linux-kernel - Re: [PATCH 1/2] Use structs instead of hardcoded offsets in x86 boot decompressor.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4837B2DD.908@zytor.com>
Date:	Fri, 23 May 2008 23:17:01 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Rik van Riel <riel@...hat.com>
CC:	Kristian Høgsberg <krh@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] Use structs instead of hardcoded offsets in x86 boot
 decompressor.

Rik van Riel wrote:
> 
> People who wonder why these pointers never get initialized: they
> point to the zeropage, which of course lives at address zero.
> 
> /* The so-called "zeropage" */
> struct boot_params {
> 	struct screen_info screen_info;                 /* 0x000 */
>         struct apm_bios_info apm_bios_info;             /* 0x040 */
>         __u8  _pad2[12];                                /* 0x054 */
>         struct ist_info ist_info;                       /* 0x060 */
> 	...
> 

Uhm... except it doesn't live at address zero, at all.

It's called "zeropage" because we used to recycle it into 
empty_zero_page, a long long time ago.

The bootparms structure is pointed to by %esi being passed from the 
setup code to the decompressor to the kernel.

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/