It takes some extra 13MB (and in dev, not out), but allows perf to show kernel
symbols when profiling. I think it is worth it.
In my NixOS, I refer to it in the system derivation, for easy telling to perf
through /run/booted-system/vmlinux:
system.extraSystemBuilderCmds = ''
ln -s ${config.boot.kernelPackages.kernel.dev}/vmlinux $out/vmlinux
'';
The following parameters are now available:
* hardeningDisable
To disable specific hardening flags
* hardeningEnable
To enable specific hardening flags
Only the cc-wrapper supports this right now, but these may be reused by
other wrappers, builders or setup hooks.
cc-wrapper supports the following flags:
* fortify
* stackprotector
* pie (disabled by default)
* pic
* strictoverflow
* format
* relro
* bindnow
Since commit 48f51f1185 we let the kernel build system compress the
modules, which makes the original strip expression not work. Let the
kernel build system strip them as well so they get stripped.
The most complex problems were from dealing with switches reverted in
the meantime (gcc5, gmp6, ncurses6).
It's likely that darwin is (still) broken nontrivially.
The current default multiple-output propagation rules don't seem to work
too well if the dev output isn't the first one; without this we get an
unnecessary runtime reference to the kernel headers.
I added platform.kernelMakeFlags. This allows setting the required
parameter to make the required kernel uImage for the sheevaplug,
since it became a platform with devicetree (3.10).
I have tried it with linux 3.18 and it built fine.
When building kernels outputting a zImage, the zImage wasn't correctly copied in
to the installation. This broke the build process entirely, at least on my ARM
machine.
Testing showed the linux build is sensitive to /usr/include/ncursesw
unless chrooted (on non-nixos).
On a single chrooted nixos machine, -A linux is binary reproducible.
CC #2281 & @alexanderkjeldaas.
Based on access analysis with strace, I determined an essentially
minimal required set of files from the kernel source that was needed to
build all current kernel packages on 3.10, which ultimately resulted in
keeping 30M of source. Generalizing from that minimal set, which
required ad-hoc specifications of which headers outside of include/ and
arch/*/include and which files in the scripts/ directory should be kept,
to a policy of keeping all non-arch-specific headers that aren't part of
the drivers/ directory and the entire scripts/ directory added an
additional 17M, but there was nothing in the analysis that indicated
that that ad-hoc specification was at all complete so I think the extra
hit is worth the likely greater compatibility.
For reference, we now keep:
* All headers that are NOT in arch/${notTargetArch}/include or drivers/
* The scripts/ directory
* Makefile
* arch/${targetArch}/Makefile
IMO the most likely cause of future problems are the headers in
drivers/, but hopefully they won't actually be needed as they add 50M
Ideally kernel packages would only use include and
arch/${targetArch}/include, but alas this is observably not the case.
master:
* $out
* size: 234M
* references-closure: linux-headers, glibc, attr, acl, zlib, gcc,
coreutils, perl, bash
merge-kernel-builds:
* $out
* size: 152M
* references-closure: none
* $dev
* size: 57M
* references-closure: linux-headers, glibc, zlib, gcc
So even with the non-minimal set we still beat out master. Keeping the
drivers headers would make us only slightly bigger.
Signed-off-by: Shea Levy <shea@shealevy.com>
In most cases, this just meant changing kernelDev (now removed from
linuxPackagesFor) to kernel.dev. Some packages needed more work (though
whether that was because of my changes or because they were already
broken, I'm not sure). Specifics:
* psmouse-alps builds on 3.4 but not 3.10, as noted in the comments that
were already there
* blcr builds on 3.4 but not 3.10, as noted in comments that were
already there
* open-iscsi, ati-drivers, wis-go7007, and openafsClient don't build on
3.4 or 3.10 on this branch or on master, so they're marked broken
* A version-specific kernelHeaders package was added
The following packages were removed:
* atheros/madwifi is superceded by official ath*k modules
* aufs is no longer used by any of our kernels
* broadcom-sta v6 (which was already packaged) replaces broadcom-sta
* exmap has not been updated since 2011 and doesn't build
* iscis-target has not been updated since 2010 and doesn't build
* iwlwifi is part of mainline now and doesn't build
* nivida-x11-legacy-96 hasn't been updated since 2008 and doesn't build
Everything not specifically mentioned above builds successfully on 3.10.
I haven't yet tested on 3.4, but will before opening a pull request.
Signed-off-by: Shea Levy <shea@shealevy.com>
This makes the disk usage footprint of building the kernel smaller in 3
ways:
1) There is no separate kernel source derivation
2) Rather than using the entire build tree, only the output of make
modules_prepare is kept in the $dev output (plus the module symbol
versioning file generated during the build)
3) Only the subset of the source tree known to be needed for external
builds is kept in $dev
Note that while 2) is supported by official kernel documentation, I
couldn't find any source describing what we need to keep for 3). I've
started with the bare minimum (the main Makefile is called by the
Makefile generated by make modules_prepare) and we can/should add more
as needed for kernelPackages.
Signed-off-by: Shea Levy <shea@shealevy.com>
This has three major benefits:
1. We no longer have two kernel build processes to maintain
2. The build process is (IMO) cleaner and cleaves more closely to
upstream. In partuclar, we use make install to install the kernel and
development source/build trees, eliminating the guesswork about which
files to copy.
3. The derivation has multiple outputs: the kernel and modules are in
the default `out' output, while the build and source trees are in a
`dev' output. This makes it possible for the full source and build tree
to be kept (which is expected by out-of-tree modules) without bloating
the closure of the system derivation.
In addition, if a solution for how to handle queries in the presence of
imports from derivations ever makes it into nix, a framework for
querying the full configuration of the kernel in nix expressions is
already in place.
Signed-off-by: Shea Levy <shea@shealevy.com>
In the most general case, the cross and native kernel may differ in
patches and configuration file as well as architecture, kernel target,
etc. It's probably overkill to support that case, but since it was
doable without much duplication and it will make integrating with the
existing cross-compilation support in the generic kernel I decided to
implement it anyway.
Signed-off-by: Shea Levy <shea@shealevy.com>
