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Commit ae1add24 authored by Mitchel Humpherys's avatar Mitchel Humpherys Committed by Rob Herring
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of: Check for overlap in reserved memory regions 



Any overlap in the reserved memory regions (those specified in the
reserved-memory DT node) is a bug.  These bugs might go undetected as
long as the contested region isn't used simultaneously by multiple
software agents, which makes such bugs hard to debug.  Fix this by
printing a scary warning during boot if overlap is detected.

Signed-off-by: default avatarMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent 4f59d711

drivers/of/of_reserved_mem.c

+42 −1
Original line number Diff line number Diff line 
/*

 * Device tree based initialization code for reserved memory.

 *

 * Copyright (c) 2013, The Linux Foundation. All Rights Reserved.

 * Copyright (c) 2013, 2015 The Linux Foundation. All Rights Reserved.

 * Copyright (c) 2013,2014 Samsung Electronics Co., Ltd.

 *		http://www.samsung.com

 * Author: Marek Szyprowski <m.szyprowski@samsung.com>
@@ -20,6 +20,7 @@ 
#include <linux/mm.h>

#include <linux/sizes.h>

#include <linux/of_reserved_mem.h>

#include <linux/sort.h>



#define MAX_RESERVED_REGIONS	16

static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
@@ -197,12 +198,52 @@ static int __init __reserved_mem_init_node(struct reserved_mem *rmem) 
	return -ENOENT;

}



static int __init __rmem_cmp(const void *a, const void *b)

{

	const struct reserved_mem *ra = a, *rb = b;



	return ra->base - rb->base;

}



static void __init __rmem_check_for_overlap(void)

{

	int i;



	if (reserved_mem_count < 2)

		return;



	sort(reserved_mem, reserved_mem_count, sizeof(reserved_mem[0]),

	     __rmem_cmp, NULL);

	for (i = 0; i < reserved_mem_count - 1; i++) {

		struct reserved_mem *this, *next;



		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;



			this_end = this->base + this->size;

			next_end = next->base + next->size;

			WARN(1,

			     "Reserved memory: OVERLAP DETECTED!\n%s (%pa--%pa) overlaps with %s (%pa--%pa)\n",

			     this->name, &this->base, &this_end,

			     next->name, &next->base, &next_end);

		}

	}

}



/**

 * fdt_init_reserved_mem - allocate and init all saved reserved memory regions

 */

void __init fdt_init_reserved_mem(void)

{

	int i;



	/* check for overlapping reserved regions */

	__rmem_check_for_overlap();



	for (i = 0; i < reserved_mem_count; i++) {

		struct reserved_mem *rmem = &reserved_mem[i];

		unsigned long node = rmem->fdt_node;