Re: [PATCH] arm64: add kc_offset_to_vaddr and kc_vaddr_to_offset macro

[Will Deacon]

On Sun, Aug 30, 2015 at 07:19:59AM +0100, yalin wang wrote:
> This patch add kc_offset_to_vaddr() and kc_vaddr_to_offset(),
> the default version doesn't work on arm64, because arm64 kernel address
> is below the PAGE_OFFSET, like module address and vmemmap address are
> all below PAGE_OFFSET address.
> 
> Signed-off-by: yalin wang <yalin.wang2010@xxxxxxxxx>
> ---
>  arch/arm64/include/asm/pgtable.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index d374191..ef1ed5c 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -660,6 +660,8 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
>  
>  #define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)
>  
> +#define	kc_vaddr_to_offset(v) ((v) & ((1UL << VA_BITS) - 1))
> +#define	kc_offset_to_vaddr(o) ((o) | ~((1UL << VA_BITS) - 1))

I think it would be cleaner to define something like VIRTUAL_BASE, and
then define the vmalloc area in terms of that as well as these kcore
macros.

Will
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