From: David Hildenbrand <david@redhat.com>
Let's drop all variants that effectively map to clear_page() and
provide it in a generic variant instead.
We'll use the macro clear_user_page to indicate whether an architecture
provides it's own variant. Maybe at some point these should be CONFIG_
options.
Also, clear_user_page() is only called from the generic variant of
clear_user_highpage(), so define it only if the architecture does
not provide a clear_user_highpage(). And, for simplicity define it
in linux/highmem.h.
Note that for parisc, clear_page() and clear_user_page() map to
clear_page_asm(), so we can just get rid of the custom clear_user_page()
implementation. There is a clear_user_page_asm() function on parisc,
that seems to be unused. Not sure what's up with that.
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
Notes:
- incorporates Christophe Leroy's suggestion of moving
clear_user_page() into linux/highmem.h.
The linkage between clear_user_highpage() and clear_user_page()
isn't completely obvious but I hope the comment above
clear_user_page() clarifies it.
Though I guess if HIGHMEM goes away, we might have to revisit it.
arch/alpha/include/asm/page.h | 1 -
arch/arc/include/asm/page.h | 2 ++
arch/arm/include/asm/page-nommu.h | 1 -
arch/arm64/include/asm/page.h | 1 -
arch/csky/abiv1/inc/abi/page.h | 1 +
arch/csky/abiv2/inc/abi/page.h | 7 -------
arch/hexagon/include/asm/page.h | 1 -
arch/loongarch/include/asm/page.h | 1 -
arch/m68k/include/asm/page_no.h | 1 -
arch/microblaze/include/asm/page.h | 1 -
arch/mips/include/asm/page.h | 1 +
arch/nios2/include/asm/page.h | 1 +
arch/openrisc/include/asm/page.h | 1 -
arch/parisc/include/asm/page.h | 1 -
arch/powerpc/include/asm/page.h | 1 +
arch/riscv/include/asm/page.h | 1 -
arch/s390/include/asm/page.h | 1 -
arch/sparc/include/asm/page_64.h | 1 +
arch/um/include/asm/page.h | 1 -
arch/x86/include/asm/page.h | 6 ------
arch/xtensa/include/asm/page.h | 1 -
include/linux/highmem.h | 23 +++++++++++++++++++++--
22 files changed, 28 insertions(+), 28 deletions(-)
diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index d2c6667d73e9..59d01f9b77f6 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h
@@ -11,7 +11,6 @@
#define STRICT_MM_TYPECHECKS
extern void clear_page(void *page);
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr)
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index 9720fe6b2c24..38214e126c6d 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -32,6 +32,8 @@ struct page;
void copy_user_highpage(struct page *to, struct page *from,
unsigned long u_vaddr, struct vm_area_struct *vma);
+
+#define clear_user_page clear_user_page
void clear_user_page(void *to, unsigned long u_vaddr, struct page *page);
typedef struct {
diff --git a/arch/arm/include/asm/page-nommu.h b/arch/arm/include/asm/page-nommu.h
index 7c2c72323d17..e74415c959be 100644
--- a/arch/arm/include/asm/page-nommu.h
+++ b/arch/arm/include/asm/page-nommu.h
@@ -11,7 +11,6 @@
#define clear_page(page) memset((page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((to), (from), PAGE_SIZE)
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
/*
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 00f117ff4f7a..b39cc1127e1f 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -36,7 +36,6 @@ struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma,
bool tag_clear_highpages(struct page *to, int numpages);
#define __HAVE_ARCH_TAG_CLEAR_HIGHPAGES
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
typedef struct page *pgtable_t;
diff --git a/arch/csky/abiv1/inc/abi/page.h b/arch/csky/abiv1/inc/abi/page.h
index 2d2159933b76..58307254e7e5 100644
--- a/arch/csky/abiv1/inc/abi/page.h
+++ b/arch/csky/abiv1/inc/abi/page.h
@@ -10,6 +10,7 @@ static inline unsigned long pages_do_alias(unsigned long addr1,
return (addr1 ^ addr2) & (SHMLBA-1);
}
+#define clear_user_page clear_user_page
static inline void clear_user_page(void *addr, unsigned long vaddr,
struct page *page)
{
diff --git a/arch/csky/abiv2/inc/abi/page.h b/arch/csky/abiv2/inc/abi/page.h
index cf005f13cd15..a5a255013308 100644
--- a/arch/csky/abiv2/inc/abi/page.h
+++ b/arch/csky/abiv2/inc/abi/page.h
@@ -1,11 +1,4 @@
/* SPDX-License-Identifier: GPL-2.0 */
-
-static inline void clear_user_page(void *addr, unsigned long vaddr,
- struct page *page)
-{
- clear_page(addr);
-}
-
static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
struct page *page)
{
diff --git a/arch/hexagon/include/asm/page.h b/arch/hexagon/include/asm/page.h
index 137ba7c5de48..f0aed3ed812b 100644
--- a/arch/hexagon/include/asm/page.h
+++ b/arch/hexagon/include/asm/page.h
@@ -113,7 +113,6 @@ static inline void clear_page(void *page)
/*
* Under assumption that kernel always "sees" user map...
*/
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
static inline unsigned long virt_to_pfn(const void *kaddr)
diff --git a/arch/loongarch/include/asm/page.h b/arch/loongarch/include/asm/page.h
index 256d1ff7a1e3..327bf0bc92bf 100644
--- a/arch/loongarch/include/asm/page.h
+++ b/arch/loongarch/include/asm/page.h
@@ -30,7 +30,6 @@
extern void clear_page(void *page);
extern void copy_page(void *to, void *from);
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
extern unsigned long shm_align_mask;
diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h
index 39db2026a4b4..d2532bc407ef 100644
--- a/arch/m68k/include/asm/page_no.h
+++ b/arch/m68k/include/asm/page_no.h
@@ -10,7 +10,6 @@ extern unsigned long memory_end;
#define clear_page(page) memset((page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((to), (from), PAGE_SIZE)
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
diff --git a/arch/microblaze/include/asm/page.h b/arch/microblaze/include/asm/page.h
index 90ac9f34b4b4..e1e396367ba7 100644
--- a/arch/microblaze/include/asm/page.h
+++ b/arch/microblaze/include/asm/page.h
@@ -45,7 +45,6 @@ typedef unsigned long pte_basic_t;
# define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
# define clear_page(pgaddr) memset((pgaddr), 0, PAGE_SIZE)
-# define clear_user_page(pgaddr, vaddr, page) memset((pgaddr), 0, PAGE_SIZE)
# define copy_user_page(vto, vfrom, vaddr, topg) \
memcpy((vto), (vfrom), PAGE_SIZE)
diff --git a/arch/mips/include/asm/page.h b/arch/mips/include/asm/page.h
index bc3e3484c1bf..5ec428fcc887 100644
--- a/arch/mips/include/asm/page.h
+++ b/arch/mips/include/asm/page.h
@@ -90,6 +90,7 @@ static inline void clear_user_page(void *addr, unsigned long vaddr,
if (pages_do_alias((unsigned long) addr, vaddr & PAGE_MASK))
flush_data_cache_page((unsigned long)addr);
}
+#define clear_user_page clear_user_page
struct vm_area_struct;
extern void copy_user_highpage(struct page *to, struct page *from,
diff --git a/arch/nios2/include/asm/page.h b/arch/nios2/include/asm/page.h
index 00a51623d38a..722956ac0bf8 100644
--- a/arch/nios2/include/asm/page.h
+++ b/arch/nios2/include/asm/page.h
@@ -45,6 +45,7 @@
struct page;
+#define clear_user_page clear_user_page
extern void clear_user_page(void *addr, unsigned long vaddr, struct page *page);
extern void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
struct page *to);
diff --git a/arch/openrisc/include/asm/page.h b/arch/openrisc/include/asm/page.h
index 85797f94d1d7..d2cdbf3579bb 100644
--- a/arch/openrisc/include/asm/page.h
+++ b/arch/openrisc/include/asm/page.h
@@ -30,7 +30,6 @@
#define clear_page(page) memset((page), 0, PAGE_SIZE)
#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
/*
diff --git a/arch/parisc/include/asm/page.h b/arch/parisc/include/asm/page.h
index 8f4e51071ea1..3630b36d07da 100644
--- a/arch/parisc/include/asm/page.h
+++ b/arch/parisc/include/asm/page.h
@@ -21,7 +21,6 @@ struct vm_area_struct;
void clear_page_asm(void *page);
void copy_page_asm(void *to, void *from);
-#define clear_user_page(vto, vaddr, page) clear_page_asm(vto)
void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr,
struct vm_area_struct *vma);
#define __HAVE_ARCH_COPY_USER_HIGHPAGE
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index b28fbb1d57eb..f2bb1f98eebe 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -271,6 +271,7 @@ static inline const void *pfn_to_kaddr(unsigned long pfn)
struct page;
extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
+#define clear_user_page clear_user_page
extern void copy_user_page(void *to, void *from, unsigned long vaddr,
struct page *p);
extern int devmem_is_allowed(unsigned long pfn);
diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index ffe213ad65a4..061b60b954ec 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -50,7 +50,6 @@ void clear_page(void *page);
#endif
#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
-#define clear_user_page(pgaddr, vaddr, page) clear_page(pgaddr)
#define copy_user_page(vto, vfrom, vaddr, topg) \
memcpy((vto), (vfrom), PAGE_SIZE)
diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index c1d63b613bf9..9c8c5283258e 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -65,7 +65,6 @@ static inline void copy_page(void *to, void *from)
: : "memory", "cc");
}
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index d764d8a8586b..fd4dc85fb38b 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -43,6 +43,7 @@ void _clear_page(void *page);
#define clear_page(X) _clear_page((void *)(X))
struct page;
void clear_user_page(void *addr, unsigned long vaddr, struct page *page);
+#define clear_user_page clear_user_page
#define copy_page(X,Y) memcpy((void *)(X), (void *)(Y), PAGE_SIZE)
void copy_user_page(void *to, void *from, unsigned long vaddr, struct page *topage);
#define __HAVE_ARCH_COPY_USER_HIGHPAGE
diff --git a/arch/um/include/asm/page.h b/arch/um/include/asm/page.h
index 2d363460d896..e348ff489b89 100644
--- a/arch/um/include/asm/page.h
+++ b/arch/um/include/asm/page.h
@@ -26,7 +26,6 @@ struct page;
#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((void *)(to), (void *)(from), PAGE_SIZE)
-#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
typedef struct { unsigned long pte; } pte_t;
diff --git a/arch/x86/include/asm/page.h b/arch/x86/include/asm/page.h
index 9265f2fca99a..416dc88e35c1 100644
--- a/arch/x86/include/asm/page.h
+++ b/arch/x86/include/asm/page.h
@@ -22,12 +22,6 @@ struct page;
extern struct range pfn_mapped[];
extern int nr_pfn_mapped;
-static inline void clear_user_page(void *page, unsigned long vaddr,
- struct page *pg)
-{
- clear_page(page);
-}
-
static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
struct page *topage)
{
diff --git a/arch/xtensa/include/asm/page.h b/arch/xtensa/include/asm/page.h
index 20655174b111..059493256765 100644
--- a/arch/xtensa/include/asm/page.h
+++ b/arch/xtensa/include/asm/page.h
@@ -126,7 +126,6 @@ void clear_user_highpage(struct page *page, unsigned long vaddr);
void copy_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma);
#else
-# define clear_user_page(page, vaddr, pg) clear_page(page)
# define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
#endif
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index abc20f9810fd..9a38512b8000 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -197,15 +197,34 @@ static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
}
#endif
-/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
#ifndef clear_user_highpage
+#ifndef clear_user_page
+/**
+ * clear_user_page() - clear a page to be mapped to user space
+ * @addr: the address of the page
+ * @vaddr: the address of the user mapping
+ * @page: the page
+ *
+ * We condition the definition of clear_user_page() on the architecture not
+ * having a custom clear_user_highpage(). That's because if there is some
+ * special flushing needed for clear_user_highpage() then it is likely that
+ * clear_user_page() also needs some magic. And, since our only caller
+ * is the generic clear_user_highpage(), not defining is not much of a loss.
+ */
+static inline void clear_user_page(void *addr, unsigned long vaddr, struct page *page)
+{
+ clear_page(addr);
+}
+#endif
+
+/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
{
void *addr = kmap_local_page(page);
clear_user_page(addr, vaddr, page);
kunmap_local(addr);
}
-#endif
+#endif /* clear_user_highpage */
#ifndef vma_alloc_zeroed_movable_folio
/**
--
2.31.1On 12/15/25 21:49, Ankur Arora wrote: > From: David Hildenbrand <david@redhat.com> > > Let's drop all variants that effectively map to clear_page() and > provide it in a generic variant instead. > > We'll use the macro clear_user_page to indicate whether an architecture > provides it's own variant. Maybe at some point these should be CONFIG_ > options. Can we drop the second sentence? > > Also, clear_user_page() is only called from the generic variant of > clear_user_highpage(), so define it only if the architecture does > not provide a clear_user_highpage(). And, for simplicity define it > in linux/highmem.h. > > Note that for parisc, clear_page() and clear_user_page() map to > clear_page_asm(), so we can just get rid of the custom clear_user_page() > implementation. There is a clear_user_page_asm() function on parisc, > that seems to be unused. Not sure what's up with that. > > Signed-off-by: David Hildenbrand <david@redhat.com> You should likely now add Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com> above your SB :) > Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Skimmed over it and nothing jumped at me. -- Cheers David
David Hildenbrand (Red Hat) <david@kernel.org> writes: > On 12/15/25 21:49, Ankur Arora wrote: >> From: David Hildenbrand <david@redhat.com> >> Let's drop all variants that effectively map to clear_page() and >> provide it in a generic variant instead. >> We'll use the macro clear_user_page to indicate whether an architecture >> provides it's own variant. Maybe at some point these should be CONFIG_ >> options. > > Can we drop the second sentence? Ack. >> Also, clear_user_page() is only called from the generic variant of >> clear_user_highpage(), so define it only if the architecture does >> not provide a clear_user_highpage(). And, for simplicity define it >> in linux/highmem.h. >> Note that for parisc, clear_page() and clear_user_page() map to >> clear_page_asm(), so we can just get rid of the custom clear_user_page() >> implementation. There is a clear_user_page_asm() function on parisc, >> that seems to be unused. Not sure what's up with that. >> Signed-off-by: David Hildenbrand <david@redhat.com> > > You should likely now add > > Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com> > > above your SB :) :). >> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> > > Skimmed over it and nothing jumped at me. Great! -- ankur
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