From: Michael Ellerman Date: Wed, 18 Nov 2015 10:46:38 +0000 (+1100) Subject: of: Fix comparison of reserved memory regions X-Git-Tag: firefly_0821_release~176^2~583^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9eb8cd2b0780bca0719e754e7bdcf5f368f001bd;p=firefly-linux-kernel-4.4.55.git 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 Signed-off-by: Rob Herring --- diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index be77e75c587d..1a3556a9e9ea 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -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)