Commit ca05f333 authored Oct 21, 2020 by Vincent Whitchurch Committed by Rob Herring Oct 25, 2020

of: Fix reserved-memory overlap detection



The reserved-memory overlap detection code fails to detect overlaps if
either of the regions starts at address 0x0.  The code explicitly checks
for and ignores such regions, apparently in order to ignore dynamically
allocated regions which have an address of 0x0 at this point.  These
dynamically allocated regions also have a size of 0x0 at this point, so
fix this by removing the check and sorting the dynamically allocated
regions ahead of any static regions at address 0x0.

For example, there are two overlaps in this case but they are not
currently reported:

	foo@0 {
	        reg = <0x0 0x2000>;
	};

	bar@0 {
	        reg = <0x0 0x1000>;
	};

	baz@1000 {
	        reg = <0x1000 0x1000>;
	};

	quux {
	        size = <0x1000>;
	};

but they are after this patch:

 OF: reserved mem: OVERLAP DETECTED!
 bar@0 (0x00000000--0x00001000) overlaps with foo@0 (0x00000000--0x00002000)
 OF: reserved mem: OVERLAP DETECTED!
 foo@0 (0x00000000--0x00002000) overlaps with baz@1000 (0x00001000--0x00002000)

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/ded6fd6b47b58741aabdcc6967f73eca6a3f311e.1603273666.git-series.vincent.whitchurch@axis.com


Signed-off-by: Rob Herring <robh@kernel.org>

parent f83b03fc

drivers/of/of_reserved_mem.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -200,6 +200,16 @@ static int __init __rmem_cmp(const void a, const void b)
		if (ra->base > rb->base)
		return 1;

		/*
		* Put the dynamic allocations (address == 0, size == 0) before static
		* allocations at address 0x0 so that overlap detection works
		* correctly.
		*/
		if (ra->size < rb->size)
		return -1;
		if (ra->size > rb->size)
		return 1;

		return 0;
		}

		@@ -217,8 +227,7 @@ static void __init __rmem_check_for_overlap(void)

		this = &reserved_mem[i];
		next = &reserved_mem[i + 1];
		if (!(this->base && next->base))
		continue;

		if (this->base + this->size > next->base) {
		phys_addr_t this_end, next_end;

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