Re: [PATCH 3/3] x86, mirror: x86 enabling - find mirrored memory ranges

From: Andrew Morton
Date: Wed May 06 2015 - 19:30:35 EST


On Tue, 3 Feb 2015 14:40:19 -0800 Tony Luck <tony.luck@xxxxxxxxx> wrote:

> UEFI GetMemoryMap() uses a new attribute bit to mark mirrored memory
> address ranges. See UEFI 2.5 spec pages 157-158:
>
> http://www.uefi.org/sites/default/files/resources/UEFI%202_5.pdf
>
> On EFI enabled systems scan the memory map and tell memblock about
> any mirrored ranges.
>
> ...
>
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -117,6 +117,27 @@ void efi_get_time(struct timespec *now)
> now->tv_nsec = 0;
> }
>
> +void __init efi_find_mirror(void)
> +{
> + void *p;
> + unsigned long long mirror_size = 0, total_size = 0;
> +
> + for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
> + efi_memory_desc_t *md = p;
> + unsigned long long start = md->phys_addr;
> + unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;

efi_memory_desc_t uses u64 for all this stuff. Was there a reason for
using ull instead?

> + total_size += size;
> + if (md->attribute & EFI_MEMORY_MORE_RELIABLE) {
> + memblock_mark_mirror(start, size);
> + mirror_size += size;
> + }
> + }
> + if (mirror_size)
> + pr_info("Memory: %lldM/%lldM mirrored memory\n",
> + mirror_size>>20, total_size>>20);
> +}
> +
>
> ...
>
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