Messages in this thread | | | From | (H. Peter Anvin) | Subject | Re: [CFT][PATCH] 2.6.4-rc1 remove x86 boot page tables | Date | Tue, 2 Mar 2004 06:47:53 +0000 (UTC) |
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Followup to: <m1vflp81kq.fsf@ebiederm.dsl.xmission.com> By author: ebiederm@xmission.com (Eric W. Biederman) In newsgroup: linux.dev.kernel > > I think I have accounted for the sub architectures but I don't have > the hardware to test them. For voyager and VISWS I actually changed > some code so I would appreciate a confirmation I didn't break > anything. >
For VISWS I think you actually need to turn paging off explicitly. Also, you probably need to check that you didn't break 4G/4G, especially on SMP.
I would also like to remove the magic %bx, which I did in the version of my patch sent to akpm and which is now in -mm (basically the SMP trampoline jumps to a different entrypoint instead.) In that patch, %ebx is still used as a flag, but it's completely internal to head.S.
See ftp://ftp.kernel.org/pub/linux/kernel/people/hpa/earlymem-7.diff
> Thanks to HPA who got the ball started :)
:)
I definitely agree that simply using no paging until we have page tables is by far the cleanest approach. I felt that is was too high risk for 2.6, basically because I'm a chicken, but more realistically because I couldn't really see the effect on all subarchitectures, and I didn't feel 100% confident that there wasn't anything that relied on memory being dual mapped; however, I'm more than happy to be proven wrong :)
Oh yes, with this change you should probably just move swapper_pg_dir (and empty_zero_page?) into .bss like anything else that should be zero after boot.
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