Re: [PATCH v9 03/10] set_memory.h: Introduce can_set_direct_map_range()

[Mike Rapoport <rppt@kernel.org>]

On Wed, Sep 02, 2026 at 11:47:05AM +0100, Vincent Donnefort wrote:
> While can_set_direct_map() tells whether the direct map can be modified
> globally, can_set_direct_map_range() checks if a specific range can be
> modified. e.g. if mapped at PTE-level.

set_direct_map are going to have number of pages parameter soon:

https://lore.kernel.org/all/20260903-execmem-set-vm-perms-v0-2-v3-1-949b64a9f755@kernel.org

so this check can be a part of arm64::set_direct_map

I wouldn't expose can_set_direct_map_range() as a public API and rely on
the callers to "Do The Right Thing".
  
> Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
> 
> diff --git a/include/linux/set_memory.h b/include/linux/set_memory.h
> index 3030d9245f5a..88175c3fa751 100644
> --- a/include/linux/set_memory.h
> +++ b/include/linux/set_memory.h
> @@ -44,6 +44,12 @@ static inline bool kernel_page_present(struct page *page)
>  {
>  	return true;
>  }
> +
> +static inline bool can_set_direct_map_range(struct page *page,
> +					    unsigned long nr_pages)
> +{
> +	return false;
> +}
>  #else /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
>  /*
>   * Some architectures, e.g. ARM64 can disable direct map modifications at
> @@ -56,6 +62,14 @@ static inline bool can_set_direct_map(void)
>  }
>  #define can_set_direct_map can_set_direct_map
>  #endif
> +
> +#ifndef can_set_direct_map_range
> +static inline bool can_set_direct_map_range(struct page *page, unsigned long nr_pages)
> +{
> +	return can_set_direct_map();
> +}
> +#define can_set_direct_map_range can_set_direct_map_range
> +#endif
>  #endif /* CONFIG_ARCH_HAS_SET_DIRECT_MAP */
>  
>  #ifdef CONFIG_X86_64
> -- 
> 2.55.0.970.g62bdec98f9-goog
> 

-- 
Sincerely yours,
Mike.