Gentoo Archives: gentoo-mips

From: Kumba <kumba@g.o>
To: gentoo-mips@l.g.o
Subject: Re: [gentoo-mips] Booting issues
Date: Tue, 01 Aug 2006 13:07:11
Message-Id: 44CF51F9.7030606@gentoo.org
In Reply to: [gentoo-mips] Booting issues by Richard
1 Richard wrote:
2 > Hi,
3 >
4 > I'm still trying to get my inaugural disk boot to work on my Octane 1.
5 > I've used Skylark's config file for the kernel build (as I couldn't find
6 > the official gentoo one, and the default gentoo install kernel doesn't
7 > seem to work for me anyway), but I get a fairly blunt error, with a few
8 > magic numbers.
9 >
10 > The results of a boot attempt follow:
11 > ARCLoader 0.43(...)
12 > Loading configuration(...)
13 > Loading scsi(0)(...)
14 > Reading 5638216 bytes... OK.
15 > Entering kernel.
16 >
17 > NESTED EXCEPTION #1 (vid 0) at EPC: ffffffff9fc6819c; first exception at
18 > PC: 0
19 >
20 > <EOF>
21 >
22 > Any suggestions as to the problem, or potential solution? Where should I
23 > look for further information? Is there additional information I should
24 > provide? What troubleshooting advice is there? Has anyone else ever seen
25 > this?
26 >
27 > This is a fresh, current Gentoo install...
28 >
29 > Thanks for your help,
30 >
31 > Richard
32
33
34 Apparently, this problem has been around, hiding for quite some time. None of
35 us ever identified it as a RealProblem(TM) because when you netboot the kernel,
36 the issue doesn't arise. Once I started testing bootable CDs again, I ran into
37 it like a bird into a glass window.
38
39 I haven't had a chance to try and isolate what the exact cause is. I suspect
40 the problem is in the Octane kernel patch itself rather than the Linux-mips
41 tree, so I doubt using tools to hunt it down in git is going to pay off. The
42 one solution I have discovered is below if you want to use disk-based booting:
43
44 1) Unmask gcc-4.1.1 by adding '>=sys-devel/gcc-4.1.1' to
45 /etc/portage/package.unmask (without the quotes). You don't have to merge it
46 yet, as it's not needed for fixing the kernel, but I made it a dependency of
47 2.6.17* for an upcoming nptl migration. It's safe to merge, however.
48
49 2) If you're running unstable (ACCEPT_KEYWORDS=~mips), then you can merge
50 sys-kernel/mips-sources-2.6.17.7 (or whatever is latest). Otherwise, you'll
51 need to add the following to /etc/portage/package.keywords temporarily:
52 'sys-kernel/mips-sources ~mips'
53
54 3) Merge sys-devel/kgcc64-3.4.6 and unmerge sys-devel/gcc-mips64. kgcc64
55 replaces gcc-mips64, and as a bonus, includes all the patches and bugfixes we
56 use in the main system compiler.
57
58 4) Compile a 2.6.17* kernel using the kgcc64 toolchain. It'll build only a
59 kernel compiler, and you can use it much the same way as you did gcc-mips64.
60
61 Boot the resultant kernel, and my testing so far shows that it will boot. I'm
62 still not sure how to go about tracking down the original problem. I have a
63 feeling it's possibly bad kernel code that gets miscompiled in kernel versions
64 from ~2.6.15 to ~2.6.16 (as 2.6.13* and 2.6.14* are known to boot off of
65 disk/cdrom). Building a 2.6.17 kernel with gcc-mips64 also re-creates the
66 problem, which somewhat indicates a compiler bug too. Hence the fuzzy nature of
67 this critter.
68
69
70 --Kumba
71
72 --
73 Gentoo/MIPS Team Lead
74 Gentoo Foundation Board of Trustees
75
76 "Such is oft the course of deeds that move the wheels of the world: small hands
77 do them because they must, while the eyes of the great are elsewhere." --Elrond
78 --
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