powerpc/kexec: Fix kexec/kdump in P9 guest kernels
authorMichael Ellerman <mpe@ellerman.id.au>
Fri, 24 Nov 2017 03:51:02 +0000 (14:51 +1100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 5 Dec 2017 10:26:31 +0000 (11:26 +0100)
commitc12e358867d2656b10ccccc36240d6ce93e0e497
treea5b506ce46a675bffd3c16623c7766dc6a2b6756
parent3bfbf2b1bc18f76dc88064b4d6354b2e4424478c
powerpc/kexec: Fix kexec/kdump in P9 guest kernels

commit 2621e945fbf1d6df5f3f0ba7be5bae3d2cf9b6a5 upstream.

The code that cleans up the IAMR/AMOR before kexec'ing failed to
remember that when we're running as a guest AMOR is not writable, it's
hypervisor privileged.

They symptom is that the kexec stops before entering purgatory and
nothing else is seen on the console. If you examine the state of the
system all threads will be in the 0x700 program check handler.

Fix it by making the write to AMOR dependent on HV mode.

Fixes: 1e2a516e89fc ("powerpc/kexec: Fix radix to hash kexec due to IAMR/AMOR")
Reported-by: Yilin Zhang <yilzhang@redhat.com>
Debugged-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/powerpc/kernel/misc_64.S