[PATCH v24 2/9] memblock: add memblock_cap_memory_range()

Hi Akashi,

On 09/08/16 02:55, AKASHI Takahiro wrote:

Crash dump kernel uses only a limited range of memory as System RAM.
On arm64 implementation, a new device tree property,
"linux,usable-memory-range," is used to notify crash dump kernel of
this range.[1]
But simply excluding all the other regions, whatever their memory types
are, doesn't work, especially, on the systems with ACPI. Since some of
such regions will be later mapped as "device memory" by ioremap()/
acpi_os_ioremap(), it can cause errors like unalignment accesses.[2]
This issue is akin to the one reported in [3].

So this patch follows Chen's approach, and implements a new function,
memblock_cap_memory_range(), which will exclude only the memory regions
that are not marked "NOMAP" from memblock.memory.

This (and the next patch) fixes the acpi related unaligned access problem I had.
I've tested it on a Juno r1 and Seattle B0.

Tested-by: James Morse <james.morse@arm.com>


Thanks,

James