/*
* Register a handler at the supplied priority. Registration is allowed only if
* a handler hasn't been registered before, or one wasn't provided at build
* time. The priority for which the handler is being registered must also accord
* with the platform-supplied data.
*/
void ehf_register_priority_handler(unsigned int pri, ehf_handler_t handler)
{
int idx;
/* Sanity check for handler */
assert(handler != NULL);
/* Handler ought to be 4-byte aligned */
assert((((uintptr_t) handler) & 3) == 0);
/* Ensure we register for valid priority */
idx = pri_to_idx(pri);
assert(idx < exception_data.num_priorities);
assert(IDX_TO_PRI(idx) == pri);
/* Return failure if a handler was already registered */
if (exception_data.ehf_priorities[idx].ehf_handler != _EHF_NO_HANDLER) {
ERROR("Handler already registered for priority 0x%x\n", pri);
panic();
}
/*
* Install handler, and retain the valid bit. We assume that the handler
* is 4-byte aligned, which is usually the case.
*/
exception_data.ehf_priorities[idx].ehf_handler =
(((uintptr_t) handler) | _EHF_PRI_VALID);
EHF_LOG("register pri=0x%x handler=%p\n", pri, handler);
}
/*
* Program Priority Mask to the original Non-secure priority such that
* Non-secure interrupts may preempt Secure execution, viz. during Yielding SMC
* calls. The 'preempt_ret_code' parameter indicates the Yielding SMC's return
* value in case the call was preempted.
*
* This API is expected to be invoked before delegating a yielding SMC to Secure
* EL1. I.e. within the window of secure execution after Non-secure context is
* saved (after entry into EL3) and Secure context is restored (before entering
* Secure EL1).
*/
void ehf_allow_ns_preemption(uint64_t preempt_ret_code)
{
cpu_context_t *ns_ctx;
unsigned int old_pmr __unused;
pe_exc_data_t *pe_data = this_cpu_data();
/*
* We should have been notified earlier of entering secure world, and
* therefore have stashed the Non-secure priority mask.
*/
assert(pe_data->ns_pri_mask != 0);
/* Make sure no priority levels are active when requesting this */
if (has_valid_pri_activations(pe_data)) {
ERROR("PE %lx has priority activations: 0x%x\n",
read_mpidr_el1(), pe_data->active_pri_bits);
panic();
}
/*
* Program preempted return code to x0 right away so that, if the
* Yielding SMC was indeed preempted before a dispatcher gets a chance
* to populate it, the caller would find the correct return value.
*/
ns_ctx = cm_get_context(NON_SECURE);
assert(ns_ctx);
write_ctx_reg(get_gpregs_ctx(ns_ctx), CTX_GPREG_X0, preempt_ret_code);
old_pmr = plat_ic_set_priority_mask(pe_data->ns_pri_mask);
EHF_LOG("Priority Mask: 0x%x => 0x%x\n", old_pmr, pe_data->ns_pri_mask);
pe_data->ns_pri_mask = 0;
}
/*
* After leaving Non-secure world, stash current Non-secure Priority Mask, and
* set Priority Mask to the highest Non-secure priority so that Non-secure
* interrupts cannot preempt Secure execution.
*
* If the current running priority is in the secure range, or if there are
* outstanding priority activations, this function does nothing.
*
* This function subscribes to the 'cm_exited_normal_world' event published by
* the Context Management Library.
*/
static void *ehf_exited_normal_world(const void *arg)
{
unsigned int run_pri;
pe_exc_data_t *pe_data = this_cpu_data();
/* If the running priority is in the secure range, do nothing */
run_pri = plat_ic_get_running_priority();
if (IS_PRI_SECURE(run_pri))
return 0;
/* Do nothing if there are explicit activations */
if (has_valid_pri_activations(pe_data))
return 0;
assert(pe_data->ns_pri_mask == 0);
pe_data->ns_pri_mask =
plat_ic_set_priority_mask(GIC_HIGHEST_NS_PRIORITY);
/* The previous Priority Mask is not expected to be in secure range */
if (IS_PRI_SECURE(pe_data->ns_pri_mask)) {
ERROR("Priority Mask (0x%x) already in secure range\n",
pe_data->ns_pri_mask);
panic();
}
EHF_LOG("Priority Mask: 0x%x => 0x%x\n", pe_data->ns_pri_mask,
GIC_HIGHEST_NS_PRIORITY);
return 0;
}
/*
* Mark priority active by setting the corresponding bit in active_pri_bits and
* programming the priority mask.
*
* This API is to be used as part of delegating to lower ELs other than for
* interrupts; e.g. while handling synchronous exceptions.
*
* This API is expected to be invoked before restoring context (Secure or
* Non-secure) in preparation for the respective dispatch.
*/
void ehf_activate_priority(unsigned int priority)
{
int cur_pri_idx;
unsigned int old_mask, run_pri, idx;
pe_exc_data_t *pe_data = this_cpu_data();
/*
* Query interrupt controller for the running priority, or idle priority
* if no interrupts are being handled. The requested priority must be
* less (higher priority) than the active running priority.
*/
run_pri = plat_ic_get_running_priority();
if (priority >= run_pri) {
ERROR("Running priority higher (0x%x) than requested (0x%x)\n",
run_pri, priority);
panic();
}
/*
* If there were priority activations already, the requested priority
* must be less (higher priority) than the current highest priority
* activation so far.
*/
cur_pri_idx = get_pe_highest_active_idx(pe_data);
idx = pri_to_idx(priority);
if ((cur_pri_idx != EHF_INVALID_IDX) &&
(idx >= ((unsigned int) cur_pri_idx))) {
ERROR("Activation priority mismatch: req=0x%x current=0x%x\n",
priority, IDX_TO_PRI(cur_pri_idx));
panic();
}
/* Set the bit corresponding to the requested priority */
pe_data->active_pri_bits |= PRI_BIT(idx);
/*
* Program priority mask for the activated level. Check that the new
* priority mask is setting a higher priority level than the existing
* mask.
*/
old_mask = plat_ic_set_priority_mask(priority);
if (priority >= old_mask) {
ERROR("Requested priority (0x%x) lower than Priority Mask (0x%x)\n",
priority, old_mask);
panic();
}
/*
* If this is the first activation, save the priority mask. This will be
* restored after the last deactivation.
*/
if (cur_pri_idx == EHF_INVALID_IDX)
pe_data->init_pri_mask = (uint8_t) old_mask;
EHF_LOG("activate prio=%d\n", get_pe_highest_active_idx(pe_data));
}
/*
* Mark priority inactive by clearing the corresponding bit in active_pri_bits,
* and programming the priority mask.
*
* This API is expected to be used as part of delegating to to lower ELs other
* than for interrupts; e.g. while handling synchronous exceptions.
*
* This API is expected to be invoked after saving context (Secure or
* Non-secure), having concluded the respective dispatch.
*/
void ehf_deactivate_priority(unsigned int priority)
{
int cur_pri_idx;
pe_exc_data_t *pe_data = this_cpu_data();
unsigned int old_mask, run_pri, idx;
/*
* Query interrupt controller for the running priority, or idle priority
* if no interrupts are being handled. The requested priority must be
* less (higher priority) than the active running priority.
*/
run_pri = plat_ic_get_running_priority();
if (priority >= run_pri) {
ERROR("Running priority higher (0x%x) than requested (0x%x)\n",
run_pri, priority);
panic();
}
/*
* Deactivation is allowed only when there are priority activations, and
* the deactivation priority level must match the current activated
* priority.
*/
cur_pri_idx = get_pe_highest_active_idx(pe_data);
idx = pri_to_idx(priority);
if ((cur_pri_idx == EHF_INVALID_IDX) ||
(idx != ((unsigned int) cur_pri_idx))) {
ERROR("Deactivation priority mismatch: req=0x%x current=0x%x\n",
priority, IDX_TO_PRI(cur_pri_idx));
panic();
}
/* Clear bit corresponding to highest priority */
pe_data->active_pri_bits &= (pe_data->active_pri_bits - 1u);
/*
* Restore priority mask corresponding to the next priority, or the
* one stashed earlier if there are no more to deactivate.
*/
cur_pri_idx = get_pe_highest_active_idx(pe_data);
if (cur_pri_idx == EHF_INVALID_IDX)
old_mask = plat_ic_set_priority_mask(pe_data->init_pri_mask);
else
old_mask = plat_ic_set_priority_mask(priority);
if (old_mask > priority) {
ERROR("Deactivation priority (0x%x) lower than Priority Mask (0x%x)\n",
priority, old_mask);
panic();
}
EHF_LOG("deactivate prio=%d\n", get_pe_highest_active_idx(pe_data));
}
/*
* Conclude Secure execution and prepare for return to Non-secure world. Restore
* the Non-secure Priority Mask previously stashed upon leaving Non-secure
* world.
*
* If there the current running priority is in the secure range, or if there are
* outstanding priority activations, this function does nothing.
*
* This function subscribes to the 'cm_entering_normal_world' event published by
* the Context Management Library.
*/
static void *ehf_entering_normal_world(const void *arg)
{
unsigned int old_pmr, run_pri;
pe_exc_data_t *pe_data = this_cpu_data();
/* If the running priority is in the secure range, do nothing */
run_pri = plat_ic_get_running_priority();
if (IS_PRI_SECURE(run_pri))
return 0;
/*
* If there are explicit activations, do nothing. The Priority Mask will
* be restored upon the last deactivation.
*/
if (has_valid_pri_activations(pe_data))
return 0;
/* Do nothing if we don't have a valid Priority Mask to restore */
if (pe_data->ns_pri_mask == 0)
return 0;
old_pmr = plat_ic_set_priority_mask(pe_data->ns_pri_mask);
/*
* When exiting secure world, the current Priority Mask must be
* GIC_HIGHEST_NS_PRIORITY (as set during entry), or the Non-secure
* priority mask set upon calling ehf_allow_ns_preemption()
*/
if ((old_pmr != GIC_HIGHEST_NS_PRIORITY) &&
(old_pmr != pe_data->ns_pri_mask)) {
ERROR("Invalid Priority Mask (0x%x) restored\n", old_pmr);
panic();
}
EHF_LOG("Priority Mask: 0x%x => 0x%x\n", old_pmr, pe_data->ns_pri_mask);
pe_data->ns_pri_mask = 0;
return 0;
}
