Re: [PATCH 2/2] x86/mm/KASLR: Correct the upper boundary of KALSR mm regions if adjacent to EFI

[Dave Young]

On 03/08/17 at 03:47pm, Baoquan He wrote:
> EFI allocates runtime services regions top-down, starting from EFI_VA_START
> to EFI_VA_END. So EFI_VA_START is bigger than EFI_VA_END and is the end of
> EFI region. The upper boundary of memory regions randomized by KASLR should
> be EFI_VA_END if it's adjacent to EFI region, but not EFI_VA_START.
> 
> Correct it in this patch.
> 
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
>  arch/x86/mm/kaslr.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
> index 887e571..aed2064 100644
> --- a/arch/x86/mm/kaslr.c
> +++ b/arch/x86/mm/kaslr.c
> @@ -48,7 +48,7 @@ static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
>  #if defined(CONFIG_X86_ESPFIX64)
>  static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
>  #elif defined(CONFIG_EFI)
> -static const unsigned long vaddr_end = EFI_VA_START;
> +static const unsigned long vaddr_end = EFI_VA_END;
>  #else
>  static const unsigned long vaddr_end = __START_KERNEL_map;
>  #endif
> @@ -105,7 +105,7 @@ void __init kernel_randomize_memory(void)
>  	 */
>  	BUILD_BUG_ON(vaddr_start >= vaddr_end);
>  	BUILD_BUG_ON(IS_ENABLED(CONFIG_X86_ESPFIX64) &&
> -		     vaddr_end >= EFI_VA_START);
> +		     vaddr_end >= EFI_VA_END);
>  	BUILD_BUG_ON((IS_ENABLED(CONFIG_X86_ESPFIX64) ||
>  		      IS_ENABLED(CONFIG_EFI)) &&
>  		     vaddr_end >= __START_KERNEL_map);
> -- 
> 2.5.5
> 

Acked-by: Dave Young <dyoung@xxxxxxxxxx>

Thanks
Dave