From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <ak@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
Mike Frysinger <vapier@gentoo.org>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [patch] use __asm__ and __volatile__ in asm-x86_64/msr.h
Date: Wed, 20 Jun 2007 08:46:42 -0700 [thread overview]
Message-ID: <46794BE2.5020108@zytor.com> (raw)
In-Reply-To: <200706182053.04116.ak@suse.de>
Andi Kleen wrote:
>> asm-i386/msr.h should not be exported to userspace at all, it contains
>> nothing but kernel-internal helpers.
>
> Actually rdtsc and rdtscll and potentially rdpmc which is in there can be very
> useful in user space if you know what you're doing. Unfortunately a lot of its users don't,
> but not having the include probably won't stop them either.
More likely, people will just re-implement them incorrectly.
However, the rdtsc() definition in the kernel is weird (and removable, I
think there are no more users -- I have it removed in my MSR driver
rewrite tree which I need to get off my arse and push.) Most users
would expect the rdtscll() functionality with the rdtsc() name.
-hpa
next prev parent reply other threads:[~2007-06-20 15:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-18 6:09 Mike Frysinger
2007-06-18 7:35 ` H. Peter Anvin
2007-06-18 14:02 ` Mike Frysinger
2007-06-18 18:36 ` Christoph Hellwig
2007-06-18 18:53 ` Andi Kleen
2007-06-20 15:46 ` H. Peter Anvin [this message]
2007-07-23 0:45 ` Mike Frysinger
2007-07-23 1:18 ` H. Peter Anvin
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