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);
if (nomap)
return memblock_remove(base, size);
return memblock_reserve(base, size);
--
1.7.10.4
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