Merge pull request #476 from Gelbpunkt/aarch64_be-part1

Add support for aarch64_be

Author: mkroening

.github/workflows/ci.yml

@@ -42,7 +42,7 @@ jobs:
     name: Run
     strategy:
       matrix:
-        target: [x86_64, aarch64, riscv64]
+        target: [x86_64, aarch64, aarch64_be, riscv64]
         os: [ubuntu-latest, macos-latest, windows-latest]
         include:
           - target: x86_64
@@ -83,8 +83,11 @@ jobs:
       - uses: actions/checkout@v5
         with:
             lfs: true
-      - name: Install stable Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.target == 'aarch64_be' && 'nightly' || 'stable' }}
+          components: ${{ matrix.target == 'aarch64_be' && 'rust-src' || '' }}
       - name: Dowload OpenSBI
         if: matrix.target == 'riscv64'
         run: |

data/aarch64_be/hello_world

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:652a3617267de4e2dc79533188dfb35e165ca4324dd354b9ed9c434de2f6320b
+size 801232

src/arch/aarch64/entry.rs

@@ -165,10 +165,13 @@ unsafe fn pre_init() -> ! {
 			 or if loading and not setting them would be the appropriate action.
 	*/
 
+	#[cfg(target_endian = "big")]
+	let endian = SCTLR_EL1::EE::BigEndian + SCTLR_EL1::E0E::BigEndian;
+	#[cfg(target_endian = "little")]
+	let endian = SCTLR_EL1::EE::LittleEndian + SCTLR_EL1::E0E::LittleEndian;
+
 	SCTLR_EL1.write(
 		SCTLR_EL1::UCI::DontTrap
-			+ SCTLR_EL1::EE::LittleEndian
-			+ SCTLR_EL1::E0E::LittleEndian
 			+ SCTLR_EL1::WXN::Disable
 			+ SCTLR_EL1::NTWE::DontTrap
 			+ SCTLR_EL1::NTWI::DontTrap
@@ -181,7 +184,8 @@ unsafe fn pre_init() -> ! {
 			+ SCTLR_EL1::SA::Enable
 			+ SCTLR_EL1::C::Cacheable
 			+ SCTLR_EL1::A::Disable
-			+ SCTLR_EL1::M::Disable,
+			+ SCTLR_EL1::M::Disable
+			+ endian,
 	);
 
 	// Enter loader

src/arch/aarch64/link.ld

@@ -2,8 +2,6 @@
  * https://github.com/rust-embedded/rust-raspberrypi-OS-tutorials/blob/master/16_virtual_mem_part4_higher_half_kernel/src/bsp/raspberrypi/link.ld 
 */
 
-OUTPUT_FORMAT("elf64-littleaarch64")
-OUTPUT_ARCH("aarch64")
 ENTRY(_start)
 phys = 0x40200000;
 

xtask/src/ci/qemu.rs

@@ -63,8 +63,8 @@ impl Qemu {
 		}
 
 		let target = self.build.target();
-		let arch = target.arch();
-		let qemu = env::var("QEMU").unwrap_or_else(|_| format!("qemu-system-{arch}"));
+		let qemu = target.qemu();
+		let qemu = env::var("QEMU").unwrap_or_else(|_| format!("qemu-system-{qemu}"));
 		let program = if self.sudo { "sudo" } else { qemu.as_str() };
 		let arg = self.sudo.then_some(qemu.as_str());
 
@@ -96,7 +96,7 @@ impl Qemu {
 				"-append".to_string(),
 				format!("-freq {frequency}"),
 			]
-		} else if self.build.target() == Target::Aarch64 {
+		} else if matches!(self.build.target(), Target::Aarch64 | Target::Aarch64Be) {
 			vec!["-machine".to_string(), "virt,gic-version=3".to_string()]
 		} else if self.build.target() == Target::Riscv64 {
 			vec![
@@ -174,7 +174,7 @@ impl Qemu {
 				cpu_args
 			}
 			Target::X86_64Fc => panic!("unsupported"),
-			Target::Aarch64 => {
+			Target::Aarch64 | Target::Aarch64Be => {
 				let mut cpu_args = if self.accel {
 					todo!()
 				} else {
@@ -233,7 +233,7 @@ impl Qemu {
 			Target::X86_64Uefi => {
 				memory = memory.max(512);
 			}
-			Target::Aarch64 => {
+			Target::Aarch64 | Target::Aarch64Be => {
 				memory = memory.max(256);
 			}
 			Target::Riscv64 => {

xtask/src/target.rs

@@ -9,15 +9,18 @@ pub enum Target {
 	X86_64Fc,
 	X86_64Uefi,
 	Aarch64,
+	Aarch64Be,
 	Riscv64,
 }
 
 impl Target {
 	pub fn install(&self) -> xshell::Result<()> {
 		let sh = Shell::new()?;
 
-		let triple = self.triple();
-		cmd!(sh, "rustup target add {triple}").run()?;
+		if self.tier() <= 2 {
+			let triple = self.triple();
+			cmd!(sh, "rustup target add {triple}").run()?;
+		}
 
 		if self == &Self::X86_64 {
 			cmd!(sh, "rustup component add llvm-tools-preview").run()?;
@@ -32,6 +35,7 @@ impl Target {
 			Self::X86_64Fc => "x86_64",
 			Self::X86_64Uefi => "x86_64",
 			Self::Aarch64 => "aarch64",
+			Self::Aarch64Be => "aarch64_be",
 			Self::Riscv64 => "riscv64",
 		}
 	}
@@ -42,16 +46,28 @@ impl Target {
 			Self::X86_64Fc => "x86_64-unknown-none",
 			Self::X86_64Uefi => "x86_64-unknown-uefi",
 			Self::Aarch64 => "aarch64-unknown-none-softfloat",
+			Self::Aarch64Be => "aarch64_be-unknown-none-softfloat",
 			Self::Riscv64 => "riscv64imac-unknown-none-elf",
 		}
 	}
 
+	pub fn tier(&self) -> u8 {
+		match self {
+			Self::Aarch64Be => 3,
+			_ => 2,
+		}
+	}
+
 	pub fn cargo_args(&self) -> &'static [&'static str] {
 		match self {
 			Self::X86_64 => &["--target=x86_64-unknown-none"],
 			Self::X86_64Fc => &["--target=x86_64-unknown-none"],
 			Self::X86_64Uefi => &["--target=x86_64-unknown-uefi"],
 			Self::Aarch64 => &["--target=aarch64-unknown-none-softfloat"],
+			Self::Aarch64Be => &[
+				"--target=aarch64_be-unknown-none-softfloat",
+				"-Zbuild-std=core,alloc,panic_abort",
+			],
 			Self::Riscv64 => &["--target=riscv64imac-unknown-none-elf"],
 		}
 	}
@@ -67,7 +83,7 @@ impl Target {
 				"-Crelocation-model=static",
 			],
 			Self::X86_64Uefi => &[],
-			Self::Aarch64 => &["-Clink-arg=-Tsrc/arch/aarch64/link.ld"],
+			Self::Aarch64 | Self::Aarch64Be => &["-Clink-arg=-Tsrc/arch/aarch64/link.ld"],
 			Self::Riscv64 => &["-Clink-arg=-Tsrc/arch/riscv64/link.ld"],
 		}
 	}
@@ -92,9 +108,18 @@ impl Target {
 			Self::X86_64Fc => "hermit-loader-x86_64-fc",
 			Self::X86_64Uefi => "hermit-loader-x86_64.efi",
 			Self::Aarch64 => "hermit-loader-aarch64",
+			Self::Aarch64Be => "hermit-loader-aarch64_be",
 			Self::Riscv64 => "hermit-loader-riscv64",
 		}
 	}
+
+	pub fn qemu(&self) -> &'static str {
+		match self {
+			Self::X86_64 | Self::X86_64Fc | Self::X86_64Uefi => "x86_64",
+			Self::Aarch64 | Self::Aarch64Be => "aarch64",
+			Self::Riscv64 => "riscv64",
+		}
+	}
 }
 
 impl FromStr for Target {
@@ -106,6 +131,7 @@ impl FromStr for Target {
 			"x86_64-fc" => Ok(Self::X86_64Fc),
 			"x86_64-uefi" => Ok(Self::X86_64Uefi),
 			"aarch64" => Ok(Self::Aarch64),
+			"aarch64_be" => Ok(Self::Aarch64Be),
 			"riscv64" => Ok(Self::Riscv64),
 			s => Err(anyhow!("Unsupported target: {s}")),
 		}