arch_helpers.h

/*
 * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#ifndef ARCH_HELPERS_H
#define ARCH_HELPERS_H

#include <cdefs.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>

#include <arch.h>

/**********************************************************************
 * Macros which create inline functions to read or write CPU system
 * registers
 *********************************************************************/

#define _DEFINE_SYSREG_READ_FUNC(_name, _reg_name)		\
static inline u_register_t read_ ## _name(void)			\
{								\
	u_register_t v;						\
	__asm__ volatile ("mrs %0, " #_reg_name : "=r" (v));	\
	return v;						\
}

#define _DEFINE_SYSREG_WRITE_FUNC(_name, _reg_name)			\
static inline void write_ ## _name(u_register_t v)			\
{									\
	__asm__ volatile ("msr " #_reg_name ", %0" : : "r" (v));	\
}

#define SYSREG_WRITE_CONST(reg_name, v)				\
	__asm__ volatile ("msr " #reg_name ", %0" : : "i" (v))

/* Define read function for system register */
#define DEFINE_SYSREG_READ_FUNC(_name) 			\
	_DEFINE_SYSREG_READ_FUNC(_name, _name)

/* Define read & write function for system register */
#define DEFINE_SYSREG_RW_FUNCS(_name)			\
	_DEFINE_SYSREG_READ_FUNC(_name, _name)		\
	_DEFINE_SYSREG_WRITE_FUNC(_name, _name)

/* Define read & write function for renamed system register */
#define DEFINE_RENAME_SYSREG_RW_FUNCS(_name, _reg_name)	\
	_DEFINE_SYSREG_READ_FUNC(_name, _reg_name)	\
	_DEFINE_SYSREG_WRITE_FUNC(_name, _reg_name)

/* Define read function for renamed system register */
#define DEFINE_RENAME_SYSREG_READ_FUNC(_name, _reg_name)	\
	_DEFINE_SYSREG_READ_FUNC(_name, _reg_name)

/* Define write function for renamed system register */
#define DEFINE_RENAME_SYSREG_WRITE_FUNC(_name, _reg_name)	\
	_DEFINE_SYSREG_WRITE_FUNC(_name, _reg_name)

/**********************************************************************
 * Macros to create inline functions for system instructions
 *********************************************************************/

/* Define function for simple system instruction */
#define DEFINE_SYSOP_FUNC(_op)				\
static inline void _op(void)				\
{							\
	__asm__ (#_op);					\
}

/* Define function for system instruction with type specifier */
#define DEFINE_SYSOP_TYPE_FUNC(_op, _type)		\
static inline void _op ## _type(void)			\
{							\
	__asm__ (#_op " " #_type);			\
}

/* Define function for system instruction with register parameter */
#define DEFINE_SYSOP_TYPE_PARAM_FUNC(_op, _type)	\
static inline void _op ## _type(uint64_t v)		\
{							\
	 __asm__ (#_op " " #_type ", %0" : : "r" (v));	\
}

/*******************************************************************************
 * TLB maintenance accessor prototypes
 ******************************************************************************/

#if ERRATA_A57_813419
/*
 * Define function for TLBI instruction with type specifier that implements
 * the workaround for errata 813419 of Cortex-A57.
 */
#define DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_FUNC(_type)\
static inline void tlbi ## _type(void)			\
{							\
	__asm__("tlbi " #_type "\n"			\
		"dsb ish\n"				\
		"tlbi " #_type);			\
}

/*
 * Define function for TLBI instruction with register parameter that implements
 * the workaround for errata 813419 of Cortex-A57.
 */
#define DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_PARAM_FUNC(_type)	\
static inline void tlbi ## _type(uint64_t v)			\
{								\
	__asm__("tlbi " #_type ", %0\n"				\
		"dsb ish\n"					\
		"tlbi " #_type ", %0" : : "r" (v));		\
}
#endif /* ERRATA_A57_813419 */

#if ERRATA_A53_819472 || ERRATA_A53_824069 || ERRATA_A53_827319
/*
 * Define function for DC instruction with register parameter that enables
 * the workaround for errata 819472, 824069 and 827319 of Cortex-A53.
 */
#define DEFINE_DCOP_ERRATA_A53_TYPE_PARAM_FUNC(_name, _type)	\
static inline void dc ## _name(uint64_t v)			\
{								\
	__asm__("dc " #_type ", %0" : : "r" (v));		\
}
#endif /* ERRATA_A53_819472 || ERRATA_A53_824069 || ERRATA_A53_827319 */

DEFINE_SYSOP_TYPE_FUNC(tlbi, alle1)
DEFINE_SYSOP_TYPE_FUNC(tlbi, alle1is)
DEFINE_SYSOP_TYPE_FUNC(tlbi, alle2)
DEFINE_SYSOP_TYPE_FUNC(tlbi, alle2is)
#if ERRATA_A57_813419
DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_FUNC(alle3)
DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_FUNC(alle3is)
#else
DEFINE_SYSOP_TYPE_FUNC(tlbi, alle3)
DEFINE_SYSOP_TYPE_FUNC(tlbi, alle3is)
#endif
DEFINE_SYSOP_TYPE_FUNC(tlbi, vmalle1)

DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vaae1is)
DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vaale1is)
DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vae2is)
DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vale2is)
#if ERRATA_A57_813419
DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_PARAM_FUNC(vae3is)
DEFINE_TLBIOP_ERRATA_A57_813419_TYPE_PARAM_FUNC(vale3is)
#else
DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vae3is)
DEFINE_SYSOP_TYPE_PARAM_FUNC(tlbi, vale3is)
#endif

/*******************************************************************************
 * Cache maintenance accessor prototypes
 ******************************************************************************/
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, isw)
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, cisw)
#if ERRATA_A53_827319
DEFINE_DCOP_ERRATA_A53_TYPE_PARAM_FUNC(csw, cisw)
#else
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, csw)
#endif
#if ERRATA_A53_819472 || ERRATA_A53_824069 || ERRATA_A53_827319
DEFINE_DCOP_ERRATA_A53_TYPE_PARAM_FUNC(cvac, civac)
#else
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, cvac)
#endif
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, ivac)
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, civac)
#if ERRATA_A53_819472 || ERRATA_A53_824069 || ERRATA_A53_827319
DEFINE_DCOP_ERRATA_A53_TYPE_PARAM_FUNC(cvau, civac)
#else
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, cvau)
#endif
DEFINE_SYSOP_TYPE_PARAM_FUNC(dc, zva)

/*******************************************************************************
 * Address translation accessor prototypes
 ******************************************************************************/
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e1r)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e1w)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e0r)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s12e0w)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e1r)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e2r)
DEFINE_SYSOP_TYPE_PARAM_FUNC(at, s1e3r)

void flush_dcache_range(uintptr_t addr, size_t size);
void clean_dcache_range(uintptr_t addr, size_t size);
void inv_dcache_range(uintptr_t addr, size_t size);

void dcsw_op_louis(u_register_t op_type);
void dcsw_op_all(u_register_t op_type);

void disable_mmu_el1(void);
void disable_mmu_el3(void);
void disable_mmu_icache_el1(void);
void disable_mmu_icache_el3(void);

/*******************************************************************************
 * Misc. accessor prototypes
 ******************************************************************************/

#define write_daifclr(val) SYSREG_WRITE_CONST(daifclr, val)
#define write_daifset(val) SYSREG_WRITE_CONST(daifset, val)

DEFINE_SYSREG_RW_FUNCS(par_el1)
DEFINE_SYSREG_READ_FUNC(id_pfr1_el1)
DEFINE_SYSREG_READ_FUNC(id_aa64isar1_el1)
DEFINE_SYSREG_READ_FUNC(id_aa64pfr0_el1)
DEFINE_SYSREG_READ_FUNC(id_aa64pfr1_el1)
DEFINE_SYSREG_READ_FUNC(id_aa64dfr0_el1)
DEFINE_SYSREG_READ_FUNC(id_afr0_el1)
DEFINE_SYSREG_READ_FUNC(CurrentEl)
DEFINE_SYSREG_READ_FUNC(ctr_el0)
DEFINE_SYSREG_RW_FUNCS(daif)
DEFINE_SYSREG_RW_FUNCS(spsr_el1)
DEFINE_SYSREG_RW_FUNCS(spsr_el2)
DEFINE_SYSREG_RW_FUNCS(spsr_el3)
DEFINE_SYSREG_RW_FUNCS(elr_el1)
DEFINE_SYSREG_RW_FUNCS(elr_el2)
DEFINE_SYSREG_RW_FUNCS(elr_el3)

DEFINE_SYSOP_FUNC(wfi)
DEFINE_SYSOP_FUNC(wfe)
DEFINE_SYSOP_FUNC(sev)
DEFINE_SYSOP_TYPE_FUNC(dsb, sy)
DEFINE_SYSOP_TYPE_FUNC(dmb, sy)
DEFINE_SYSOP_TYPE_FUNC(dmb, st)
DEFINE_SYSOP_TYPE_FUNC(dmb, ld)
DEFINE_SYSOP_TYPE_FUNC(dsb, ish)
DEFINE_SYSOP_TYPE_FUNC(dsb, nsh)
DEFINE_SYSOP_TYPE_FUNC(dsb, ishst)
DEFINE_SYSOP_TYPE_FUNC(dmb, oshld)
DEFINE_SYSOP_TYPE_FUNC(dmb, oshst)
DEFINE_SYSOP_TYPE_FUNC(dmb, osh)
DEFINE_SYSOP_TYPE_FUNC(dmb, nshld)
DEFINE_SYSOP_TYPE_FUNC(dmb, nshst)
DEFINE_SYSOP_TYPE_FUNC(dmb, nsh)
DEFINE_SYSOP_TYPE_FUNC(dmb, ishld)
DEFINE_SYSOP_TYPE_FUNC(dmb, ishst)
DEFINE_SYSOP_TYPE_FUNC(dmb, ish)
DEFINE_SYSOP_FUNC(isb)

static inline void enable_irq(void)
{
	/*
	 * The compiler memory barrier will prevent the compiler from
	 * scheduling non-volatile memory access after the write to the
	 * register.
	 *
	 * This could happen if some initialization code issues non-volatile
	 * accesses to an area used by an interrupt handler, in the assumption
	 * that it is safe as the interrupts are disabled at the time it does
	 * that (according to program order). However, non-volatile accesses
	 * are not necessarily in program order relatively with volatile inline
	 * assembly statements (and volatile accesses).
	 */
	COMPILER_BARRIER();
	write_daifclr(DAIF_IRQ_BIT);
	isb();
}

static inline void enable_fiq(void)
{
	COMPILER_BARRIER();
	write_daifclr(DAIF_FIQ_BIT);
	isb();
}

static inline void enable_serror(void)
{
	COMPILER_BARRIER();
	write_daifclr(DAIF_ABT_BIT);
	isb();
}

static inline void enable_debug_exceptions(void)
{
	COMPILER_BARRIER();
	write_daifclr(DAIF_DBG_BIT);
	isb();
}

static inline void disable_irq(void)
{
	COMPILER_BARRIER();
	write_daifset(DAIF_IRQ_BIT);
	isb();
}

static inline void disable_fiq(void)
{
	COMPILER_BARRIER();
	write_daifset(DAIF_FIQ_BIT);
	isb();
}

static inline void disable_serror(void)
{
	COMPILER_BARRIER();
	write_daifset(DAIF_ABT_BIT);
	isb();
}

static inline void disable_debug_exceptions(void)
{
	COMPILER_BARRIER();
	write_daifset(DAIF_DBG_BIT);
	isb();
}

void __dead2 smc(uint64_t x0, uint64_t x1, uint64_t x2, uint64_t x3,
		 uint64_t x4, uint64_t x5, uint64_t x6, uint64_t x7);

/*******************************************************************************
 * System register accessor prototypes
 ******************************************************************************/
DEFINE_SYSREG_READ_FUNC(midr_el1)
DEFINE_SYSREG_READ_FUNC(mpidr_el1)
DEFINE_SYSREG_READ_FUNC(id_aa64mmfr0_el1)

DEFINE_SYSREG_RW_FUNCS(scr_el3)
DEFINE_SYSREG_RW_FUNCS(hcr_el2)

DEFINE_SYSREG_RW_FUNCS(vbar_el1)
DEFINE_SYSREG_RW_FUNCS(vbar_el2)
DEFINE_SYSREG_RW_FUNCS(vbar_el3)

DEFINE_SYSREG_RW_FUNCS(sctlr_el1)
DEFINE_SYSREG_RW_FUNCS(sctlr_el2)
DEFINE_SYSREG_RW_FUNCS(sctlr_el3)

DEFINE_SYSREG_RW_FUNCS(actlr_el1)
DEFINE_SYSREG_RW_FUNCS(actlr_el2)
DEFINE_SYSREG_RW_FUNCS(actlr_el3)

DEFINE_SYSREG_RW_FUNCS(esr_el1)
DEFINE_SYSREG_RW_FUNCS(esr_el2)
DEFINE_SYSREG_RW_FUNCS(esr_el3)

DEFINE_SYSREG_RW_FUNCS(afsr0_el1)
DEFINE_SYSREG_RW_FUNCS(afsr0_el2)
DEFINE_SYSREG_RW_FUNCS(afsr0_el3)

DEFINE_SYSREG_RW_FUNCS(afsr1_el1)
DEFINE_SYSREG_RW_FUNCS(afsr1_el2)
DEFINE_SYSREG_RW_FUNCS(afsr1_el3)

DEFINE_SYSREG_RW_FUNCS(far_el1)
DEFINE_SYSREG_RW_FUNCS(far_el2)
DEFINE_SYSREG_RW_FUNCS(far_el3)

DEFINE_SYSREG_RW_FUNCS(mair_el1)
DEFINE_SYSREG_RW_FUNCS(mair_el2)
DEFINE_SYSREG_RW_FUNCS(mair_el3)

DEFINE_SYSREG_RW_FUNCS(amair_el1)
DEFINE_SYSREG_RW_FUNCS(amair_el2)
DEFINE_SYSREG_RW_FUNCS(amair_el3)

DEFINE_SYSREG_READ_FUNC(rvbar_el1)
DEFINE_SYSREG_READ_FUNC(rvbar_el2)
DEFINE_SYSREG_READ_FUNC(rvbar_el3)

DEFINE_SYSREG_RW_FUNCS(rmr_el1)
DEFINE_SYSREG_RW_FUNCS(rmr_el2)
DEFINE_SYSREG_RW_FUNCS(rmr_el3)

DEFINE_SYSREG_RW_FUNCS(tcr_el1)
DEFINE_SYSREG_RW_FUNCS(tcr_el2)
DEFINE_SYSREG_RW_FUNCS(tcr_el3)

DEFINE_SYSREG_RW_FUNCS(ttbr0_el1)
DEFINE_SYSREG_RW_FUNCS(ttbr0_el2)
DEFINE_SYSREG_RW_FUNCS(ttbr0_el3)

DEFINE_SYSREG_RW_FUNCS(ttbr1_el1)

DEFINE_SYSREG_RW_FUNCS(vttbr_el2)

DEFINE_SYSREG_RW_FUNCS(cptr_el2)
DEFINE_SYSREG_RW_FUNCS(cptr_el3)

DEFINE_SYSREG_RW_FUNCS(cpacr_el1)
DEFINE_SYSREG_RW_FUNCS(cntfrq_el0)
DEFINE_SYSREG_RW_FUNCS(cnthp_ctl_el2)
DEFINE_SYSREG_RW_FUNCS(cnthp_tval_el2)
DEFINE_SYSREG_RW_FUNCS(cnthp_cval_el2)
DEFINE_SYSREG_RW_FUNCS(cntps_ctl_el1)
DEFINE_SYSREG_RW_FUNCS(cntps_tval_el1)
DEFINE_SYSREG_RW_FUNCS(cntps_cval_el1)
DEFINE_SYSREG_RW_FUNCS(cntp_ctl_el0)
DEFINE_SYSREG_RW_FUNCS(cntp_tval_el0)
DEFINE_SYSREG_RW_FUNCS(cntp_cval_el0)
DEFINE_SYSREG_READ_FUNC(cntpct_el0)
DEFINE_SYSREG_RW_FUNCS(cnthctl_el2)

#define get_cntp_ctl_enable(x)  (((x) >> CNTP_CTL_ENABLE_SHIFT) & \
					CNTP_CTL_ENABLE_MASK)
#define get_cntp_ctl_imask(x)   (((x) >> CNTP_CTL_IMASK_SHIFT) & \
					CNTP_CTL_IMASK_MASK)
#define get_cntp_ctl_istatus(x) (((x) >> CNTP_CTL_ISTATUS_SHIFT) & \
					CNTP_CTL_ISTATUS_MASK)

#define set_cntp_ctl_enable(x)  ((x) |= (U(1) << CNTP_CTL_ENABLE_SHIFT))
#define set_cntp_ctl_imask(x)   ((x) |= (U(1) << CNTP_CTL_IMASK_SHIFT))

#define clr_cntp_ctl_enable(x)  ((x) &= ~(U(1) << CNTP_CTL_ENABLE_SHIFT))
#define clr_cntp_ctl_imask(x)   ((x) &= ~(U(1) << CNTP_CTL_IMASK_SHIFT))

DEFINE_SYSREG_RW_FUNCS(tpidr_el3)

DEFINE_SYSREG_RW_FUNCS(cntvoff_el2)

DEFINE_SYSREG_RW_FUNCS(vpidr_el2)
DEFINE_SYSREG_RW_FUNCS(vmpidr_el2)

DEFINE_SYSREG_READ_FUNC(isr_el1)

DEFINE_SYSREG_RW_FUNCS(mdcr_el2)
DEFINE_SYSREG_RW_FUNCS(mdcr_el3)
DEFINE_SYSREG_RW_FUNCS(hstr_el2)
DEFINE_SYSREG_RW_FUNCS(pmcr_el0)

/* GICv3 System Registers */

DEFINE_RENAME_SYSREG_RW_FUNCS(icc_sre_el1, ICC_SRE_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_sre_el2, ICC_SRE_EL2)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_sre_el3, ICC_SRE_EL3)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_pmr_el1, ICC_PMR_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(icc_rpr_el1, ICC_RPR_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_igrpen1_el3, ICC_IGRPEN1_EL3)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_igrpen1_el1, ICC_IGRPEN1_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_igrpen0_el1, ICC_IGRPEN0_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(icc_hppir0_el1, ICC_HPPIR0_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(icc_hppir1_el1, ICC_HPPIR1_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(icc_iar0_el1, ICC_IAR0_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(icc_iar1_el1, ICC_IAR1_EL1)
DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_eoir0_el1, ICC_EOIR0_EL1)
DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_eoir1_el1, ICC_EOIR1_EL1)
DEFINE_RENAME_SYSREG_WRITE_FUNC(icc_sgi0r_el1, ICC_SGI0R_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(icc_sgi1r, ICC_SGI1R)

DEFINE_RENAME_SYSREG_RW_FUNCS(amcgcr_el0, AMCGCR_EL0)
DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenclr0_el0, AMCNTENCLR0_EL0)
DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenset0_el0, AMCNTENSET0_EL0)
DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenclr1_el0, AMCNTENCLR1_EL0)
DEFINE_RENAME_SYSREG_RW_FUNCS(amcntenset1_el0, AMCNTENSET1_EL0)

DEFINE_RENAME_SYSREG_READ_FUNC(mpamidr_el1, MPAMIDR_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(mpam3_el3, MPAM3_EL3)
DEFINE_RENAME_SYSREG_RW_FUNCS(mpam2_el2, MPAM2_EL2)
DEFINE_RENAME_SYSREG_RW_FUNCS(mpamhcr_el2, MPAMHCR_EL2)

DEFINE_RENAME_SYSREG_RW_FUNCS(pmblimitr_el1, PMBLIMITR_EL1)

DEFINE_RENAME_SYSREG_WRITE_FUNC(zcr_el3, ZCR_EL3)
DEFINE_RENAME_SYSREG_WRITE_FUNC(zcr_el2, ZCR_EL2)

DEFINE_RENAME_SYSREG_READ_FUNC(erridr_el1, ERRIDR_EL1)
DEFINE_RENAME_SYSREG_WRITE_FUNC(errselr_el1, ERRSELR_EL1)

DEFINE_RENAME_SYSREG_READ_FUNC(erxfr_el1, ERXFR_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(erxctlr_el1, ERXCTLR_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(erxstatus_el1, ERXSTATUS_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(erxaddr_el1, ERXADDR_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(erxmisc0_el1, ERXMISC0_EL1)
DEFINE_RENAME_SYSREG_READ_FUNC(erxmisc1_el1, ERXMISC1_EL1)

/* Armv8.2 Registers */
DEFINE_RENAME_SYSREG_READ_FUNC(id_aa64mmfr2_el1, ID_AA64MMFR2_EL1)

/* Armv8.3 Pointer Authentication Registers */
DEFINE_RENAME_SYSREG_RW_FUNCS(apiakeyhi_el1, APIAKeyHi_EL1)
DEFINE_RENAME_SYSREG_RW_FUNCS(apiakeylo_el1, APIAKeyLo_EL1)

#define IS_IN_EL(x) \
	(GET_EL(read_CurrentEl()) == MODE_EL##x)

#define IS_IN_EL1() IS_IN_EL(1)
#define IS_IN_EL2() IS_IN_EL(2)
#define IS_IN_EL3() IS_IN_EL(3)

static inline unsigned int get_current_el(void)
{
	return GET_EL(read_CurrentEl());
}

/*
 * Check if an EL is implemented from AA64PFR0 register fields.
 */
static inline uint64_t el_implemented(unsigned int el)
{
	if (el > 3U) {
		return EL_IMPL_NONE;
	} else {
		unsigned int shift = ID_AA64PFR0_EL1_SHIFT * el;

		return (read_id_aa64pfr0_el1() >> shift) & ID_AA64PFR0_ELX_MASK;
	}
}

/* Previously defined accesor functions with incomplete register names  */

#define read_current_el()	read_CurrentEl()

#define dsb()			dsbsy()

#define read_midr()		read_midr_el1()

#define read_mpidr()		read_mpidr_el1()

#define read_scr()		read_scr_el3()
#define write_scr(_v)		write_scr_el3(_v)

#define read_hcr()		read_hcr_el2()
#define write_hcr(_v)		write_hcr_el2(_v)

#define read_cpacr()		read_cpacr_el1()
#define write_cpacr(_v)		write_cpacr_el1(_v)

#endif /* ARCH_HELPERS_H */