Updates for Powerpc kexec
Description: Updates for Powerpc kexec
JIRA: https://issues.redhat.com/browse/RHEL-14159
Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=62861128
Tested: Verified Brew build test kernel RPMs and confirmed issue is resovled
Signed-off-by: Mamatha Inamdar minamdar@redhat.com
commit 21a741eb75f80397e5f7d3739e24d7d75e619011 Author: Nicholas Piggin npiggin@gmail.com Date: Tue Jun 25 23:40:47 2024 +1000
powerpc/pseries: Fix scv instruction crash with kexec
kexec on pseries disables AIL (reloc_on_exc), required for scv
instruction support, before other CPUs have been shut down. This means
they can execute scv instructions after AIL is disabled, which causes an
interrupt at an unexpected entry location that crashes the kernel.
Change the kexec sequence to disable AIL after other CPUs have been
brought down.
As a refresher, the real-mode scv interrupt vector is 0x17000, and the
fixed-location head code probably couldn't easily deal with implementing
such high addresses so it was just decided not to support that interrupt
at all.
Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Closes: https://lore.kernel.org/3b4b2943-49ad-4619-b195-bc416f1d1409@linux.ibm.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Tested-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Link: https://msgid.link/20240625134047.298759-1-npiggin@gmail.com
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Mamatha Inamdar minamdar@redhat.com