Add support for handling runtime service requests

This patch uses the reworked exception handling support to handle
runtime service requests through SMCs following the SMC calling
convention. This is a giant commit since all the changes are
inter-related. It does the following:

1. Replace the old exception handling mechanism with the new one
2. Enforce that SP_EL0 is used C runtime stacks.
3. Ensures that the cold and warm boot paths use the 'cpu_context'
   structure to program an ERET into the next lower EL.
4. Ensures that SP_EL3 always points to the next 'cpu_context'
   structure prior to an ERET into the next lower EL
5. Introduces a PSCI SMC handler which completes the use of PSCI as a
   runtime service

Change-Id: I661797f834c0803d2c674d20f504df1b04c2b852
Co-authored-by: Achin Gupta <achin.gupta@arm.com>

19 files changed, 561 insertions, 943 deletions

diff --git a/bl31/aarch64/bl31_entrypoint.S b/bl31/aarch64/bl31_entrypoint.S
index cd0c023..1b8488d 100644
--- a/bl31/aarch64/bl31_entrypoint.S
+++ b/bl31/aarch64/bl31_entrypoint.S
@@ -31,6 +31,7 @@
 #include <bl_common.h>
 #include <platform.h>
 #include <arch.h>
+#include "cm_macros.S"
 
 
 	.globl	bl31_entrypoint
@@ -129,6 +130,12 @@ bl31_entrypoint: ; .type bl31_entrypoint, %function
 	ldr	x1, =__COHERENT_RAM_UNALIGNED_SIZE__
 	bl	zeromem16
 
+	/* ---------------------------------------------
+	 * Use SP_EL0 for the C runtime stack.
+	 * ---------------------------------------------
+	 */
+	msr	spsel, #0
+
 	/* --------------------------------------------
 	 * Give ourselves a small coherent stack to
 	 * ease the pain of initializing the MMU
@@ -155,32 +162,26 @@ bl31_entrypoint: ; .type bl31_entrypoint, %function
 	bl	platform_set_stack
 
 	/* ---------------------------------------------
-	 * Use the more complex exception vectors now
-	 * the stacks are setup.
+	 * Jump to main function.
 	 * ---------------------------------------------
 	 */
-	adr	x1, runtime_exceptions
-	msr	vbar_el3, x1
+	bl	bl31_main
 
 	/* ---------------------------------------------
-	 * Use SP_EL0 to initialize BL31. It allows us
-	 * to jump to the next image without having to
-	 * come back here to ensure all of the stack's
-	 * been popped out. run_image() is not nice
-	 * enough to reset the stack pointer before
-	 * handing control to the next stage.
+	 * Use the more complex exception vectors now
+	 * that context management is setup. SP_EL3 is
+	 * pointing to a 'cpu_context' structure which
+	 * has an exception stack allocated. Since
+	 * we're just about to leave this EL with ERET,
+	 * we don't need an ISB here
 	 * ---------------------------------------------
 	 */
-	mov	x0, sp
-	msr	sp_el0, x0
-	msr	spsel, #0
-	isb
+	adr	x1, runtime_exceptions
+	msr	vbar_el3, x1
 
-	/* ---------------------------------------------
-	 * Jump to main function.
-	 * ---------------------------------------------
-	 */
-	bl	bl31_main
+	zero_callee_saved_regs
+	b	el3_exit
 
 _panic:
+	wfi
 	b	_panic
diff --git a/bl31/aarch64/exception_handlers.c b/bl31/aarch64/exception_handlers.c
deleted file mode 100644
index 3151294..0000000
--- a/bl31/aarch64/exception_handlers.c
+++ /dev/null
@@ -1,184 +0,0 @@
-/*
- * 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 <arch_helpers.h>
-#include <platform.h>
-#include <bl_common.h>
-#include <bl31.h>
-#include <psci.h>
-#include <assert.h>
-#include <runtime_svc.h>
-
-/*******************************************************************************
- * This function checks whether this is a valid smc e.g.
- * the function id is correct, top word of args are zeroed
- * when aarch64 makes an aarch32 call etc.
- ******************************************************************************/
-int validate_smc(gp_regs *regs)
-{
-	unsigned int rw = GET_RW(regs->spsr);
-	unsigned int cc = GET_SMC_CC(regs->x0);
-
-	/* Check if there is a difference in the caller RW and SMC CC */
-	if (rw == cc) {
-
-		/* Check whether the caller has chosen the right func. id */
-		if (cc == SMC_64) {
-			regs->x0 = SMC_UNK;
-			return SMC_UNK;
-		}
-
-		/*
-		 * Paranoid check to zero the top word of passed args
-		 * irrespective of caller's register width.
-		 *
-		 * TODO: Check if this needed if the caller is aarch32
-		 */
-		regs->x0 &= (unsigned int) 0xFFFFFFFF;
-		regs->x1 &= (unsigned int) 0xFFFFFFFF;
-		regs->x2 &= (unsigned int) 0xFFFFFFFF;
-		regs->x3 &= (unsigned int) 0xFFFFFFFF;
-		regs->x4 &= (unsigned int) 0xFFFFFFFF;
-		regs->x5 &= (unsigned int) 0xFFFFFFFF;
-		regs->x6 &= (unsigned int) 0xFFFFFFFF;
-	}
-
-	return 0;
-}
-
-/* TODO: Break down the SMC handler into fast and standard SMC handlers. */
-void smc_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
-	/* Check if the SMC has been correctly called */
-	if (validate_smc(regs) != 0)
-		return;
-
-	switch (regs->x0) {
-	case PSCI_VERSION:
-		regs->x0 = psci_version();
-		break;
-
-	case PSCI_CPU_OFF:
-		regs->x0 = __psci_cpu_off();
-		break;
-
-	case PSCI_CPU_SUSPEND_AARCH64:
-	case PSCI_CPU_SUSPEND_AARCH32:
-		regs->x0 = __psci_cpu_suspend(regs->x1, regs->x2, regs->x3);
-		break;
-
-	case PSCI_CPU_ON_AARCH64:
-	case PSCI_CPU_ON_AARCH32:
-		regs->x0 = psci_cpu_on(regs->x1, regs->x2, regs->x3);
-		break;
-
-	case PSCI_AFFINITY_INFO_AARCH32:
-	case PSCI_AFFINITY_INFO_AARCH64:
-		regs->x0 = psci_affinity_info(regs->x1, regs->x2);
-		break;
-
-	default:
-		regs->x0 = SMC_UNK;
-	}
-
-	return;
-}
-
-void irq_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
-	plat_report_exception(type);
-	assert(0);
-}
-
-void fiq_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
-	plat_report_exception(type);
-	assert(0);
-}
-
-void serror_handler(unsigned type, unsigned long esr, gp_regs *regs)
-{
-	plat_report_exception(type);
-	assert(0);
-}
-
-void sync_exception_handler(unsigned type, gp_regs *regs)
-{
-	unsigned long esr = read_esr();
-	unsigned int ec = EC_BITS(esr);
-
-	switch (ec) {
-
-	case EC_AARCH32_SMC:
-	case EC_AARCH64_SMC:
-		smc_handler(type, esr, regs);
-		break;
-
-	default:
-		plat_report_exception(type);
-		assert(0);
-	}
-	return;
-}
-
-void async_exception_handler(unsigned type, gp_regs *regs)
-{
-	unsigned long esr = read_esr();
-
-	switch (type) {
-
-	case IRQ_SP_EL0:
-	case IRQ_SP_ELX:
-	case IRQ_AARCH64:
-	case IRQ_AARCH32:
-		irq_handler(type, esr, regs);
-		break;
-
-	case FIQ_SP_EL0:
-	case FIQ_SP_ELX:
-	case FIQ_AARCH64:
-	case FIQ_AARCH32:
-		fiq_handler(type, esr, regs);
-		break;
-
-	case SERROR_SP_EL0:
-	case SERROR_SP_ELX:
-	case SERROR_AARCH64:
-	case SERROR_AARCH32:
-		serror_handler(type, esr, regs);
-		break;
-
-	default:
-		plat_report_exception(type);
-		assert(0);
-	}
-
-	return;
-}
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 92835dc..10e65dc 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -30,12 +30,13 @@
 
 #include <arch.h>
 #include <runtime_svc.h>
+#include <platform.h>
+#include <context.h>
+#include "cm_macros.S"
 
 	.globl	runtime_exceptions
-
-
-#include <asm_macros.S>
-
+	.globl	el3_exit
+	.globl	get_exception_stack
 
 	.section	.vectors, "ax"; .align 11
 
@@ -46,39 +47,32 @@ runtime_exceptions:
 	 * -----------------------------------------------------
 	 */
 sync_exception_sp_el0:
-	exception_entry save_regs
-	mov	x0, #SYNC_EXCEPTION_SP_EL0
-	mov	x1, sp
-	bl	sync_exception_handler
-	exception_exit restore_regs
-	eret
+	/* -----------------------------------------------------
+	 * We don't expect any synchronous exceptions from EL3
+	 * -----------------------------------------------------
+	 */
+	wfi
+	b	sync_exception_sp_el0
 
 	.align	7
+	/* -----------------------------------------------------
+	 * EL3 code is non-reentrant. Any asynchronous exception
+	 * is a serious error. Loop infinitely.
+	 * -----------------------------------------------------
+	 */
 irq_sp_el0:
-	exception_entry save_regs
-	mov	x0, #IRQ_SP_EL0
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception IRQ_SP_EL0
+	b	irq_sp_el0
 
 	.align	7
 fiq_sp_el0:
-	exception_entry save_regs
-	mov	x0, #FIQ_SP_EL0
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception FIQ_SP_EL0
+	b	fiq_sp_el0
 
 	.align	7
 serror_sp_el0:
-	exception_entry save_regs
-	mov	x0, #SERROR_SP_EL0
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception SERROR_SP_EL0
+	b	serror_sp_el0
 
 	/* -----------------------------------------------------
 	 * Current EL with SPx: 0x200 - 0x380
@@ -86,39 +80,35 @@ serror_sp_el0:
 	 */
 	.align	7
 sync_exception_sp_elx:
-	exception_entry save_regs
-	mov	x0, #SYNC_EXCEPTION_SP_ELX
-	mov	x1, sp
-	bl	sync_exception_handler
-	exception_exit restore_regs
-	eret
+	/* -----------------------------------------------------
+	 * This exception will trigger if anything went wrong
+	 * during a previous exception entry or exit or while
+	 * handling an earlier unexpected synchronous exception.
+	 * In any case we cannot rely on SP_EL3. Switching to a
+	 * known safe area of memory will corrupt at least a
+	 * single register. It is best to enter wfi in loop as
+	 * that will preserve the system state for analysis
+	 * through a debugger later.
+	 * -----------------------------------------------------
+	 */
+	wfi
+	b	sync_exception_sp_elx
 
+	/* -----------------------------------------------------
+	 * As mentioned in the previous comment, all bets are
+	 * off if SP_EL3 cannot be relied upon. Report their
+	 * occurrence.
+	 * -----------------------------------------------------
+	 */
 	.align	7
 irq_sp_elx:
-	exception_entry save_regs
-	mov	x0, #IRQ_SP_ELX
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
-
+	b	irq_sp_elx
 	.align	7
 fiq_sp_elx:
-	exception_entry save_regs
-	mov	x0, #FIQ_SP_ELX
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
-
+	b	fiq_sp_elx
 	.align	7
 serror_sp_elx:
-	exception_entry save_regs
-	mov	x0, #SERROR_SP_ELX
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	b	serror_sp_elx
 
 	/* -----------------------------------------------------
 	 * Lower EL using AArch64 : 0x400 - 0x580
@@ -126,39 +116,35 @@ serror_sp_elx:
 	 */
 	.align	7
 sync_exception_aarch64:
-	exception_entry save_regs
-	mov	x0, #SYNC_EXCEPTION_AARCH64
-	mov	x1, sp
-	bl	sync_exception_handler
-	exception_exit restore_regs
-	eret
+	/* -----------------------------------------------------
+	 * This exception vector will be the entry point for
+	 * SMCs and traps that are unhandled at lower ELs most
+	 * commonly. SP_EL3 should point to a valid cpu context
+	 * where the general purpose and system register state
+	 * can be saved.
+	 * -----------------------------------------------------
+	 */
+	handle_sync_exception
 
 	.align	7
+	/* -----------------------------------------------------
+	 * Asynchronous exceptions from lower ELs are not
+	 * currently supported. Report their occurrence.
+	 * -----------------------------------------------------
+	 */
 irq_aarch64:
-	exception_entry save_regs
-	mov	x0, #IRQ_AARCH64
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception IRQ_AARCH64
+	b	irq_aarch64
 
 	.align	7
 fiq_aarch64:
-	exception_entry save_regs
-	mov	x0, #FIQ_AARCH64
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception FIQ_AARCH64
+	b	fiq_aarch64
 
 	.align	7
 serror_aarch64:
-	exception_entry save_regs
-	mov	x0, #IRQ_AARCH32
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception SERROR_AARCH64
+	b	serror_aarch64
 
 	/* -----------------------------------------------------
 	 * Lower EL using AArch32 : 0x600 - 0x780
@@ -166,39 +152,281 @@ serror_aarch64:
 	 */
 	.align	7
 sync_exception_aarch32:
-	exception_entry save_regs
-	mov	x0, #SYNC_EXCEPTION_AARCH32
-	mov	x1, sp
-	bl	sync_exception_handler
-	exception_exit restore_regs
-	eret
+	/* -----------------------------------------------------
+	 * This exception vector will be the entry point for
+	 * SMCs and traps that are unhandled at lower ELs most
+	 * commonly. SP_EL3 should point to a valid cpu context
+	 * where the general purpose and system register state
+	 * can be saved.
+	 * -----------------------------------------------------
+	 */
+	handle_sync_exception
 
 	.align	7
+	/* -----------------------------------------------------
+	 * Asynchronous exceptions from lower ELs are not
+	 * currently supported. Report their occurrence.
+	 * -----------------------------------------------------
+	 */
 irq_aarch32:
-	exception_entry save_regs
-	mov	x0, #IRQ_AARCH32
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception IRQ_AARCH32
+	b	irq_aarch32
 
 	.align	7
 fiq_aarch32:
-	exception_entry save_regs
-	mov	x0, #FIQ_AARCH32
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
-	eret
+	handle_async_exception FIQ_AARCH32
+	b	fiq_aarch32
 
 	.align	7
 serror_aarch32:
-	exception_entry save_regs
-	mov	x0, #SERROR_AARCH32
-	mov	x1, sp
-	bl	async_exception_handler
-	exception_exit restore_regs
+	handle_async_exception SERROR_AARCH32
+	b	serror_aarch32
+	.align	7
+
+	.section	.text, "ax"
+	/* -----------------------------------------------------
+	 * The following code handles secure monitor calls.
+	 * Depending upon the execution state from where the SMC
+	 * has been invoked, it frees some general purpose
+	 * registers to perform the remaining tasks. They
+	 * involve finding the runtime service handler that is
+	 * the target of the SMC & switching to runtime stacks
+	 * (SP_EL0) before calling the handler.
+	 *
+	 * Note that x30 has been explicitly saved and can be
+	 * used here
+	 * -----------------------------------------------------
+	 */
+smc_handler32:
+	/* Check whether aarch32 issued an SMC64 */
+	tbnz	x0, #FUNCID_CC_SHIFT, smc_prohibited
+
+	/* -----------------------------------------------------
+	 * Since we're are coming from aarch32, x8-x18 need to
+	 * be saved as per SMC32 calling convention. If a lower
+	 * EL in aarch64 is making an SMC32 call then it must
+	 * have saved x8-x17 already therein.
+	 * -----------------------------------------------------
+	 */
+	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+
+	/* x4-x7, x18, sp_el0 are saved below */
+
+smc_handler64:
+	/* -----------------------------------------------------
+	 * Populate the parameters for the SMC handler. We
+	 * already have x0-x4 in place. x5 will point to a
+	 * cookie (not used now). x6 will point to the context
+	 * structure (SP_EL3) and x7 will contain flags we need
+	 * to pass to the handler Hence save x5-x7. Note that x4
+	 * only needs to be preserved for AArch32 callers but we
+	 * do it for AArch64 callers as well for convenience
+	 * -----------------------------------------------------
+	 */
+	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+
+	mov	x5, xzr
+	mov	x6, sp
+
+	/* Get the unique owning entity number */
+	ubfx	x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
+	ubfx	x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
+	orr	x16, x16, x15, lsl #FUNCID_OEN_WIDTH
+
+	adr	x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
+
+	/* Load descriptor index from array of indices */
+	adr	x14, rt_svc_descs_indices
+	ldrb	w15, [x14, x16]
+
+	/* Save x18 and SP_EL0 */
+	mrs	x17, sp_el0
+	stp	x18, x17, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+
+	/* -----------------------------------------------------
+	 * Restore the saved C runtime stack value which will
+	 * become the new SP_EL0 i.e. EL3 runtime stack. It was
+	 * saved in the 'cpu_context' structure prior to the last
+	 * ERET from EL3.
+	 * -----------------------------------------------------
+	 */
+	ldr	x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
+
+	/*
+	 * Any index greater than 127 is invalid. Check bit 7 for
+	 * a valid index
+	 */
+	tbnz	w15, 7, smc_unknown
+
+	/* Switch to SP_EL0 */
+	msr	spsel, #0
+
+	/* -----------------------------------------------------
+	 * Get the descriptor using the index
+	 * x11 = (base + off), x15 = index
+	 *
+	 * handler = (base + off) + (index << log2(size))
+	 * -----------------------------------------------------
+	 */
+	lsl	w10, w15, #RT_SVC_SIZE_LOG2
+	ldr	x15, [x11, w10, uxtw]
+
+	/* -----------------------------------------------------
+	 * Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there
+	 * is a world switch during SMC handling.
+	 * TODO: Revisit if all system registers can be saved
+	 * later.
+	 * -----------------------------------------------------
+	 */
+	mrs	x16, spsr_el3
+	mrs	x17, elr_el3
+	mrs	x18, scr_el3
+	stp	x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
+	stp	x18, xzr, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
+
+	/* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
+	bfi	x7, x18, #0, #1
+
+	mov	sp, x12
+
+	/* -----------------------------------------------------
+	 * Call the Secure Monitor Call handler and then drop
+	 * directly into el3_exit() which will program any
+	 * remaining architectural state prior to issuing the
+	 * ERET to the desired lower EL.
+	 * -----------------------------------------------------
+	 */
+#if DEBUG
+	cbz	x15, rt_svc_fw_critical_error
+#endif
+	blr	x15
+
+	/* -----------------------------------------------------
+	 * This routine assumes that the SP_EL3 is pointing to
+	 * a valid context structure from where the gp regs and
+	 * other special registers can be retrieved.
+	 * -----------------------------------------------------
+	 */
+el3_exit: ; .type el3_exit, %function
+	/* -----------------------------------------------------
+	 * Save the current SP_EL0 i.e. the EL3 runtime stack
+	 * which will be used for handling the next SMC. Then
+	 * switch to SP_EL3
+	 * -----------------------------------------------------
+	 */
+	mov	x17, sp
+	msr	spsel, #1
+	str	x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
+
+	/* -----------------------------------------------------
+	 * Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
+	 * -----------------------------------------------------
+	 */
+	ldp	x18, xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
+	ldp	x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
+	msr	scr_el3, x18
+	msr	spsr_el3, x16
+	msr	elr_el3, x17
+
+	/* Restore saved general purpose registers and return */
+	bl	restore_scratch_registers
+	ldp	x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
 	eret
 
-	.align	7
+smc_unknown:
+	/*
+	 * Here we restore x4-x18 regardless of where we came from. AArch32
+	 * callers will find the registers contents unchanged, but AArch64
+	 * callers will find the registers modified (with stale earlier NS
+	 * content). Either way, we aren't leaking any secure information
+	 * through them
+	 */
+	bl	restore_scratch_registers_callee
+
+smc_prohibited:
+	ldp	x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
+	mov	w0, #SMC_UNK
+	eret
+
+rt_svc_fw_critical_error:
+	b	rt_svc_fw_critical_error
+
+	/* -----------------------------------------------------
+	 * The following functions are used to saved and restore
+	 * all the caller saved registers as per the aapcs_64.
+	 * These are not macros to ensure their invocation fits
+	 * within the 32 instructions per exception vector.
+	 * -----------------------------------------------------
+	 */
+save_scratch_registers: ; .type save_scratch_registers, %function
+	stp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	stp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+	mrs	x17, sp_el0
+	stp	x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+	ret
+
+restore_scratch_registers: ; .type restore_scratch_registers, %function
+	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
+	ldp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
+
+restore_scratch_registers_callee:
+	ldp	x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
+
+	ldp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
+	ldp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
+	ldp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
+	ldp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
+	ldp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
+	ldp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
+
+	msr	sp_el0, x17
+	ldp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
+	ret
+
+	/* -----------------------------------------------------
+	 * 256 bytes of exception stack for each cpu
+	 * -----------------------------------------------------
+	 */
+#if DEBUG
+#define PCPU_EXCEPTION_STACK_SIZE	0x300
+#else
+#define PCPU_EXCEPTION_STACK_SIZE	0x100
+#endif
+	/* -----------------------------------------------------
+	 * void get_exception_stack (uint64_t mpidr) : This
+	 * function is used to allocate a small stack for
+	 * reporting unhandled exceptions
+	 * -----------------------------------------------------
+	 */
+get_exception_stack: ; .type get_exception_stack, %function
+	mov	x10, x30 // lr
+	bl	platform_get_core_pos
+	add	x0, x0, #1
+	mov	x1, #PCPU_EXCEPTION_STACK_SIZE
+	mul	x0, x0, x1
+	ldr	x1, =pcpu_exception_stack
+	add	x0, x1, x0
+	ret	x10
+
+	/* -----------------------------------------------------
+	 * Per-cpu exception stacks in normal memory.
+	 * -----------------------------------------------------
+	 */
+	.section	data, "aw", %nobits; .align 6
+
+pcpu_exception_stack:
+	/* Zero fill */
+	.space (PLATFORM_CORE_COUNT * PCPU_EXCEPTION_STACK_SIZE), 0
 
diff --git a/bl31/aarch64/runtime_exceptions_next.S b/bl31/aarch64/runtime_exceptions_next.S
deleted file mode 100644
index 10e65dc..0000000
--- a/bl31/aarch64/runtime_exceptions_next.S
+++ /dev/null
@@ -1,432 +0,0 @@
-/*
- * 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 <arch.h>
-#include <runtime_svc.h>
-#include <platform.h>
-#include <context.h>
-#include "cm_macros.S"
-
-	.globl	runtime_exceptions
-	.globl	el3_exit
-	.globl	get_exception_stack
-
-	.section	.vectors, "ax"; .align 11
-
-	.align	7
-runtime_exceptions:
-	/* -----------------------------------------------------
-	 * Current EL with _sp_el0 : 0x0 - 0x180
-	 * -----------------------------------------------------
-	 */
-sync_exception_sp_el0:
-	/* -----------------------------------------------------
-	 * We don't expect any synchronous exceptions from EL3
-	 * -----------------------------------------------------
-	 */
-	wfi
-	b	sync_exception_sp_el0
-
-	.align	7
-	/* -----------------------------------------------------
-	 * EL3 code is non-reentrant. Any asynchronous exception
-	 * is a serious error. Loop infinitely.
-	 * -----------------------------------------------------
-	 */
-irq_sp_el0:
-	handle_async_exception IRQ_SP_EL0
-	b	irq_sp_el0
-
-	.align	7
-fiq_sp_el0:
-	handle_async_exception FIQ_SP_EL0
-	b	fiq_sp_el0
-
-	.align	7
-serror_sp_el0:
-	handle_async_exception SERROR_SP_EL0
-	b	serror_sp_el0
-
-	/* -----------------------------------------------------
-	 * Current EL with SPx: 0x200 - 0x380
-	 * -----------------------------------------------------
-	 */
-	.align	7
-sync_exception_sp_elx:
-	/* -----------------------------------------------------
-	 * This exception will trigger if anything went wrong
-	 * during a previous exception entry or exit or while
-	 * handling an earlier unexpected synchronous exception.
-	 * In any case we cannot rely on SP_EL3. Switching to a
-	 * known safe area of memory will corrupt at least a
-	 * single register. It is best to enter wfi in loop as
-	 * that will preserve the system state for analysis
-	 * through a debugger later.
-	 * -----------------------------------------------------
-	 */
-	wfi
-	b	sync_exception_sp_elx
-
-	/* -----------------------------------------------------
-	 * As mentioned in the previous comment, all bets are
-	 * off if SP_EL3 cannot be relied upon. Report their
-	 * occurrence.
-	 * -----------------------------------------------------
-	 */
-	.align	7
-irq_sp_elx:
-	b	irq_sp_elx
-	.align	7
-fiq_sp_elx:
-	b	fiq_sp_elx
-	.align	7
-serror_sp_elx:
-	b	serror_sp_elx
-
-	/* -----------------------------------------------------
-	 * Lower EL using AArch64 : 0x400 - 0x580
-	 * -----------------------------------------------------
-	 */
-	.align	7
-sync_exception_aarch64:
-	/* -----------------------------------------------------
-	 * This exception vector will be the entry point for
-	 * SMCs and traps that are unhandled at lower ELs most
-	 * commonly. SP_EL3 should point to a valid cpu context
-	 * where the general purpose and system register state
-	 * can be saved.
-	 * -----------------------------------------------------
-	 */
-	handle_sync_exception
-
-	.align	7
-	/* -----------------------------------------------------
-	 * Asynchronous exceptions from lower ELs are not
-	 * currently supported. Report their occurrence.
-	 * -----------------------------------------------------
-	 */
-irq_aarch64:
-	handle_async_exception IRQ_AARCH64
-	b	irq_aarch64
-
-	.align	7
-fiq_aarch64:
-	handle_async_exception FIQ_AARCH64
-	b	fiq_aarch64
-
-	.align	7
-serror_aarch64:
-	handle_async_exception SERROR_AARCH64
-	b	serror_aarch64
-
-	/* -----------------------------------------------------
-	 * Lower EL using AArch32 : 0x600 - 0x780
-	 * -----------------------------------------------------
-	 */
-	.align	7
-sync_exception_aarch32:
-	/* -----------------------------------------------------
-	 * This exception vector will be the entry point for
-	 * SMCs and traps that are unhandled at lower ELs most
-	 * commonly. SP_EL3 should point to a valid cpu context
-	 * where the general purpose and system register state
-	 * can be saved.
-	 * -----------------------------------------------------
-	 */
-	handle_sync_exception
-
-	.align	7
-	/* -----------------------------------------------------
-	 * Asynchronous exceptions from lower ELs are not
-	 * currently supported. Report their occurrence.
-	 * -----------------------------------------------------
-	 */
-irq_aarch32:
-	handle_async_exception IRQ_AARCH32
-	b	irq_aarch32
-
-	.align	7
-fiq_aarch32:
-	handle_async_exception FIQ_AARCH32
-	b	fiq_aarch32
-
-	.align	7
-serror_aarch32:
-	handle_async_exception SERROR_AARCH32
-	b	serror_aarch32
-	.align	7
-
-	.section	.text, "ax"
-	/* -----------------------------------------------------
-	 * The following code handles secure monitor calls.
-	 * Depending upon the execution state from where the SMC
-	 * has been invoked, it frees some general purpose
-	 * registers to perform the remaining tasks. They
-	 * involve finding the runtime service handler that is
-	 * the target of the SMC & switching to runtime stacks
-	 * (SP_EL0) before calling the handler.
-	 *
-	 * Note that x30 has been explicitly saved and can be
-	 * used here
-	 * -----------------------------------------------------
-	 */
-smc_handler32:
-	/* Check whether aarch32 issued an SMC64 */
-	tbnz	x0, #FUNCID_CC_SHIFT, smc_prohibited
-
-	/* -----------------------------------------------------
-	 * Since we're are coming from aarch32, x8-x18 need to
-	 * be saved as per SMC32 calling convention. If a lower
-	 * EL in aarch64 is making an SMC32 call then it must
-	 * have saved x8-x17 already therein.
-	 * -----------------------------------------------------
-	 */
-	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
-	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
-	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
-	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
-	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
-
-	/* x4-x7, x18, sp_el0 are saved below */
-
-smc_handler64:
-	/* -----------------------------------------------------
-	 * Populate the parameters for the SMC handler. We
-	 * already have x0-x4 in place. x5 will point to a
-	 * cookie (not used now). x6 will point to the context
-	 * structure (SP_EL3) and x7 will contain flags we need
-	 * to pass to the handler Hence save x5-x7. Note that x4
-	 * only needs to be preserved for AArch32 callers but we
-	 * do it for AArch64 callers as well for convenience
-	 * -----------------------------------------------------
-	 */
-	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
-	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
-
-	mov	x5, xzr
-	mov	x6, sp
-
-	/* Get the unique owning entity number */
-	ubfx	x16, x0, #FUNCID_OEN_SHIFT, #FUNCID_OEN_WIDTH
-	ubfx	x15, x0, #FUNCID_TYPE_SHIFT, #FUNCID_TYPE_WIDTH
-	orr	x16, x16, x15, lsl #FUNCID_OEN_WIDTH
-
-	adr	x11, (__RT_SVC_DESCS_START__ + RT_SVC_DESC_HANDLE)
-
-	/* Load descriptor index from array of indices */
-	adr	x14, rt_svc_descs_indices
-	ldrb	w15, [x14, x16]
-
-	/* Save x18 and SP_EL0 */
-	mrs	x17, sp_el0
-	stp	x18, x17, [x6, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
-
-	/* -----------------------------------------------------
-	 * Restore the saved C runtime stack value which will
-	 * become the new SP_EL0 i.e. EL3 runtime stack. It was
-	 * saved in the 'cpu_context' structure prior to the last
-	 * ERET from EL3.
-	 * -----------------------------------------------------
-	 */
-	ldr	x12, [x6, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
-
-	/*
-	 * Any index greater than 127 is invalid. Check bit 7 for
-	 * a valid index
-	 */
-	tbnz	w15, 7, smc_unknown
-
-	/* Switch to SP_EL0 */
-	msr	spsel, #0
-
-	/* -----------------------------------------------------
-	 * Get the descriptor using the index
-	 * x11 = (base + off), x15 = index
-	 *
-	 * handler = (base + off) + (index << log2(size))
-	 * -----------------------------------------------------
-	 */
-	lsl	w10, w15, #RT_SVC_SIZE_LOG2
-	ldr	x15, [x11, w10, uxtw]
-
-	/* -----------------------------------------------------
-	 * Save the SPSR_EL3, ELR_EL3, & SCR_EL3 in case there
-	 * is a world switch during SMC handling.
-	 * TODO: Revisit if all system registers can be saved
-	 * later.
-	 * -----------------------------------------------------
-	 */
-	mrs	x16, spsr_el3
-	mrs	x17, elr_el3
-	mrs	x18, scr_el3
-	stp	x16, x17, [x6, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
-	stp	x18, xzr, [x6, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
-
-	/* Copy SCR_EL3.NS bit to the flag to indicate caller's security */
-	bfi	x7, x18, #0, #1
-
-	mov	sp, x12
-
-	/* -----------------------------------------------------
-	 * Call the Secure Monitor Call handler and then drop
-	 * directly into el3_exit() which will program any
-	 * remaining architectural state prior to issuing the
-	 * ERET to the desired lower EL.
-	 * -----------------------------------------------------
-	 */
-#if DEBUG
-	cbz	x15, rt_svc_fw_critical_error
-#endif
-	blr	x15
-
-	/* -----------------------------------------------------
-	 * This routine assumes that the SP_EL3 is pointing to
-	 * a valid context structure from where the gp regs and
-	 * other special registers can be retrieved.
-	 * -----------------------------------------------------
-	 */
-el3_exit: ; .type el3_exit, %function
-	/* -----------------------------------------------------
-	 * Save the current SP_EL0 i.e. the EL3 runtime stack
-	 * which will be used for handling the next SMC. Then
-	 * switch to SP_EL3
-	 * -----------------------------------------------------
-	 */
-	mov	x17, sp
-	msr	spsel, #1
-	str	x17, [sp, #CTX_EL3STATE_OFFSET + CTX_RUNTIME_SP]
-
-	/* -----------------------------------------------------
-	 * Restore SPSR_EL3, ELR_EL3 and SCR_EL3 prior to ERET
-	 * -----------------------------------------------------
-	 */
-	ldp	x18, xzr, [sp, #CTX_EL3STATE_OFFSET + CTX_SCR_EL3]
-	ldp	x16, x17, [sp, #CTX_EL3STATE_OFFSET + CTX_SPSR_EL3]
-	msr	scr_el3, x18
-	msr	spsr_el3, x16
-	msr	elr_el3, x17
-
-	/* Restore saved general purpose registers and return */
-	bl	restore_scratch_registers
-	ldp	x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
-	eret
-
-smc_unknown:
-	/*
-	 * Here we restore x4-x18 regardless of where we came from. AArch32
-	 * callers will find the registers contents unchanged, but AArch64
-	 * callers will find the registers modified (with stale earlier NS
-	 * content). Either way, we aren't leaking any secure information
-	 * through them
-	 */
-	bl	restore_scratch_registers_callee
-
-smc_prohibited:
-	ldp	x30, xzr, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_LR]
-	mov	w0, #SMC_UNK
-	eret
-
-rt_svc_fw_critical_error:
-	b	rt_svc_fw_critical_error
-
-	/* -----------------------------------------------------
-	 * The following functions are used to saved and restore
-	 * all the caller saved registers as per the aapcs_64.
-	 * These are not macros to ensure their invocation fits
-	 * within the 32 instructions per exception vector.
-	 * -----------------------------------------------------
-	 */
-save_scratch_registers: ; .type save_scratch_registers, %function
-	stp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
-	stp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
-	stp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
-	stp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
-	stp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
-	stp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
-	stp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
-	stp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
-	stp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
-	mrs	x17, sp_el0
-	stp	x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
-	ret
-
-restore_scratch_registers: ; .type restore_scratch_registers, %function
-	ldp	x0, x1, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X0]
-	ldp	x2, x3, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X2]
-
-restore_scratch_registers_callee:
-	ldp	x18, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X18]
-
-	ldp	x4, x5, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X4]
-	ldp	x6, x7, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X6]
-	ldp	x8, x9, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X8]
-	ldp	x10, x11, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X10]
-	ldp	x12, x13, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X12]
-	ldp	x14, x15, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X14]
-
-	msr	sp_el0, x17
-	ldp	x16, x17, [sp, #CTX_GPREGS_OFFSET + CTX_GPREG_X16]
-	ret
-
-	/* -----------------------------------------------------
-	 * 256 bytes of exception stack for each cpu
-	 * -----------------------------------------------------
-	 */
-#if DEBUG
-#define PCPU_EXCEPTION_STACK_SIZE	0x300
-#else
-#define PCPU_EXCEPTION_STACK_SIZE	0x100
-#endif
-	/* -----------------------------------------------------
-	 * void get_exception_stack (uint64_t mpidr) : This
-	 * function is used to allocate a small stack for
-	 * reporting unhandled exceptions
-	 * -----------------------------------------------------
-	 */
-get_exception_stack: ; .type get_exception_stack, %function
-	mov	x10, x30 // lr
-	bl	platform_get_core_pos
-	add	x0, x0, #1
-	mov	x1, #PCPU_EXCEPTION_STACK_SIZE
-	mul	x0, x0, x1
-	ldr	x1, =pcpu_exception_stack
-	add	x0, x1, x0
-	ret	x10
-
-	/* -----------------------------------------------------
-	 * Per-cpu exception stacks in normal memory.
-	 * -----------------------------------------------------
-	 */
-	.section	data, "aw", %nobits; .align 6
-
-pcpu_exception_stack:
-	/* Zero fill */
-	.space (PLATFORM_CORE_COUNT * PCPU_EXCEPTION_STACK_SIZE), 0
-
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 280aa88..fec8ebe 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -49,7 +49,6 @@ vpath			%.S	lib/arch/${ARCH}			\
 
 BL31_OBJS		+=	bl31_arch_setup.o			\
 				bl31_entrypoint.o			\
-				exception_handlers.o			\
 				runtime_exceptions.o			\
 				bl31_main.o				\
 				psci_entry.o				\
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index dc65b60..9d2dc29 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -48,15 +48,18 @@ void bl31_lib_init()
 	cm_init();
 }
 
-void bl31_arch_next_el_setup(void);
-
 /*******************************************************************************
  * BL31 is responsible for setting up the runtime services for the primary cpu
- * before passing control to the bootloader (UEFI) or Linux.
+ * before passing control to the bootloader (UEFI) or Linux. This function calls
+ * runtime_svc_init() which initializes all registered runtime services. The run
+ * time services would setup enough context for the core to swtich to the next
+ * exception level. When this function returns, the core will switch to the
+ * programmed exception level via. an ERET.
  ******************************************************************************/
 void bl31_main(void)
 {
-	el_change_info *image_info;
+	el_change_info *next_image_info;
+	uint32_t scr;
 
 	/* Perform remaining generic architectural setup from EL3 */
 	bl31_arch_setup();
@@ -76,10 +79,27 @@ void bl31_main(void)
 	/* Clean caches before re-entering normal world */
 	dcsw_op_all(DCCSW);
 
-	image_info = bl31_get_next_image_info();
+	/*
+	 * Setup minimal architectural state of the next highest EL to
+	 * allow execution in it immediately upon entering it.
+	 */
 	bl31_arch_next_el_setup();
-	change_el(image_info);
 
-	/* There is no valid reason for change_el() to return */
-	assert(0);
+	/* Program EL3 registers to enable entry into the next EL */
+	next_image_info = bl31_get_next_image_info();
+	scr = read_scr();
+	if (next_image_info->security_state == NON_SECURE)
+		scr |= SCR_NS_BIT;
+
+	/*
+	 * Tell the context mgmt. library to ensure that SP_EL3 points to
+	 * the right context to exit from EL3 correctly.
+	 */
+	cm_set_el3_eret_context(next_image_info->security_state,
+			next_image_info->entrypoint,
+			next_image_info->spsr,
+			scr);
+
+	/* Finally set the next context */
+	cm_set_next_eret_context(next_image_info->security_state);
 }
diff --git a/bl31/context_mgmt.c b/bl31/context_mgmt.c
index bbdbad2..44ef0d9 100644
--- a/bl31/context_mgmt.c
+++ b/bl31/context_mgmt.c
@@ -143,11 +143,31 @@ void cm_el1_sysregs_context_restore(uint32_t security_state)
 }
 
 /*******************************************************************************
- * This function is used to program SP_EL3 to point to the 'cpu_context'
- * structure which will be used for programming the EL3 architectural state to
- * enable an ERET into a lower EL e.g. general purpose registers and system
- * registers like SCR_EL3, SPSR_EL3, SCR_EL3 etc. The same structure will be
- * used to save the same registers after an exception entry from the lower EL.
+ * This function function populates 'cpu_context' pertaining to the given
+ * security state with the entrypoint, SPSR and SCR values so that an ERET from
+ * this securit state correctly restores corresponding values to drop the CPU to
+ * the next exception level
+ ******************************************************************************/
+void cm_set_el3_eret_context(uint32_t security_state, uint64_t entrypoint,
+		uint32_t spsr, uint32_t scr)
+{
+	cpu_context *ctx;
+	el3_state *state;
+
+	ctx = cm_get_context(read_mpidr(), security_state);
+	assert(ctx);
+
+	/* Populate EL3 state so that we've the right context before doing ERET */
+	state = get_el3state_ctx(ctx);
+	write_ctx_reg(state, CTX_SPSR_EL3, spsr);
+	write_ctx_reg(state, CTX_ELR_EL3, entrypoint);
+	write_ctx_reg(state, CTX_SCR_EL3, scr);
+}
+
+/*******************************************************************************
+ * This function is used to program the context that's used for exception
+ * return. This initializes the SP_EL3 to a pointer to a 'cpu_context' set for
+ * the required security state
  ******************************************************************************/
 void cm_set_next_eret_context(uint32_t security_state)
 {
@@ -155,6 +175,7 @@ void cm_set_next_eret_context(uint32_t security_state)
 #if DEBUG
 	uint64_t sp_mode;
 #endif
+
 	ctx = cm_get_context(read_mpidr(), security_state);
 	assert(ctx);
 
@@ -174,3 +195,22 @@ void cm_set_next_eret_context(uint32_t security_state)
 			 "msr	spsel, #0\n"
 			 : : "r" (ctx));
 }
+
+/*******************************************************************************
+ * This function is used to program exception stack in the 'cpu_context'
+ * structure. This is the initial stack used for taking and handling exceptions
+ * at EL3. This stack is expected to be initialized once by each security state
+ ******************************************************************************/
+void cm_init_exception_stack(uint64_t mpidr, uint32_t security_state)
+{
+	cpu_context *ctx;
+	el3_state *state;
+
+	ctx = cm_get_context(mpidr, security_state);
+	assert(ctx);
+
+	/* Set exception stack in the context */
+	state = get_el3state_ctx(ctx);
+
+	write_ctx_reg(state, CTX_EXCEPTION_SP, get_exception_stack(mpidr));
+}
diff --git a/common/psci/psci_common.c b/common/psci/psci_common.c
index 193655d..214db78 100644
--- a/common/psci/psci_common.c
+++ b/common/psci/psci_common.c
@@ -36,6 +36,7 @@
 #include <platform.h>
 #include <psci.h>
 #include <psci_private.h>
+#include <context_mgmt.h>
 #include <runtime_svc.h>
 #include "debug.h"
 
@@ -86,7 +87,8 @@ int get_power_on_target_afflvl(unsigned long mpidr)
 	unsigned int state;
 
 	/* Retrieve our node from the topology tree */
-	node = psci_get_aff_map_node(mpidr & MPIDR_AFFINITY_MASK, MPIDR_AFFLVL0);
+	node = psci_get_aff_map_node(mpidr & MPIDR_AFFINITY_MASK,
+			MPIDR_AFFLVL0);
 	assert(node);
 
 	/*
@@ -222,13 +224,12 @@ int psci_validate_mpidr(unsigned long mpidr, int level)
 void psci_get_ns_entry_info(unsigned int index)
 {
 	unsigned long sctlr = 0, scr, el_status, id_aa64pfr0;
-	gp_regs *ns_gp_regs;
+	uint64_t mpidr = read_mpidr();
+	cpu_context *ns_entry_context;
+	gp_regs *ns_entry_gpregs;
 
 	scr = read_scr();
 
-	/* Switch to the non-secure view of the registers */
-	write_scr(scr | SCR_NS_BIT);
-
 	/* Find out which EL we are going to */
 	id_aa64pfr0 = read_id_aa64pfr0_el1();
 	el_status = (id_aa64pfr0 >> ID_AA64PFR0_EL2_SHIFT) &
@@ -257,23 +258,29 @@ void psci_get_ns_entry_info(unsigned int index)
 		write_sctlr_el1(sctlr);
 
 	/* Fulfill the cpu_on entry reqs. as per the psci spec */
-	write_scr(scr);
-	write_elr(psci_ns_entry_info[index].eret_info.entrypoint);
+	ns_entry_context = (cpu_context *) cm_get_context(mpidr, NON_SECURE);
+	assert(ns_entry_context);
 
 	/*
-	 * Set the general purpose registers to ~0 upon entry into the
-	 * non-secure world except for x0 which should contain the
-	 * context id & spsr. This is done directly on the "would be"
-	 * stack pointer. Prior to entry into the non-secure world, an
-	 * offset equivalent to the size of the 'gp_regs' structure is
-	 * added to the sp. This general purpose register context is
-	 * retrieved then.
+	 * Setup general purpose registers to return the context id and
+	 * prevent leakage of secure information into the normal world.
 	 */
-	ns_gp_regs = (gp_regs *) platform_get_stack(read_mpidr());
-	ns_gp_regs--;
-	memset(ns_gp_regs, ~0, sizeof(*ns_gp_regs));
-	ns_gp_regs->x0 = psci_ns_entry_info[index].context_id;
-	ns_gp_regs->spsr = psci_ns_entry_info[index].eret_info.spsr;
+	ns_entry_gpregs = get_gpregs_ctx(ns_entry_context);
+	write_ctx_reg(ns_entry_gpregs,
+		      CTX_GPREG_X0,
+		      psci_ns_entry_info[index].context_id);
+
+	/*
+	 * Tell the context management library to setup EL3 system registers to
+	 * be able to ERET into the ns state, and SP_EL3 points to the right
+	 * context to exit from EL3 correctly.
+	 */
+	cm_set_el3_eret_context(NON_SECURE,
+			psci_ns_entry_info[index].eret_info.entrypoint,
+			psci_ns_entry_info[index].eret_info.spsr,
+			scr);
+
+	cm_set_next_eret_context(NON_SECURE);
 }
 
 /*******************************************************************************
@@ -344,7 +351,7 @@ int psci_set_ns_entry_info(unsigned int index,
 		 */
 		spsr |= DAIF_ABT_BIT | DAIF_IRQ_BIT | DAIF_FIQ_BIT;
 		spsr <<= PSR_DAIF_SHIFT;
-		if(ee)
+		if (ee)
 			spsr |= SPSR32_EE_BIT;
 		spsr |= mode;
 
@@ -500,7 +507,7 @@ void psci_afflvl_power_on_finish(unsigned long mpidr,
 	mpidr_aff_map_nodes mpidr_nodes;
 	int rc;
 
-	mpidr &= MPIDR_AFFINITY_MASK;;
+	mpidr &= MPIDR_AFFINITY_MASK;
 
 	/*
 	 * Collect the pointers to the nodes in the topology tree for
diff --git a/common/psci/psci_entry.S b/common/psci/psci_entry.S
index 28a4143..15e074c 100644
--- a/common/psci/psci_entry.S
+++ b/common/psci/psci_entry.S
@@ -34,6 +34,7 @@
 #include <psci_private.h>
 #include <runtime_svc.h>
 #include <asm_macros.S>
+#include <cm_macros.S>
 
 	.globl	psci_aff_on_finish_entry
 	.globl	psci_aff_suspend_finish_entry
@@ -74,6 +75,13 @@ psci_aff_common_finish_entry:
 	msr	vbar_el3, x0
 	isb
 
+	/* ---------------------------------------------
+	 * Use SP_EL0 for the C runtime stack.
+	 * ---------------------------------------------
+	 */
+	msr	spsel, #0
+	isb
+
 	bl	read_mpidr
 	mov	x19, x0
 	bl	platform_set_coherent_stack
@@ -102,31 +110,19 @@ psci_aff_common_finish_entry:
 	bl	platform_set_stack
 
 	/* ---------------------------------------------
-	 * Now that the execution stack has been set
+	 * Now that the context management has been set
 	 * up, enable full runtime exception handling.
-	 * Since we're just about to leave this EL with
-	 * ERET, we don't need an ISB here
+	 * SP_EL3 is pointing to a 'cpu_context'
+	 * structure which has an exception stack
+	 * allocated. Since we're just about to leave
+	 * this EL with ERET, we don't need an ISB here
 	 * ---------------------------------------------
 	 */
 	adr	x0, runtime_exceptions
 	msr	vbar_el3, x0
 
-	/* --------------------------------------------
-	 * Use the size of the general purpose register
-	 * context to restore the register state
-	 * stashed by earlier code
-	 * --------------------------------------------
-	 */
-	sub	sp, sp, #SIZEOF_GPREGS
-	exception_exit	restore_regs
-
-	/* --------------------------------------------
-	 * Jump back to the non-secure world assuming
-	 * that the elr and spsr setup has been done
-	 * by the finishers
-	 * --------------------------------------------
-	 */
-	eret
+	zero_callee_saved_regs
+	b	el3_exit
 _panic:
 	b	_panic
 
diff --git a/common/psci/psci_main.c b/common/psci/psci_main.c
index a70a21a..67f189d 100644
--- a/common/psci/psci_main.c
+++ b/common/psci/psci_main.c
@@ -35,6 +35,9 @@
 #include <console.h>
 #include <platform.h>
 #include <psci_private.h>
+#include <runtime_svc.h>
+#include <debug.h>
+#include <context_mgmt.h>
 
 /*******************************************************************************
  * PSCI frontend api for servicing SMCs. Described in the PSCI spec.
@@ -199,3 +202,70 @@ void psci_system_reset(void)
 	assert(0);
 }
 
+/*******************************************************************************
+ * PSCI top level handler for servicing SMCs.
+ ******************************************************************************/
+uint64_t psci_smc_handler(uint32_t smc_fid,
+			  uint64_t x1,
+			  uint64_t x2,
+			  uint64_t x3,
+			  uint64_t x4,
+			  void *cookie,
+			  void *handle,
+			  uint64_t flags)
+{
+	uint64_t rc;
+
+	switch (smc_fid) {
+	case PSCI_VERSION:
+		rc = psci_version();
+		break;
+
+	case PSCI_CPU_OFF:
+		rc = __psci_cpu_off();
+		break;
+
+	case PSCI_CPU_SUSPEND_AARCH64:
+	case PSCI_CPU_SUSPEND_AARCH32:
+		rc = __psci_cpu_suspend(x1, x2, x3);
+		break;
+
+	case PSCI_CPU_ON_AARCH64:
+	case PSCI_CPU_ON_AARCH32:
+		rc = psci_cpu_on(x1, x2, x3);
+		break;
+
+	case PSCI_AFFINITY_INFO_AARCH32:
+	case PSCI_AFFINITY_INFO_AARCH64:
+		rc = psci_affinity_info(x1, x2);
+		break;
+
+	case PSCI_MIG_AARCH32:
+	case PSCI_MIG_AARCH64:
+		rc = psci_migrate(x1);
+		break;
+
+	case PSCI_MIG_INFO_TYPE:
+		rc = psci_migrate_info_type();
+		break;
+
+	case PSCI_MIG_INFO_UP_CPU_AARCH32:
+	case PSCI_MIG_INFO_UP_CPU_AARCH64:
+		rc = psci_migrate_info_up_cpu();
+		break;
+
+	case PSCI_SYSTEM_OFF:
+		psci_system_off();
+		assert(0);
+
+	case PSCI_SYSTEM_RESET:
+		psci_system_reset();
+		assert(0);
+
+	default:
+		rc = SMC_UNK;
+		WARN("Unimplemented psci call -> 0x%x \n", smc_fid);
+	}
+
+	SMC_RET1(handle, rc);
+}
diff --git a/common/psci/psci_private.h b/common/psci/psci_private.h
index de9c291..3d7ae74 100644
--- a/common/psci/psci_private.h
+++ b/common/psci/psci_private.h
@@ -151,6 +151,16 @@ extern int psci_afflvl_suspend(unsigned long,
 			       int,
 			       int);
 extern unsigned int psci_afflvl_suspend_finish(unsigned long, int, int);
+
+/* Private exported functions from psci_main.c */
+extern uint64_t psci_smc_handler(uint32_t smc_fid,
+				 uint64_t x1,
+				 uint64_t x2,
+				 uint64_t x3,
+				 uint64_t x4,
+				 void *cookie,
+				 void *handle,
+				 uint64_t flags);
 #endif /*__ASSEMBLY__*/
 
 #endif /* __PSCI_PRIVATE_H__ */
diff --git a/common/psci/psci_setup.c b/common/psci/psci_setup.c
index c471d1f..8d7903c 100644
--- a/common/psci/psci_setup.c
+++ b/common/psci/psci_setup.c
@@ -195,6 +195,9 @@ static void psci_init_aff_map_node(unsigned long mpidr,
 		cm_set_context(mpidr,
 				(void *) &psci_ns_context[linear_id],
 				NON_SECURE);
+
+		/* Initialize exception stack in the context */
+		cm_init_exception_stack(mpidr, NON_SECURE);
 	}
 
 	return;
@@ -348,5 +351,5 @@ DECLARE_RT_SVC(
 		OEN_STD_END,
 		SMC_TYPE_FAST,
 		psci_setup,
-		NULL
+		psci_smc_handler
 );
diff --git a/common/runtime_svc.c b/common/runtime_svc.c
index 0ea1bf5..6e8a1bb 100644
--- a/common/runtime_svc.c
+++ b/common/runtime_svc.c
@@ -41,6 +41,7 @@
 #include <runtime_svc.h>
 #include <context.h>
 #include <debug.h>
+#include <context_mgmt.h>
 
 /*******************************************************************************
  * The 'rt_svc_descs' array holds the runtime service descriptors exported by
@@ -146,7 +147,7 @@ error:
 
 void fault_handler(void *handle)
 {
-	gp_regs_next *gpregs_ctx = get_gpregs_ctx(handle);
+	gp_regs *gpregs_ctx = get_gpregs_ctx(handle);
 	ERROR("Unhandled synchronous fault. Register dump @ 0x%x \n",
 	      gpregs_ctx);
 	panic();
diff --git a/include/aarch64/arch.h b/include/aarch64/arch.h
index e8773d9..69926a3 100644
--- a/include/aarch64/arch.h
+++ b/include/aarch64/arch.h
@@ -320,7 +320,7 @@ extern void runtime_exceptions(void);
 extern void bl1_arch_setup(void);
 extern void bl2_arch_setup(void);
 extern void bl31_arch_setup(void);
-
+extern void bl31_arch_next_el_setup(void);
 #endif /*__ASSEMBLY__*/
 
 #endif /* __ARCH_H__ */
diff --git a/include/asm_macros.S b/include/asm_macros.S
index 9de135c..decef0b 100644
--- a/include/asm_macros.S
+++ b/include/asm_macros.S
@@ -54,18 +54,6 @@
 	.endm
 
 
-	.macro	exception_entry  func
-	stp	x29, x30, [sp, #-(SIZEOF_GPREGS - GPREGS_FP_OFF)]!
-	bl	\func
-	.endm
-
-
-	.macro	exception_exit  func
-	bl	\func
-	ldp	x29, x30, [sp], #(SIZEOF_GPREGS - GPREGS_FP_OFF)
-	.endm
-
-
 	.macro	smc_check  label
 	bl	read_esr
 	ubfx	x0, x0, #ESR_EC_SHIFT, #ESR_EC_LENGTH
diff --git a/include/context.h b/include/context.h
index 1c1a3a2..082e511 100644
--- a/include/context.h
+++ b/include/context.h
@@ -193,7 +193,7 @@
  * callee saved registers if used by the C runtime and the assembler
  * does not touch the remaining.
  */
-DEFINE_REG_STRUCT(gp_regs_next, CTX_GPREG_ALL);
+DEFINE_REG_STRUCT(gp_regs, CTX_GPREG_ALL);
 
 /*
  * AArch64 EL1 system register context structure for preserving the
@@ -233,7 +233,7 @@ DEFINE_REG_STRUCT(el3_state, CTX_EL3STATE_ALL);
  * correspond to either the secure or the non-secure state.
  */
 typedef struct {
-	gp_regs_next gpregs_ctx;
+	gp_regs gpregs_ctx;
 	el3_state el3state_ctx;
 	el1_sys_regs sysregs_ctx;
 	fp_regs fpregs_ctx;
diff --git a/include/context_mgmt.h b/include/context_mgmt.h
index 2150a55..b8c8077 100644
--- a/include/context_mgmt.h
+++ b/include/context_mgmt.h
@@ -46,6 +46,9 @@ extern void cm_el3_sysregs_context_save(uint32_t security_state);
 extern void cm_el3_sysregs_context_restore(uint32_t security_state);
 extern void cm_el1_sysregs_context_save(uint32_t security_state);
 extern void cm_el1_sysregs_context_restore(uint32_t security_state);
+extern void cm_set_el3_eret_context(uint32_t security_state, uint64_t entrypoint,
+		uint32_t spsr, uint32_t scr);
 extern void cm_set_next_eret_context(uint32_t security_state);
+extern void cm_init_exception_stack(uint64_t mpidr, uint32_t security_state);
 #endif /*__ASSEMBLY__*/
 #endif /* __CM_H__ */
diff --git a/include/runtime_svc.h b/include/runtime_svc.h
index 3ee043e..ad202a9 100644
--- a/include/runtime_svc.h
+++ b/include/runtime_svc.h
@@ -101,43 +101,8 @@
 #define SERROR_AARCH32			0xf
 
 /*******************************************************************************
- * Constants that allow assembler code to access members of the 'gp_regs'
- * structure at their correct offsets.
+ * Structure definition, typedefs & constants for the runtime service framework
  ******************************************************************************/
-#define SIZEOF_GPREGS		0x110
-#define GPREGS_X0_OFF		0x0
-#define GPREGS_X1_OFF		0x8
-#define GPREGS_X2_OFF		0x10
-#define GPREGS_X3_OFF		0x18
-#define GPREGS_X4_OFF		0x20
-#define GPREGS_X5_OFF		0x28
-#define GPREGS_X6_OFF		0x30
-#define GPREGS_X7_OFF		0x38
-#define GPREGS_X8_OFF		0x40
-#define GPREGS_X9_OFF		0x48
-#define GPREGS_X10_OFF		0x50
-#define GPREGS_X11_OFF		0x58
-#define GPREGS_X12_OFF		0x60
-#define GPREGS_X13_OFF		0x68
-#define GPREGS_X14_OFF		0x70
-#define GPREGS_X15_OFF		0x78
-#define GPREGS_X16_OFF		0x80
-#define GPREGS_X17_OFF		0x88
-#define GPREGS_X18_OFF		0x90
-#define GPREGS_X19_OFF		0x98
-#define GPREGS_X20_OFF		0xA0
-#define GPREGS_X21_OFF		0xA8
-#define GPREGS_X22_OFF		0xB0
-#define GPREGS_X23_OFF		0xB8
-#define GPREGS_X24_OFF		0xC0
-#define GPREGS_X25_OFF		0xC8
-#define GPREGS_X26_OFF		0xD0
-#define GPREGS_X27_OFF		0xD8
-#define GPREGS_X28_OFF		0xE0
-#define GPREGS_SP_EL0_OFF	0xE8
-#define GPREGS_SPSR_OFF		0xF0
-#define GPREGS_FP_OFF		0x100
-#define GPREGS_LR_OFF		0x108
 
 /*
  * Constants to allow the assembler access a runtime service
@@ -219,46 +184,6 @@ typedef uint64_t (*rt_svc_handle)(uint32_t smc_fid,
 				  void *handle,
 				  uint64_t flags);
 typedef struct {
-	uint64_t x0;
-	uint64_t x1;
-	uint64_t x2;
-	uint64_t x3;
-	uint64_t x4;
-	uint64_t x5;
-	uint64_t x6;
-	uint64_t x7;
-	uint64_t x8;
-	uint64_t x9;
-	uint64_t x10;
-	uint64_t x11;
-	uint64_t x12;
-	uint64_t x13;
-	uint64_t x14;
-	uint64_t x15;
-	uint64_t x16;
-	uint64_t x17;
-	uint64_t x18;
-	uint64_t x19;
-	uint64_t x20;
-	uint64_t x21;
-	uint64_t x22;
-	uint64_t x23;
-	uint64_t x24;
-	uint64_t x25;
-	uint64_t x26;
-	uint64_t x27;
-	uint64_t x28;
-	uint64_t sp_el0;
-	uint32_t spsr;
-	/*
-	 * Alignment constraint which allows save & restore of fp & lr on the
-	 * stack during exception handling
-	 */
-	uint64_t fp __aligned(16);
-	uint64_t lr;
-} __aligned(16) gp_regs;
-
-typedef struct {
 	uint8_t start_oen;
 	uint8_t end_oen;
 	uint8_t call_type;
@@ -280,16 +205,6 @@ typedef struct {
 			_setup, \
 			_smch }
 
-/*******************************************************************************
- * Compile time assertions to ensure that:
- * 1)  the assembler code's view of the size of the 'gp_regs' data structure is
- *     the same as the actual size of this data structure.
- * 2)  the assembler code's view of the offset of the frame pointer member of
- *     the 'gp_regs' structure is the same as the actual offset of this member.
- ******************************************************************************/
-CASSERT((sizeof(gp_regs) == SIZEOF_GPREGS), assert_sizeof_gpregs_mismatch);
-CASSERT(GPREGS_FP_OFF == __builtin_offsetof(gp_regs, fp), \
-	assert_gpregs_fp_offset_mismatch);
 /*
  * Compile time assertions related to the 'rt_svc_desc' structure to:
  * 1. ensure that the assembler and the compiler view of the size
@@ -323,6 +238,7 @@ CASSERT(RT_SVC_DESC_HANDLE == __builtin_offsetof(rt_svc_desc, handle), \
 extern void runtime_svc_init();
 extern uint64_t __RT_SVC_DESCS_START__;
 extern uint64_t __RT_SVC_DESCS_END__;
-
+extern uint64_t get_exception_stack(uint64_t mpidr);
+extern void fault_handler(void *handle);
 #endif /*__ASSEMBLY__*/
 #endif /* __RUNTIME_SVC_H__ */
diff --git a/lib/arch/aarch64/misc_helpers.S b/lib/arch/aarch64/misc_helpers.S
index 37258e1..324be76 100644
--- a/lib/arch/aarch64/misc_helpers.S
+++ b/lib/arch/aarch64/misc_helpers.S
@@ -31,9 +31,6 @@
 #include <arch_helpers.h>
 #include <runtime_svc.h>
 
-	.globl	save_regs
-	.globl	restore_regs
-
 	.globl	enable_irq
 	.globl	disable_irq
 
@@ -84,51 +81,6 @@
 
 	.section	.text, "ax"
 
-save_regs: ; .type save_regs, %function
-	sub	sp, sp, #GPREGS_FP_OFF
-	stp	x0, x1, [sp, #GPREGS_X0_OFF]
-	stp	x2, x3, [sp, #GPREGS_X2_OFF]
-	stp	x4, x5, [sp, #GPREGS_X4_OFF]
-	stp	x6, x7, [sp, #GPREGS_X6_OFF]
-	stp	x8, x9, [sp, #GPREGS_X8_OFF]
-	stp	x10, x11, [sp, #GPREGS_X10_OFF]
-	stp	x12, x13, [sp, #GPREGS_X12_OFF]
-	stp	x14, x15, [sp, #GPREGS_X14_OFF]
-	stp	x16, x17, [sp, #GPREGS_X16_OFF]
-	stp	x18, x19, [sp, #GPREGS_X18_OFF]
-	stp	x20, x21, [sp, #GPREGS_X20_OFF]
-	stp	x22, x23, [sp, #GPREGS_X22_OFF]
-	stp	x24, x25, [sp, #GPREGS_X24_OFF]
-	stp	x26, x27, [sp, #GPREGS_X26_OFF]
-	mrs     x0, sp_el0
-	stp	x28, x0, [sp, #GPREGS_X28_OFF]
-	mrs     x0, spsr_el3
-	str	w0, [sp, #GPREGS_SPSR_OFF]
-	ret
-
-
-restore_regs: ; .type restore_regs, %function
-	ldr	w9, [sp, #GPREGS_SPSR_OFF]
-	msr	spsr_el3, x9
-	ldp	x28, x9, [sp, #GPREGS_X28_OFF]
-	msr	sp_el0, x9
-	ldp	x26, x27, [sp, #GPREGS_X26_OFF]
-	ldp	x24, x25, [sp, #GPREGS_X24_OFF]
-	ldp	x22, x23, [sp, #GPREGS_X22_OFF]
-	ldp	x20, x21, [sp, #GPREGS_X20_OFF]
-	ldp	x18, x19, [sp, #GPREGS_X18_OFF]
-	ldp	x16, x17, [sp, #GPREGS_X16_OFF]
-	ldp	x14, x15, [sp, #GPREGS_X14_OFF]
-	ldp	x12, x13, [sp, #GPREGS_X12_OFF]
-	ldp	x10, x11, [sp, #GPREGS_X10_OFF]
-	ldp	x8, x9, [sp, #GPREGS_X8_OFF]
-	ldp	x6, x7, [sp, #GPREGS_X6_OFF]
-	ldp	x4, x5, [sp, #GPREGS_X4_OFF]
-	ldp	x2, x3, [sp, #GPREGS_X2_OFF]
-	ldp	x0, x1, [sp, #GPREGS_X0_OFF]
-	add	sp, sp, #GPREGS_FP_OFF
-	ret
-
 get_afflvl_shift: ; .type get_afflvl_shift, %function
 	cmp	x0, #3
 	cinc	x0, x0, eq