Add helper library for cpu context management

This patch introduces functions for saving and restoring shared system
registers between secure and non-secure EL1 exception levels, VFP
registers and essential EL3 system register and other state. It also
defines the 'cpu_context' data structure which will used for saving and
restoring execution context for a given security state. These functions
will allow runtime services like PSCI and Secure payload dispatcher to
implement logic for switching between the secure and non-secure states.

The save and restore functions follow AArch64 PCS and only use
caller-saved temporary registers.

Change-Id: I8ee3aaa061d3caaedb28ae2c5becb9a206b6fd74

bl31/aarch64/context.S

+/*
+ * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <context.h>
+
+/* -----------------------------------------------------
+ * The following function strictly follows the AArch64
+ * PCS to use x9-x17 (temporary caller-saved registers)
+ * to save essential EL3 system register context. It
+ * assumes that 'x0' is pointing to a 'el1_sys_regs'
+ * structure where the register context will be saved.
+ * -----------------------------------------------------
+ */
+	.global el3_sysregs_context_save
+el3_sysregs_context_save:
+
+	mrs	x9, scr_el3
+	mrs	x10, sctlr_el3
+	stp	x9, x10, [x0, #CTX_SCR_EL3]
+
+	mrs	x11, cptr_el3
+	stp	x11, xzr, [x0, #CTX_CPTR_EL3]
+
+	mrs	x13, cntfrq_el0
+	mrs	x14, mair_el3
+	stp	x13, x14, [x0, #CTX_CNTFRQ_EL0]
+
+	mrs	x15, tcr_el3
+	mrs	x16, ttbr0_el3
+	stp	x15, x16, [x0, #CTX_TCR_EL3]
+
+	mrs	x17, daif
+	and	x17, x17, #(DAIF_ABT_BIT | DAIF_DBG_BIT)
+	stp	x17, xzr, [x0, #CTX_DAIF_EL3]
+
+	ret
+
+/* -----------------------------------------------------
+ * The following function strictly follows the AArch64
+ * PCS to use x9-x17 (temporary caller-saved registers)
+ * to restore essential EL3 system register context. It
+ * assumes that 'x0' is pointing to a 'el1_sys_regs'
+ * structure from where the register context will be
+ * restored.
+ *
+ * Note that the sequence differs from that of the save
+ * function as we want the MMU to be enabled last
+ * -----------------------------------------------------
+ */
+	.global el3_sysregs_context_restore
+el3_sysregs_context_restore:
+
+	ldp	x11, xzr, [x0, #CTX_CPTR_EL3]
+	msr	cptr_el3, x11
+
+	ldp	x13, x14, [x0, #CTX_CNTFRQ_EL0]
+	msr	cntfrq_el0, x13
+	msr	mair_el3, x14
+
+	ldp	x15, x16, [x0, #CTX_TCR_EL3]
+	msr	tcr_el3, x15
+	msr	ttbr0_el3, x16
+
+	ldp	x17, xzr, [x0, #CTX_DAIF_EL3]
+	mrs	x11, daif
+	orr	x17, x17, x11
+	msr	daif, x17
+
+	/* Make sure all the above changes are observed */
+	isb
+
+	ldp	x9, x10, [x0, #CTX_SCR_EL3]
+	msr	scr_el3, x9
+	msr	sctlr_el3, x10
+	isb
+
+	ret
+
+/* -----------------------------------------------------
+ * The following function strictly follows the AArch64
+ * PCS to use x9-x17 (temporary caller-saved registers)
+ * to save EL1 system register context. It assumes that
+ * 'x0' is pointing to a 'el1_sys_regs' structure where
+ * the register context will be saved.
+ * -----------------------------------------------------
+ */
+	.global el1_sysregs_context_save
+el1_sysregs_context_save:
+
+	mrs	x9, spsr_el1
+	mrs	x10, elr_el1
+	stp	x9, x10, [x0, #CTX_SPSR_EL1]
+
+	mrs	x11, spsr_abt
+	mrs	x12, spsr_und
+	stp	x11, x12, [x0, #CTX_SPSR_ABT]
+
+	mrs	x13, spsr_irq
+	mrs	x14, spsr_fiq
+	stp	x13, x14, [x0, #CTX_SPSR_IRQ]
+
+	mrs	x15, sctlr_el1
+	mrs	x16, actlr_el1
+	stp	x15, x16, [x0, #CTX_SCTLR_EL1]
+
+	mrs	x17, cpacr_el1
+	mrs	x9, csselr_el1
+	stp	x17, x9, [x0, #CTX_CPACR_EL1]
+
+	mrs	x10, sp_el1
+	mrs	x11, esr_el1
+	stp	x10, x11, [x0, #CTX_SP_EL1]
+
+	mrs	x12, ttbr0_el1
+	mrs	x13, ttbr1_el1
+	stp	x12, x13, [x0, #CTX_TTBR0_EL1]
+
+	mrs	x14, mair_el1
+	mrs	x15, amair_el1
+	stp	x14, x15, [x0, #CTX_MAIR_EL1]
+
+	mrs	x16, tcr_el1
+	mrs	x17, tpidr_el1
+	stp	x16, x17, [x0, #CTX_TCR_EL1]
+
+	mrs	x9, tpidr_el0
+	mrs	x10, tpidrro_el0
+	stp	x9, x10, [x0, #CTX_TPIDR_EL0]
+
+	mrs	x11, dacr32_el2
+	mrs	x12, ifsr32_el2
+	stp	x11, x12, [x0, #CTX_DACR32_EL2]
+
+	mrs	x13, par_el1
+	mrs	x14, far_el1
+	stp	x13, x14, [x0, #CTX_PAR_EL1]
+
+	mrs	x15, afsr0_el1
+	mrs	x16, afsr1_el1
+	stp	x15, x16, [x0, #CTX_AFSR0_EL1]
+
+	mrs	x17, contextidr_el1
+	mrs	x9, vbar_el1
+	stp	x17, x9, [x0, #CTX_CONTEXTIDR_EL1]
+
+	mrs	x10, cntp_ctl_el0
+	mrs	x11, cntp_cval_el0
+	stp	x10, x11, [x0, #CTX_CNTP_CTL_EL0]
+
+	mrs	x12, cntv_ctl_el0
+	mrs	x13, cntv_cval_el0
+	stp	x12, x13, [x0, #CTX_CNTV_CTL_EL0]
+
+	mrs	x14, cntkctl_el1
+	mrs	x15, fpexc32_el2
+	stp	x14, x15, [x0, #CTX_CNTKCTL_EL1]
+
+	ret
+
+/* -----------------------------------------------------
+ * The following function strictly follows the AArch64
+ * PCS to use x9-x17 (temporary caller-saved registers)
+ * to restore EL1 system register context.  It assumes
+ * that 'x0' is pointing to a 'el1_sys_regs' structure
+ * from where the register context will be restored
+ * -----------------------------------------------------
+ */
+	.global el1_sysregs_context_restore
+el1_sysregs_context_restore:
+
+	ldp	x9, x10, [x0, #CTX_SPSR_EL1]
+	msr	spsr_el1, x9
+	msr	elr_el1, x10
+
+	ldp	x11, x12, [x0, #CTX_SPSR_ABT]
+	msr	spsr_abt, x11
+	msr	spsr_und, x12
+
+	ldp	x13, x14, [x0, #CTX_SPSR_IRQ]
+	msr	spsr_irq, x13
+	msr	spsr_fiq, x14
+
+	ldp	x15, x16, [x0, #CTX_SCTLR_EL1]
+	msr	sctlr_el1, x15
+	msr	actlr_el1, x16
+
+	ldp	x17, x9, [x0, #CTX_CPACR_EL1]
+	msr	cpacr_el1, x17
+	msr	csselr_el1, x9
+
+	ldp	x10, x11, [x0, #CTX_SP_EL1]
+	msr	sp_el1, x10
+	msr	esr_el1, x11
+
+	ldp	x12, x13, [x0, #CTX_TTBR0_EL1]
+	msr	ttbr0_el1, x12
+	msr	ttbr1_el1, x13
+
+	ldp	x14, x15, [x0, #CTX_MAIR_EL1]
+	msr	mair_el1, x14
+	msr	amair_el1, x15
+
+	ldp	x16, x17, [x0, #CTX_TCR_EL1]
+	msr	tcr_el1, x16
+	msr	tpidr_el1, x17
+
+	ldp	x9, x10, [x0, #CTX_TPIDR_EL0]
+	msr	tpidr_el0, x9
+	msr	tpidrro_el0, x10
+
+	ldp	x11, x12, [x0, #CTX_DACR32_EL2]
+	msr	dacr32_el2, x11
+	msr	ifsr32_el2, x12
+
+	ldp	x13, x14, [x0, #CTX_PAR_EL1]
+	msr	par_el1, x13
+	msr	far_el1, x14
+
+	ldp	x15, x16, [x0, #CTX_AFSR0_EL1]
+	msr	afsr0_el1, x15
+	msr	afsr1_el1, x16
+
+	ldp	x17, x9, [x0, #CTX_CONTEXTIDR_EL1]
+	msr	contextidr_el1, x17
+	msr	vbar_el1, x9
+
+	ldp	x10, x11, [x0, #CTX_CNTP_CTL_EL0]
+	msr	cntp_ctl_el0, x10
+	msr	cntp_cval_el0, x11
+
+	ldp	x12, x13, [x0, #CTX_CNTV_CTL_EL0]
+	msr	cntv_ctl_el0, x12
+	msr	cntv_cval_el0, x13
+
+	ldp	x14, x15, [x0, #CTX_CNTKCTL_EL1]
+	msr	cntkctl_el1, x14
+	msr	fpexc32_el2, x15
+
+	/* No explict ISB required here as ERET covers it */
+
+	ret
+
+/* -----------------------------------------------------
+ * The followsing function follows the aapcs_64 strictly
+ * to use x9-x17 (temporary caller-saved registers
+ * according to AArch64 PCS) to save floating point
+ * register context. It assumes that 'x0' is pointing to
+ * a 'fp_regs' structure where the register context will
+ * be saved.
+ *
+ * Access to VFP registers will trap if CPTR_EL3.TFP is
+ * set.  However currently we don't use VFP registers
+ * nor set traps in Trusted Firmware, and assume it's
+ * cleared
+ *
+ * TODO: Revisit when VFP is used in secure world
+ * -----------------------------------------------------
+ */
+	.global fpregs_context_save
+fpregs_context_save:
+	stp	q0, q1, [x0, #CTX_FP_Q0]
+	stp	q2, q3, [x0, #CTX_FP_Q2]
+	stp	q4, q5, [x0, #CTX_FP_Q4]
+	stp	q6, q7, [x0, #CTX_FP_Q6]
+	stp	q8, q9, [x0, #CTX_FP_Q8]
+	stp	q10, q11, [x0, #CTX_FP_Q10]
+	stp	q12, q13, [x0, #CTX_FP_Q12]
+	stp	q14, q15, [x0, #CTX_FP_Q14]
+	stp	q16, q17, [x0, #CTX_FP_Q16]
+	stp	q18, q19, [x0, #CTX_FP_Q18]
+	stp	q20, q21, [x0, #CTX_FP_Q20]
+	stp	q22, q23, [x0, #CTX_FP_Q22]
+	stp	q24, q25, [x0, #CTX_FP_Q24]
+	stp	q26, q27, [x0, #CTX_FP_Q26]
+	stp	q28, q29, [x0, #CTX_FP_Q28]
+	stp	q30, q31, [x0, #CTX_FP_Q30]
+
+	mrs	x9, fpsr
+	str	x9, [x0, #CTX_FP_FPSR]
+
+	mrs	x10, fpcr
+	str	x10, [x0, #CTX_FP_FPCR]
+
+	ret
+
+/* -----------------------------------------------------
+ * The following function follows the aapcs_64 strictly
+ * to use x9-x17 (temporary caller-saved registers
+ * according to AArch64 PCS) to restore floating point
+ * register context. It assumes that 'x0' is pointing to
+ * a 'fp_regs' structure from where the register context
+ * will be restored.
+ *
+ * Access to VFP registers will trap if CPTR_EL3.TFP is
+ * set.  However currently we don't use VFP registers
+ * nor set traps in Trusted Firmware, and assume it's
+ * cleared
+ *
+ * TODO: Revisit when VFP is used in secure world
+ * -----------------------------------------------------
+ */
+	.global fpregs_context_restore
+fpregs_context_restore:
+	ldp	q0, q1, [x0, #CTX_FP_Q0]
+	ldp	q2, q3, [x0, #CTX_FP_Q2]
+	ldp	q4, q5, [x0, #CTX_FP_Q4]
+	ldp	q6, q7, [x0, #CTX_FP_Q6]
+	ldp	q8, q9, [x0, #CTX_FP_Q8]
+	ldp	q10, q11, [x0, #CTX_FP_Q10]
+	ldp	q12, q13, [x0, #CTX_FP_Q12]
+	ldp	q14, q15, [x0, #CTX_FP_Q14]
+	ldp	q16, q17, [x0, #CTX_FP_Q16]
+	ldp	q18, q19, [x0, #CTX_FP_Q18]
+	ldp	q20, q21, [x0, #CTX_FP_Q20]
+	ldp	q22, q23, [x0, #CTX_FP_Q22]
+	ldp	q24, q25, [x0, #CTX_FP_Q24]
+	ldp	q26, q27, [x0, #CTX_FP_Q26]
+	ldp	q28, q29, [x0, #CTX_FP_Q28]
+	ldp	q30, q31, [x0, #CTX_FP_Q30]
+
+	ldr	x9, [x0, #CTX_FP_FPSR]
+	msr	fpsr, x9
+
+	str	x10, [x0, #CTX_FP_FPCR]
+	msr	fpcr, x10
+
+	/*
+	 * No explict ISB required here as ERET to
+	 * swtich to secure EL1 or non-secure world
+	 * covers it
+	 */
+
+	ret

bl31/bl31.mk

@@ -63,7 +63,8 @@ BL31_OBJS		+=	bl31_arch_setup.o			\
 				gic_v3_sysregs.o			\
 				bakery_lock.o				\
 				runtime_svc.o				\
-				early_exceptions.o
+				early_exceptions.o			\
+				context.o
 
 BL31_ENTRY_POINT	:=	bl31_entrypoint
 BL31_MAPFILE		:=	bl31.map

include/context.h

+/*
+ * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __CONTEXT_H__
+#define __CONTEXT_H__
+
+#include <bl_common.h>
+#include <arch.h>
+
+/*******************************************************************************
+ * Constants that allow assembler code to access members of and the 'el3_state'
+ * structure at their correct offsets. Note that some of the registers are only
+ * 32-bits wide but are stored as 64-bit values for convenience
+ ******************************************************************************/
+#define CTX_EL3STATE_OFFSET	0x0
+#define CTX_SAVED_SP_EL3	0x0
+#define CTX_SAVED_SP_EL0	0x8
+#define CTX_SPSR_EL3		0x10
+#define CTX_ELR_EL3		0x18
+#define CTX_SCR_EL3		0x20
+#define CTX_SCTLR_EL3		0x28
+#define CTX_CPTR_EL3		0x30
+/* Unused space to allow registers to be stored as pairs */
+#define CTX_CNTFRQ_EL0		0x40
+#define CTX_MAIR_EL3		0x48
+#define CTX_TCR_EL3		0x50
+#define CTX_TTBR0_EL3		0x58
+#define CTX_DAIF_EL3		0x60
+#define CTX_VBAR_EL3		0x68	/* Currently unused */
+#define CTX_EL3STATE_END	0x70
+
+/*******************************************************************************
+ * Constants that allow assembler code to access members of and the
+ * 'el1_sys_regs' structure at their correct offsets. Note that some of the
+ * registers are only 32-bits wide but are stored as 64-bit values for
+ * convenience
+ ******************************************************************************/
+#define CTX_SYSREGS_OFFSET	(CTX_EL3STATE_OFFSET + CTX_EL3STATE_END)
+#define CTX_SPSR_EL1		0x0
+#define CTX_ELR_EL1		0x8
+#define CTX_SPSR_ABT		0x10
+#define CTX_SPSR_UND		0x18
+#define CTX_SPSR_IRQ		0x20
+#define CTX_SPSR_FIQ		0x28
+#define CTX_SCTLR_EL1		0x30
+#define CTX_ACTLR_EL1		0x38
+#define CTX_CPACR_EL1		0x40
+#define CTX_CSSELR_EL1		0x48
+#define CTX_SP_EL1		0x50
+#define CTX_ESR_EL1		0x58
+#define CTX_TTBR0_EL1		0x60
+#define CTX_TTBR1_EL1		0x68
+#define CTX_MAIR_EL1		0x70
+#define CTX_AMAIR_EL1		0x78
+#define CTX_TCR_EL1		0x80
+#define CTX_TPIDR_EL1		0x88
+#define CTX_TPIDR_EL0		0x90
+#define CTX_TPIDRRO_EL0		0x98
+#define CTX_DACR32_EL2		0xa0
+#define CTX_IFSR32_EL2		0xa8
+#define CTX_PAR_EL1		0xb0
+#define CTX_FAR_EL1		0xb8
+#define CTX_AFSR0_EL1		0xc0
+#define CTX_AFSR1_EL1		0xc8
+#define CTX_CONTEXTIDR_EL1	0xd0
+#define CTX_VBAR_EL1		0xd8
+#define CTX_CNTP_CTL_EL0	0xe0
+#define CTX_CNTP_CVAL_EL0	0xe8
+#define CTX_CNTV_CTL_EL0	0xf0
+#define CTX_CNTV_CVAL_EL0	0xf8
+#define CTX_CNTKCTL_EL1		0x100
+#define CTX_FP_FPEXC32_EL2	0x108
+#define CTX_SYSREGS_END		0x110
+
+/*******************************************************************************
+ * Constants that allow assembler code to access members of and the 'fp_regs'
+ * structure at their correct offsets.
+ ******************************************************************************/
+#define CTX_FPREGS_OFFSET	(CTX_SYSREGS_OFFSET + CTX_SYSREGS_END)
+#define CTX_FP_Q0		0x0
+#define CTX_FP_Q1		0x10
+#define CTX_FP_Q2		0x20
+#define CTX_FP_Q3		0x30
+#define CTX_FP_Q4		0x40
+#define CTX_FP_Q5		0x50
+#define CTX_FP_Q6		0x60
+#define CTX_FP_Q7		0x70
+#define CTX_FP_Q8		0x80
+#define CTX_FP_Q9		0x90
+#define CTX_FP_Q10		0xa0
+#define CTX_FP_Q11		0xb0
+#define CTX_FP_Q12		0xc0
+#define CTX_FP_Q13		0xd0
+#define CTX_FP_Q14		0xe0
+#define CTX_FP_Q15		0xf0
+#define CTX_FP_Q16		0x100
+#define CTX_FP_Q17		0x110
+#define CTX_FP_Q18		0x120
+#define CTX_FP_Q19		0x130
+#define CTX_FP_Q20		0x140
+#define CTX_FP_Q21		0x150
+#define CTX_FP_Q22		0x160
+#define CTX_FP_Q23		0x170
+#define CTX_FP_Q24		0x180
+#define CTX_FP_Q25		0x190
+#define CTX_FP_Q26		0x1a0
+#define CTX_FP_Q27		0x1b0
+#define CTX_FP_Q28		0x1c0
+#define CTX_FP_Q29		0x1d0
+#define CTX_FP_Q30		0x1e0
+#define CTX_FP_Q31		0x1f0
+#define CTX_FP_FPSR		0x200
+#define CTX_FP_FPCR		0x208
+#define CTX_FPREGS_END		0x210
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Common constants to help define the 'cpu_context' structure and its
+ * members below.
+ */
+#define DWORD_SHIFT		3
+#define DEFINE_REG_STRUCT(name, num_regs)	\
+	typedef struct {			\
+		uint64_t _regs[num_regs];	\
+	}  __aligned(16) name
+
+/* Constants to determine the size of individual context structures */
+#define CTX_SYSREG_ALL		(CTX_SYSREGS_END >> DWORD_SHIFT)
+#define CTX_FPREG_ALL		(CTX_FPREGS_END >> DWORD_SHIFT)
+#define CTX_EL3STATE_ALL	(CTX_EL3STATE_END >> DWORD_SHIFT)
+
+/*
+ * AArch64 EL1 system register context structure for preserving the
+ * architectural state during switches from one security state to
+ * another in EL1.
+ */
+DEFINE_REG_STRUCT(el1_sys_regs, CTX_SYSREG_ALL);
+
+/*
+ * AArch64 floating point register context structure for preserving
+ * the floating point state during switches from one security state to
+ * another.
+ */
+DEFINE_REG_STRUCT(fp_regs, CTX_FPREG_ALL);
+
+/*
+ * Miscellaneous registers used by EL3 firmware to maintain its state
+ * across exception entries and exits
+ */
+DEFINE_REG_STRUCT(el3_state, CTX_EL3STATE_ALL);
+
+/*
+ * Macros to access members of any of the above structures using their
+ * offsets
+ */
+#define read_ctx_reg(ctx, offset)	((ctx)->_regs[offset >> DWORD_SHIFT])
+#define write_ctx_reg(ctx, offset, val)	(((ctx)->_regs[offset >> DWORD_SHIFT]) \
+					 = val)
+
+/*
+ * Top-level context structure which is used by EL3 firmware to
+ * preserve the state of a core at EL1 in one of the two security
+ * states and save enough EL3 meta data to be able to return to that
+ * EL and security state. The context management library will be used
+ * to ensure that SP_EL3 always points to an instance of this
+ * structure at exception entry and exit. Each instance will
+ * correspond to either the secure or the non-secure state.
+ */
+typedef struct {
+	el3_state el3state_ctx;
+	el1_sys_regs sysregs_ctx;
+	fp_regs fpregs_ctx;
+} cpu_context;
+
+/* Macros to access members of the 'cpu_context' structure */
+#define get_el3state_ctx(h)	(&((cpu_context *) h)->el3state_ctx)
+#define get_fpregs_ctx(h)	(&((cpu_context *) h)->fpregs_ctx)
+#define get_sysregs_ctx(h)	(&((cpu_context *) h)->sysregs_ctx)
+
+/*
+ * Compile time assertions related to the 'cpu_context' structure to
+ * ensure that the assembler and the compiler view of the offsets of
+ * the structure members is the same.
+ */
+CASSERT(CTX_SYSREGS_OFFSET == __builtin_offsetof(cpu_context, sysregs_ctx), \
+	assert_core_context_sys_offset_mismatch);
+CASSERT(CTX_FPREGS_OFFSET == __builtin_offsetof(cpu_context, fpregs_ctx), \
+	assert_core_context_fp_offset_mismatch);
+CASSERT(CTX_EL3STATE_OFFSET == __builtin_offsetof(cpu_context, el3state_ctx), \
+	assert_core_context_el3state_offset_mismatch);
+
+/*******************************************************************************
+ * Function prototypes
+ ******************************************************************************/
+void el3_sysregs_context_save(el3_state *regs);
+void el3_sysregs_context_restore(el3_state *regs);
+void el1_sysregs_context_save(el1_sys_regs *regs);
+void el1_sysregs_context_restore(el1_sys_regs *regs);
+void fpregs_context_save(fp_regs *regs);
+void fpregs_context_restore(fp_regs *regs);
+
+#undef CTX_SYSREG_ALL
+#undef CTX_FP_ALL
+#undef CTX_EL3STATE_ALL
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __CONTEXT_H__ */