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From: "Yoshinori K. Okuji" <okuji@enbug.org>
To: The development of GRUB 2 <grub-devel@gnu.org>
Subject: Re: multiboot2: variable data size
Date: Wed, 29 Nov 2006 00:29:55 +0100	[thread overview]
Message-ID: <200611290029.55561.okuji@enbug.org> (raw)
In-Reply-To: <456C2F8C.1040709@intel.com>

On Tuesday 28 November 2006 13:46, bibo,mao wrote:
> yes, x84_64EFI starts with 64-bit long mode and page enabled(virtual
> address equals physical address) if it is x86_64 efi bios, it is defined in
> section 2.3.4 of UEFI Specification Version 2.0.
>
> If kernel image is bzImage, x64 efi bootloader need switch to 32 bit
> protect mode(or real mode) from 64 bit long mode, and if kernel image is
> gzipped/plain format, efi bootloader can directly jump to 64-bit kernel
> entry address without mode switch.

Thanks for your detailed information. So does it mean that GRUB needs to 
provide a PE32+ application to EFI, if it is on x86_64? Or does it understand 
PE32? More information is welcome.

BTW, in the current implementation, GRUB skips real mode setup code in Linux 
and directly jumps to a protected mode entry on EFI. Can we use the same 
trick with bzImage on x86_64? Mode switching is not difficult, but if we can 
omit it, that would be much easier to implement.

Okuji




  reply	other threads:[~2006-11-28 23:30 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <iss.8f960c3c.4ebf.45648480.44026.78@relay0i.sun.com>
2006-11-22 20:55 ` Grub-devel Digest, Vol 33, Issue 19 Joe Bonasera
2006-11-25  2:09   ` multiboot2: variable data size Hollis Blanchard
2006-11-25  3:10     ` Yoshinori K. Okuji
2006-11-25  3:33       ` Hollis Blanchard
2006-11-25  3:46         ` Yoshinori K. Okuji
2006-11-25  4:08           ` Hollis Blanchard
2006-11-25  4:36             ` Yoshinori K. Okuji
2006-11-25  5:01               ` Hollis Blanchard
2006-11-28  9:29           ` Johan Rydberg
2006-11-28 11:35             ` Yoshinori K. Okuji
2006-11-28 12:46               ` bibo,mao
2006-11-28 23:29                 ` Yoshinori K. Okuji [this message]
2006-11-29  1:55                   ` bibo,mao
2006-11-29  2:37                     ` Andrei E. Warkentin
2006-11-29  0:22                 ` Johan Rydberg
2006-11-29  2:13                   ` bibo,mao
2006-11-28 12:50               ` tgingold

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