The `sheevaplug` kernel configuration was added a very long time
ago and has not been adjusted for years. `pogoplug4` was identical
to `sheevaplug` except for an even more stripped‐down kernel
configuration, no device tree support, and a different load address
for the uImage.
These days, the stock kernel configuration builds and there has been
an upstream device tree for the Pogoplug Series 4 for years; unify
`sheevaplug` and `pogoplug4` into an `armv5tel-multiplatform` that
uses the standard configuration.
ARMv5 was also the only platform that defaulted to uImage, the [legacy
U‐Boot image format] that is deprecated upstream. Our bootloader
machinery in NixOS does not handle these images in any special way
and even the original ARMv6 Raspberry Pi platform defaults to the
standard zImage. We switch `armv5tel-multiplatform` to zImage to match.
[legacy U‐Boot image format]: https://docs.u-boot.org/en/latest/usage/cmd/bootm.html#legacy-boot
It is of course natural to worry about backwards compatibility
here: this switches to a different kernel image format and drops
support for root on NFS along with random oddities like KGDB and
LatencyTOP. Renaming the platform is intended to help mitigate
this risk.
The reality, however, is that it is currently very
difficult to build a configuration for ARMv5. I found
<https://github.com/thefloweringash/sheevaplug-nix> online as
an example configuration from many years ago; it already set
`autoModules`, and builds U‐Boot using `CONFIG_DISTRO_DEFAULTS`,
which should work out of the box without requiring the legacy U‐Boot
image format.
Even then, however, I confirmed with the author that it hasn’t
been used in years, and I could barely get it to build with
a modern Nixpkgs: OpenSSH is broken, Nix is broken, multiple
default `environment.systemPackages` in the SD image profile
are broken, `boot.initrd.includeDefaultModules` is broken, and
`hardware.enableAllHardware` is broken.
I conclude that if anyone is actively building systems on ARMv5, they
have a forked Nixpkgs or a very custom setup. Given our general move
to standard boot chains and no platform‐specific hacks, and the
decaying state of our unofficial support for 32‐bit ARM, I think
it is not worth maintaining support for the legacy image format for
this one ancient platform.
If anyone is running a heavily stripped‐down NixOS configuration on
mission‐critical SheevaPlugs using a custom Nix‐free deployment
setup relying on the legacy U‐Boot image format and somehow none
of these kernel changes manage to loudly break their build, hopefully
they’ll at least notice the release notes entry! Otherwise there’s
always JTAG…
By doing this, we can cache the rest of the file, including the import
of problems.nix. This allows genCheckProblems to be cached on every
bootstrapping stage, and not re-called each time.
warnIf sends our warning message through a function call, even if the
warning condition doesn't trigger. This requires a lot of thunk
allocation that can be easily avoided.
This might be a nice way to use our reach to remind users to donate to
FLOSS projects that they use and love.
Signed-off-by: Ethan Carter Edwards <ethan@ethancedwards.com>
Convert 3 optionalAttrs in the stdenv derivation call to nullable
attribute names: allowedRequisites, contentAddressedByDefault, and
isDarwin sandbox/impureHostDeps.
The comment claimed configureFlags is "sometimes a string, sometimes
null, and sometimes a list" — the normalization it referenced was
removed long ago; configureFlags is always a list now.
We can safely check `elem "all" hardeningDisable'` on the original list,
because calling `unique` and `concretizeFlagImplications` will never
change whether the list contains "all".
We define a meta variable in the same let block as the result of
the `commonMeta` call. Avoiding evaluating the result of that call
until we need to is preferable.
As suggested in PR review:
"It seems like when `!stdenvHasCC`, `stdenv.cc` is `null`. So this could
probably just be `defaultHardeningFlags =
stdenv.cc.defaultHardeningFlags or knownHardeningFlags;`?"
