Add support for the 32 Bit Arm architectures.

Author: dinkelhacker

Makefile

@@ -1,16 +1,20 @@
 TARGET_AARCH64 := aarch64-unknown-none-softfloat
+TARGET_AARCH32 := thumbv7em-none-eabi
 LINKER_SCRIPT_AARCH64 := tests/aarch64_raspi3/link.ld
+LINKER_SCRIPT_AARCH32 := tests/armv7m_mps2an500/link.ld
 
 TARGET_RISCV64 := riscv64gc-unknown-none-elf
 LINKER_SCRIPT_RISCV64 := tests/riscv64_virt/link.ld
 
 default:
 	cargo build --target $(TARGET_AARCH64) --release
+	cargo build --target $(TARGET_AARCH32) --release
 	cargo build --target $(TARGET_RISCV64) --release
 	cargo build --release
 
 clippy:
 	cargo clippy --target $(TARGET_AARCH64)
+	cargo clippy --target $(TARGET_AARCH32)
 	cargo clippy --target $(TARGET_RISCV64)
 	cargo clippy
 
@@ -19,6 +23,10 @@ test:
                 cargo test \
                 --target $(TARGET_AARCH64) \
                 --release
+	RUSTFLAGS="-C link-arg=-T$(LINKER_SCRIPT_AARCH32) -Clink-args=-Map=/tmp/qemuexit-mapfile.map" \
+                cargo test \
+                --target $(TARGET_AARCH32) \
+                --release
 	RUSTFLAGS="-C link-arg=-T$(LINKER_SCRIPT_RISCV64)" \
                 cargo test \
                 --target $(TARGET_RISCV64) \

README.md

@@ -35,11 +35,13 @@ qemu_exit_handle.exit_failure();
 
 ## Architecture Specific Configuration
 
-### AArch64
+### AArch64/AArch32
 
 Pass the `-semihosting` argument to the QEMU invocation, e.g.:
 ```
 qemu-system-aarch64 -M raspi3 -serial stdio -semihosting -kernel kernel8.img
+qemu-system-arm -nographic -M mps2-an500 -cpu cortex-m7 -serial mon:stdio -semihosting -kernel
+kernel.img
 ```
 
 ### RISCV64

src/aarch32.rs

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+//
+// Copyright (c) 2024 Philipp Schulz <[email protected]>
+
+//! AArch32.
+
+use crate::QEMUExit;
+use core::arch::asm;
+
+const EXIT_SUCCESS: u32 = 0;
+const EXIT_FAILURE: u32 = 1;
+
+#[allow(non_upper_case_globals)]
+const ADP_Stopped_ApplicationExit: u32 = 0x20026;
+
+/// The parameter block layout that is expected by QEMU.
+///
+/// If QEMU finds `ADP_Stopped_ApplicationExit` in the first parameter, it uses the second parameter
+/// as exit code.
+///
+/// If first paraemter != `ADP_Stopped_ApplicationExit`, exit code `1` is used.
+#[repr(C)]
+struct QEMUParameterBlock {
+    arg0: u32,
+    arg1: u32,
+}
+
+/// AArch32 configuration.
+pub struct AArch32 {}
+
+/// A Semihosting call using `0x20` - `SYS_EXIT_EXTENDED`.
+fn semihosting_sys_exit_call(block: &QEMUParameterBlock) -> ! {
+    unsafe {
+        asm!(
+            "bkpt #0xab",
+            in("r0") 0x20,
+            in("r1") block as *const _ as u32,
+            options(nostack)
+        );
+
+        // For the case that the QEMU exit attempt did not work, transition into an infinite loop.
+        // Calling `panic!()` here is unfeasible, since there is a good chance this function here is
+        // the last expression in the `panic!()` handler itself. This prevents a possible
+        // infinite loop.
+        loop {
+            asm!("wfe", options(nomem, nostack));
+        }
+    }
+}
+
+impl AArch32 {
+    /// Create an instance.
+    pub const fn new() -> Self {
+        AArch32 {}
+    }
+}
+
+impl QEMUExit for AArch32 {
+    fn exit(&self, code: u32) -> ! {
+        let block = QEMUParameterBlock {
+            arg0: ADP_Stopped_ApplicationExit,
+            arg1: code as u32,
+        };
+
+        semihosting_sys_exit_call(&block)
+    }
+
+    fn exit_success(&self) -> ! {
+        self.exit(EXIT_SUCCESS)
+    }
+
+    fn exit_failure(&self) -> ! {
+        self.exit(EXIT_FAILURE)
+    }
+}

src/lib.rs

@@ -15,6 +15,9 @@
 //! #[cfg(target_arch = "aarch64")]
 //! let qemu_exit_handle = qemu_exit::AArch64::new();
 //!
+//! #[cfg(target_arch = "arm")]
+//! let qemu_exit_handle = qemu_exit::Aarch32::new();
+//!
 //! // addr: The address of sifive_test.
 //! #[cfg(target_arch = "riscv64")]
 //! let qemu_exit_handle = qemu_exit::RISCV64::new(addr);
@@ -36,6 +39,15 @@
 //! Pass the `-semihosting` argument to the QEMU invocation, e.g.:
 //! ```
 //! qemu-system-aarch64 -M raspi3 -serial stdio -semihosting -kernel kernel8.img
+//!
+//! ```
+//!
+//! ### AArch32
+//!
+//! Pass the `-semihosting` argument to the QEMU invocation, e.g.:
+//! ```
+//! qemu-system-arm -m 16M -nographic -M mps2-an500 -cpu cortex-m7 -serial mon:stdio -semihosting -kernel kernel.img
+//!
 //! ```
 //!
 //! ### RISCV64
@@ -78,6 +90,12 @@ pub mod aarch64;
 #[cfg(target_arch = "aarch64")]
 pub use aarch64::*;
 
+#[cfg(target_arch = "arm")]
+pub mod aarch32;
+
+#[cfg(target_arch = "arm")]
+pub use aarch32::*;
+
 #[cfg(target_arch = "riscv64")]
 pub mod riscv64;
 

tests/armv7m_mps2an500/link.ld

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: MIT OR Apache-2.0
+ *
+ * Copyright (c) 2024 Philipp Schulz <[email protected]>
+ */
+ENTRY(_vectors)
+
+SECTIONS
+{
+    . = 0x0;
+    .boot :
+    {
+        KEEP(*(.text.boot))
+        KEEP(*(.data.boot))
+    }
+
+    .text :
+    {
+        *(.vectors)
+        *(.text._start)
+        *(.text)
+    }
+}

tests/armv7m_mps2an500/mod.rs

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
+//
+// Copyright (c) 2024 Philipp Schulz <[email protected]>
+
+//! AArch32 specific setup code.
+
+use core::arch::global_asm;
+
+global_asm!(
+    include_str!("./startup.S")
+);
+
+#[no_mangle]
+extern "C" fn entry() {
+    super::test_main()
+}

tests/armv7m_mps2an500/startup.S

@@ -0,0 +1,12 @@
+.section ".text.boot","ax"
+
+.thumb
+.thumb_func
+.globl _vectors
+_vectors:
+.word 0x2000
+.word reset
+
+.thumb_func
+reset:
+    bl entry

tests/exit_13.rs

@@ -20,6 +20,16 @@ const QEMU_EXIT_HANDLE: qemu_exit::AArch64 = qemu_exit::AArch64::new();
 #[cfg(target_arch = "aarch64")]
 mod aarch64_raspi3;
 
+//--------------------------------------------------------------------------------------------------
+// Aarch32
+//--------------------------------------------------------------------------------------------------
+
+#[cfg(target_arch = "arm")]
+const QEMU_EXIT_HANDLE: qemu_exit::AArch32 = qemu_exit::AArch32::new();
+
+#[cfg(target_arch = "arm")]
+mod armv7m_mps2an500;
+
 //--------------------------------------------------------------------------------------------------
 // RISCV64
 //--------------------------------------------------------------------------------------------------

tests/test_runner_wrapper.sh

@@ -1,9 +1,11 @@
 #!/usr/bin/env bash
 
 TIMEOUT="timeout 10"
-
 if [[ $1 == *"aarch64"* ]]; then
     $TIMEOUT qemu-system-aarch64 -M raspi3b -display none -semihosting -kernel $1
+elif [[ $1 == *"thumbv7em"* ]]; then
+    arm-none-eabi-objcopy -O binary $1 /tmp/qemu_exit_armv7em.bin
+    qemu-system-arm -m 16M -nographic -M mps2-an500 -cpu cortex-m7 -serial mon:stdio -semihosting -kernel /tmp/qemu_exit_armv7em.bin
 elif [[ $1 == *"riscv64"* ]]; then
     $TIMEOUT qemu-system-riscv64 -M virt -bios tests/riscv64_virt/fw_jump.elf -display none -kernel $1
 fi