Re: [patch 29/29] initrd: Fix virtual/physical mix-up in overwritetest

From: Geert Uytterhoeven
Date: Thu Jul 24 2008 - 14:49:41 EST


Hi Nemoto-san,

On Fri, 25 Jul 2008, Atsushi Nemoto wrote:
> On Thu, 17 Jul 2008 21:16:36 +0200, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > if (initrd_start && !initrd_below_start_ok &&
> > - initrd_start < min_low_pfn << PAGE_SHIFT) {
> > + page_to_pfn(virt_to_page(initrd_start)) < min_low_pfn) {
> > printk(KERN_CRIT "initrd overwritten (0x%08lx < 0x%08lx) - "
> > - "disabling it.\n",initrd_start,min_low_pfn << PAGE_SHIFT);
> > + "disabling it.\n",
> > + page_to_pfn(virt_to_page(initrd_start)), min_low_pfn);
> > initrd_start = 0;
> > }
>
> This patch causes warnings on mips:
>
> linux/init/main.c: In function 'start_kernel':
> linux/init/main.c:633: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast
> linux/init/main.c:636: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast
>
> Because an argument of mips virt_to_phys() is an pointer and
> initrd_start is unsigned long. It seems most (all?) arch's
> virt_to_phys() casts its argument to unsigned long internally. Should
> mips follow?

Alternatively, as initrd_start is really a virtual kernel address,
perhaps it should be changed from unsigned long to void * instead?

It's cast to `void *' in several place. arch/xtensa/kernel/setup.c even
has `extern void *initrd_start' to fool around this?

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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/