ARM64 Support Status

ARM64 Support

ARM64 support was contributed to the Asterinas project and is independently maintained in KEI.

Current Capabilities

OSTD (ostd/src/arch/aarch64/):

• boot/ — BSP entry, boot page tables
• mm/ — ARM64 page tables (4-level paging), MMU setup
• task/ — Context switching, FPU/SIMD save/restore
• irq/ — GICv3 interrupt controller (uses third-party crate)
• timer/ — ARM Generic Timer (EL1 physical)
• trap/ — EL1 exception handling (sync/IRQ/FIQ/SError)
• cpu/ — CPU features, SMP via PSCI
• iommu/ — IOMMU stub
• device/ — Device discovery via FDT
• io/ — MMIO abstraction
• power.rs — PSCI power management (shutdown/reboot)
• serial.rs — PL011 UART console

Kernel (kernel/src/arch/aarch64/):

• Process / thread support
• Syscall table (EL0 → EL1)
• TLS handling (TPIDR_EL0)
• PCI enumeration
• VirtIO support
• TLB flush bugfix in KVirtArea::drop()

OSDK:

• Raw ARM64 Image format for QEMU Linux boot protocol
• Arm64 QEMU scheme in OSDK.toml
• GitHub Actions CI for arm64 lint + compile

kei's Strategy

The ARM64 code is maintained directly in kei's repository. This means:

1. 1
   The full ostd/src/arch/aarch64/ tree exists in kei's repo
2. 2
   We can modify any file directly
3. 3
   Upstream is not tracked, so this tree is the source of truth — there is no rebase onto a new upstream arch implementation

Known Issues

QEMU Test Matrix