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Am Montag, 4. Januar 2021, 13:57:37 EET schrieb Thomas Mueller: |
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> > > That's what I did: I found a 2017 stage3 with a still older glibc and |
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> > > managed to upgrade to a 2020 gentoo while masking the last glibc |
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> > > versions. That was tricky because I had to git-checkout intermediate |
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> > > versions of the portage tree in order to deal with the EAPI changes but |
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> > > I have a working chroot now. Thanks. |
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> > |
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> > That's the easy way to do it, yes. |
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> > |
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> > The hard way is to treat this as a cross-compilation problem and bootstrap |
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> > your own stages from scratch. Instructions would be a bit longer... |
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> > |
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> > Andreas K. Hüttel |
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> |
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> I have looked through crossdev. Is that what it would take to cross-compile |
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> and bootstrap stages from scratch? |
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> |
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> Could that be done from (instead of an old glibc) musl, uClibc, or FreeBSD |
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> or NetBSD? |
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In principle yes, but every experimental piece can add more problems. |
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It's probably best to start with a base that is as boring as possible. |
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What crossdev does is (simplified) |
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* "create" (as symlinks) ebuilds for cross-compiler, cross-binutils, and |
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target glibc |
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* build cross-compiler, cross-binutils, and target glibc |
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* installs a wrapper for emerge that uses these |
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For example, you end up on an amd64 system with an additional directory /usr/ |
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riscv64-unknown-linux-gnu that contains |
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* a gcc that runs on amd64 (CBUILD) but generates code for riscv64 (CTARGET) |
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* a binutils that runs on amd64 but works with files for riscv64 |
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* a glibc for riscv64 |
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Then, using commands like |
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riscv64-unknown-linux-gnu-emerge -av @system |
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you can build in /usr/riscv64-unknown-linux-gnu pieces of the target system. |
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This works only in a very limited way, since many upstream build systems do |
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not support cross-compiling. However, with some patience you can get to the |
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point where the directory can be tarred up and used as a chroot on the target |
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architecture. |
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-- |
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Andreas K. Hüttel |
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dilfridge@g.o |
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Gentoo Linux developer |
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(council, qa, toolchain, base-system, perl, libreoffice) |
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