblaze_ksyms.c
+++ b/arch/microblaze/kernel/microblaze_ksyms.c

@@ -33,8 +33,6 @@ EXPORT_SYMBOL(memcpy);
 EXPORT_SYMBOL(memmove);
 #endif
 
-EXPORT_SYMBOL(empty_zero_page);
-
 EXPORT_SYMBOL(mbc);
 
 extern void __divsi3(void);

diff --git a/arch/nios2/include/asm/pgtable.h b/arch/nios2/include/asm/pgtable.h
index 844dce55569f..d389aa9ca57c 100644
--- a/arch/nios2/include/asm/pgtable.h
+++ b/arch/nios2/include/asm/pgtable.h

@@ -65,13 +65,6 @@ struct mm_struct;
 #define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
 #define PGDIR_MASK	(~(PGDIR_SIZE-1))
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr)	(virt_to_page(empty_zero_page))
-
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];

diff --git a/arch/nios2/kernel/head.S b/arch/nios2/kernel/head.S
index 372ce4a33018..613212e1a63a 100644
--- a/arch/nios2/kernel/head.S
+++ b/arch/nios2/kernel/head.S

@@ -23,16 +23,6 @@
 #include <asm/asm-offsets.h>
 #include <asm/asm-macros.h>
 
-/*
- * ZERO_PAGE is a special page that is used for zero-initialized
- * data and COW.
- */
-.data
-.global empty_zero_page
-.align 12
-empty_zero_page:
-	.space	PAGE_SIZE
-
 /*
  * This global variable is used as an extension to the nios'
  * STATUS register to emulate a user/supervisor mode.

diff --git a/arch/nios2/kernel/nios2_ksyms.c b/arch/nios2/kernel/nios2_ksyms.c
index 54f7b23df1bf..c40aa39e8658 100644
--- a/arch/nios2/kernel/nios2_ksyms.c
+++ b/arch/nios2/kernel/nios2_ksyms.c

@@ -20,7 +20,6 @@ EXPORT_SYMBOL(memmove);
 
 /* memory management */
 
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(flush_icache_range);
 
 /*

diff --git a/arch/openrisc/include/asm/pgtable.h b/arch/openrisc/include/asm/pgtable.h
index b218050e2f6d..6b89996d0b62 100644
--- a/arch/openrisc/include/asm/pgtable.h
+++ b/arch/openrisc/include/asm/pgtable.h

@@ -179,10 +179,6 @@ extern void paging_init(void);
 	__pgprot(_PAGE_ALL | _PAGE_SRE | _PAGE_SWE \
 		 | _PAGE_SHARED | _PAGE_DIRTY | _PAGE_EXEC | _PAGE_CI)
 
-/* zero page used for uninitialized stuff */
-extern unsigned long empty_zero_page[2048];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #define pte_none(x)	(!pte_val(x))
 #define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
 #define pte_clear(mm, addr, xp)	do { pte_val(*(xp)) = 0; } while (0)

diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S
index bd760066f1cd..45890393947d 100644
--- a/arch/openrisc/kernel/head.S
+++ b/arch/openrisc/kernel/head.S

@@ -1563,9 +1563,6 @@ _string_nl:
  */
 	.section .data,"aw"
 	.align	8192
-	.global  empty_zero_page
-empty_zero_page:
-	.space  8192
 
 	.global  swapper_pg_dir
 swapper_pg_dir:

diff --git a/arch/openrisc/kernel/or32_ksyms.c b/arch/openrisc/kernel/or32_ksyms.c
index 212e5f85004c..84a937a64e2a 100644
--- a/arch/openrisc/kernel/or32_ksyms.c
+++ b/arch/openrisc/kernel/or32_ksyms.c

@@ -40,7 +40,6 @@ DECLARE_EXPORT(__ashldi3);
 DECLARE_EXPORT(__lshrdi3);
 DECLARE_EXPORT(__ucmpdi2);
 
-EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(__copy_tofrom_user);
 EXPORT_SYMBOL(__clear_user);
 EXPORT_SYMBOL(memset);

diff --git a/arch/openrisc/mm/init.c b/arch/openrisc/mm/init.c
index 78fb0734cdbc..89d8c6df8855 100644
--- a/arch/openrisc/mm/init.c
+++ b/arch/openrisc/mm/init.c

@@ -188,9 +188,6 @@ void __init mem_init(void)
 {
 	BUG_ON(!mem_map);
 
-	/* clear the zero-page */
-	memset((void *)empty_zero_page, 0, PAGE_SIZE);
-
 	printk("mem_init_done ...........................................\n");
 	mem_init_done = 1;
 	return;

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 2c139a4dbf4b..cbdc01a26ea0 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h

@@ -262,17 +262,6 @@ extern pgd_t swapper_pg_dir[]; /* declared in init_task.c */
 
 extern pte_t pg0[];
 
-/* zero page used for uninitialized stuff */
-
-extern unsigned long *empty_zero_page;
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #define pte_none(x)     (pte_val(x) == 0)
 #define pte_present(x)	(pte_val(x) & _PAGE_PRESENT)
 #define pte_user(x)	(pte_val(x) & _PAGE_USER)

diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c
index 6a39e031e5ff..be3380c9bcda 100644
--- a/arch/parisc/mm/init.c
+++ b/arch/parisc/mm/init.c

@@ -604,9 +604,6 @@ void __init mem_init(void)
 #endif
 }
 
-unsigned long *empty_zero_page __ro_after_init;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * pagetable_init() sets up the page tables
  *

@@ -639,9 +636,6 @@ static void __init pagetable_init(void)
 			  initrd_end - initrd_start, PAGE_KERNEL, 0);
 	}
 #endif
-
-	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
-
 }
 
 static void __init gateway_init(void)

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index dcd3a88caaf6..b27d94c06d0e 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h

@@ -76,12 +76,6 @@ static inline const void *pmd_page_vaddr(pmd_t pmd)
 }
 #define pmd_page_vaddr pmd_page_vaddr
 #endif
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 
 extern pgd_t swapper_pg_dir[];

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 3789a51bdaae..85508392a6b6 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -34,9 +34,6 @@
 
 unsigned long long memory_limit __initdata;
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 pgprot_t __phys_mem_access_prot(unsigned long pfn, unsigned long size,
 				pgprot_t vma_prot)
 {

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9ecbf0366719..a6b496f4944f 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h

@@ -1258,13 +1258,6 @@ extern u64 satp_mode;
 void paging_init(void);
 void misc_mem_init(void);
 
-/*
- * ZERO_PAGE is a global shared page that is always zero,
- * used for zero-mapped memory areas, etc.
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 /*
  * Use set_p*_safe(), and elide TLB flushing, when confident that *no*
  * TLB flush will be required as a result of the "set". For example, use

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 848efeb9e163..95ac79c62067 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c

@@ -69,10 +69,6 @@ unsigned long vmemmap_start_pfn __ro_after_init;
 EXPORT_SYMBOL(vmemmap_start_pfn);
 #endif
 
-unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-							__page_aligned_bss;
-EXPORT_SYMBOL(empty_zero_page);
-
 extern char _start[];
 void *_dtb_early_va __initdata;
 uintptr_t _dtb_early_pa __initdata;

diff --git a/arch/sh/include/asm/pgtable.h b/arch/sh/include/asm/pgtable.h
index 10fa8f2bb8d1..d5ce0950a323 100644
--- a/arch/sh/include/asm/pgtable.h
+++ b/arch/sh/include/asm/pgtable.h

@@ -20,14 +20,6 @@
 #ifndef __ASSEMBLER__
 #include <asm/addrspace.h>
 #include <asm/fixmap.h>
-
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #endif /* !__ASSEMBLER__ */
 
 /*

diff --git a/arch/sh/include/asm/setup.h b/arch/sh/include/asm/setup.h
index 84bb23a771f3..63c9efc06348 100644
--- a/arch/sh/include/asm/setup.h
+++ b/arch/sh/include/asm/setup.h

@@ -7,7 +7,8 @@
 /*
  * This is set up by the setup-routine at boot-time
  */
-#define PARAM	((unsigned char *)empty_zero_page)
+extern unsigned char *boot_params_page;
+#define PARAM boot_params_page
 
 #define MOUNT_ROOT_RDONLY (*(unsigned long *) (PARAM+0x000))
 #define RAMDISK_FLAGS (*(unsigned long *) (PARAM+0x004))

diff --git a/arch/sh/kernel/head_32.S b/arch/sh/kernel/head_32.S
index b603b7968b38..0b91bb85d40a 100644
--- a/arch/sh/kernel/head_32.S
+++ b/arch/sh/kernel/head_32.S

@@ -26,7 +26,7 @@
 #endif
 
 	.section	.empty_zero_page, "aw"
-ENTRY(empty_zero_page)
+ENTRY(boot_params_page)
 	.long	1		/* MOUNT_ROOT_RDONLY */
 	.long	0		/* RAMDISK_FLAGS */
 	.long	0x0200		/* ORIG_ROOT_DEV */

@@ -39,7 +39,7 @@ ENTRY(empty_zero_page)
 	.long	0x53453f00 + 29	/* "SE?" = 29 bit */
 #endif
 1:
-	.skip	PAGE_SIZE - empty_zero_page - 1b
+	.skip	PAGE_SIZE - boot_params_page - 1b
 
 	__HEAD

diff --git a/arch/sh/kernel/sh_ksyms_32.c b/arch/sh/kernel/sh_ksyms_32.c
index 5858936cb431..041191002e2e 100644
--- a/arch/sh/kernel/sh_ksyms_32.c
+++ b/arch/sh/kernel/sh_ksyms_32.c

@@ -20,7 +20,6 @@ EXPORT_SYMBOL(csum_partial);
 EXPORT_SYMBOL(csum_partial_copy_generic);
 EXPORT_SYMBOL(copy_page);
 EXPORT_SYMBOL(__clear_user);
-EXPORT_SYMBOL(empty_zero_page);
 #ifdef CONFIG_FLATMEM
 /* need in pfn_valid macro */
 EXPORT_SYMBOL(min_low_pfn);

diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 464a3a63e2fa..4e40d5e96be9 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c

@@ -332,7 +332,6 @@ void __init mem_init(void)
 	cpu_cache_init();
 
 	/* clear the zero-page */
-	memset(empty_zero_page, 0, PAGE_SIZE);
 	__flush_wback_region(empty_zero_page, PAGE_SIZE);
 
 	vsyscall_init();

diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index a9f802d1dd64..f89b1250661d 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h

@@ -71,14 +71,6 @@ extern unsigned long ptr_in_current_pgd;
 extern unsigned long phys_base;
 extern unsigned long pfn_base;
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 /*
  * In general all page table modifications should use the V8 atomic
  * swap instruction.  This insures the mmu and the cpu are in sync

diff --git a/arch/sparc/include/asm/setup.h b/arch/sparc/include/asm/setup.h
index 72205684e51e..21bed5514028 100644
--- a/arch/sparc/include/asm/setup.h
+++ b/arch/sparc/include/asm/setup.h

@@ -17,8 +17,6 @@ extern char reboot_command[];
  */
 extern unsigned char boot_cpu_id;
 
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
-
 extern int serial_console;
 static inline int con_is_present(void)
 {

diff --git a/arch/sparc/kernel/head_32.S b/arch/sparc/kernel/head_32.S
index 38345460d542..8c320fa25a67 100644
--- a/arch/sparc/kernel/head_32.S
+++ b/arch/sparc/kernel/head_32.S

@@ -57,13 +57,6 @@ sun4e_notsup:
 
 	.align PAGE_SIZE
 
-/* This was the only reasonable way I could think of to properly align
- * these page-table data structures.
- */
-	.globl empty_zero_page
-empty_zero_page:	.skip PAGE_SIZE
-EXPORT_SYMBOL(empty_zero_page)
-
 	.global root_flags
 	.global ram_flags
 	.global root_dev

diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index fdc93dd12c3e..e0e66f91ceeb 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c

@@ -246,10 +246,6 @@ void __init arch_mm_preinit(void)
 		prom_halt();
 	}
 
-
-	/* Saves us work later. */
-	memset((void *)empty_zero_page, 0, PAGE_SIZE);
-
 	i = last_valid_pfn >> ((20 - PAGE_SHIFT) + 5);
 	i += 1;
 	sparc_valid_addr_bitmap = (unsigned long *)

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 4f7bdb18774b..0cc8de2fea90 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c

@@ -2498,6 +2498,9 @@ static void __init register_page_bootmem_info(void)
 }
 void __init mem_init(void)
 {
+	phys_addr_t zero_page_pa = kern_base +
+		((unsigned long)&empty_zero_page[0] - KERNBASE);
+
 	/*
 	 * Must be done after boot memory is put on freelist, because here we
 	 * might set fields in deferred struct pages that have not yet been

@@ -2510,13 +2513,7 @@ void __init mem_init(void)
 	 * Set up the zero page, mark it reserved, so that page count
 	 * is not manipulated when freeing the page from user ptes.
 	 */
-	mem_map_zero = alloc_pages(GFP_KERNEL|__GFP_ZERO, 0);
-	if (mem_map_zero == NULL) {
-		prom_printf("paging_init: Cannot alloc zero page.\n");
-		prom_halt();
-	}
-	mark_page_reserved(mem_map_zero);
-
+	mem_map_zero = pfn_to_page(PHYS_PFN(zero_page_pa));
 
 	if (tlb_type == cheetah || tlb_type == cheetah_plus)
 		cheetah_ecache_flush_init();

diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 3b42b0f45bf6..19e0608fb649 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h

@@ -34,9 +34,6 @@
 
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 
-/* zero page used for uninitialized stuff */
-extern unsigned long *empty_zero_page;
-
 /* Just any arbitrary offset to the start of the vmalloc VM area: the
  * current 8MB value just means that there will be a 8MB "hole" after the
  * physical memory until the kernel virtual memory starts.  That means that

@@ -74,12 +71,6 @@ extern unsigned long *empty_zero_page;
  * get..
  */
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr) virt_to_page(empty_zero_page)
-
 #define pte_clear(mm, addr, xp) pte_set_val(*(xp), (phys_t) 0, __pgprot(_PAGE_NEEDSYNC))
 
 #define pmd_none(x)	(!((unsigned long)pmd_val(x) & ~_PAGE_NEEDSYNC))

diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index 38321188c04c..9812efd14ec0 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h

@@ -38,7 +38,6 @@ extern void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs
 extern void uml_pm_wake(void);
 
 extern int start_uml(void);
-extern void paging_init(void);
 
 extern void uml_cleanup(void);
 extern void do_uml_exitcalls(void);

diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 89c8c8b94a79..1eef0e42ef5d 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c

@@ -44,10 +44,6 @@ __section(".kasan_init") __used
 = kasan_init;
 #endif
 
-/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
-unsigned long *empty_zero_page = NULL;
-EXPORT_SYMBOL(empty_zero_page);
-
 /*
  * Initialized during boot, and readonly for initializing page tables
  * afterwards

@@ -65,9 +61,6 @@ void __init arch_mm_preinit(void)
 	/* Safe to call after jump_label_init(). Enables KASAN. */
 	kasan_init_generic();
 
-	/* clear the zero-page */
-	memset(empty_zero_page, 0, PAGE_SIZE);
-
 	/* Map in the area just after the brk now that kmalloc is about
 	 * to be turned on.
 	 */

@@ -89,15 +82,6 @@ void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
 	max_zone_pfns[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT;
 }
 
-void __init paging_init(void)
-{
-	empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
-							       PAGE_SIZE);
-	if (!empty_zero_page)
-		panic("%s: Failed to allocate %lu bytes align=%lx\n",
-		      __func__, PAGE_SIZE, PAGE_SIZE);
-}
-
 /*
  * This can't do anything because nothing in the kernel image can be freed
  * since it's not in kernel physical memory.

diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index e2b24e1ecfa6..2141f5f1f5a2 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c

@@ -413,7 +413,6 @@ void __init setup_arch(char **cmdline_p)
 	uml_dtb_init();
 	read_initrd();
 
-	paging_init();
 	strscpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 	*cmdline_p = command_line;
 	setup_hostinfo(host_info, sizeof host_info);

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1662c5a8f445..54289f4587a4 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h

@@ -47,14 +47,6 @@ void ptdump_walk_user_pgd_level_checkwx(void);
 #define debug_checkwx_user()	do { } while (0)
 #endif
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
-	__visible;
-#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
-
 extern spinlock_t pgd_lock;
 extern struct list_head pgd_list;

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 80ef5d386b03..5171cb746444 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S

@@ -441,10 +441,6 @@ initial_pg_fixmap:
 swapper_pg_dir:
 	.fill 1024,4,0
 	.fill PTI_USER_PGD_FILL,4,0
-.globl empty_zero_page
-empty_zero_page:
-	.fill 4096,1,0
-EXPORT_SYMBOL(empty_zero_page)
 
 /*
  * This starts the data section.

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 21816b48537c..cbf7647a25d8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S

@@ -712,10 +712,3 @@ SYM_PIC_ALIAS(phys_base);
 EXPORT_SYMBOL(phys_base)
 
 #include "../xen/xen-head.S"
-
-	__PAGE_ALIGNED_BSS
-SYM_DATA_START_PAGE_ALIGNED(empty_zero_page)
-	.skip PAGE_SIZE
-SYM_DATA_END(empty_zero_page)
-EXPORT_SYMBOL(empty_zero_page)
-

diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 50a136213b2b..61f07d981a94 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h

@@ -209,10 +209,6 @@
 #define pgd_ERROR(e) \
 	printk("%s:%d: bad pgd entry %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 
-extern unsigned long empty_zero_page[1024];
-
-#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
-
 #ifdef CONFIG_MMU
 extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
 extern void paging_init(void);

diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 8484294bc623..4b0c5c5e685a 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S

@@ -381,6 +381,3 @@ ENTRY(swapper_pg_dir)
 	.fill	PAGE_SIZE, 1, 0
 END(swapper_pg_dir)
 #endif
-ENTRY(empty_zero_page)
-	.fill	PAGE_SIZE, 1, 0
-END(empty_zero_page)

diff --git a/arch/xtensa/kernel/xtensa_ksyms.c b/arch/xtensa/kernel/xtensa_ksyms.c
index 62d81e76e18e..ced335b4df5f 100644
--- a/arch/xtensa/kernel/xtensa_ksyms.c
+++ b/arch/xtensa/kernel/xtensa_ksyms.c

@@ -15,8 +15,6 @@
 #include <linux/module.h>
 #include <asm/pgtable.h>
 
-EXPORT_SYMBOL(empty_zero_page);
-
 unsigned int __sync_fetch_and_and_4(volatile void *p, unsigned int v)
 {
 	BUG();

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 9bacf4df9769..3d48eea57cd2 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1890,6 +1890,9 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
  * for different ranges in the virtual address space.
  *
  * zero_page_pfn identifies the first (or the only) pfn for these pages.
+ *
+ * For architectures that don't __HAVE_COLOR_ZERO_PAGE the zero page lives in
+ * empty_zero_page in BSS.
  */
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)

@@ -1916,6 +1919,13 @@ static inline unsigned long zero_pfn(unsigned long addr)
 
 	return zero_page_pfn;
 }
+
+extern uint8_t empty_zero_page[PAGE_SIZE];
+
+#ifndef ZERO_PAGE
+#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
+#endif
+
 #endif /* __HAVE_COLOR_ZERO_PAGE */
 
 #ifdef CONFIG_MMU

diff --git a/mm/mm_init.c b/mm/mm_init.c
index a0ca236eb4f5..1eac634ece1a 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -56,6 +56,11 @@ EXPORT_SYMBOL(high_memory);
 unsigned long zero_page_pfn __ro_after_init;
 EXPORT_SYMBOL(zero_page_pfn);
 
+#ifndef __HAVE_COLOR_ZERO_PAGE
+uint8_t empty_zero_page[PAGE_SIZE] __page_aligned_bss;
+EXPORT_SYMBOL(empty_zero_page);
+#endif
+
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

-- 
2.51.0

Re: [PATCH v3 4/4] mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()

From: Liam R. Howlett <hidden>
Date: 2026-02-12 18:42:12

* Mike Rapoport [off-list ref] [260211 05:32]:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

For most architectures every invocation of ZERO_PAGE() does
virt_to_page(empty_zero_page). But empty_zero_page is in BSS and it is
enough to get its struct page once at initialization time and then use
it whenever a zero page should be accessed.

Add yet another __zero_page variable that will be initialized as
virt_to_page(empty_zero_page) for most architectures in a weak
arch_setup_zero_pages() function.

For architectures that use colored zero pages (MIPS and s390) rename their
setup_zero_pages() to arch_setup_zero_pages() and make it global rather
than static.

For architectures that cannot use virt_to_page() for BSS (arm64 and
sparc64) add override of arch_setup_zero_pages().

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

Acked-by: Liam R. Howlett <redacted>

quoted hunk

---
 arch/arm64/include/asm/pgtable.h    |  6 ------
 arch/arm64/mm/init.c                |  5 +++++
 arch/mips/mm/init.c                 | 11 +----------
 arch/s390/mm/init.c                 |  4 +---
 arch/sparc/include/asm/pgtable_64.h |  3 ---
 arch/sparc/mm/init_64.c             | 17 +++++++----------
 include/linux/pgtable.h             | 11 ++++++++---
 mm/mm_init.c                        | 21 +++++++++++++++++----
 8 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 63da07398a30..2c1ec7cc8612 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -106,12 +106,6 @@ static inline void arch_leave_lazy_mmu_mode(void)
 #define flush_tlb_fix_spurious_fault_pmd(vma, address, pmdp)	\
 	local_flush_tlb_page_nonotify(vma, address)
 
-/*
- * ZERO_PAGE is a global shared page that is always zero: used
- * for zero-mapped memory areas etc..
- */
-#define ZERO_PAGE(vaddr)	phys_to_page(__pa_symbol(empty_zero_page))
-
 #define pte_ERROR(e)	\
 	pr_err("%s:%d: bad pte %016llx.\n", __FILE__, __LINE__, pte_val(e))

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 96711b8578fd..417ec7efe569 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c

@@ -328,6 +328,11 @@ void __init bootmem_init(void)
 	memblock_dump_all();
 }
 
+void __init arch_setup_zero_pages(void)
+{
+	__zero_page = phys_to_page(__pa_symbol(empty_zero_page));
+}
+
 void __init arch_mm_preinit(void)
 {
 	unsigned int flags = SWIOTLB_VERBOSE;

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 4f6449ad02ca..55b25e85122a 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c

@@ -56,10 +56,7 @@ unsigned long empty_zero_page, zero_page_mask;
 EXPORT_SYMBOL_GPL(empty_zero_page);
 EXPORT_SYMBOL(zero_page_mask);
 
-/*
- * Not static inline because used by IP27 special magic initialization code
- */
-static void __init setup_zero_pages(void)
+void __init arch_setup_zero_pages(void)
 {
 	unsigned int order;

@@ -450,7 +447,6 @@ void __init arch_mm_preinit(void)
 	BUILD_BUG_ON(IS_ENABLED(CONFIG_32BIT) && (PFN_PTE_SHIFT > PAGE_SHIFT));
 
 	maar_init();
-	setup_zero_pages();	/* Setup zeroed pages.  */
 	highmem_init();
 
 #ifdef CONFIG_64BIT

@@ -461,11 +457,6 @@ void __init arch_mm_preinit(void)
 				0x80000000 - 4, KCORE_TEXT);
 #endif
 }
-#else  /* CONFIG_NUMA */
-void __init arch_mm_preinit(void)
-{
-	setup_zero_pages();	/* This comes from node 0 */
-}
 #endif /* !CONFIG_NUMA */
 
 void free_init_pages(const char *what, unsigned long begin, unsigned long end)

diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 3c20475cbee2..1f72efc2a579 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c

@@ -69,7 +69,7 @@ unsigned long empty_zero_page, zero_page_mask;
 EXPORT_SYMBOL(empty_zero_page);
 EXPORT_SYMBOL(zero_page_mask);
 
-static void __init setup_zero_pages(void)
+void __init arch_setup_zero_pages(void)
 {
 	unsigned long total_pages = memblock_estimated_nr_free_pages();
 	unsigned int order;

@@ -159,8 +159,6 @@ void __init arch_mm_preinit(void)
 	cpumask_set_cpu(0, mm_cpumask(&init_mm));
 
 	pv_init();
-
-	setup_zero_pages();	/* Setup zeroed pages. */
 }
 
 unsigned long memory_block_size_bytes(void)

diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 615f460c50af..74ede706fb32 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h

@@ -210,9 +210,6 @@ extern unsigned long _PAGE_CACHE;
 extern unsigned long pg_iobits;
 extern unsigned long _PAGE_ALL_SZ_BITS;
 
-extern struct page *mem_map_zero;
-#define ZERO_PAGE(vaddr)	(mem_map_zero)
-
 /* PFNs are real physical page numbers.  However, mem_map only begins to record
  * per-page information starting at pfn_base.  This is to handle systems where
  * the first physical page in the machine is at some huge physical address,

diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 0cc8de2fea90..707c1df67d79 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c

@@ -177,9 +177,6 @@ extern unsigned long sparc_ramdisk_image64;
 extern unsigned int sparc_ramdisk_image;
 extern unsigned int sparc_ramdisk_size;
 
-struct page *mem_map_zero __read_mostly;
-EXPORT_SYMBOL(mem_map_zero);
-
 unsigned int sparc64_highest_unlocked_tlb_ent __read_mostly;
 
 unsigned long sparc64_kern_pri_context __read_mostly;

@@ -2496,11 +2493,17 @@ static void __init register_page_bootmem_info(void)
 			register_page_bootmem_info_node(NODE_DATA(i));
 #endif
 }
-void __init mem_init(void)
+
+void __init arch_setup_zero_pages(void)
 {
 	phys_addr_t zero_page_pa = kern_base +
 		((unsigned long)&empty_zero_page[0] - KERNBASE);
 
+	__zero_page = phys_to_page(zero_page_pa);
+}
+
+void __init mem_init(void)
+{
 	/*
 	 * Must be done after boot memory is put on freelist, because here we
 	 * might set fields in deferred struct pages that have not yet been

@@ -2509,12 +2512,6 @@ void __init mem_init(void)
 	 */
 	register_page_bootmem_info();
 
-	/*
-	 * Set up the zero page, mark it reserved, so that page count
-	 * is not manipulated when freeing the page from user ptes.
-	 */
-	mem_map_zero = pfn_to_page(PHYS_PFN(zero_page_pa));
-
 	if (tlb_type == cheetah || tlb_type == cheetah_plus)
 		cheetah_ecache_flush_init();
 }

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 3d48eea57cd2..1da21ec62836 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1894,6 +1894,8 @@ static inline void pfnmap_setup_cachemode_pfn(unsigned long pfn, pgprot_t *prot)
  * For architectures that don't __HAVE_COLOR_ZERO_PAGE the zero page lives in
  * empty_zero_page in BSS.
  */
+void arch_setup_zero_pages(void);
+
 #ifdef __HAVE_COLOR_ZERO_PAGE
 static inline int is_zero_pfn(unsigned long pfn)
 {

@@ -1921,10 +1923,13 @@ static inline unsigned long zero_pfn(unsigned long addr)
 }
 
 extern uint8_t empty_zero_page[PAGE_SIZE];
+extern struct page *__zero_page;
 
-#ifndef ZERO_PAGE
-#define ZERO_PAGE(vaddr) ((void)(vaddr),virt_to_page(empty_zero_page))
-#endif
+static inline struct page *_zero_page(unsigned long addr)
+{
+	return __zero_page;
+}
+#define ZERO_PAGE(vaddr) _zero_page(vaddr)
 
 #endif /* __HAVE_COLOR_ZERO_PAGE */

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 1eac634ece1a..b08608c1b71d 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c

@@ -59,7 +59,10 @@ EXPORT_SYMBOL(zero_page_pfn);
 #ifndef __HAVE_COLOR_ZERO_PAGE
 uint8_t empty_zero_page[PAGE_SIZE] __page_aligned_bss;
 EXPORT_SYMBOL(empty_zero_page);
-#endif
+
+struct page *__zero_page __ro_after_init;
+EXPORT_SYMBOL(__zero_page);
+#endif /* __HAVE_COLOR_ZERO_PAGE */
 
 #ifdef CONFIG_DEBUG_MEMORY_INIT
 int __meminitdata mminit_loglevel;

@@ -2675,12 +2678,21 @@ static void __init mem_init_print_info(void)
 		);
 }
 
-static int __init init_zero_page_pfn(void)
+#ifndef __HAVE_COLOR_ZERO_PAGE
+/*
+ * architectures that __HAVE_COLOR_ZERO_PAGE must define this function
+ */
+void __init __weak arch_setup_zero_pages(void)
+{
+	__zero_page = virt_to_page(empty_zero_page);
+}
+#endif
+
+static void __init init_zero_page_pfn(void)
 {
+	arch_setup_zero_pages();
 	zero_page_pfn = page_to_pfn(ZERO_PAGE(0));
-	return 0;
 }
-early_initcall(init_zero_page_pfn);
 
 void __init __weak arch_mm_preinit(void)
 {

@@ -2704,6 +2716,7 @@ void __init mm_core_init_early(void)
 void __init mm_core_init(void)
 {
 	arch_mm_preinit();
+	init_zero_page_pfn();
 
 	/* Initializations relying on SMP setup */
 	BUILD_BUG_ON(MAX_ZONELISTS > 2);

-- 
2.51.0

Re: [PATCH v3 0/4] arch, mm: consolidate empty_zero_page

From: patchwork-bot+linux-riscv@kernel.org
Date: 2026-04-30 03:25:54

Hello:

This series was applied to riscv/linux.git (fixes)
by Andrew Morton [off-list ref]:

On Wed, 11 Feb 2026 12:31:37 +0200 you wrote:

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

Hi,

These patches cleanup handling of ZERO_PAGE() and zero_pfn.

v3 changes:
* move zero_page_pfn extern declaration back inside the helpers
* add tags, thanks all!

[...]

Here is the summary with links:
  - [v3,1/4] mm: don't special case !MMU for is_zero_pfn() and my_zero_pfn()
    https://git.kernel.org/riscv/c/652d12bc74a0
  - [v3,2/4] mm: rename my_zero_pfn() to zero_pfn()
    https://git.kernel.org/riscv/c/9a1d0c738b45
  - [v3,3/4] arch, mm: consolidate empty_zero_page
    https://git.kernel.org/riscv/c/6215d9f4470f
  - [v3,4/4] mm: cache struct page for empty_zero_page and return it from ZERO_PAGE()
    https://git.kernel.org/riscv/c/26513781d1b3

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

`h`	back out one level
`j`	next message in thread
`k`	previous message in thread
`l`	drill in
`Esc`	close help / fold thread tree
`?`	toggle this help