Re: Use SMP kernel for Alpha (udeb) builds
On Sat, Dec 08, 2018 at 07:41:15PM +0100, Frank Scheiner wrote:
> On 12/8/18 15:05, Bob Tracy wrote:
> > From the "image.squashfs" file on the Gentoo "install-alpha-minimal"
> > image, attached is "etc/kernels/kernel-config-alpha-4.14.65-gentoo"
> > which appears to correspond to the "nolsa" kernel variant. To your
> > question about whether SMP is configured, most definitely "yes" with
> > CONFIG_NR_CPUS=32.
>
> Thanks for checking. This seems to be definitely a SMP capable kernel, as
> `CONFIG_SMP=y` is also set.
>
> About the `CONFIG_ALPHA_LEGACY_START_ADDRESS`, [1] mentions this is actually
> needed for older boot loaders only which hardcoded the kernel start address.
> And the Gentoo config shows it as inactive: `#
> CONFIG_ALPHA_LEGACY_START_ADDRESS is not set`
>
> [1]: https://cateee.net/lkddb/web-lkddb/ALPHA_LEGACY_START_ADDRESS.html
>
> But interesting, [1] also says, that this option depends on
> CONFIG_ALPHA_GENERIC, which is actually set (`CONFIG_ALPHA_GENERIC=y`) in
> the Gentoo config.
>
> So can we assume `CONFIG_ALPHA_GENERIC=y` also activates
> `CONFIG_ALPHA_LEGACY_START_ADDRESS`?
I wouldn't assume so, particularly for the Gentoo kernel source tree to
whatever extent it differs from the kernel.org source tree.
What the dependency is saying is, you can't have the legacy start address
config option force-enabled unless you're building a generic kernel.
Otherwise, the (alpha) processor-specific config options presumably
dictate whether the legacy start address is used. This is, I think,
why Gentoo includes a generic+lsa kernel and a generic+nolsa kernel in
their install image.
BUT, in your defense, it's possible an unpatched kernel.org source tree
might be doing (or might have done -- this could have been patched upstream)
exactly as you suggest. I haven't investigated this, because I've never used
the alpha generic kernel except for the initial installation on a system.
Just to be clear, Gentoo's generic kernel *does* have SMP configured, and
*with* the legacy start address enabled should boot just fine on your PWS
as it does on mine. The kernel version is 4.14(.65).
--Bob
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