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@xxxxxxxxxxxxxx> --- drivers/of/of_reserved_mem.c | 45 +++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 726ebe792813..5246d346cee0 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -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@xxxxxxxxxxx> @@ -20,9 +20,11 @@ #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]; +static struct reserved_mem sorted_reserved_mem[MAX_RESERVED_REGIONS] __initdata; static int reserved_mem_count; #if defined(CONFIG_HAVE_MEMBLOCK) @@ -197,12 +199,53 @@ 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; + + memcpy(sorted_reserved_mem, reserved_mem, sizeof(sorted_reserved_mem)); + sort(sorted_reserved_mem, reserved_mem_count, + sizeof(sorted_reserved_mem[0]), __rmem_cmp, NULL); + for (i = 0; i < reserved_mem_count - 1; i++) { + struct reserved_mem *this, *next; + + this = &sorted_reserved_mem[i]; + next = &sorted_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 mem: OVERLAP DETECTED!\n"); + pr_err("%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; -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
