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of: Fix comparison of reserved memory regions

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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>
This commit is contained in:
Michael Ellerman 2015-11-18 21:46:38 +11:00 committed by Rob Herring
parent 31ade3b83e
commit 9eb8cd2b07
1 changed files with 7 additions and 1 deletions
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8
drivers/of/of_reserved_mem.c
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@ -206,7 +206,13 @@ static int __init __rmem_cmp(const void *a, const void *b)
{
const struct reserved_mem *ra = a, *rb = b;
return ra->base - rb->base;
if (ra->base < rb->base)
return -1;
if (ra->base > rb->base)
return 1;
return 0;
}
static void __init __rmem_check_for_overlap(void)