Re: [PATCH] x86: efi/e820 table merge fix

From: H. Peter Anvin
Date: Tue Jun 16 2009 - 21:39:56 EST


Huang Ying wrote:
> On Wed, 2009-06-17 at 05:43 +0800, Cliff Wickman wrote:
>> From: Cliff Wickman <cpw@xxxxxxx>
>> --- linux.orig/arch/x86/kernel/efi.c
>> +++ linux/arch/x86/kernel/efi.c
>> @@ -240,10 +240,35 @@ static void __init do_add_efi_memmap(voi
>> unsigned long long size = md->num_pages << EFI_PAGE_SHIFT;
>> int e820_type;
>>
>> - if (md->attribute & EFI_MEMORY_WB)
>> - e820_type = E820_RAM;
>> - else
>> + switch (md->type) {
>> + case EFI_LOADER_CODE:
>> + case EFI_LOADER_DATA:
>> + case EFI_BOOT_SERVICES_CODE:
>> + case EFI_BOOT_SERVICES_DATA:
>> + case EFI_CONVENTIONAL_MEMORY:
>> + if (md->attribute & EFI_MEMORY_WB)
>> + e820_type = E820_RAM;
>> + else
>> + e820_type = E820_RESERVED;
>> + break;
>
> Why does BIOS mark memory region without EFI_MEMORY_WB as these types?
> Any example?
>

Probably not, but if it does, it's broken, and the memory should be
ignored. The original code had the EFI_MEMORY_WB check already, so it
seems prudent to keep it.

-hpa
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