Re: [PATCH 2/2] x86/mm: nuke PAGE_KERNEL_IO

[Lucas De Marchi <lucas.demarchi@xxxxxxxxx>]

Hi, gentle ping on this. Is it something that could go through the tip
tree?

thanks
Lucas De Marchi

On Thu, Oct 21, 2021 at 11:15:11AM -0700, Lucas De Marchi wrote:
> PAGE_KERNEL_IO is only defined for x86 and nowadays is the same as
> PAGE_KERNEL. It was different for some time, OR'ing a `_PAGE_IOMAP` flag
> in commit be43d72835ba ("x86: add _PAGE_IOMAP pte flag for IO
> mappings").  This got removed in commit f955371ca9d3 ("x86: remove the
> Xen-specific _PAGE_IOMAP PTE flag"), so today they are just the same.
>
> With the last users outside arch/x86 being remove we can now remove
> PAGE_KERNEL_IO.
>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> ---
> arch/x86/include/asm/fixmap.h        | 2 +-
> arch/x86/include/asm/pgtable_types.h | 7 -------
> arch/x86/mm/ioremap.c                | 2 +-
> arch/x86/xen/setup.c                 | 2 +-
> include/asm-generic/fixmap.h         | 2 +-
> 5 files changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
> index d0dcefb5cc59..5e186a69db10 100644
> --- a/arch/x86/include/asm/fixmap.h
> +++ b/arch/x86/include/asm/fixmap.h
> @@ -173,7 +173,7 @@ static inline void __set_fixmap(enum fixed_addresses idx,
>  * supported for MMIO addresses, so make sure that the memory encryption
>  * mask is not part of the page attributes.
>  */
> -#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_IO_NOCACHE
> +#define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
>
> /*
>  * Early memremap routines used for in-place encryption. The mappings created
> diff --git a/arch/x86/include/asm/pgtable_types.h 
> b/arch/x86/include/asm/pgtable_types.h
> index 40497a9020c6..a87224767ff3 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -199,10 +199,6 @@ enum page_cache_mode {
> #define __PAGE_KERNEL_WP         (__PP|__RW|   0|___A|__NX|___D|   0|___G| __WP)
>
>
> -#define __PAGE_KERNEL_IO               __PAGE_KERNEL
> -#define __PAGE_KERNEL_IO_NOCACHE       __PAGE_KERNEL_NOCACHE
> -
> -
> #ifndef __ASSEMBLY__
>
> #define __PAGE_KERNEL_ENC       (__PAGE_KERNEL    | _ENC)
> @@ -223,9 +219,6 @@ enum page_cache_mode {
> #define PAGE_KERNEL_LARGE_EXEC  __pgprot_mask(__PAGE_KERNEL_LARGE_EXEC | _ENC)
> #define PAGE_KERNEL_VVAR        __pgprot_mask(__PAGE_KERNEL_VVAR       | _ENC)
>
> -#define PAGE_KERNEL_IO         __pgprot_mask(__PAGE_KERNEL_IO)
> -#define PAGE_KERNEL_IO_NOCACHE __pgprot_mask(__PAGE_KERNEL_IO_NOCACHE)
> -
> #endif  /* __ASSEMBLY__ */
>
> /*         xwr */
> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
> index 026031b3b782..3102dda4b152 100644
> --- a/arch/x86/mm/ioremap.c
> +++ b/arch/x86/mm/ioremap.c
> @@ -243,7 +243,7 @@ __ioremap_caller(resource_size_t phys_addr, unsigned long 
> size,
>          * make sure the memory encryption attribute is enabled in the
>          * resulting mapping.
>          */
> -       prot = PAGE_KERNEL_IO;
> +       prot = PAGE_KERNEL;
>         if ((io_desc.flags & IORES_MAP_ENCRYPTED) || encrypted)
>                 prot = pgprot_encrypted(prot);
>
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index 8bfc10330107..5dc0771a50f3 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -435,7 +435,7 @@ static unsigned long __init 
> xen_set_identity_and_remap_chunk(
>         for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
>                 (void)HYPERVISOR_update_va_mapping(
>                         (unsigned long)__va(pfn << PAGE_SHIFT),
> -                       mfn_pte(pfn, PAGE_KERNEL_IO), 0);
> +                       mfn_pte(pfn, PAGE_KERNEL), 0);
>
>         return remap_pfn;
> }
> diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h
> index 8cc7b09c1bc7..f1b0c6f3d0be 100644
> --- a/include/asm-generic/fixmap.h
> +++ b/include/asm-generic/fixmap.h
> @@ -54,7 +54,7 @@ static inline unsigned long virt_to_fix(const unsigned long 
> vaddr)
> #define FIXMAP_PAGE_NOCACHE PAGE_KERNEL_NOCACHE
> #endif
> #ifndef FIXMAP_PAGE_IO
> -#define FIXMAP_PAGE_IO PAGE_KERNEL_IO
> +#define FIXMAP_PAGE_IO PAGE_KERNEL
> #endif
> #ifndef FIXMAP_PAGE_CLEAR
> #define FIXMAP_PAGE_CLEAR __pgprot(0)
> --
> 2.33.1