Subject: Re: Problems with system makefiles and optimization flags
To: Andrew Brown <>
From: Frederick Bruckman <>
List: tech-toolchain
Date: 11/07/2002 10:02:09
On Thu, 7 Nov 2002, Andrew Brown wrote:

> >>        2. The kernel and userland Makefiles now use completely
> >>           different variables for holding the optimization flags.
> >
> >Currently, if I set "COPTS" to apply a sub-model optimization to the
> >userland binaries, it also applies to the GENERIC and INSTALL kernels
> >and the ramdisk, which is undesirable, and usually breaks the release.
> >Is there (will there) be a way to do that?
> yes.  i have a small patch to config(8) that simply sets
> KERNEL_BUILD=<CONFIGNAME> at the top of the kernel makefile.  that
> means you can (or will soon be able to) define things in your mk.conf
> that only apply to kernels.

That would almost work, though it would be awkward to turn it around,
but what about the ramdisks?

I realize there's a limit as to how much variation we support, but I
think it's reasonable to want to build sets with, say, -march=i486, or
-m68020-60, just to see what it does. The ramdisks and kernels, on the
other hand, seem to already be carefully tuned, and shouldn't be
messed with. For custom kernels, I think it makes more sense to set
"makeoptions=COPTS=-O2 -msomething" in the kernel's config, since
you're going to want to comment out Mxxxxx options there anyhow. That
neatly overrides conditionally (globally) set COPTS in "/etc/mk.conf"
or COPTS set in the environment. The problem is that globally set
COPTS leaks into sysinstall, and the GENERIC and INSTALL kernels,
because they don't override it.