On Fri, Sep 11, 2015 at 12:31 PM, Mitchel Humpherys <mitchelh@xxxxxxxxxxxxxx> wrote: > 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); Why not just sort reserved_mem? > + 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 seems overly verbose having both WARN and pr_err. I'd combine these. I don't think the stack trace from a WARN is too useful here given it is the DT file that users will need to go look at. > + 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
