Something about entering the long mode

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xtricman
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Something about entering the long mode

Post by xtricman »

Does GRUB2 x86-64 work in true long mode?I want use GRUB2 as payload of coreboot,

If GRUB2 works in true long mode,I can just re-set the page tables(PML4T,PDPT,PDT,PT),CR3,and the IDT,no need to worry about how to enter true long mode.

Am I right?
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Brendan
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Re: Something about entering the long mode

Post by Brendan »

Hi,
xtricman wrote:Am I right?
I'd assume (I don't know) that GRUB2 is capable of running in long mode (e.g. to support 64-bit UEFI systems properly); will use the kernel's 64-bit entry point if the Linux boot protocol is being used; and will switch back to protected mode if multi-boot was used.


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Brendan
For all things; perfection is, and will always remain, impossible to achieve in practice. However; by striving for perfection we create things that are as perfect as practically possible. Let the pursuit of perfection be our guide.
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sortie
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Re: Something about entering the long mode

Post by sortie »

It doesn't matter how GRUB works internally, only what formats it can load. It can load 64-bit kernels, for instance 64-bit Linux, though I don't know much about that. Multiboot is a 32-bit format, there is no usable 64-bit multiboot counterpart last I checked.
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