pvmfw: Move aarch64 exceptions handling to new `arch` module

Due to incoming changes in libvmbase and pvmfw that will introduce new CPU architecture, there is necessary to separate code basing on platform. To achieve this new module/directory `arch` is introduced by this commit. This new module should be used as split point between architectures - new platform specific code should be only added behind `arch` module and exposed in platform independent way to the rest of the program.

Bug: 362733888
Test: m pvmfw

Change-Id: Ife352453563232d8313061a1ada844b01011a9bc
diff --git a/guest/pvmfw/src/arch/aarch64.rs b/guest/pvmfw/src/arch/aarch64.rs
new file mode 100644
index 0000000..8e7126d
--- /dev/null
+++ b/guest/pvmfw/src/arch/aarch64.rs
@@ -0,0 +1,17 @@
+// Copyright 2024, The Android Open Source Project
+//
+// 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.
+
+//! aarch64 platform specific code
+
+pub mod exceptions;
diff --git a/guest/pvmfw/src/arch/aarch64/exceptions.rs b/guest/pvmfw/src/arch/aarch64/exceptions.rs
new file mode 100644
index 0000000..4c867fb
--- /dev/null
+++ b/guest/pvmfw/src/arch/aarch64/exceptions.rs
@@ -0,0 +1,95 @@
+// Copyright 2022, The Android Open Source Project
+//
+// 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.
+
+//! Exception handlers.
+
+use vmbase::{
+    arch::aarch64::exceptions::{
+        handle_permission_fault, handle_translation_fault, ArmException, Esr, HandleExceptionError,
+    },
+    eprintln, logger,
+    power::reboot,
+    read_sysreg,
+};
+
+fn handle_exception(exception: &ArmException) -> Result<(), HandleExceptionError> {
+    // Handle all translation faults on both read and write, and MMIO guard map
+    // flagged invalid pages or blocks that caused the exception.
+    // Handle permission faults for DBM flagged entries, and flag them as dirty on write.
+    match exception.esr {
+        Esr::DataAbortTranslationFault => handle_translation_fault(exception.far),
+        Esr::DataAbortPermissionFault => handle_permission_fault(exception.far),
+        _ => Err(HandleExceptionError::UnknownException),
+    }
+}
+
+#[no_mangle]
+extern "C" fn sync_exception_current(elr: u64, _spsr: u64) {
+    // Disable logging in exception handler to prevent unsafe writes to UART.
+    let _guard = logger::suppress();
+
+    let exception = ArmException::from_el1_regs();
+    if let Err(e) = handle_exception(&exception) {
+        exception.print("sync_exception_current", e, elr);
+        reboot()
+    }
+}
+
+#[no_mangle]
+extern "C" fn irq_current(_elr: u64, _spsr: u64) {
+    eprintln!("irq_current");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn fiq_current(_elr: u64, _spsr: u64) {
+    eprintln!("fiq_current");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn serr_current(_elr: u64, _spsr: u64) {
+    let esr = read_sysreg!("esr_el1");
+    eprintln!("serr_current");
+    eprintln!("esr={esr:#08x}");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn sync_lower(_elr: u64, _spsr: u64) {
+    let esr = read_sysreg!("esr_el1");
+    eprintln!("sync_lower");
+    eprintln!("esr={esr:#08x}");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn irq_lower(_elr: u64, _spsr: u64) {
+    eprintln!("irq_lower");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn fiq_lower(_elr: u64, _spsr: u64) {
+    eprintln!("fiq_lower");
+    reboot();
+}
+
+#[no_mangle]
+extern "C" fn serr_lower(_elr: u64, _spsr: u64) {
+    let esr = read_sysreg!("esr_el1");
+    eprintln!("serr_lower");
+    eprintln!("esr={esr:#08x}");
+    reboot();
+}