[PATCH v2 2/6] aarch64: Prepare for lower EL booting

[Luca Fancellu]

Store the value of the initial SPSR into a variable during
EL3 initialization and load it from the variable before dropping
EL, this is done as preparation work to be able to boot from a
different exception level.

Signed-off-by: Luca Fancellu <luca.fancellu at arm.com>
Reviewed-by: Andre Przywara <andre.przywara at arm.com>
---
v2 changes:
 - add Andre R-by
---
 arch/aarch64/boot.S | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
index 7727475925c1..211077af17c8 100644
--- a/arch/aarch64/boot.S
+++ b/arch/aarch64/boot.S
@@ -51,6 +51,10 @@ reset_at_el3:
 	b.eq	err_invalid_id
 	bl	setup_stack
 
+	mov	w0, #SPSR_KERNEL
+	ldr	x1, =spsr_to_elx
+	str	w0, [x1]
+
 	bl	cpu_init_bootwrapper
 
 	bl	cpu_init_el3
@@ -135,7 +139,7 @@ ASM_FUNC(jump_kernel)
 	b.eq	1f
 	br	x19			// Keep EL
 
-1:	mov	x4, #SPSR_KERNEL
+1:	ldr	w4, spsr_to_elx
 
 	/*
 	 * If bit 0 of the kernel address is set, we're entering in AArch32
@@ -153,3 +157,5 @@ ASM_FUNC(jump_kernel)
 	.align 3
 flag_keep_el:
 	.long 0
+spsr_to_elx:
+	.long 0
-- 
2.34.1