arm64 crashkernel fails to boot on acpi-only machines due to ACPI regions being no longer mapped as NOMAP

[Ard Biesheuvel]

On 13 November 2017 at 09:27, AKASHI Takahiro
<takahiro.akashi at linaro.org> wrote:
> Hi,
>
> On Fri, Nov 10, 2017 at 05:41:56PM +0530, Bhupesh Sharma wrote:
>> Resent with Akashi's correct email address.
>>
>> On Fri, Nov 10, 2017 at 5:39 PM, Bhupesh Sharma <bhsharma at redhat.com> wrote:
>> > Hi Ard, Akashi
>> >
>> > I have met an issue on an arm64 board using the latest master branch from Linus.
>   (snip)
>> >
>> > 8. Also, I think now the crashkernel handling changed by
>> > e7cd190385d17790cc3eb3821b1094b00aacf325 (arm64: mark reserved
>> > memblock regions explicitly in iomem), needs to be changed to handle
>> > the change added by Ard to fix this issue on ACPI only machines.
>> >
>> > I have a dirty hack in place, but I would like to have your opinions
>> > about what can be a more concrete fix to this issue (as we mark these
>> > regions as System RAM now rather than NOMAP) and I don't have a DTB
>> > based machine to test on currently.
>
> I don't know much about acpi reclaim regions,
> can you please tell me how your change affects your panic case?
>

Does this help at all?

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 7768423b39d3..61d867647cca 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -213,7 +213,7 @@ static void __init request_standard_resources(void)

        for_each_memblock(memory, region) {
                res = alloc_bootmem_low(sizeof(*res));
-               if (memblock_is_nomap(region)) {
+               if (memblock_is_nomap(region) || memblock_is_reserved(region)) {
                        res->name  = "reserved";
                        res->flags = IORESOURCE_MEM;
                } else {