lib/el3_runtime/aarch32/context_mgmt.c - filogic/atf - Gitiles

 /*
  * Copyright (c) 2016-2022, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */

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

 #include <platform_def.h>

 #include <arch.h>
 #include <arch_features.h>
 #include <arch_helpers.h>
 #include <common/bl_common.h>
 #include <context.h>
 #include <lib/el3_runtime/context_mgmt.h>
 #include <lib/extensions/amu.h>
 #include <lib/extensions/sys_reg_trace.h>
 #include <lib/extensions/trf.h>
 #include <lib/utils.h>

 /*******************************************************************************
  * Context management library initialisation routine. This library is used by
  * runtime services to share pointers to 'cpu_context' structures for the secure
  * and non-secure states. Management of the structures and their associated
  * memory is not done by the context management library e.g. the PSCI service
  * manages the cpu context used for entry from and exit to the non-secure state.
  * The Secure payload manages the context(s) corresponding to the secure state.
  * It also uses this library to get access to the non-secure
  * state cpu context pointers.
  ******************************************************************************/
 void cm_init(void)
 {
 	/*
 	 * The context management library has only global data to initialize, but
 	 * that will be done when the BSS is zeroed out
 	 */
 }

 /*******************************************************************************
  * The following function initializes the cpu_context 'ctx' for
  * first use, and sets the initial entrypoint state as specified by the
  * entry_point_info structure.
  *
  * The security state to initialize is determined by the SECURE attribute
  * of the entry_point_info.
  *
  * The EE and ST attributes are used to configure the endianness and secure
  * timer availability for the new execution context.
  *
  * To prepare the register state for entry call cm_prepare_el3_exit() and
  * el3_exit(). For Secure-EL1 cm_prepare_el3_exit() is equivalent to
  * cm_el1_sysregs_context_restore().
  ******************************************************************************/
 void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
 {
 	unsigned int security_state;
 	uint32_t scr, sctlr;
 	regs_t *reg_ctx;

 	assert(ctx != NULL);

 	security_state = GET_SECURITY_STATE(ep->h.attr);

 	/* Clear any residual register values from the context */
 	zeromem(ctx, sizeof(*ctx));

 	reg_ctx = get_regs_ctx(ctx);

 	/*
 	 * Base the context SCR on the current value, adjust for entry point
 	 * specific requirements
 	 */
 	scr = read_scr();
 	scr &= ~(SCR_NS_BIT | SCR_HCE_BIT);

 	if (security_state != SECURE)
 		scr |= SCR_NS_BIT;

 	if (security_state != SECURE) {
 		/*
 		 * Set up SCTLR for the Non-secure context.
 		 *
 		 * SCTLR.EE: Endianness is taken from the entrypoint attributes.
 		 *
 		 * SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as
 		 *  required by PSCI specification)
 		 *
 		 * Set remaining SCTLR fields to their architecturally defined
 		 * values. Some fields reset to an IMPLEMENTATION DEFINED value:
 		 *
 		 * SCTLR.TE: Set to zero so that exceptions to an Exception
 		 *  Level executing at PL1 are taken to A32 state.
 		 *
 		 * SCTLR.V: Set to zero to select the normal exception vectors
 		 *  with base address held in VBAR.
 		 */
 		assert(((ep->spsr >> SPSR_E_SHIFT) & SPSR_E_MASK) ==
 			(EP_GET_EE(ep->h.attr) >> EP_EE_SHIFT));

 		sctlr = (EP_GET_EE(ep->h.attr) != 0U) ? SCTLR_EE_BIT : 0U;
 		sctlr |= (SCTLR_RESET_VAL & ~(SCTLR_TE_BIT | SCTLR_V_BIT));
 		write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr);
 	}

 	/*
 	 * The target exception level is based on the spsr mode requested. If
 	 * execution is requested to hyp mode, HVC is enabled via SCR.HCE.
 	 */
 	if (GET_M32(ep->spsr) == MODE32_hyp)
 		scr |= SCR_HCE_BIT;

 	/*
 	 * Store the initialised values for SCTLR and SCR in the cpu_context.
 	 * The Hyp mode registers are not part of the saved context and are
 	 * set-up in cm_prepare_el3_exit().
 	 */
 	write_ctx_reg(reg_ctx, CTX_SCR, scr);
 	write_ctx_reg(reg_ctx, CTX_LR, ep->pc);
 	write_ctx_reg(reg_ctx, CTX_SPSR, ep->spsr);

 	/*
 	 * Store the r0-r3 value from the entrypoint into the context
 	 * Use memcpy as we are in control of the layout of the structures
 	 */
 	memcpy((void *)reg_ctx, (void *)&ep->args, sizeof(aapcs32_params_t));
 }

 /*******************************************************************************
  * Enable architecture extensions on first entry to Non-secure world.
  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
  * it is zero.
  ******************************************************************************/
 static void enable_extensions_nonsecure(bool el2_unused)
 {
 #if IMAGE_BL32
 #if ENABLE_AMU
 	amu_enable(el2_unused);
 #endif

 #if ENABLE_SYS_REG_TRACE_FOR_NS
 	sys_reg_trace_enable();
 #endif /* ENABLE_SYS_REG_TRACE_FOR_NS */

 	if (is_feat_trf_supported()) {
 		trf_enable();
 	}
 #endif
 }

 /*******************************************************************************
  * The following function initializes the cpu_context for a CPU specified by
  * its `cpu_idx` for first use, and sets the initial entrypoint state as
  * specified by the entry_point_info structure.
  ******************************************************************************/
 void cm_init_context_by_index(unsigned int cpu_idx,
 			      const entry_point_info_t *ep)
 {
 	cpu_context_t *ctx;
 	ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
 	cm_setup_context(ctx, ep);
 }

 /*******************************************************************************
  * The following function initializes the cpu_context for the current CPU
  * for first use, and sets the initial entrypoint state as specified by the
  * entry_point_info structure.
  ******************************************************************************/
 void cm_init_my_context(const entry_point_info_t *ep)
 {
 	cpu_context_t *ctx;
 	ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
 	cm_setup_context(ctx, ep);
 }

 /*******************************************************************************
  * Prepare the CPU system registers for first entry into secure or normal world
  *
  * If execution is requested to hyp mode, HSCTLR is initialized
  * If execution is requested to non-secure PL1, and the CPU supports
  * HYP mode then HYP mode is disabled by configuring all necessary HYP mode
  * registers.
  ******************************************************************************/
 void cm_prepare_el3_exit(uint32_t security_state)
 {
 	uint32_t hsctlr, scr;
 	cpu_context_t *ctx = cm_get_context(security_state);
 	bool el2_unused = false;

 	assert(ctx != NULL);

 	if (security_state == NON_SECURE) {
 		scr = read_ctx_reg(get_regs_ctx(ctx), CTX_SCR);
 		if ((scr & SCR_HCE_BIT) != 0U) {
 			/* Use SCTLR value to initialize HSCTLR */
 			hsctlr = read_ctx_reg(get_regs_ctx(ctx),
 						 CTX_NS_SCTLR);
 			hsctlr |= HSCTLR_RES1;
 			/* Temporarily set the NS bit to access HSCTLR */
 			write_scr(read_scr() | SCR_NS_BIT);
 			/*
 			 * Make sure the write to SCR is complete so that
 			 * we can access HSCTLR
 			 */
 			isb();
 			write_hsctlr(hsctlr);
 			isb();

 			write_scr(read_scr() & ~SCR_NS_BIT);
 			isb();
 		} else if ((read_id_pfr1() &
 			(ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) != 0U) {
 			el2_unused = true;

 			/*
 			 * Set the NS bit to access NS copies of certain banked
 			 * registers
 			 */
 			write_scr(read_scr() | SCR_NS_BIT);
 			isb();

 			/*
 			 * Hyp / PL2 present but unused, need to disable safely.
 			 * HSCTLR can be ignored in this case.
 			 *
 			 * Set HCR to its architectural reset value so that
 			 * Non-secure operations do not trap to Hyp mode.
 			 */
 			write_hcr(HCR_RESET_VAL);

 			/*
 			 * Set HCPTR to its architectural reset value so that
 			 * Non-secure access from EL1 or EL0 to trace and to
 			 * Advanced SIMD and floating point functionality does
 			 * not trap to Hyp mode.
 			 */
 			write_hcptr(HCPTR_RESET_VAL);

 			/*
 			 * Initialise CNTHCTL. All fields are architecturally
 			 * UNKNOWN on reset and are set to zero except for
 			 * field(s) listed below.
 			 *
 			 * CNTHCTL.PL1PCEN: Disable traps to Hyp mode of
 			 *  Non-secure EL0 and EL1 accessed to the physical
 			 *  timer registers.
 			 *
 			 * CNTHCTL.PL1PCTEN: Disable traps to Hyp mode of
 			 *  Non-secure EL0 and EL1 accessed to the physical
 			 *  counter registers.
 			 */
 			write_cnthctl(CNTHCTL_RESET_VAL |
 					PL1PCEN_BIT | PL1PCTEN_BIT);

 			/*
 			 * Initialise CNTVOFF to zero as it resets to an
 			 * IMPLEMENTATION DEFINED value.
 			 */
 			write64_cntvoff(0);

 			/*
 			 * Set VPIDR and VMPIDR to match MIDR_EL1 and MPIDR
 			 * respectively.
 			 */
 			write_vpidr(read_midr());
 			write_vmpidr(read_mpidr());

 			/*
 			 * Initialise VTTBR, setting all fields rather than
 			 * relying on the hw. Some fields are architecturally
 			 * UNKNOWN at reset.
 			 *
 			 * VTTBR.VMID: Set to zero which is the architecturally
 			 *  defined reset value. Even though EL1&0 stage 2
 			 *  address translation is disabled, cache maintenance
 			 *  operations depend on the VMID.
 			 *
 			 * VTTBR.BADDR: Set to zero as EL1&0 stage 2 address
 			 *  translation is disabled.
 			 */
 			write64_vttbr(VTTBR_RESET_VAL &
 				~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
 				| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));

 			/*
 			 * Initialise HDCR, setting all the fields rather than
 			 * relying on hw.
 			 *
 			 * HDCR.HPMN: Set to value of PMCR.N which is the
 			 *  architecturally-defined reset value.
 			 *
 			 * HDCR.HLP: Set to one so that event counter
 			 *  overflow, that is recorded in PMOVSCLR[0-30],
 			 *  occurs on the increment that changes
 			 *  PMEVCNTR<n>[63] from 1 to 0, when ARMv8.5-PMU is
 			 *  implemented. This bit is RES0 in versions of the
 			 *  architecture earlier than ARMv8.5, setting it to 1
 			 *  doesn't have any effect on them.
 			 *  This bit is Reserved, UNK/SBZP in ARMv7.
 			 *
 			 * HDCR.HPME: Set to zero to disable EL2 Event
 			 *  counters.
 			 */
 #if (ARM_ARCH_MAJOR > 7)
 			write_hdcr((HDCR_RESET_VAL | HDCR_HLP_BIT |
 				   ((read_pmcr() & PMCR_N_BITS) >>
 				    PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
 #else
 			write_hdcr((HDCR_RESET_VAL |
 				   ((read_pmcr() & PMCR_N_BITS) >>
 				    PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
 #endif
 			/*
 			 * Set HSTR to its architectural reset value so that
 			 * access to system registers in the cproc=1111
 			 * encoding space do not trap to Hyp mode.
 			 */
 			write_hstr(HSTR_RESET_VAL);
 			/*
 			 * Set CNTHP_CTL to its architectural reset value to
 			 * disable the EL2 physical timer and prevent timer
 			 * interrupts. Some fields are architecturally UNKNOWN
 			 * on reset and are set to zero.
 			 */
 			write_cnthp_ctl(CNTHP_CTL_RESET_VAL);
 			isb();

 			write_scr(read_scr() & ~SCR_NS_BIT);
 			isb();
 		}
 		enable_extensions_nonsecure(el2_unused);
 	}
 }

 /*******************************************************************************
  * This function is used to exit to Non-secure world. It simply calls the
  * cm_prepare_el3_exit function for AArch32.
  ******************************************************************************/
 void cm_prepare_el3_exit_ns(void)
 {
 	cm_prepare_el3_exit(NON_SECURE);
 }
	/*
	* Copyright (c) 2016-2022, ARM Limited and Contributors. All rights reserved.
	*
	* SPDX-License-Identifier: BSD-3-Clause
	*/

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

	#include <platform_def.h>

	#include <arch.h>
	#include <arch_features.h>
	#include <arch_helpers.h>
	#include <common/bl_common.h>
	#include <context.h>
	#include <lib/el3_runtime/context_mgmt.h>
	#include <lib/extensions/amu.h>
	#include <lib/extensions/sys_reg_trace.h>
	#include <lib/extensions/trf.h>
	#include <lib/utils.h>

	/*******************************************************************************
	* Context management library initialisation routine. This library is used by
	* runtime services to share pointers to 'cpu_context' structures for the secure
	* and non-secure states. Management of the structures and their associated
	* memory is not done by the context management library e.g. the PSCI service
	* manages the cpu context used for entry from and exit to the non-secure state.
	* The Secure payload manages the context(s) corresponding to the secure state.
	* It also uses this library to get access to the non-secure
	* state cpu context pointers.
	******************************************************************************/
	void cm_init(void)
	{
	/*
	* The context management library has only global data to initialize, but
	* that will be done when the BSS is zeroed out
	*/
	}

	/*******************************************************************************
	* The following function initializes the cpu_context 'ctx' for
	* first use, and sets the initial entrypoint state as specified by the
	* entry_point_info structure.
	*
	* The security state to initialize is determined by the SECURE attribute
	* of the entry_point_info.
	*
	* The EE and ST attributes are used to configure the endianness and secure
	* timer availability for the new execution context.
	*
	* To prepare the register state for entry call cm_prepare_el3_exit() and
	* el3_exit(). For Secure-EL1 cm_prepare_el3_exit() is equivalent to
	* cm_el1_sysregs_context_restore().
	******************************************************************************/
	void cm_setup_context(cpu_context_t ctx, const entry_point_info_t ep)
	{
	unsigned int security_state;
	uint32_t scr, sctlr;
	regs_t *reg_ctx;

	assert(ctx != NULL);

	security_state = GET_SECURITY_STATE(ep->h.attr);

	/* Clear any residual register values from the context */
	zeromem(ctx, sizeof(*ctx));

	reg_ctx = get_regs_ctx(ctx);

	/*
	* Base the context SCR on the current value, adjust for entry point
	* specific requirements
	*/
	scr = read_scr();
	scr &= ~(SCR_NS_BIT \| SCR_HCE_BIT);

	if (security_state != SECURE)
	scr \|= SCR_NS_BIT;

	if (security_state != SECURE) {
	/*
	* Set up SCTLR for the Non-secure context.
	*
	* SCTLR.EE: Endianness is taken from the entrypoint attributes.
	*
	* SCTLR.M, SCTLR.C and SCTLR.I: These fields must be zero (as
	* required by PSCI specification)
	*
	* Set remaining SCTLR fields to their architecturally defined
	* values. Some fields reset to an IMPLEMENTATION DEFINED value:
	*
	* SCTLR.TE: Set to zero so that exceptions to an Exception
	* Level executing at PL1 are taken to A32 state.
	*
	* SCTLR.V: Set to zero to select the normal exception vectors
	* with base address held in VBAR.
	*/
	assert(((ep->spsr >> SPSR_E_SHIFT) & SPSR_E_MASK) ==
	(EP_GET_EE(ep->h.attr) >> EP_EE_SHIFT));

	sctlr = (EP_GET_EE(ep->h.attr) != 0U) ? SCTLR_EE_BIT : 0U;
	sctlr \|= (SCTLR_RESET_VAL & ~(SCTLR_TE_BIT \| SCTLR_V_BIT));
	write_ctx_reg(reg_ctx, CTX_NS_SCTLR, sctlr);
	}

	/*
	* The target exception level is based on the spsr mode requested. If
	* execution is requested to hyp mode, HVC is enabled via SCR.HCE.
	*/
	if (GET_M32(ep->spsr) == MODE32_hyp)
	scr \|= SCR_HCE_BIT;

	/*
	* Store the initialised values for SCTLR and SCR in the cpu_context.
	* The Hyp mode registers are not part of the saved context and are
	* set-up in cm_prepare_el3_exit().
	*/
	write_ctx_reg(reg_ctx, CTX_SCR, scr);
	write_ctx_reg(reg_ctx, CTX_LR, ep->pc);
	write_ctx_reg(reg_ctx, CTX_SPSR, ep->spsr);

	/*
	* Store the r0-r3 value from the entrypoint into the context
	* Use memcpy as we are in control of the layout of the structures
	*/
	memcpy((void )reg_ctx, (void )&ep->args, sizeof(aapcs32_params_t));
	}

	/*******************************************************************************
	* Enable architecture extensions on first entry to Non-secure world.
	* When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
	* it is zero.
	******************************************************************************/
	static void enable_extensions_nonsecure(bool el2_unused)
	{
	#if IMAGE_BL32
	#if ENABLE_AMU
	amu_enable(el2_unused);
	#endif

	#if ENABLE_SYS_REG_TRACE_FOR_NS
	sys_reg_trace_enable();
	#endif /* ENABLE_SYS_REG_TRACE_FOR_NS */

	if (is_feat_trf_supported()) {
	trf_enable();
	}
	#endif
	}

	/*******************************************************************************
	* The following function initializes the cpu_context for a CPU specified by
	* its `cpu_idx` for first use, and sets the initial entrypoint state as
	* specified by the entry_point_info structure.
	******************************************************************************/
	void cm_init_context_by_index(unsigned int cpu_idx,
	const entry_point_info_t *ep)
	{
	cpu_context_t *ctx;
	ctx = cm_get_context_by_index(cpu_idx, GET_SECURITY_STATE(ep->h.attr));
	cm_setup_context(ctx, ep);
	}

	/*******************************************************************************
	* The following function initializes the cpu_context for the current CPU
	* for first use, and sets the initial entrypoint state as specified by the
	* entry_point_info structure.
	******************************************************************************/
	void cm_init_my_context(const entry_point_info_t *ep)
	{
	cpu_context_t *ctx;
	ctx = cm_get_context(GET_SECURITY_STATE(ep->h.attr));
	cm_setup_context(ctx, ep);
	}

	/*******************************************************************************
	* Prepare the CPU system registers for first entry into secure or normal world
	*
	* If execution is requested to hyp mode, HSCTLR is initialized
	* If execution is requested to non-secure PL1, and the CPU supports
	* HYP mode then HYP mode is disabled by configuring all necessary HYP mode
	* registers.
	******************************************************************************/
	void cm_prepare_el3_exit(uint32_t security_state)
	{
	uint32_t hsctlr, scr;
	cpu_context_t *ctx = cm_get_context(security_state);
	bool el2_unused = false;

	assert(ctx != NULL);

	if (security_state == NON_SECURE) {
	scr = read_ctx_reg(get_regs_ctx(ctx), CTX_SCR);
	if ((scr & SCR_HCE_BIT) != 0U) {
	/* Use SCTLR value to initialize HSCTLR */
	hsctlr = read_ctx_reg(get_regs_ctx(ctx),
	CTX_NS_SCTLR);
	hsctlr \|= HSCTLR_RES1;
	/* Temporarily set the NS bit to access HSCTLR */
	write_scr(read_scr() \| SCR_NS_BIT);
	/*
	* Make sure the write to SCR is complete so that
	* we can access HSCTLR
	*/
	isb();
	write_hsctlr(hsctlr);
	isb();

	write_scr(read_scr() & ~SCR_NS_BIT);
	isb();
	} else if ((read_id_pfr1() &
	(ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) != 0U) {
	el2_unused = true;

	/*
	* Set the NS bit to access NS copies of certain banked
	* registers
	*/
	write_scr(read_scr() \| SCR_NS_BIT);
	isb();

	/*
	* Hyp / PL2 present but unused, need to disable safely.
	* HSCTLR can be ignored in this case.
	*
	* Set HCR to its architectural reset value so that
	* Non-secure operations do not trap to Hyp mode.
	*/
	write_hcr(HCR_RESET_VAL);

	/*
	* Set HCPTR to its architectural reset value so that
	* Non-secure access from EL1 or EL0 to trace and to
	* Advanced SIMD and floating point functionality does
	* not trap to Hyp mode.
	*/
	write_hcptr(HCPTR_RESET_VAL);

	/*
	* Initialise CNTHCTL. All fields are architecturally
	* UNKNOWN on reset and are set to zero except for
	* field(s) listed below.
	*
	* CNTHCTL.PL1PCEN: Disable traps to Hyp mode of
	* Non-secure EL0 and EL1 accessed to the physical
	* timer registers.
	*
	* CNTHCTL.PL1PCTEN: Disable traps to Hyp mode of
	* Non-secure EL0 and EL1 accessed to the physical
	* counter registers.
	*/
	write_cnthctl(CNTHCTL_RESET_VAL \|
	PL1PCEN_BIT \| PL1PCTEN_BIT);

	/*
	* Initialise CNTVOFF to zero as it resets to an
	* IMPLEMENTATION DEFINED value.
	*/
	write64_cntvoff(0);

	/*
	* Set VPIDR and VMPIDR to match MIDR_EL1 and MPIDR
	* respectively.
	*/
	write_vpidr(read_midr());
	write_vmpidr(read_mpidr());

	/*
	* Initialise VTTBR, setting all fields rather than
	* relying on the hw. Some fields are architecturally
	* UNKNOWN at reset.
	*
	* VTTBR.VMID: Set to zero which is the architecturally
	* defined reset value. Even though EL1&0 stage 2
	* address translation is disabled, cache maintenance
	* operations depend on the VMID.
	*
	* VTTBR.BADDR: Set to zero as EL1&0 stage 2 address
	* translation is disabled.
	*/
	write64_vttbr(VTTBR_RESET_VAL &
	~((VTTBR_VMID_MASK << VTTBR_VMID_SHIFT)
	\| (VTTBR_BADDR_MASK << VTTBR_BADDR_SHIFT)));

	/*
	* Initialise HDCR, setting all the fields rather than
	* relying on hw.
	*
	* HDCR.HPMN: Set to value of PMCR.N which is the
	* architecturally-defined reset value.
	*
	* HDCR.HLP: Set to one so that event counter
	* overflow, that is recorded in PMOVSCLR[0-30],
	* occurs on the increment that changes
	* PMEVCNTR<n>[63] from 1 to 0, when ARMv8.5-PMU is
	* implemented. This bit is RES0 in versions of the
	* architecture earlier than ARMv8.5, setting it to 1
	* doesn't have any effect on them.
	* This bit is Reserved, UNK/SBZP in ARMv7.
	*
	* HDCR.HPME: Set to zero to disable EL2 Event
	* counters.
	*/
	#if (ARM_ARCH_MAJOR > 7)
	write_hdcr((HDCR_RESET_VAL \| HDCR_HLP_BIT \|
	((read_pmcr() & PMCR_N_BITS) >>
	PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
	#else
	write_hdcr((HDCR_RESET_VAL \|
	((read_pmcr() & PMCR_N_BITS) >>
	PMCR_N_SHIFT)) & ~HDCR_HPME_BIT);
	#endif
	/*
	* Set HSTR to its architectural reset value so that
	* access to system registers in the cproc=1111
	* encoding space do not trap to Hyp mode.
	*/
	write_hstr(HSTR_RESET_VAL);
	/*
	* Set CNTHP_CTL to its architectural reset value to
	* disable the EL2 physical timer and prevent timer
	* interrupts. Some fields are architecturally UNKNOWN
	* on reset and are set to zero.
	*/
	write_cnthp_ctl(CNTHP_CTL_RESET_VAL);
	isb();

	write_scr(read_scr() & ~SCR_NS_BIT);
	isb();
	}
	enable_extensions_nonsecure(el2_unused);
	}
	}

	/*******************************************************************************
	* This function is used to exit to Non-secure world. It simply calls the
	* cm_prepare_el3_exit function for AArch32.
	******************************************************************************/
	void cm_prepare_el3_exit_ns(void)
	{
	cm_prepare_el3_exit(NON_SECURE);
	}