Re: [PATCH 04/14] sh: Obliterate the P1 area macros

[Matt Fleming <matt@console-pimps.org>]

On Thu, Oct 15, 2009 at 03:05:32PM +0900, Magnus Damm wrote:
> Hey Matt,
> 
> [CC Morimoto-san]
> 
> Thanks for your work on this!
> 

Hi Magnus, no problem. Sorry I haven't replied more quickly, I've been
at ELC Europe this week.

> On Wed, Oct 7, 2009 at 6:22 AM, Matt Fleming <matt@console-pimps.org> wrote:
> >  * Map an address to a certain privileged segment
> > diff --git a/arch/sh/kernel/machine_kexec.c b/arch/sh/kernel/machine_kexec.c
> > index 7ea2704..de7cf54 100644
> > --- a/arch/sh/kernel/machine_kexec.c
> > +++ b/arch/sh/kernel/machine_kexec.c
> > @@ -49,7 +49,7 @@ int machine_kexec_prepare(struct kimage *image)
> >        /* older versions of kexec-tools are passing
> >         * the zImage entry point as a virtual address.
> >         */
> > -       if (image->start != PHYSADDR(image->start))
> > +       if (image->start != __pa(image->start))
> >                return -EINVAL; /* upgrade your kexec-tools */
> >
> >        return 0;
> 
> This change unfortunately breaks kexec. The PHYSADDR() macro masks but
> __pa() subtracts so this breaks the physical address case.
> 
> Do you have any idea how to keep the previous behaviour? Worst case we
> can just remove this check - it's been a while since I updated
> kexec-tools now.
> 

Damn, sorry I missed this. Is image->start a virtual address? If so,
this check doesn't make sense when CONFIG_PMB is enabled because virtual
addresses do not have to be mapped to physical addresses 1:1.

If image->start is a physical address, I don't think it's ever true that
image->start = __pa(image->start) beacuse you can't apply __pa() to a
physical address and get the same address, e.g.

	 __pa(addr) != __pa(__pa(addr))

So, unless I'm mistaken this test can just be removed.