From 38bafce42de94a7408760ccfca059b0681d77d51 Mon Sep 17 00:00:00 2001
From: Alex White <alex.white@oarcorp.com>
Date: Tue, 10 Sep 2024 10:08:07 -0500
Subject: [PATCH] Add aarch64 cpukit paravirtualization support

---
 cpukit/score/cpu/aarch64/cpu.c                |  2 +
 .../aarch64/include/rtems/score/paravirt.h    | 73 +++++++++++++++++++
 spec/build/cpukit/cpuaarch64.yml              |  1 +
 3 files changed, 76 insertions(+)
 create mode 100644 cpukit/score/cpu/aarch64/include/rtems/score/paravirt.h

diff --git a/cpukit/score/cpu/aarch64/cpu.c b/cpukit/score/cpu/aarch64/cpu.c
index b0320ad77b..88df9d6e02 100644
--- a/cpukit/score/cpu/aarch64/cpu.c
+++ b/cpukit/score/cpu/aarch64/cpu.c
@@ -146,6 +146,7 @@ void _CPU_Context_Initialize(
   }
 }
 
+#if !defined(RTEMS_PARAVIRT)
 void _CPU_ISR_Set_level( uint32_t level )
 {
   /* Set the mask bit if interrupts are disabled */
@@ -173,6 +174,7 @@ uint32_t _CPU_ISR_Get_level( void )
 
   return ( level & AARCH64_PSTATE_I ) != 0;
 }
+#endif /* RTEMS_PARAVIRT */
 
 void _CPU_Initialize( void )
 {
diff --git a/cpukit/score/cpu/aarch64/include/rtems/score/paravirt.h b/cpukit/score/cpu/aarch64/include/rtems/score/paravirt.h
new file mode 100644
index 0000000000..bbd1e0f216
--- /dev/null
+++ b/cpukit/score/cpu/aarch64/include/rtems/score/paravirt.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup RTEMSScoreCPUAArch64Paravirt
+ *
+ * @brief This header file provides definitions pertaining to
+ *   paravirtualization of the AArch64 port.
+ */
+
+/*
+ *  COPYRIGHT (c) 2023-2024.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * 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 OWNER 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.
+ */
+
+#ifndef RTEMS_PARAVIRT
+#error "This file should only be included with paravirtualization is enabled."
+#endif
+
+#ifndef _RTEMS_SCORE_PARAVIRT_H
+#define _RTEMS_SCORE_PARAVIRT_H
+
+/**
+ * @defgroup RTEMSScoreCPUAArch64Paravirt AArch64 Paravirtualization Support
+ *
+ * @ingroup RTEMSScoreCPUAArch64
+ *
+ * @brief This handler encapulates the functionality (primarily conditional
+ *        feature defines) related to paravirtualization on the AArch64.
+ *
+ * Paravirtualization on the AArch64 makes the following assumptions:
+ *
+ *   - RTEMS executes in user space (EL0)
+ *   - Interrupt enable/disable support using the MSR must be disabled
+ *     and replaced with BSP provided methods which are adapted to the
+ *     hosting environment.
+ *
+ * @{
+ */
+
+/**
+ * In a paravirtualized environment, RTEMS executes in user space
+ * and cannot disable/enable external exceptions (e.g. interrupts).
+ * The BSP which acts as an adapter to the hosting environment will
+ * provide the interrupt enable/disable methods.
+ */
+#define AARCH64_DISABLE_INLINE_ISR_DISABLE_ENABLE
+
+/** @} */
+
+#endif
diff --git a/spec/build/cpukit/cpuaarch64.yml b/spec/build/cpukit/cpuaarch64.yml
index a4ed464fa1..1c44d63739 100644
--- a/spec/build/cpukit/cpuaarch64.yml
+++ b/spec/build/cpukit/cpuaarch64.yml
@@ -26,6 +26,7 @@ install:
   - cpukit/score/cpu/aarch64/include/rtems/score/cpuimpl.h
   - cpukit/score/cpu/aarch64/include/rtems/score/aarch64.h
   - cpukit/score/cpu/aarch64/include/rtems/score/cpu_irq.h
+  - cpukit/score/cpu/aarch64/include/rtems/score/paravirt.h
 links: []
 source:
 - cpukit/score/cpu/aarch64/aarch64-context-validate.S