On Thu, 2016-11-24 at 09:39:54 UTC, "Aneesh Kumar K.V" wrote:

With commit e58e87adc8bf9 ("powerpc/mm: Update _PAGE_KERNEL_RO") we started
using the ppp value 0b110 to map kernel readonly. But that facility
was only added as part of ISA 2.04. For earlier ISA version only supported ppp
bit value for readonly mapping is 0b011. (This implies both user and kernel
get mapped using the same ppp bit value for readonly mapping.).

Update the code such that for earlier architecture version we use ppp value
0b011 for readonly mapping. We don't differentiate between power5+ and power5
here and apply the new ppp bits only from power6 (ISA 2.05). This keep the
changes minimal.

This fixes issue with PS3 spu usage reported at
https://lkml.kernel.org/r/rep.1421449714.geoff@infradead.org

Fixes: e58e87adc8bf9 ("powerpc/mm: Update _PAGE_KERNEL_RO")
Tested-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Aneesh Kumar K.V <redacted>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/984d7a1ec67ce3a46324fa4bcb4c74

cheers