Date: Mon, 28 Nov 2005 15:08:43 -0700 From: Scott Long <scottl@samsco.org> To: John Baldwin <jhb@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/amd64/amd64 machdep.c Message-ID: <438B7FEB.4090801@samsco.org> In-Reply-To: <200511281704.59091.jhb@freebsd.org> References: <200511211839.jALIdIff064683@repoman.freebsd.org> <200511281637.11153.jhb@freebsd.org> <438B7BFC.7030604@samsco.org> <200511281704.59091.jhb@freebsd.org>
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John Baldwin wrote: > On Monday 28 November 2005 04:51 pm, Scott Long wrote: > >>John Baldwin wrote: >> >>>On Monday 28 November 2005 04:06 pm, Scott Long wrote: >>> >>>>John Baldwin wrote: >>>> >>>>>On Monday 21 November 2005 01:39 pm, John Baldwin wrote: >>>>> >>>>>>jhb 2005-11-21 18:39:17 UTC >>>>>> >>>>>>FreeBSD src repository >>>>>> >>>>>>Modified files: >>>>>> sys/amd64/amd64 machdep.c >>>>>>Log: >>>>>>Expand the hack to mask the atpics if 'device atpic' is not in the >>>>>>kernel during boot up. Now we do a full reset of the 8259As and setup >>>>>>a simple interrupt handler (we actually borrow the apic one that just >>>>>>does an immediate iret) to handle any spurious interrupts triggered by >>>>>>either chip. This should fix some folks that were getting a Trap 30 >>>>>>during bootup of certain SMP AMD systems. This might get pushed into >>>>>>the 6.0 branch as an errata. For now a suitable workaround is to add >>>>>>'device atpic' to your kernel config. >>>>>> >>>>>>Tested by: scottl >>>>>>Helpful info from: dillon >>>>>>MFC after: 1 week >>>>> >>>>>Hmm, we probably still need to reprogram the ATPIC on resume as well. >>>>>I'm not sure it's actually worth not just compiling the atpic code in on >>>>>amd64. >>>> >>>>Problems aside, what are the benefits to not having the atpic >>>>unconditionally included on amd64? >>> >>>Purely space savings. It's whatever the size of atpic.o, elcr.o, and the >>>bits of atpic_vector.S that make it into exception.o are. >> >>Ok, so it doesn't cut down on runtime overhead? The file sizes look to >>be: >> >>atpic.o 15k >>elcr.o 2.5k >>exception.o 200byte delta > > > No, there isn't any effect on runtime. > > >>If, down the road, a motherboard shows up without an atpic or one that >>is horribly broken, would we be worse off for having the atpic code in >>there? > > > Well, both i386 and amd64 assume an atpic is there. Even if you don't include > 'device atpic' on amd64, we do the manual bit banging to the I/O ports that > assume it is there in the code I just changed. > So yeah, might as well just make it conditional then. Scott
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