linux-kernel - Re: Alpha: suspicious compiler warning in entry.S

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]

Date:	Fri, 30 Oct 2009 13:16:59 +0000
From:	David Howells <dhowells@...hat.com>
To:	Michael Cree <mcree@...on.net.nz>
Cc:	dhowells@...hat.com, linux-alpha@...r.kernel.org,
	linux-kernel@...r.kernel.org, rth@...ddle.net,
	ink@...assic.park.msu.ru
Subject: Re: Alpha: suspicious compiler warning in entry.S

Michael Cree <mcree@...on.net.nz> wrote:

> On the assumption that it is important to include the TIF_NOTIFY_RESUME bit
> one might be tempted to modify the code to:
> 
>    lda    $2, _TIF_WORK_MASK
>    and    $5, $2, $2
> 
> but this is time critical code.  I am wondering whether it might be better
> to rearrange the bits in the thread information flags so that _TIF_WORK_MASK
> has a value less than 255 and the single instruction to perform an and
> operation can be maintained.

Unless the LDA can be interleaved around some memory accesses, then yes,
compressing _TIF_WORK_MASK would be good.

David
--
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/