Gentoo Archives: gentoo-dev

From: Ben Kohler <bkohler@g.o>
To: gentoo-dev@l.g.o, x86@g.o, release@g.o
Subject: [gentoo-dev] Gentoo i486 support
Date: Wed, 22 Aug 2018 12:26:33
1 Hi guys,
3 For some time now, we've been shipping broken i486 stage3s that do not
4 run on pre-i686 hardware [1]. Due to a change in catalyst [2], we no
5 longer set CXXFLAGS in the default make.conf, so the x86 profiles' (imho
6 wrong/broken) defaults [3] kick in.
8 I'd like to get this fixed, and I see 3 possible solutions, listed in
9 order of my own preference:
11 1) Adjust x86 profile defaults to drop the problematic -march=i686.
12 This would be more in line with amd64 profiles (et al), which set no
13 -march value so it can run on any hardware for this arch.
15 2) Patch catalyst to start setting CXXFLAGS again. Rather than roll
16 back to exactly CXXFLAGS="${CFLAGS}" again, it's been suggested that we
17 start setting COMMON_FLAGS, and CFLAGS="${COMMON_FLAGS}"
18 CXXFLAGS=${COMMON_FLAGS}" etc. I prepared such a patch a while back
19 [4], which seems to work but may need a bit of updating.
21 3) Drop i486 support. We're only pretending to have support now, we
22 could officially stop building these broken stages completely.
24 Personally I think #1 is the most technically correct and least amount
25 of work. The only result will be slightly less optimized builds for
26 people who choose not to customize *FLAGS at all in make.conf. But this
27 is correct behavior. What we have now is akin to setting -march=core2
28 on amd64 stage3 and saying "oops it doesn't work on early 64bit AMD
29 cpus, but oh well most people have newer and will appreciate the
30 optimization".
32 Thoughts?
34 -Ben
36 [1]
37 [2]
39 [3]
41 [4]


Subject Author
Re: [gentoo-dev] Gentoo i486 support Rich Freeman <rich0@g.o>
Re: [gentoo-dev] Gentoo i486 support James Le Cuirot <chewi@g.o>
Re: [gentoo-dev] Gentoo i486 support Mike Gilbert <floppym@g.o>
Re: [gentoo-dev] Gentoo i486 support Matt Turner <mattst88@g.o>
Re: [gentoo-dev] Gentoo i486 support Richard Yao <ryao@g.o>
Re: [gentoo-dev] Gentoo i486 support Kent Fredric <kentnl@g.o>