linux-kernel - Re: [PATCH 1/3] Add prctl commands PR_GET_TSC and PR_SET

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] [day] [month] [year] [list]

Date:	Sun, 13 Apr 2008 13:53:17 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Andi Kleen <andi@...stfloor.org>
CC:	Erik Bosman <ejbosman@...vu.nl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Arjan van de Ven <arjan@...radead.org>,
	Andrea Arcangeli <andrea@...share.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] Add prctl commands PR_GET_TSC and PR_SET_TSC

Andi Kleen wrote:
>> I think what Erik is trying to do is to make it possible to disable as
>> many of these in the kernel as possible; I/O is easy, it's off by
>> default; RDTSC and RDPMC can be disabled in the kernel, and I think
>> even XSTORE can be disabled.
> 
> I'm a little sceptical it will work reliably, but we'll see.
> 
> There's also LSL (forgot that earlier). It is used by the vgetcpu()
> because it's faster than CPUID or RDTSCP. Kernel
> sets a magic segment up which has different limits for different CPUs.
> 

Yeah, that's unlikely to be found in code that isn't actively looking 
for it, though.

	-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/