linux-kernel

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: <49A8E235.6010900@goop.org>
Date:	Fri, 27 Feb 2009 23:05:25 -0800
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Yinghai Lu <yinghai@...nel.org>
CC:	"H. Peter Anvin" <hpa@...or.com>,
	the arch/x86 maintainers <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Subject: J

Yinghai Lu wrote:
> On Fri, Feb 27, 2009 at 5:51 PM, Jeremy Fitzhardinge <jeremy@...p.org> wrote:
>   
>> From: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
>>
>> Rather than having special purpose init_pg_table_start/end variables
>> to delimit the kernel pagetable built by head_32.S, just use the brk
>> mechanism to extend the bss for the new pagetable.
>>
>> This patch removes init_pg_table_start/end and pg0, defines __brk_base
>> (which is page-aligned and immediately follows _end), initializes
>> the brk region to start there, and uses it for the 32-bit pagetable.
>>     
> ...
>
>   
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index c246dc4..ed02176 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -113,8 +113,10 @@
>>  #endif
>>
>>  unsigned int boot_cpu_id __read_mostly;
>> -__initdata unsigned long _brk_start = (unsigned long)&_end;
>> -__initdata unsigned long _brk_end = (unsigned long)&_end;
>> +
>> +extern char __brk_base[];
>> +__initdata unsigned long _brk_start = (unsigned long)__brk_base;
>> +__initdata unsigned long _brk_end = (unsigned long)&__brk_base;
>>     
>
> ?
>   

What are you asking?  __brk_base is _end rounded up to a page boundary, 
so head_32.S can use it directly for pagetable allocation.  Are you 
flagging the '&' typo?  Something else?

    J
--
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/