tree 9f5da3f090e540502f9b0f6c7ea7256a98e5f106
parent 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8
author Michael Ellerman <mpe@ellerman.id.au> 1447843598 +1100
committer Rob Herring <robh@kernel.org> 1448927804 -0600

of: Fix comparison of reserved memory regions

In order to check for overlapping reserved memory regions, we first need
to sort the array of memory regions. This is implemented using sort(),
and a custom comparison function __rmem_cmp().

Unfortunatley __rmem_cmp() doesn't work in all cases. Because the two
base values are phys_addr_t, they may be u64 on some platforms, in which
case subtracting one from the other and then (implicitly) casting to int
does not give us the -ve/0/+ve value we need.

This leads to incorrect reports about overlaps, eg:

  ibm,slw-image@1ffe600000 (0x0000001ffe600000--0x0000001ffe700000) overlaps with
  ibm,firmware-allocs-memory@1000000000 (0x0000001000000000--0x0000001000dc0200)

Fix it by just doing the standard double if and return 0 logic.

Fixes: ae1add247bf8 ("of: Check for overlap in reserved memory regions")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Rob Herring <robh@kernel.org>