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From: "H. Peter Anvin" <hpa@zytor.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Andi Kleen <ak@suse.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	akpm@linux-foundation.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86 boot: document for 32 bit boot protocol
Date: Tue, 23 Oct 2007 18:57:16 -0700	[thread overview]
Message-ID: <471EA67C.7010401@zytor.com> (raw)
In-Reply-To: <1193190817.23935.108.camel@caritas-dev.intel.com>

Huang, Ying wrote:
> This patch documents the 32-bit boot protocol of x86. It has been used
> by Kexec and LinuxBIOS. This patch is based on the proposal of Peter
> Anvin.

> +At entry, the CPU must be in 32-bit protected mode with paging
> +disabled; a GDT must be loaded with the descriptors for selectors
> +__BOOT_CS(0x10) and __BOOT_DS(0x18); both descriptors must be 4G flat
> +segment; __BOOS_CS must have execute/read permission, and __BOOT_DS
> +must have read/write permission; CS must be __BOOT_CS and DS, ES, SS
> +must be __BOOT_DS; interrupt must be disabled; %esi must hold the base
> +address of the struct boot_params; %ebp, %edi must be zero.

You missed the (ironically the only one currently existing) constraint 
that %ebx must be zero.

	-hpa

      reply	other threads:[~2007-10-24  1:57 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-24  1:53 [PATCH] x86 boot: document for 32 bit boot protocol Huang, Ying
2007-10-24  1:57 ` H. Peter Anvin [this message]

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