Re: [PATCH] initrd: Fix virtual/physical mix-up in overwrite test

From: Geert Uytterhoeven
Date: Tue Dec 18 2007 - 14:52:28 EST


On Tue, 18 Dec 2007, Andrew Morton wrote:
> On Sun, 16 Dec 2007 11:51:00 +0100 (CET) Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > On recent kernels, I get the following error when using an initrd:
> >
> > | initrd overwritten (0x00b78000 < 0x07668000) - disabling it.
> >
> > My Amiga 4000 has 12 MiB of RAM at physical address 0x07400000 (virtual
> > 0x00000000).
> > The initrd is located at the end of RAM: 0x00b78000 - 0x00c00000 (virtual).
> > The overwrite test compares the (virtual) initrd location to the (physical)
> > first available memory location, which fails.
> >
> > This patch converts initrd_start to a page frame number, so it can be safely
> > compared with min_low_pfn.
> >
> > Before the introduction of discontiguous memory support on m68k
> > (12d810c1b8c2b913d48e629e2b5c01d105029839), min_low_pfn was just left
> > untouched by the m68k-specific code (zero, I guess), and everything worked
> > fine.
>
> breaks x86.
>
> init/main.c: In function 'start_kernel':
> init/main.c:601: error: implicit declaration of function 'virt_to_pfn'
> init/main.c:603: warning: format '%08lx' expects type 'long unsigned int', but argument 2 has type 'int'

Interestingly, virt_to_pfn() exists on a few architectures only :-(

So what's the correct portable construct to use instead?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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