On Tue, Oct 20, 2020 at 8:46 AM Vincent Whitchurch
<vincent.whitchurch@xxxxxxxx> wrote:
>
> On Tue, Oct 20, 2020 at 03:00:14PM +0200, Rob Herring wrote:
> > On Tue, Oct 20, 2020 at 2:36 AM Vincent Whitchurch
> > <vincent.whitchurch@xxxxxxxx> wrote:
> > >
> > > The reserved-memory overlap detection code fails to detect overlaps if
> > > either of the regions starts at address 0x0. For some reason the code
> > > explicitly checks for and ignores such regions, but this check looks
> > > invalid. Remove the check and fix this detection.
> >
> > Wouldn't 'base' be 0 for nodes that have a 'size' and no address? The
> > base in those cases isn't set until later when
> > __reserved_mem_alloc_size() is called.
>
> Ah, yes, I guess that's why the check was there. I see that those
> entries have both a zero address and a zero size, so this seems to work:
Yes, I think it should work.
>
> diff --git a/arch/arm/boot/dts/vexpress-v2p-ca9.dts b/arch/arm/boot/dts/vexpress-v2p-ca9.dts
> index 623246f37448..6627e71c7283 100644
> --- a/arch/arm/boot/dts/vexpress-v2p-ca9.dts
> +++ b/arch/arm/boot/dts/vexpress-v2p-ca9.dts
> @@ -81,6 +81,18 @@ vram: vram@4c000000 {
> reg = <0x4c000000 0x00800000>;
> no-map;
> };
> +
> + foo@0 {
> + reg = <0x0 0x2000>;
> + };
> +
> + bar@1000 {
> + reg = <0x0 0x1000>;
0x1000 base?
> + };
> +
> + baz {
> + size = <0x1000>;
> + };
> };
>
> clcd@10020000 {
> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 46b9371c8a33..fea9433d942a 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -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;
> }
>
> @@ -212,13 +222,19 @@ static void __init __rmem_check_for_overlap(void)
>
> 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 = &reserved_mem[i];
> +
> + pr_info("i %d base %x size %x\n", i, this->base, this->size);
> + }
> +
> 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;
>
