diff options
Diffstat (limited to 'lib/psci/psci_on.c')
| -rw-r--r-- | lib/psci/psci_on.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/psci/psci_on.c b/lib/psci/psci_on.c index 16b22c2a..d3d0e2ff 100644 --- a/lib/psci/psci_on.c +++ b/lib/psci/psci_on.c @@ -64,7 +64,20 @@ int psci_cpu_on_start(u_register_t target_cpu, /* * Generic management: Ensure that the cpu is off to be * turned on. + * Perform cache maintanence ahead of reading the target CPU state to + * ensure that the data is not stale. + * There is a theoretical edge case where the cache may contain stale + * data for the target CPU data - this can occur under the following + * conditions: + * - the target CPU is in another cluster from the current + * - the target CPU was the last CPU to shutdown on its cluster + * - the cluster was removed from coherency as part of the CPU shutdown + * + * In this case the cache maintenace that was performed as part of the + * target CPUs shutdown was not seen by the current CPU's cluster. And + * so the cache may contain stale data for the target CPU. */ + flush_cpu_data_by_index(target_idx, psci_svc_cpu_data.aff_info_state); rc = cpu_on_validate_state(psci_get_aff_info_state_by_idx(target_idx)); if (rc != PSCI_E_SUCCESS) goto exit; |