diff options
Diffstat (limited to 'services')
| -rw-r--r-- | services/spd/tspd/tspd_main.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/services/spd/tspd/tspd_main.c b/services/spd/tspd/tspd_main.c index 4c4861d7..4b894258 100644 --- a/services/spd/tspd/tspd_main.c +++ b/services/spd/tspd/tspd_main.c @@ -89,18 +89,22 @@ uint64_t tspd_handle_sp_preemption(void *handle) assert(ns_cpu_context); /* - * Restore non-secure state. The secure system - * register context will be saved when required. + * To allow Secure EL1 interrupt handler to re-enter TSP while TSP + * is preempted, the secure system register context which will get + * overwritten must be additionally saved. This is currently done + * by the TSPD S-EL1 interrupt handler. + */ + + /* + * Restore non-secure state. */ cm_el1_sysregs_context_restore(NON_SECURE); cm_set_next_eret_context(NON_SECURE); /* - * We need to restore non secure context according to - * the SEL1 context which got preempted and currently - * TSP can only be preempted when a STD SMC is ongoing. - * Return SMC_PREEMPTED in x0 and restore non secure - * context. + * The TSP was preempted during STD SMC execution. + * Return back to the normal world with SMC_PREEMPTED as error + * code in x0. */ SMC_RET1(ns_cpu_context, SMC_PREEMPTED); } @@ -327,7 +331,8 @@ uint64_t tspd_smc_handler(uint32_t smc_fid, /* * This function ID is used only by the TSP to indicate that it has - * finished handling a S-EL1 interrupt. Execution should resume + * finished handling a S-EL1 interrupt or was preempted by a higher + * priority pending EL3 interrupt. Execution should resume * in the normal world. */ case TSP_HANDLED_S_EL1_INTR: |