diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/mobility.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/mobility.c | 48 |
1 files changed, 44 insertions, 4 deletions
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index ea4d6a660e0d..e83e0891272d 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -452,12 +452,28 @@ static int do_suspend(void) return ret; } +/** + * struct pseries_suspend_info - State shared between CPUs for join/suspend. + * @counter: Threads are to increment this upon resuming from suspend + * or if an error is received from H_JOIN. The thread which performs + * the first increment (i.e. sets it to 1) is responsible for + * waking the other threads. + * @done: False if join/suspend is in progress. True if the operation is + * complete (successful or not). + */ +struct pseries_suspend_info { + atomic_t counter; + bool done; +}; + static int do_join(void *arg) { - atomic_t *counter = arg; + struct pseries_suspend_info *info = arg; + atomic_t *counter = &info->counter; long hvrc; int ret; +retry: /* Must ensure MSR.EE off for H_JOIN. */ hard_irq_disable(); hvrc = plpar_hcall_norets(H_JOIN); @@ -473,8 +489,20 @@ static int do_join(void *arg) case H_SUCCESS: /* * The suspend is complete and this cpu has received a - * prod. + * prod, or we've received a stray prod from unrelated + * code (e.g. paravirt spinlocks) and we need to join + * again. + * + * This barrier orders the return from H_JOIN above vs + * the load of info->done. It pairs with the barrier + * in the wakeup/prod path below. */ + smp_mb(); + if (READ_ONCE(info->done) == false) { + pr_info_ratelimited("premature return from H_JOIN on CPU %i, retrying", + smp_processor_id()); + goto retry; + } ret = 0; break; case H_BAD_MODE: @@ -488,6 +516,13 @@ static int do_join(void *arg) if (atomic_inc_return(counter) == 1) { pr_info("CPU %u waking all threads\n", smp_processor_id()); + WRITE_ONCE(info->done, true); + /* + * This barrier orders the store to info->done vs subsequent + * H_PRODs to wake the other CPUs. It pairs with the barrier + * in the H_SUCCESS case above. + */ + smp_mb(); prod_others(); } /* @@ -535,11 +570,16 @@ static int pseries_suspend(u64 handle) int ret; while (true) { - atomic_t counter = ATOMIC_INIT(0); + struct pseries_suspend_info info; unsigned long vasi_state; int vasi_err; - ret = stop_machine(do_join, &counter, cpu_online_mask); + info = (struct pseries_suspend_info) { + .counter = ATOMIC_INIT(0), + .done = false, + }; + + ret = stop_machine(do_join, &info, cpu_online_mask); if (ret == 0) break; /* |