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of: Check for overlap in reserved memory regions

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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: Mitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: Rob Herring <robh@kernel.org>
This commit is contained in:
Mitchel Humpherys 2015-09-15 18:30:36 -07:00 committed by Rob Herring
parent 4f59d7119c
commit ae1add247b
1 changed files with 42 additions and 1 deletions
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43
drivers/of/of_reserved_mem.c
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@ -1,7 +1,7 @@
/*
* 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;