On Sun, 23 Dec 2007, Geert Uytterhoeven wrote:
> New version below. Tested on Amiga. Compile-tested on ia32 (i386_defconfig) and
> pp64 (ps3_defconfig).
Ping?
> Subject: initrd: Fix virtual/physical mix-up in overwrite test
>
> From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
>
> 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.
>
> Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> ---
> On several platforms, initrd_below_start_ok is set to 1:
>
> | arch/mips/kernel/setup.c: initrd_below_start_ok = 1;
> | arch/parisc/mm/init.c: initrd_below_start_ok = 1;
> | arch/powerpc/kernel/prom.c: initrd_below_start_ok = 1;
> | arch/ppc/platforms/hdpu.c: initrd_below_start_ok = 1;
> | arch/xtensa/kernel/setup.c: initrd_below_start_ok = 1;
>
> Some of these may be workarounds for this bug. Please check.
>
> init/main.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> --- a/init/main.c
> +++ b/init/main.c
> @@ -598,9 +598,10 @@ asmlinkage void __init start_kernel(void
>
> #ifdef CONFIG_BLK_DEV_INITRD
> 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;
> }
> #endif
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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