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: <4A0463D1.9090800@zytor.com>
Date:	Fri, 08 May 2009 09:54:41 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Sam Ravnborg <sam@...nborg.org>
CC:	"H. Peter Anvin" <hpa@...ux.intel.com>,
	linux-kernel@...r.kernel.org, vgoyal@...hat.com, hbabu@...ibm.com,
	kexec@...ts.infradead.org, ying.huang@...el.com, mingo@...e.hu,
	tglx@...utronix.de, ebiederm@...ssion.com
Subject: Re: [PATCH 01/14] x86, boot: align the .bss section in the decompressor

Sam Ravnborg wrote:
>>  	}
>> +	. = ALIGN(32);
> 
> Where does this magic 32 comes from?
> I would assume the better choice would be:
> 	. = ALIGN(L1_CACHE_BYTES);
> 
> So we match the relevant CPU.
> 
> In general for alignmnet of output sections I see the need for:
> 1) Function call
> 2) L1_CACHE_BYTES
> 3) PAGE_SIZE
> 4) 2*PAGE_SIZE
> 
> But I see magic constant used here and there that does not match
> the above (when looking at all archs).
> So I act when I see a new 'magic' number..
> 

I picked 32 as being larger than the maximum known size that affects rep
performance, but L1_CACHE_BYTES really would make more sense, you're right.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
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/

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ