From 2cee0669299cd2b980aa9ae253c24107a4813b26 Mon Sep 17 00:00:00 2001
From: Bin Lu <bin.lu@arm.com>
Date: Thu, 26 Sep 2019 06:09:32 +0000
Subject: enable ring0 to support arm64

This patch enabled the basic framework for arm64 guest.

Serveral jobs were finished in this patch:
1, ring0.Vectors()
2, switchToUser()
3, basic framwork for Arm64 guest.

Signed-off-by: Bin Lu <bin.lu@arm.com>
---
 pkg/sentry/platform/ring0/kernel_arm64.go | 58 +++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 pkg/sentry/platform/ring0/kernel_arm64.go

(limited to 'pkg/sentry/platform/ring0/kernel_arm64.go')

diff --git a/pkg/sentry/platform/ring0/kernel_arm64.go b/pkg/sentry/platform/ring0/kernel_arm64.go
new file mode 100644
index 000000000..ed82a131e
--- /dev/null
+++ b/pkg/sentry/platform/ring0/kernel_arm64.go
@@ -0,0 +1,58 @@
+// Copyright 2019 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build arm64
+
+package ring0
+
+// init initializes architecture-specific state.
+func (k *Kernel) init(opts KernelOpts) {
+	// Save the root page tables.
+	k.PageTables = opts.PageTables
+}
+
+// init initializes architecture-specific state.
+func (c *CPU) init() {
+	// Set the kernel stack pointer(virtual address).
+	c.registers.Sp = uint64(c.StackTop())
+
+}
+
+// StackTop returns the kernel's stack address.
+//
+//go:nosplit
+func (c *CPU) StackTop() uint64 {
+	return uint64(kernelAddr(&c.stack[0])) + uint64(len(c.stack))
+}
+
+// IsCanonical indicates whether addr is canonical per the arm64 spec.
+//
+//go:nosplit
+func IsCanonical(addr uint64) bool {
+	return addr <= 0x0000ffffffffffff || addr > 0xffff000000000000
+}
+
+//go:nosplit
+func (c *CPU) SwitchToUser(switchOpts SwitchOpts) (vector Vector) {
+	// Sanitize registers.
+	regs := switchOpts.Registers
+
+	regs.Pstate &= ^uint64(UserFlagsClear)
+	regs.Pstate |= UserFlagsSet
+	kernelExitToEl0()
+	vector = c.vecCode
+
+	// Perform the switch.
+	return
+}
-- 
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