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-rw-r--r--arch/arm/cpu/armv8/transition.S83
1 files changed, 83 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S
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+++ b/arch/arm/cpu/armv8/transition.S
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+/*
+ * (C) Copyright 2013
+ * David Feng <fenghua@phytium.com.cn>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm-offsets.h>
+#include <config.h>
+#include <version.h>
+#include <linux/linkage.h>
+#include <asm/macro.h>
+
+ENTRY(armv8_switch_to_el2)
+ switch_el x0, 1f, 0f, 0f
+0: ret
+1:
+ mov x0, #0x5b1 /* Non-secure EL0/EL1 | HVC | 64bit EL2 */
+ msr scr_el3, x0
+ msr cptr_el3, xzr /* Disable coprocessor traps to EL3 */
+ mov x0, #0x33ff
+ msr cptr_el2, x0 /* Disable coprocessor traps to EL2 */
+
+ /* Initialize SCTLR_EL2 */
+ msr sctlr_el2, xzr
+
+ /* Return to the EL2_SP2 mode from EL3 */
+ mov x0, sp
+ msr sp_el2, x0 /* Migrate SP */
+ mrs x0, vbar_el3
+ msr vbar_el2, x0 /* Migrate VBAR */
+ mov x0, #0x3c9
+ msr spsr_el3, x0 /* EL2_SP2 | D | A | I | F */
+ msr elr_el3, lr
+ eret
+ENDPROC(armv8_switch_to_el2)
+
+ENTRY(armv8_switch_to_el1)
+ switch_el x0, 0f, 1f, 0f
+0: ret
+1:
+ /* Initialize Generic Timers */
+ mrs x0, cnthctl_el2
+ orr x0, x0, #0x3 /* Enable EL1 access to timers */
+ msr cnthctl_el2, x0
+ msr cntvoff_el2, x0
+ mrs x0, cntkctl_el1
+ orr x0, x0, #0x3 /* Enable EL0 access to timers */
+ msr cntkctl_el1, x0
+
+ /* Initilize MPID/MPIDR registers */
+ mrs x0, midr_el1
+ mrs x1, mpidr_el1
+ msr vpidr_el2, x0
+ msr vmpidr_el2, x1
+
+ /* Disable coprocessor traps */
+ mov x0, #0x33ff
+ msr cptr_el2, x0 /* Disable coprocessor traps to EL2 */
+ msr hstr_el2, xzr /* Disable coprocessor traps to EL2 */
+ mov x0, #3 << 20
+ msr cpacr_el1, x0 /* Enable FP/SIMD at EL1 */
+
+ /* Initialize HCR_EL2 */
+ mov x0, #(1 << 31) /* 64bit EL1 */
+ orr x0, x0, #(1 << 29) /* Disable HVC */
+ msr hcr_el2, x0
+
+ /* SCTLR_EL1 initialization */
+ mov x0, #0x0800
+ movk x0, #0x30d0, lsl #16
+ msr sctlr_el1, x0
+
+ /* Return to the EL1_SP1 mode from EL2 */
+ mov x0, sp
+ msr sp_el1, x0 /* Migrate SP */
+ mrs x0, vbar_el2
+ msr vbar_el1, x0 /* Migrate VBAR */
+ mov x0, #0x3c5
+ msr spsr_el2, x0 /* EL1_SP1 | D | A | I | F */
+ msr elr_el2, lr
+ eret
+ENDPROC(armv8_switch_to_el1)