linux-kernel - Re: [PATCH] percpu: add optimized generic percpu accessors

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: <49709547.7060001@rtr.ca>
Date:	Fri, 16 Jan 2009 09:10:15 -0500
From:	Mark Lord <lkml@....ca>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Ingo Molnar <mingo@...e.hu>, Tejun Heo <tj@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>, Brian Gerst <brgerst@...il.com>,
	ebiederm@...ssion.com, cl@...ux-foundation.org,
	rusty@...tcorp.com.au, travis@....com,
	linux-kernel@...r.kernel.org, steiner@....com, hugh@...itas.com
Subject: Re: [PATCH] percpu: add optimized generic percpu accessors

Andrew Morton wrote:
> On Thu, 15 Jan 2009 19:02:59 +0100 Ingo Molnar <mingo@...e.hu> wrote:
> 
>> * Andrew Morton <akpm@...ux-foundation.org> wrote:
..
>>> I wonder if the preempt_disable()/preempt_enable() in here actually
>>> does anything useful on any architecture.
>> Provides "this is IRQ safe"
> 
> ?
> 
>> and "this is preempt safe" semantics.
> 
> Of course.  But do any architectures actually _need_ that for a single read?
..

If the target is unaligned, then RISC architectures will need protection there.
If we can guarantee correct memory alignment of the target, then no / none.

Cheers
--
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/