[Skiboot] [PATCH] core/cpu.c: Use a device-tree node to detect nest mmu presence

[Stewart Smith]

Alistair Popple <alistair at popple.id.au> writes:
> The nest mmu address scom was hardcoded which could lead to boot
> failure on POWER9 systems without a nest mmu. For example Mambo
> doesn't model the nest mmu which results in the following failure when
> calling opal_nmmu_set_ptcr() during kernel load:
>
> WARNING: 20856759: (20856757): Invalid address 0x0000000028096258 in XSCOM range,  SCOM=0x00280962b
> WARNING: 20856759: (20856757): Attempt to store non-existent address 0x00001A0028096258
> 20856759: (20856757): 0x000000003002DA08 : stdcix  r26,r0,r3
> FATAL ERROR: 20856759: (20856757): Check Stop for 0:0: Machine Check with ME bit of MSR off
>
> This patch instead reads the address from the device-tree and makes
> opal_nmmu_set_ptcr return OPAL_UNSUPPORTED on systems without a nest
> mmu.
>
> Signed-off-by: Alistair Popple <alistair at popple.id.au>

Looks good, merged to master as of 9418533911728f6d8bb7aa647033c317772ddb97

-- 
Stewart Smith
OPAL Architect, IBM.