Date: Tue, 3 Oct 2006 22:33:56 +0100 From: Andrea Bittau <a.bittau@cs.ucl.ac.uk> To: Nate Lawson <nate@root.org> Cc: freebsd-acpi@freebsd.org, freebsd-mobile@freebsd.org Subject: Re: hack for getting suspend/resume to half work on an IBM Thinkpad x60s [SMP] Message-ID: <20061003213356.GA6149@shorty.sorbonet.org> In-Reply-To: <4522D023.9090501@root.org> References: <20060921000628.GA1832@shorty.sorbonet.org> <200610021424.18562.jhb@freebsd.org> <20061002223055.GA8217@shorty.sorbonet.org> <200610031302.34835.jhb@freebsd.org> <4522D023.9090501@root.org>
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On Tue, Oct 03, 2006 at 02:03:31PM -0700, Nate Lawson wrote: > I agree. The standard switch to protected mode, paging, etc. needs to > be performed and then resume from the saved register context. I guess my point was that there are two pieces of code that do that: 1) mpboot.s bootMP() used by system bootstrap and what my current patch uses. I think this is what you guys are suggesting to use, and I'm doing it anyway in my patch, but I just want to be the devil's advocate =D. 2) acpi_wakecode.S wakeup_16() used by the BSP to wake itself up. This is what I was suggesting should be generalized and used by the other cores too. The difference of this code as opposed to #1 is that #2 can "cheat". That is, we can create the code for #2 on the fly and do stuff like mov old_eax,eax etc and don't have to be smart about figuring out where the CPU should land and how it should initialize itself [as in the case of #1]. I'm just wondering whether we should do something about the assembly "code duplication" in #1 and #2. I understand they serve a different purpose, but arguably, they do the same thing: real-mode -> jump in kernel. What is different is what happens once in kernel mode: boot or resume? That difference could be coded in the C part of the kernel leaving a single asm entry point both for bootstrap and wakeup code. Am I making any sense? =D
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