On Tue, 25 Nov 2014 12:54:55 +0000
, Ian Campbell <ian.campbell@xxxxxxxxxx>
wrote:
> memblock_is_region_reserved() returns true in the case of a partial
> overlap, meaning that the current code fails to reserve the
> non-overlapping portion.
>
> I observed this causing a Midway system with a buggy fdt (the header
> declares itself to be larger than it really is) failing to boot
> because the over-inflated size of the fdt was causing it to seem to
> run into the swapper_pg_dir region, meaning the DT wasn't reserved.
> The symptoms were failing to find an disks or network and failing to
> boot. I think it is work printing a warning in this case.
>
> However given the ambiguity of whether things like the initrd are
> covered by /memreserve/ and similar I think it is best to also
> register the region rather than just ignoring it.
>
> Since memblock_reserve() handles overlaps just fine lets just warn and
> carry on.
>
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: devicetree@xxxxxxxxxxxxxxx
> ---
> drivers/of/fdt.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 30e97bc..4f0f24c 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -965,7 +965,8 @@ int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
> phys_addr_t size, bool nomap)
> {
> if (memblock_is_region_reserved(base, size))
> - return -EBUSY;
> + pr_warning("DT reserved region at 0x%pa is already reserved\n",
> + &base);
Since memblock_remove/reserve does the right thing anyway, let's just
drop the test entirely.
g.
> if (nomap)
> return memblock_remove(base, size);
> return memblock_reserve(base, size);
> --
> 1.7.10.4
>
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