[PATCH v5sub1 2/8] arm64: add support for ioremap() block mappings

[Mark Rutland]

On Mon, Feb 01, 2016 at 11:54:47AM +0100, Ard Biesheuvel wrote:
> This wires up the existing generic huge-vmap feature, which allows
> ioremap() to use PMD or PUD sized block mappings. It also adds support
> to the unmap path for dealing with block mappings, which will allow us
> to unmap the __init region using unmap_kernel_range() in a subsequent
> patch.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

Reviewed-by: Mark Rutland <mark.rutland at arm.com>

I was a little bit worried about this potentially not matching the
granularity we used when creating mappings, but seeing how
p?d_clear_huge are called by unmap_kernel_range, I think this is fine.

Thanks,
Mark

> ---
>  Documentation/features/vm/huge-vmap/arch-support.txt |  2 +-
>  arch/arm64/Kconfig                                   |  1 +
>  arch/arm64/include/asm/memory.h                      |  6 +++
>  arch/arm64/mm/mmu.c                                  | 41 ++++++++++++++++++++
>  4 files changed, 49 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/features/vm/huge-vmap/arch-support.txt b/Documentation/features/vm/huge-vmap/arch-support.txt
> index af6816bccb43..df1d1f3c9af2 100644
> --- a/Documentation/features/vm/huge-vmap/arch-support.txt
> +++ b/Documentation/features/vm/huge-vmap/arch-support.txt
> @@ -9,7 +9,7 @@
>      |       alpha: | TODO |
>      |         arc: | TODO |
>      |         arm: | TODO |
> -    |       arm64: | TODO |
> +    |       arm64: |  ok  |
>      |       avr32: | TODO |
>      |    blackfin: | TODO |
>      |         c6x: | TODO |
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 8cc62289a63e..cd767fa3037a 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -49,6 +49,7 @@ config ARM64
>  	select HAVE_ALIGNED_STRUCT_PAGE if SLUB
>  	select HAVE_ARCH_AUDITSYSCALL
>  	select HAVE_ARCH_BITREVERSE
> +	select HAVE_ARCH_HUGE_VMAP
>  	select HAVE_ARCH_JUMP_LABEL
>  	select HAVE_ARCH_KASAN if SPARSEMEM_VMEMMAP && !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
>  	select HAVE_ARCH_KGDB
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index 853953cd1f08..c65aad7b13dc 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -100,6 +100,12 @@
>  #define MT_S2_NORMAL		0xf
>  #define MT_S2_DEVICE_nGnRE	0x1
>  
> +#ifdef CONFIG_ARM64_4K_PAGES
> +#define IOREMAP_MAX_ORDER	(PUD_SHIFT)
> +#else
> +#define IOREMAP_MAX_ORDER	(PMD_SHIFT)
> +#endif
> +
>  #ifndef __ASSEMBLY__
>  
>  extern phys_addr_t		memstart_addr;
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 7711554a94f4..73383019f212 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -714,3 +714,44 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
>  
>  	return dt_virt;
>  }
> +
> +int __init arch_ioremap_pud_supported(void)
> +{
> +	/* only 4k granule supports level 1 block mappings */
> +	return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
> +}
> +
> +int __init arch_ioremap_pmd_supported(void)
> +{
> +	return 1;
> +}
> +
> +int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
> +{
> +	BUG_ON(phys & ~PUD_MASK);
> +	set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
> +	return 1;
> +}
> +
> +int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
> +{
> +	BUG_ON(phys & ~PMD_MASK);
> +	set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
> +	return 1;
> +}
> +
> +int pud_clear_huge(pud_t *pud)
> +{
> +	if (!pud_sect(*pud))
> +		return 0;
> +	pud_clear(pud);
> +	return 1;
> +}
> +
> +int pmd_clear_huge(pmd_t *pmd)
> +{
> +	if (!pmd_sect(*pmd))
> +		return 0;
> +	pmd_clear(pmd);
> +	return 1;
> +}
> -- 
> 2.5.0
>