Re: [PATCH] Add 2 more E820 to ACPI specification

[Vladimir 'φ-coder/phcoder' Serbinenko]

Robert Millan wrote:
> On Fri, Jan 15, 2010 at 06:18:43PM +0100, Vladimir 'φ-coder/phcoder' 
> Serbinenko wrote:
>   
>> Hello. This defines 2 more types for mmap_type in a way to match E820
>> values. As grub legacy and grub2 both just pass E820 values through it
>> shouldn't be any problem.
>>     
>
> Note that although Multiboot's memory map format is modelled after e820,
> it is defined by us, not by BIOS vendors.
>
>   
Yes, but this information is needed and I prefer to provide it in
grub-legacy-compatible way.
>> -value of 1 indicates available @sc{ram}, and all other values currently
>> +value of 1 indicates available @sc{ram}, value of 3 indicates usable memory
>> +holding ACPI information,
>>     
>
> I'm concerned about increasing the amount of arch-specific references; what do
> Multiboot kernels that use ACPI currently do?
>
>   
According to a post by Bernard Trotter many of them rely on multiboot
loader passing e820 through
>> value of 4 indicates reserved memory which needs to
>> +be preserved on hibernation and all other values currently
>>  indicated a reserved area.
>>     
>
> What's the difference between this reserved memory and a reserved area?
>
>   
"which needs to be preserved on hibernation and all other values currently"
Payload should never write to or read from type 2 memory. But it needs
to save type 4 memory into its hibernation file when it hibernates and
restore on resume.


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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