lib/psci/psci_main.c

/*
 * Copyright (c) 2013-2026, Arm Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <string.h>

#include <arch.h>
#include <arch_features.h>
#include <arch_helpers.h>
#include <common/debug.h>
#include <lib/pmf/pmf.h>
#include <lib/runtime_instr.h>
#include <lib/smccc.h>
#include <plat/common/platform.h>
#include <services/arm_arch_svc.h>

#include "psci_private.h"

/*******************************************************************************
 * PSCI frontend api for servicing SMCs. Described in the PSCI spec.
 ******************************************************************************/
int psci_cpu_on(u_register_t target_cpu,
		uintptr_t entrypoint,
		u_register_t context_id)

{
	int rc;
	entry_point_info_t *ep = NULL;
	unsigned int target_idx = (unsigned int)plat_core_pos_by_mpidr(target_cpu);

	/* Validate the target CPU */
	if (!is_valid_mpidr(target_cpu)) {
		return PSCI_E_INVALID_PARAMS;
	}

	ep = get_cpu_data_by_index(target_idx, warmboot_ep_info);
	/* Validate the lower EL entry point and put it in the entry_point_info */
	rc = psci_validate_entry_point(ep, entrypoint, context_id);
	if (rc != PSCI_E_SUCCESS) {
		return rc;
	}

	/*
	 * To turn this cpu on, specify which power
	 * levels need to be turned on
	 */
	return psci_cpu_on_start(target_cpu);
}

unsigned int psci_version(void)
{
	return PSCI_MAJOR_VER | PSCI_MINOR_VER;
}

int psci_cpu_suspend(unsigned int power_state,
		     uintptr_t entrypoint,
		     u_register_t context_id)
{
	int rc;
	unsigned int target_pwrlvl, is_power_down_state;
	psci_power_state_t state_info = { {PSCI_LOCAL_STATE_RUN} };
	plat_local_state_t cpu_pd_state;
	unsigned int cpu_idx = plat_my_core_pos();

#if ERRATA_SME_POWER_DOWN
	/*
	 * If SME isn't off, attempting a real power down will only end up being
	 * rejected. If we got called with SME on, fall back to a normal
	 * suspend. We can't force SME off as in the event the power down is
	 * rejected for another reason (eg GIC) we'd lose the SME context.
	 */
	if (is_feat_sme_supported() && read_svcr() != 0) {
		power_state &= ~(PSTATE_TYPE_MASK << PSTATE_TYPE_SHIFT);
		power_state &= ~(PSTATE_PWR_LVL_MASK << PSTATE_PWR_LVL_SHIFT);
	}
#endif /* ERRATA_SME_POWER_DOWN */

	/* Validate the power_state parameter */
	rc = psci_validate_power_state(power_state, &state_info);
	if (rc != PSCI_E_SUCCESS) {
		assert(rc == PSCI_E_INVALID_PARAMS);
		return rc;
	}

	/*
	 * Get the value of the state type bit from the power state parameter.
	 */
	is_power_down_state = psci_get_pstate_type(power_state);

	/* Sanity check the requested suspend levels */
	assert(psci_validate_suspend_req(&state_info, is_power_down_state)
			== PSCI_E_SUCCESS);

	target_pwrlvl = psci_find_target_suspend_lvl(&state_info);
	if (target_pwrlvl == PSCI_INVALID_PWR_LVL) {
		ERROR("Invalid target power level for suspend operation\n");
		panic();
	}

	/* Fast path for local CPU standby, won't interact with higher power levels. */
	if (is_cpu_standby_req(is_power_down_state, target_pwrlvl)) {
		if  (psci_plat_pm_ops->cpu_standby == NULL) {
			return PSCI_E_INVALID_PARAMS;
		}

		/*
		 * Set the state of the CPU power domain to the platform
		 * specific retention state and enter the standby state.
		 */
		cpu_pd_state = state_info.pwr_domain_state[PSCI_CPU_PWR_LVL];
		psci_set_cpu_local_state(cpu_pd_state);

#if ENABLE_PSCI_STAT
		plat_psci_stat_accounting_start(&state_info);
#endif

#if ENABLE_RUNTIME_INSTRUMENTATION
		PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
		    RT_INSTR_ENTER_HW_LOW_PWR,
		    PMF_NO_CACHE_MAINT);
#endif

		psci_plat_pm_ops->cpu_standby(cpu_pd_state);

		/* Upon exit from standby, set the state back to RUN. */
		psci_set_cpu_local_state(PSCI_LOCAL_STATE_RUN);

#if ENABLE_RUNTIME_INSTRUMENTATION
		PMF_CAPTURE_TIMESTAMP(rt_instr_svc,
		    RT_INSTR_EXIT_HW_LOW_PWR,
		    PMF_NO_CACHE_MAINT);
#endif

#if ENABLE_PSCI_STAT
		plat_psci_stat_accounting_stop(&state_info);

		/* Update PSCI stats */
		psci_stats_update_pwr_up(cpu_idx, PSCI_CPU_PWR_LVL, &state_info);
#endif

		return PSCI_E_SUCCESS;
	}

	/*
	 * If a power down state has been requested, we need to verify entry
	 * point and program entry information.
	 */
	if (is_power_down_state != 0U) {
		entry_point_info_t *ep = get_cpu_data_by_index(cpu_idx, warmboot_ep_info);

		rc = psci_validate_entry_point(ep, entrypoint, context_id);
		if (rc != PSCI_E_SUCCESS) {
			return rc;
		}
	}

	/*
	 * Do what is needed to enter the power down state. Upon success,
	 * enter the final wfi which will power down this CPU. This function
	 * might return if the power down was abandoned for any reason, e.g.
	 * arrival of an interrupt
	 */
	rc = psci_cpu_suspend_start(cpu_idx,
				    target_pwrlvl,
				    &state_info,
				    is_power_down_state);

	return rc;
}


int psci_system_suspend(uintptr_t entrypoint, u_register_t context_id)
{
	int rc;
	psci_power_state_t state_info;
	unsigned int cpu_idx = plat_my_core_pos();
	entry_point_info_t *ep = get_cpu_data_by_index(cpu_idx, warmboot_ep_info);

	/* Check if the current CPU is the last ON CPU in the system */
	if (!psci_is_last_on_cpu(cpu_idx)) {
		return PSCI_E_DENIED;
	}

	/* Validate the entry point and get the entry_point_info */
	rc = psci_validate_entry_point(ep, entrypoint, context_id);
	if (rc != PSCI_E_SUCCESS) {
		return rc;
	}

	/* Query the psci_power_state for system suspend */
	psci_query_sys_suspend_pwrstate(&state_info);

	/*
	 * Check if platform allows suspend to Highest power level
	 * (System level)
	 */
	if (psci_find_target_suspend_lvl(&state_info) < PLAT_MAX_PWR_LVL) {
		return PSCI_E_DENIED;
	}
	/* Ensure that the psci_power_state makes sense */
	assert(psci_validate_suspend_req(&state_info, PSTATE_TYPE_POWERDOWN)
						== PSCI_E_SUCCESS);
	assert(is_local_state_off(
			state_info.pwr_domain_state[PLAT_MAX_PWR_LVL]) != 0);

	/*
	 * Do what is needed to enter the system suspend state. This function
	 * might return if the power down was abandoned for any reason, e.g.
	 * arrival of an interrupt
	 */
	rc = psci_cpu_suspend_start(cpu_idx,
				    PLAT_MAX_PWR_LVL,
				    &state_info,
				    PSTATE_TYPE_POWERDOWN);

	return rc;
}

int psci_cpu_off(void)
{
	int rc;
	unsigned int target_pwrlvl = PLAT_MAX_PWR_LVL;

	/*
	 * Do what is needed to power off this CPU and possible higher power
	 * levels if it able to do so. Upon success, enter the final wfi
	 * which will power down this CPU.
	 */
	rc = psci_do_cpu_off(target_pwrlvl);

	/*
	 * The only error cpu_off can return is E_DENIED. So check if that's
	 * indeed the case.
	 */
	assert(rc == PSCI_E_DENIED);

	return rc;
}

int psci_affinity_info(u_register_t target_affinity,
		       unsigned int lowest_affinity_level)
{
	unsigned int target_idx;

	/* Validate the target affinity */
	if (!is_valid_mpidr(target_affinity)) {
		return PSCI_E_INVALID_PARAMS;
	}

	/* We dont support level higher than PSCI_CPU_PWR_LVL */
	if (lowest_affinity_level > PSCI_CPU_PWR_LVL) {
		return PSCI_E_INVALID_PARAMS;
	}
	/* Calculate the cpu index of the target */
	target_idx = (unsigned int) plat_core_pos_by_mpidr(target_affinity);

	/*
	 * Generic management:
	 * 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);

	return (int)psci_get_aff_info_state_by_idx(target_idx);
}

int psci_migrate(u_register_t target_cpu)
{
	int rc;
	u_register_t resident_cpu_mpidr = 0;

	/* Validate the target cpu */
	if (!is_valid_mpidr(target_cpu)) {
		return PSCI_E_INVALID_PARAMS;
	}

	rc = psci_spd_migrate_info(&resident_cpu_mpidr);
	if (rc != PSCI_TOS_UP_MIG_CAP) {
		return (rc == PSCI_TOS_NOT_UP_MIG_CAP) ?
			  PSCI_E_DENIED : PSCI_E_NOT_SUPPORTED;
	}

	/*
	 * Migrate should only be invoked on the CPU where
	 * the Secure OS is resident.
	 */
	if (resident_cpu_mpidr != read_mpidr_el1()) {
		return PSCI_E_NOT_PRESENT;
	}

	/* Check the validity of the specified target cpu */
	if (!is_valid_mpidr(target_cpu)) {
		return PSCI_E_INVALID_PARAMS;
	}

	assert((psci_spd_pm != NULL) && (psci_spd_pm->svc_migrate != NULL));

	rc = psci_spd_pm->svc_migrate(read_mpidr_el1(), target_cpu);
	assert((rc == PSCI_E_SUCCESS) || (rc == PSCI_E_INTERN_FAIL));

	return rc;
}

int psci_migrate_info_type(void)
{
	u_register_t resident_cpu_mpidr = 0;

	return psci_spd_migrate_info(&resident_cpu_mpidr);
}

u_register_t psci_migrate_info_up_cpu(void)
{
	u_register_t resident_cpu_mpidr = 0;
	int rc;

	/*
	 * Return value of this depends upon what
	 * psci_spd_migrate_info() returns.
	 */
	rc = psci_spd_migrate_info(&resident_cpu_mpidr);
	if ((rc != PSCI_TOS_NOT_UP_MIG_CAP) && (rc != PSCI_TOS_UP_MIG_CAP)) {
		return (u_register_t)(register_t) PSCI_E_INVALID_PARAMS;
	}

	return resident_cpu_mpidr;
}

int psci_node_hw_state(u_register_t target_cpu,
		       unsigned int power_level)
{
	int rc;

	/* Validate target_cpu */
	if (!is_valid_mpidr(target_cpu)) {
		return PSCI_E_INVALID_PARAMS;
	}

	/* Validate power_level against PLAT_MAX_PWR_LVL */
	if (power_level > PLAT_MAX_PWR_LVL) {
		return PSCI_E_INVALID_PARAMS;
	}

	/*
	 * Dispatch this call to platform to query power controller, and pass on
	 * to the caller what it returns
	 */
	assert(psci_plat_pm_ops->get_node_hw_state != NULL);
	rc = psci_plat_pm_ops->get_node_hw_state(target_cpu, power_level);
	assert(((rc >= HW_ON) && (rc <= HW_STANDBY))
		|| (rc == PSCI_E_NOT_SUPPORTED)
		|| (rc == PSCI_E_INVALID_PARAMS));
	return rc;
}

int psci_features(unsigned int psci_fid)
{
	unsigned int local_caps = psci_caps;

	if (psci_fid == SMCCC_VERSION) {
		return PSCI_E_SUCCESS;
	}
	/* Check if it is a 64 bit function */
	if (((psci_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_64) {
		local_caps &= PSCI_CAP_64BIT_MASK;
	}
	/* Check for invalid fid */
	if (!(is_std_svc_call(psci_fid) && is_valid_fast_smc(psci_fid)
			&& is_psci_fid(psci_fid))) {
		return PSCI_E_NOT_SUPPORTED;
	}

	/* Check if the psci fid is supported or not */
	if ((local_caps & define_psci_cap(psci_fid)) == 0U) {
		return PSCI_E_NOT_SUPPORTED;
	}
	/* Format the feature flags */
	if ((psci_fid == PSCI_CPU_SUSPEND_AARCH32) ||
	    (psci_fid == PSCI_CPU_SUSPEND_AARCH64)) {
		unsigned int ret = ((FF_PSTATE << FF_PSTATE_SHIFT) |
			(FF_SUPPORTS_OS_INIT_MODE << FF_MODE_SUPPORT_SHIFT));
		return (int)ret;
	}

	/* Return 0 for all other fid's */
	return PSCI_E_SUCCESS;
}

#if PSCI_OS_INIT_MODE
int psci_set_suspend_mode(unsigned int mode)
{
	suspend_mode_t new_mode;
	unsigned int this_core = plat_my_core_pos();

	if ((mode != (unsigned int)PLAT_COORD) &&
	    (mode != (unsigned int)OS_INIT)) {
		return PSCI_E_INVALID_PARAMS;
	}

	new_mode = (suspend_mode_t)mode;

	if (psci_suspend_mode == new_mode) {
		return PSCI_E_SUCCESS;
	}

	if (new_mode == PLAT_COORD) {
		/* Check if the current CPU is the last ON CPU in the system */
		if (!psci_is_last_on_cpu_safe(this_core)) {
			return PSCI_E_DENIED;
		}
	}

	if (new_mode == OS_INIT) {
		/*
		 * Check if all CPUs in the system are ON or if the current
		 * CPU is the last ON CPU in the system.
		 */
		if (!(psci_are_all_cpus_on_safe(this_core) ||
		      psci_is_last_on_cpu_safe(this_core))) {
			return PSCI_E_DENIED;
		}
	}

	psci_suspend_mode = new_mode;
	psci_flush_dcache_range((uintptr_t)&psci_suspend_mode,
				sizeof(psci_suspend_mode));

	return PSCI_E_SUCCESS;
}
#endif

/*******************************************************************************
 * PSCI top level handler for servicing SMCs.
 ******************************************************************************/
u_register_t psci_smc_handler(uint32_t smc_fid,
			  u_register_t x1,
			  u_register_t x2,
			  u_register_t x3,
			  u_register_t x4,
			  void *cookie,
			  void *handle,
			  u_register_t flags)
{
	(void)x4;
	(void)cookie;
	(void)handle;
	u_register_t ret;

	if (!is_caller_non_secure(flags)) {
		return (u_register_t)SMC_UNK;
	}

	/* Check the fid against the capabilities */
	if ((psci_caps & define_psci_cap(smc_fid)) == 0U) {
		return (u_register_t)SMC_UNK;
	}

	if (((smc_fid >> FUNCID_CC_SHIFT) & FUNCID_CC_MASK) == SMC_32) {
		/* 32-bit PSCI function, clear top parameter bits */

		uint32_t r1 = (uint32_t)x1;
		uint32_t r2 = (uint32_t)x2;
		uint32_t r3 = (uint32_t)x3;

		switch (smc_fid) {
		case PSCI_VERSION:
			ret = (u_register_t)psci_version();
			break;

		case PSCI_CPU_OFF:
			ret = (u_register_t)psci_cpu_off();
			break;

		case PSCI_CPU_SUSPEND_AARCH32:
			ret = (u_register_t)psci_cpu_suspend(r1, r2, r3);
			break;

		case PSCI_CPU_ON_AARCH32:
			ret = (u_register_t)psci_cpu_on(r1, r2, r3);
			break;

		case PSCI_AFFINITY_INFO_AARCH32:
			ret = (u_register_t)psci_affinity_info(r1, r2);
			break;

		case PSCI_MIG_AARCH32:
			ret = (u_register_t)psci_migrate(r1);
			break;

		case PSCI_MIG_INFO_TYPE:
			ret = (u_register_t)psci_migrate_info_type();
			break;

		case PSCI_MIG_INFO_UP_CPU_AARCH32:
			ret = psci_migrate_info_up_cpu();
			break;

		case PSCI_NODE_HW_STATE_AARCH32:
			ret = (u_register_t)psci_node_hw_state(r1, r2);
			break;

		case PSCI_SYSTEM_SUSPEND_AARCH32:
			ret = (u_register_t)psci_system_suspend(r1, r2);
			break;

		case PSCI_SYSTEM_OFF:
			psci_system_off();
			/* We should never return from psci_system_off() */
			break;

		case PSCI_SYSTEM_RESET:
			psci_system_reset();
			/* We should never return from psci_system_reset() */
			break;

		case PSCI_FEATURES:
			ret = (u_register_t)psci_features(r1);
			break;

#if PSCI_OS_INIT_MODE
		case PSCI_SET_SUSPEND_MODE:
			ret = (u_register_t)psci_set_suspend_mode(r1);
			break;
#endif

#if ENABLE_PSCI_STAT
		case PSCI_STAT_RESIDENCY_AARCH32:
			ret = psci_stat_residency(r1, r2);
			break;

		case PSCI_STAT_COUNT_AARCH32:
			ret = psci_stat_count(r1, r2);
			break;
#endif
		case PSCI_MEM_PROTECT:
			ret = psci_mem_protect(r1);
			break;

		case PSCI_MEM_CHK_RANGE_AARCH32:
			ret = psci_mem_chk_range(r1, r2);
			break;

		case PSCI_SYSTEM_RESET2_AARCH32:
			/* We should never return from psci_system_reset2() */
			ret = psci_system_reset2(r1, r2);
			break;

		default:
			WARN("Unimplemented PSCI Call: 0x%x\n", smc_fid);
			ret = (u_register_t)SMC_UNK;
			break;
		}
	} else {
		/* 64-bit PSCI function */

		switch (smc_fid) {
		case PSCI_CPU_SUSPEND_AARCH64:
			ret = (u_register_t)
				psci_cpu_suspend((unsigned int)x1, x2, x3);
			break;

		case PSCI_CPU_ON_AARCH64:
			ret = (u_register_t)psci_cpu_on(x1, x2, x3);
			break;

		case PSCI_AFFINITY_INFO_AARCH64:
			ret = (u_register_t)
				psci_affinity_info(x1, (unsigned int)x2);
			break;

		case PSCI_MIG_AARCH64:
			ret = (u_register_t)psci_migrate(x1);
			break;

		case PSCI_MIG_INFO_UP_CPU_AARCH64:
			ret = psci_migrate_info_up_cpu();
			break;

		case PSCI_NODE_HW_STATE_AARCH64:
			ret = (u_register_t)psci_node_hw_state(
					x1, (unsigned int) x2);
			break;

		case PSCI_SYSTEM_SUSPEND_AARCH64:
			ret = (u_register_t)psci_system_suspend(x1, x2);
			break;

#if ENABLE_PSCI_STAT
		case PSCI_STAT_RESIDENCY_AARCH64:
			ret = psci_stat_residency(x1, (unsigned int) x2);
			break;

		case PSCI_STAT_COUNT_AARCH64:
			ret = psci_stat_count(x1, (unsigned int) x2);
			break;
#endif

		case PSCI_MEM_CHK_RANGE_AARCH64:
			ret = psci_mem_chk_range(x1, x2);
			break;

		case PSCI_SYSTEM_RESET2_AARCH64:
			/* We should never return from psci_system_reset2() */
			ret = psci_system_reset2((uint32_t) x1, x2);
			break;

		default:
			WARN("Unimplemented PSCI Call: 0x%x\n", smc_fid);
			ret = (u_register_t)SMC_UNK;
			break;
		}
	}

	return ret;
}