Re: [PATCH] RISC-V: fix virtual address overlapped in FIXADDR_START and VMEMMAP_START

[Anup Patel]

On Wed, Oct 16, 2019 at 1:04 PM <greentime.hu@xxxxxxxxxx> wrote:
>
> From: Greentime Hu <greentime.hu@xxxxxxxxxx>
>
> This patch fixes the virtual address layout in pgtable.h.
> The virtual address of FIXADDR_START and VMEMMAP_START should not be overlapped.
> These addresses will be existed at the same time in Linux kernel that they can't
> be overlapped.
>
> Fixes: d95f1a542c3d ("RISC-V: Implement sparsemem")
> Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
> ---
>  arch/riscv/include/asm/pgtable.h | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 4f4162d90586..b927fb4ecf1c 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -87,14 +87,6 @@ extern pgd_t swapper_pg_dir[];
>  #define VMALLOC_END      (PAGE_OFFSET - 1)
>  #define VMALLOC_START    (PAGE_OFFSET - VMALLOC_SIZE)
>
> -#define FIXADDR_TOP      VMALLOC_START
> -#ifdef CONFIG_64BIT
> -#define FIXADDR_SIZE     PMD_SIZE
> -#else
> -#define FIXADDR_SIZE     PGDIR_SIZE
> -#endif
> -#define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
> -
>  /*
>   * Roughly size the vmemmap space to be large enough to fit enough
>   * struct pages to map half the virtual address space. Then
> @@ -108,6 +100,14 @@ extern pgd_t swapper_pg_dir[];
>
>  #define vmemmap                ((struct page *)VMEMMAP_START)
>
> +#define FIXADDR_TOP      (VMEMMAP_START)
> +#ifdef CONFIG_64BIT
> +#define FIXADDR_SIZE     PMD_SIZE
> +#else
> +#define FIXADDR_SIZE     PGDIR_SIZE
> +#endif
> +#define FIXADDR_START    (FIXADDR_TOP - FIXADDR_SIZE)
> +
>  /*
>   * ZERO_PAGE is a global shared page that is always zero,
>   * used for zero-mapped memory areas, etc.
> --
> 2.17.1
>

Looks good to me.

Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>

Regards,
Anup