[PATCH] riscv: mm: define copy_user_page() as copy_page()

[PATCH] riscv: mm: define copy_user_page() as copy_page()

[Florian Schmaus]

Currently, the implementation of copy_user_page() is identical to
copy_page().

Align riscv with other architectures (alpha, arc, arm64, hexagon,
longarch, m68k, openrisc, s390, um, xtensa) and map copy_user_page()
to copy_page() given that their implementation is identical.

In addition to following a common pattern, this centralizes the
implementation. Any changes to the underlying page copy logic (e.g.,
for CHERI) will now automatically propagate to copy_user_page().

Signed-off-by: Florian Schmaus <florian.schmaus@codasip.com>
---
 arch/riscv/include/asm/page.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
index ffe213ad65a4..3c517bc9eac5 100644
--- a/arch/riscv/include/asm/page.h
+++ b/arch/riscv/include/asm/page.h
@@ -51,8 +51,7 @@ void clear_page(void *page);
 #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)
+#define copy_user_page(vto, vfrom, vaddr, topg) copy_page(vto, vfrom)
 
 /*
  * Use struct definitions to apply C type checking
-- 
2.52.0


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

Re: [PATCH] riscv: mm: define copy_user_page() as copy_page()

[김동현]

Hello,

2026년 1월 13일 (화) 오후 10:42, Florian Schmaus <florian.schmaus@codasip.com>님이 작성:
>
> Currently, the implementation of copy_user_page() is identical to
> copy_page().
>
> Align riscv with other architectures (alpha, arc, arm64, hexagon,
> longarch, m68k, openrisc, s390, um, xtensa) and map copy_user_page()
> to copy_page() given that their implementation is identical.
>
> In addition to following a common pattern, this centralizes the
> implementation. Any changes to the underlying page copy logic (e.g.,
> for CHERI) will now automatically propagate to copy_user_page().
>
> Signed-off-by: Florian Schmaus <florian.schmaus@codasip.com>
> ---
>  arch/riscv/include/asm/page.h | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h
> index ffe213ad65a4..3c517bc9eac5 100644
> --- a/arch/riscv/include/asm/page.h
> +++ b/arch/riscv/include/asm/page.h
> @@ -51,8 +51,7 @@ void clear_page(void *page);
>  #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)
> +#define copy_user_page(vto, vfrom, vaddr, topg) copy_page(vto, vfrom)

Here are the observation over this patch:

1. After compiling with 'CROSS_COMPILE=riscv64-linux-gnu-' option,
the following is the corresponding statement for copy_user_page() in
preprocessed file.

 do { do { __attribute__((__noreturn__)) extern void
__compiletime_assert_333(void) __attribute__((__error__("BUILD_BUG_ON
failed: " "__same_type((vto), struct page *)"))); if
(!(!(__builtin_types_compatible_p(typeof((vto)), typeof(struct page
*))))) __compiletime_assert_333(); } while (0); __kunmap_atomic(vto);
} while (0);

Output is the same - before/after patch: That means that the generated
risc-v instruction is the same.

2. copy_user_page() is only used in dax file system (fs/dax.c)

3. With the new patch, the full compilation for all of the code happens.

BR,
Austin Kim
>
>  /*
>   * Use struct definitions to apply C type checking
> --
> 2.52.0
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv