From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Williamson Subject: Re: [ACPI] PATCH-ACPI based CPU hotplug[2/6]-ACPI Eject interfacesupport Date: Tue, 21 Sep 2004 12:10:52 -0600 Sender: linux-ia64-owner@vger.kernel.org Message-ID: <1095790252.24751.41.camel@tdi> References: <3ACA40606221794F80A5670F0AF15F84059309EF@pdsmsx403> <1095735738.3920.29.camel@mythbox> <20040921172546.GA7077@thunk.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20040921172546.GA7077@thunk.org> To: Theodore Ts'o Cc: "Yu, Luming" , Dmitry Torokhov , acpi-devel , "Keshavamurthy, Anil S" , "Brown, Len" , LHNS list , Linux IA64 , linux-kernel List-Id: linux-acpi@vger.kernel.org On Tue, 2004-09-21 at 13:25 -0400, Theodore Ts'o wrote: > On Mon, Sep 20, 2004 at 09:02:18PM -0600, Alex Williamson wrote: > > > But, some AML methods are risky to be called directly from user space, > > > Not only because the side effect of its execution, but also because > > > it could trigger potential AML method bug or interpreter bug, or even > > > architectural defect. All of these headache is due to the AML method > > > is NOT intended for being used by userspace program. > > > > I've made an attempt to hide the most obvious dangerous methods, but > > undoubtedly, there will be some. Why are we any more likely to hit an > > AML method bug, interpreter bug or architectural bug by having a > > userspace interface? > > As long as the userspace interfaces are only available to the root > filesystem, I'm not sure it's worth it to hide any of the methods. > It's added complexity, and in any case, root can do untold amounts of > damage by writing to /dev/mem, trying to upload firmware to IDE > drives, etc., etc., etc. Yes, very true. I think the difference is that in my current implementation, objects are evaluated on read. This makes it terribly easy to do the wrong thing "Hmm, I wonder what that file does... oops". Evaluating on write would set the bar a little higher, but still has some of the same issues. In theory, I definitely agree, the interface shouldn't need to hide anything. (I'm sure there are ACPI firmware folks frightened by that idea) Thanks, Alex -- Alex Williamson HP Linux & Open Source Lab