Hi Dave,

In my develop enviroment,  kaslr offset will be stored in SoC on-chip memory for debuging, but crash utility is not work if i only set kaslr offset by command '--kaslr XXX', it also need correct kimage_voffset. 

error message without the patch:

VA_BITS: 39
using 40000000 as phys_offset
kimage_voffset: 0
phys_offset: 40000000
.....cut....
<readmem: ffffff9381e074a0, KVADDR, "cpu_possible_mask", 8, (FOE), 7fffce0dfa48>
<read_ramdump: addr: ffffff9381e074a0 paddr: 13b9e074a0 cnt: 8>
read_ramdump: READ_ERROR: offset not found for paddr: 13b9e074a0
crash: read error: kernel virtual address: ffffff9381e074a0  type: "cpu_possible_mask"

This patch add a function to auto calculate kimage_voffset by kaslr offset. Please review it.

Thanks,

Yueyi Li