diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2018-05-10 22:21:48 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-06-03 20:40:30 +1000 |
| commit | ee03b9b4479d1302d01cebedda3518dc967697b7 (patch) | |
| tree | 9386d5d153273203946726d7ee5d07a382fe7e2b /arch/powerpc/include/asm/opal.h | |
| parent | 3130a7bb6eb595f2d963976a4d3e57db77bcf06f (diff) | |
| download | linux-ee03b9b4479d1302d01cebedda3518dc967697b7.tar.bz2 | |
powerpc/powernv: call OPAL_QUIESCE before OPAL_SIGNAL_SYSTEM_RESET
Although it is often possible to recover a CPU that was interrupted
from OPAL with a system reset NMI, it's undesirable to interrupt them
for a few reasons. Firstly because dump/debug code itself needs to
call firmware, so it could hang on a lock or possibly corrupt a
per-cpu data structure if it or another CPU was interrupted from
OPAL. Secondly, the kexec crash dump code will not return from
interrupt to unwind the OPAL call.
Call OPAL_QUIESCE with QUIESCE_HOLD before sending an NMI IPI to
another CPU, which wait for it to leave firmware (or time out) to
avoid this problem in normal conditions. Firmware bugs may still
result in a timeout and interrupting OPAL, but that is the best
option (stops the CPU, and possibly allows firmware to be debugged).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/opal.h')
| -rw-r--r-- | arch/powerpc/include/asm/opal.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h index 3960def0e39c..1dbeb6cd68fa 100644 --- a/arch/powerpc/include/asm/opal.h +++ b/arch/powerpc/include/asm/opal.h @@ -294,6 +294,7 @@ int opal_set_power_shift_ratio(u32 handle, int token, u32 psr); int opal_sensor_group_clear(u32 group_hndl, int token); s64 opal_signal_system_reset(s32 cpu); +s64 opal_quiesce(u64 shutdown_type, s32 cpu); /* Internal functions */ extern int early_init_dt_scan_opal(unsigned long node, const char *uname, |