RE: [PATCH] Hexagon: Make pfn accessors statics inlines

[Brian Cain]

> -----Original Message-----
> From: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Sent: Tuesday, August 8, 2023 3:30 AM
> To: Brian Cain <bcain@xxxxxxxxxxx>
> Cc: linux-hexagon@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Linus Walleij
> <linus.walleij@xxxxxxxxxx>
> Subject: [PATCH] Hexagon: Make pfn accessors statics inlines
> 
> WARNING: This email originated from outside of Qualcomm. Please be wary of
> any links or attachments, and do not enable macros.
> 
> Making virt_to_pfn() a static inline taking a strongly typed
> (const void *) makes the contract of a passing a pointer of that
> type to the function explicit and exposes any misuse of the
> macro virt_to_pfn() acting polymorphic and accepting many types
> such as (void *), (unitptr_t) or (unsigned long) as arguments
> without warnings.
> 
> For symmetry do the same with pfn_to_virt().
> 
> For compiletime resolution of __pa() we need PAGE_OFFSET which
> was not available to __pa() and resolved by the preprocessor
> wherever __pa() was used. Fix this by explicitly including
> <asm/mem-layout.h> where required, following the pattern of the
> architectures page.h file.
> 
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
>  arch/hexagon/include/asm/page.h | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/hexagon/include/asm/page.h
> b/arch/hexagon/include/asm/page.h
> index 9c03b9965f07..b3d4a2c065be 100644
> --- a/arch/hexagon/include/asm/page.h
> +++ b/arch/hexagon/include/asm/page.h
> @@ -78,6 +78,9 @@ typedef struct page *pgtable_t;
>  #define __pgd(x)       ((pgd_t) { (x) })
>  #define __pgprot(x)    ((pgprot_t) { (x) })
> 
> +/* Needed for PAGE_OFFSET used in the macro right below */
> +#include <asm/mem-layout.h>
> +
>  /*
>   * We need a __pa and a __va routine for kernel space.
>   * MIPS says they're only used during mem_init.
> @@ -125,8 +128,16 @@ static inline void clear_page(void *page)
>   */
>  #define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
> 
> -#define virt_to_pfn(kaddr)      (__pa(kaddr) >> PAGE_SHIFT)
> -#define pfn_to_virt(pfn)        __va((pfn) << PAGE_SHIFT)
> +static inline unsigned long virt_to_pfn(const void *kaddr)
> +{
> +       return __pa(kaddr) >> PAGE_SHIFT;
> +}
> +
> +static inline void * pfn_to_virt(unsigned long pfn)
> +{
> +       return __va(pfn) << PAGE_SHIFT;
> +}
> +
> 
>  #define page_to_virt(page)     __va(page_to_phys(page))
> 
> 
> ---
> base-commit: 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5
> change-id: 20230808-hexagon-virt-to-pfn-457bd51a5744
> 
> Best regards,
> --
> Linus Walleij <linus.walleij@xxxxxxxxxx>

Acked-by: Brian Cain <bcain@xxxxxxxxxxx>