Re: [PATCH v2 1/7] cmdline: Add generic function to build command line.

Segher Boessenkool
2021-03-05T18:41:22Z

On Fri, Mar 05, 2021 at 10:58:02PM +1100, Michael Ellerman wrote:
> Will Deacon <will@kernel.org> writes:
> > That's very similar to us; we're not relocated, although we are at least
> > in control of the MMU (which is using a temporary set of page-tables).
>
> prom_init runs as an OF client, with the MMU off (except on some Apple
> machines), and we don't own the MMU. So there's really nothing we can do :)

You *could* take over all memory mapping. This is complex, and I
estimate the change you get this to work correctly on all supported
systems to be between -400% and 0%.

And not very long later Linux jettisons OF completely anyway.

> Though now that I look at it, I don't think we should be doing this
> level of commandline handling in prom_init. It should just grab the
> value from firmware and pass it to the kernel proper, and then all the
> prepend/append/force etc. logic should happen there.

That sounds much simpler, yes :-)

Segher