ARM: 9206/1: A9: Add ARM ERRATA 764319 workaround (Updated)

mainline inclusion
from mainline-v5.19-rc1
commit 8294fec1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6O293

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8294fec1cab7ae6153525eb68401ed5905921371



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Enable the workaround for the 764319 Cortex A-9 erratum.
CP14 read accesses to the DBGPRSR and DBGOSLSR registers generate an
unexpected Undefined Instruction exception when the DBGSWENABLE external
pin is set to 0, even when the CP14 accesses are performed from a
privileged mode. The work around catches the exception in a way
the kernel does not stop execution with the use of undef_hook. This
has been found to effect the HPE GXP SoC.

Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Lin Yujun <linyujun809@huawei.com>
Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>