[PATCH v34 05/14] arm64: mm: add set_memory_valid()

[Ard Biesheuvel]

On 28 March 2017 at 07:51, AKASHI Takahiro <takahiro.akashi at linaro.org> wrote:
> This function validates and invalidates PTE entries, and will be utilized
> in kdump to protect loaded crash dump kernel image.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

> ---
>  arch/arm64/include/asm/cacheflush.h |  1 +
>  arch/arm64/mm/pageattr.c            | 15 +++++++++------
>  2 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
> index 5a2a6ee65f65..728f933cef8c 100644
> --- a/arch/arm64/include/asm/cacheflush.h
> +++ b/arch/arm64/include/asm/cacheflush.h
> @@ -154,5 +154,6 @@ int set_memory_ro(unsigned long addr, int numpages);
>  int set_memory_rw(unsigned long addr, int numpages);
>  int set_memory_x(unsigned long addr, int numpages);
>  int set_memory_nx(unsigned long addr, int numpages);
> +int set_memory_valid(unsigned long addr, unsigned long size, int enable);
>
>  #endif
> diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
> index 8def55e7249b..3212ee0558f6 100644
> --- a/arch/arm64/mm/pageattr.c
> +++ b/arch/arm64/mm/pageattr.c
> @@ -125,20 +125,23 @@ int set_memory_x(unsigned long addr, int numpages)
>  }
>  EXPORT_SYMBOL_GPL(set_memory_x);
>
> -#ifdef CONFIG_DEBUG_PAGEALLOC
> -void __kernel_map_pages(struct page *page, int numpages, int enable)
> +int set_memory_valid(unsigned long addr, int numpages, int enable)
>  {
> -       unsigned long addr = (unsigned long) page_address(page);
> -
>         if (enable)
> -               __change_memory_common(addr, PAGE_SIZE * numpages,
> +               return __change_memory_common(addr, PAGE_SIZE * numpages,
>                                         __pgprot(PTE_VALID),
>                                         __pgprot(0));
>         else
> -               __change_memory_common(addr, PAGE_SIZE * numpages,
> +               return __change_memory_common(addr, PAGE_SIZE * numpages,
>                                         __pgprot(0),
>                                         __pgprot(PTE_VALID));
>  }
> +
> +#ifdef CONFIG_DEBUG_PAGEALLOC
> +void __kernel_map_pages(struct page *page, int numpages, int enable)
> +{
> +       set_memory_valid((unsigned long)page_address(page), numpages, enable);
> +}
>  #ifdef CONFIG_HIBERNATION
>  /*
>   * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function
> --
> 2.11.1
>