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From ce628de7699dd6401ddf713efaa49872e2733619 Mon Sep 17 00:00:00 2001
From: Jaxson Han <jaxson.han@arm.com>
Date: Tue, 25 May 2021 07:25:00 +0100
Subject: [PATCH] aarch64: Prepare for lower EL booting
Save SPSR_KERNEL into spsr_to_elx during el3_init.
The jump_kernel will load spsr_to_elx into spsr_el3.
This change will make it easier to control whether drop to lower EL
before jumping to the kernel.
Upstream-Status: Pending
Signed-off-by: Jaxson Han <jaxson.han@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
---
arch/aarch64/boot.S | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/aarch64/boot.S b/arch/aarch64/boot.S
index b589744..6b45afc 100644
--- a/arch/aarch64/boot.S
+++ b/arch/aarch64/boot.S
@@ -130,7 +130,16 @@ el3_init:
mov x0, #ZCR_EL3_LEN_MASK // SVE: Enable full vector len
msr ZCR_EL3, x0 // for EL2.
-1:
+ /*
+ * Save SPSR_KERNEL into spsr_to_elx.
+ * The jump_kernel will load spsr_to_elx into spsr_el3
+ */
+1: mov w0, #SPSR_KERNEL
+ ldr x1, =spsr_to_elx
+ str w0, [x1]
+ b el_max_init
+
+el_max_init:
ldr x0, =COUNTER_FREQ
msr cntfrq_el0, x0
@@ -178,7 +187,7 @@ ASM_FUNC(jump_kernel)
b.eq 1f
br x19 // Keep current 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
@@ -196,3 +205,5 @@ ASM_FUNC(jump_kernel)
.align 3
flag_keep_el:
.long 0
+spsr_to_elx:
+ .long 0
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