Re: [PATCH v2 2/4] kaslr: select the memory region in immovable node to process

[Baoquan He]

Hi Chao,

On 11/01/17 at 07:32pm, Chao Fan wrote:
> Compare the region of memmap entry and immovable_mem, then choose the
> intersection to process_mem_region.
> 
> Since the interrelationship between e820 or efi entries and memory
> region in immovable_mem is different:

Could you paste a bootlog with efi=debug specified in cmdline on the
system you tested? I want to check what kind of intersection between
them. The adding makes code pretty ugly, want to make sure if we have
to do like this.

Thanks
Baoquan

> One memory region in one node may contain several entries of e820 or
> efi sometimes, and one entry of e820 or efi may contain the memory in
> different nodes sometimes.
> It may split one node or one entry to several regions.
> 
> Signed-off-by: Chao Fan <fanc.f...@cn.fujitsu.com>
> ---
>  arch/x86/boot/compressed/kaslr.c | 60 
> ++++++++++++++++++++++++++++++++++------
>  1 file changed, 52 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/boot/compressed/kaslr.c 
> b/arch/x86/boot/compressed/kaslr.c
> index 0a591c0023f1..fcd640fdeaed 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -634,6 +634,54 @@ static void process_mem_region(struct mem_vector *entry,
>       }
>  }
>  
> +static bool select_immovable_node(struct mem_vector region,
> +                               unsigned long long minimum,
> +                               unsigned long long image_size)
> +{
> +     int i;
> +
> +     /* If no immovable_mem stored, use region directly */
> +     if (num_immovable_region == 0) {
> +             process_mem_region(&region, minimum, image_size);
> +
> +             if (slot_area_index == MAX_SLOT_AREA) {
> +                     debug_putstr("Aborted memmap scan (slot_areas 
> full)!\n");
> +                     return 1;
> +             }
> +     } else {
> +             /*
> +              * Walk all immovable regions, and filter the intersection
> +              * to process_mem_region.
> +              */
> +             for (i = 0; i < num_immovable_region; i++) {
> +                     struct mem_vector entry;
> +                     unsigned long long start, end, select_end, region_end;
> +
> +                     region_end = region.start + region.size - 1;
> +                     start = immovable_mem[i].start;
> +                     end = start + immovable_mem[i].size - 1;
> +
> +                     if (region_end < start || region.start > end)
> +                             continue;
> +
> +                     /* May split one region to several entries. */
> +                     entry.start = start > region.start ?
> +                                   start : region.start;
> +                     select_end = end > region_end ? region_end : end;
> +
> +                     entry.size = select_end - entry.start + 1;
> +
> +                     process_mem_region(&entry, minimum, image_size);
> +
> +                     if (slot_area_index == MAX_SLOT_AREA) {
> +                             debug_putstr("Aborted memmap scan (slot_areas 
> full)!\n");
> +                             return 1;
> +                     }
> +             }
> +     }
> +     return 0;
> +}
> +
>  #ifdef CONFIG_EFI
>  /*
>   * Returns true if mirror region found (and must have been processed
> @@ -699,11 +747,9 @@ process_efi_entries(unsigned long minimum, unsigned long 
> image_size)
>  
>               region.start = md->phys_addr;
>               region.size = md->num_pages << EFI_PAGE_SHIFT;
> -             process_mem_region(&region, minimum, image_size);
> -             if (slot_area_index == MAX_SLOT_AREA) {
> -                     debug_putstr("Aborted EFI scan (slot_areas full)!\n");
> +
> +             if (select_immovable_node(region, minimum, image_size))
>                       break;
> -             }
>       }
>       return true;
>  }
> @@ -730,11 +776,9 @@ static void process_e820_entries(unsigned long minimum,
>                       continue;
>               region.start = entry->addr;
>               region.size = entry->size;
> -             process_mem_region(&region, minimum, image_size);
> -             if (slot_area_index == MAX_SLOT_AREA) {
> -                     debug_putstr("Aborted e820 scan (slot_areas full)!\n");
> +
> +             if (select_immovable_node(region, minimum, image_size))
>                       break;
> -             }
>       }
>  }
>  
> -- 
> 2.13.6
> 
> 
>