ANBZ: #9396
When the clocksource of the system is HPET，a CPU executing read_hpet might
be interrupted by #GP/#PF to executing the panic，this may lead to
read_hpet dead loops:
CPU x CPU x
---- ----
read_hpet()
arch_spin_trylock(&hpet.lock)
[CPU x got the hpet.lock] #GP/#PF happened
panic()
kmsg_dump()
pstore_dump()
pstore_record_init()
ktime_get_real_fast_ns()
read_hpet()
[dead loops]
To avoid this dead loops, read HPET directly if panic in progress.
Signed-off-by: leoliu-oc <leoliu-oc@zhaoxin.com>
Reviewed-by: Artie Ding <artie.ding@linux.alibaba.com>
Link: https://gitee.com/anolis/cloud-kernel/pulls/3396
8cfe551cd7