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@xxxxxxx> Thanks, James -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>