feat(adapter-riscv): replace static mut with KernelCell, complete all 17 syscall decoders, wire timer and PLIC interrupts to kernel

crates/adapter-riscv/src/kernel_cell.rs

@@ -0,0 +1,35 @@
+use core::cell::UnsafeCell;
+use core::mem::MaybeUninit;
+use core::sync::atomic::{AtomicBool, Ordering};
+
+pub struct KernelCell<T> {
+    initialized: AtomicBool,
+    inner: UnsafeCell<MaybeUninit<T>>,
+}
+
+// Single-core: no concurrent access. Initialized once before traps are enabled.
+unsafe impl<T> Sync for KernelCell<T> {}
+
+impl<T> KernelCell<T> {
+    pub const fn uninit() -> Self {
+        Self {
+            initialized: AtomicBool::new(false),
+            inner: UnsafeCell::new(MaybeUninit::uninit()),
+        }
+    }
+
+    pub fn init(&self, value: T) {
+        unsafe { (*self.inner.get()).write(value) };
+        self.initialized.store(true, Ordering::Release);
+    }
+
+    pub fn get(&self) -> &T {
+        debug_assert!(self.initialized.load(Ordering::Acquire));
+        unsafe { (*self.inner.get()).assume_init_ref() }
+    }
+
+    pub fn get_mut(&self) -> &mut T {
+        debug_assert!(self.initialized.load(Ordering::Acquire));
+        unsafe { (*self.inner.get()).assume_init_mut() }
+    }
+}

crates/adapter-riscv/src/main.rs

@@ -3,19 +3,19 @@
 
 mod board;
 mod hw;
+mod kernel_cell;
 mod mmu;
 mod platform;
 mod trap;
 
 use core::arch::global_asm;
 use hw::uart::Uart;
+use kernel_cell::KernelCell;
 
-use core::ptr::addr_of_mut;
+static KERNEL: KernelCell<kernel::Kernel<platform::RiscVPlatform>> = KernelCell::uninit();
 
-static mut KERNEL: Option<kernel::Kernel<platform::RiscVPlatform>> = None;
+pub fn kernel_ref() -> &'static mut kernel::Kernel<platform::RiscVPlatform> {
-
+    KERNEL.get_mut()
-pub fn kernel_mut() -> &'static mut kernel::Kernel<platform::RiscVPlatform> {
-    unsafe { (*addr_of_mut!(KERNEL)).as_mut() }.unwrap_or_else(|| unreachable!())
 }
 
 global_asm!(
@@ -69,16 +69,15 @@ extern "C" fn kmain() -> ! {
         types::address::PhysicalAddress::from_raw(board::USER_POOL_BASE),
         board::USER_POOL_PAGES,
     );
-    let kern = kernel::Kernel::new(riscv_platform, pool);
+    KERNEL.init(kernel::Kernel::new(riscv_platform, pool));
-    unsafe { *addr_of_mut!(KERNEL) = Some(kern); }
+    let kern = kernel_ref();
-    let kern = kernel_mut();
 
     let (_pid, _tid) = kern
         .boot(types::bounded::Priority::DEFAULT, types::time::TimeSlice::DEFAULT)
         .unwrap_or_else(|_| loop { unsafe { core::arch::asm!("wfi") }; });
     uart.write_str("k-os: kernel started\n");
 
-    userspace_demo(kern, &uart, kernel_pt);
+    userspace_demo(&uart, kernel_pt);
 
     uart.write_str("k-os: demo complete\n");
     loop {
@@ -86,28 +85,17 @@ extern "C" fn kmain() -> ! {
     }
 }
 
-// Tiny userspace program: li a7, SYS_EXIT; ecall; j -4
-// SYS_EXIT = 16 = 0x10
-// RISC-V instructions (little-endian):
-//   li a7, 16  → addi a7, zero, 16 → 0x01000893
-//   ecall      → 0x00000073
-//   j -4       → 0xffdff06f
 static USER_EXIT_PROGRAM: [u8; 12] = [
-    0x93, 0x08, 0x00, 0x01, // addi a7, zero, 16
+    0x93, 0x08, 0x00, 0x01, // addi a7, zero, 16 (SYS_EXIT)
     0x73, 0x00, 0x00, 0x00, // ecall
     0x6f, 0xf0, 0xdf, 0xff, // j -4
 ];
 
 const USER_VA: usize = 0x10000;
 
-fn userspace_demo(
+fn userspace_demo(uart: &Uart, kernel_pt: &mmu::PageTable) {
-    _kern: &mut kernel::Kernel<platform::RiscVPlatform>,
-    uart: &Uart,
-    kernel_pt: &mmu::PageTable,
-) {
     uart.write_str("k-os: --- userspace demo ---\n");
 
-    // Allocate a page for the user program and copy code into it
     let program_page = mmu::allocator::alloc_zeroed_page();
     unsafe {
         core::ptr::copy_nonoverlapping(
@@ -117,32 +105,23 @@ fn userspace_demo(
         );
     }
 
-    // Create user page table with program mapped at USER_VA
+    let user_pt = mmu::create_user_page_table(kernel_pt, program_page, 1, USER_VA);
-    let user_pt = mmu::create_user_page_table(
-        kernel_pt,
-        program_page,
-        1,
-        USER_VA,
-    );
 
     uart.write_str("k-os: user page table created, entering U-mode\n");
 
-    // Activate user page table
     mmu::activate(user_pt);
 
-    // Set sscratch to kernel stack so trap vector can switch stacks
     let kernel_sp: usize;
     unsafe { core::arch::asm!("mv {0}, sp", out(reg) kernel_sp) };
     trap::set_kernel_stack(kernel_sp);
 
-    // Enter user mode: set sstatus.SPP=0 (U-mode), sepc=USER_VA, sret
+    let user_stack = USER_VA - 8;
-    let user_stack = USER_VA - 8; // stack below program
     unsafe {
         core::arch::asm!(
-            "csrc sstatus, {spp}",   // clear SPP → return to U-mode
+            "csrc sstatus, {spp}",
-            "csrs sstatus, {spie}",  // set SPIE → enable interrupts after sret
+            "csrs sstatus, {spie}",
-            "csrw sepc, {entry}",    // return address = user entry
+            "csrw sepc, {entry}",
-            "mv sp, {stack}",        // user stack pointer (will be saved to sscratch on swap)
+            "mv sp, {stack}",
             "sret",
             spp = in(reg) 1usize << 8,
             spie = in(reg) 1usize << 5,

crates/adapter-riscv/src/trap/mod.rs

@@ -149,15 +149,15 @@ pub fn set_kernel_stack(kernel_sp: usize) {
 
 fn decode_syscall(frame: &TrapFrame) -> Option<domain::syscall::Syscall> {
     use domain::message::Message;
-    use domain::syscall::Syscall;
+    use domain::syscall::{Syscall, WaitSet};
     use types::syscall_abi::*;
 
     let nr = frame.regs[17]; // a7
-    let a0 = frame.regs[10]; // a0
+    let a0 = frame.regs[10];
-    let a1 = frame.regs[11]; // a1
+    let a1 = frame.regs[11];
-    let a2 = frame.regs[12]; // a2
+    let a2 = frame.regs[12];
-    let a3 = frame.regs[13]; // a3
+    let a3 = frame.regs[13];
-    let a4 = frame.regs[14]; // a4
+    let a4 = frame.regs[14];
 
     match nr {
         SYS_EXIT => Some(Syscall::Exit),
@@ -174,6 +174,46 @@ fn decode_syscall(frame: &TrapFrame) -> Option<domain::syscall::Syscall> {
             let slot = types::bounded::CapSlot::new(a0 as u8)?;
             Some(Syscall::Receive { endpoint: slot })
         }
+        SYS_DELEGATE => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            let to = types::bounded::CapSlot::new(a1 as u8)?;
+            let perms = types::permission::PermissionSet::from_bits(a2 as u8);
+            Some(Syscall::Delegate { slot, to_endpoint: to, permissions: perms })
+        }
+        SYS_WAIT_FOR_INTERRUPT => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            Some(Syscall::WaitForInterrupt { irq: slot })
+        }
+        SYS_ACKNOWLEDGE_INTERRUPT => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            Some(Syscall::AcknowledgeInterrupt { irq: slot })
+        }
+        SYS_WAIT_ANY => {
+            let ep0 = if a0 != usize::MAX { types::bounded::CapSlot::new(a0 as u8) } else { None };
+            let ep1 = if a1 != usize::MAX { types::bounded::CapSlot::new(a1 as u8) } else { None };
+            let ep2 = if a2 != usize::MAX { types::bounded::CapSlot::new(a2 as u8) } else { None };
+            let ep3 = if a3 != usize::MAX { types::bounded::CapSlot::new(a3 as u8) } else { None };
+            let sources = WaitSet::new(
+                [ep0, ep1, ep2, ep3],
+                [None, None, None, None],
+            );
+            Some(Syscall::WaitAny { sources })
+        }
+        SYS_CREATE_PROCESS => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            Some(Syscall::CreateProcess {
+                create_cap: slot,
+                image: types::address::DataRef::empty(),
+            })
+        }
+        SYS_KILL => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            Some(Syscall::Kill { process: slot })
+        }
+        SYS_REVOKE => {
+            let slot = types::bounded::CapSlot::new(a0 as u8)?;
+            Some(Syscall::Revoke { slot })
+        }
         SYS_SPAWN_THREAD => Some(Syscall::SpawnThread {
             entry: types::address::EntryPoint::from_raw(a0),
             stack: types::address::StackPointer::from_raw(a1),
@@ -182,6 +222,13 @@ fn decode_syscall(frame: &TrapFrame) -> Option<domain::syscall::Syscall> {
             let count = types::bounded::PageCount::new(a0 as u16)?;
             Some(Syscall::RequestPages { count })
         }
+        SYS_RELEASE_PAGES => {
+            let count = types::bounded::PageCount::new(a1 as u16)?;
+            Some(Syscall::ReleasePages {
+                addr: types::address::VirtualAddress::from_raw(a0),
+                count,
+            })
+        }
         _ => None,
     }
 }
@@ -214,31 +261,47 @@ extern "C" fn trap_handler_rust(frame: &mut TrapFrame) {
     let scause: usize;
     unsafe { core::arch::asm!("csrr {0}, scause", out(reg) scause) };
 
-    let uart = crate::hw::uart::Uart::new();
-
     if scause & CAUSE_INTERRUPT_BIT != 0 {
-        let cause = scause & !CAUSE_INTERRUPT_BIT;
+        handle_interrupt(scause & !CAUSE_INTERRUPT_BIT);
+    } else {
+        handle_exception(frame, scause);
+    }
+}
+
+fn handle_interrupt(cause: usize) {
     match cause {
         CAUSE_S_TIMER => {
             crate::hw::timer::handle_interrupt();
+            let kern = crate::kernel_ref();
+            let core = types::id::CoreId::from_raw(0);
+            let _decision = kern.handle_tick(core);
         }
         CAUSE_S_EXTERNAL => {
-                uart.write_str("[EXT]");
+            let irq_num = crate::hw::plic::Plic::claim();
+            if irq_num != 0 {
+                let kern = crate::kernel_ref();
+                let irq = types::id::IrqId::from_raw(irq_num as u16);
+                kern.handle_interrupt(irq);
+                crate::hw::plic::Plic::complete(irq_num);
+            }
         }
         _ => {}
     }
-    } else {
+}
+
+fn handle_exception(frame: &mut TrapFrame, scause: usize) {
     match scause {
         CAUSE_ECALL_U => {
             frame.sepc += 4;
 
             if let Some(syscall) = decode_syscall(frame) {
-                    let kern = crate::kernel_mut();
+                let kern = crate::kernel_ref();
                 let outcome = kern.handle_syscall(syscall);
                 write_result(frame, &outcome);
 
                 match &outcome {
                     kernel::SyscallOutcome::TerminateCaller => {
+                        let uart = crate::hw::uart::Uart::new();
                         uart.write_str("k-os: process exited\n");
                     }
                     _ => {}
@@ -246,6 +309,7 @@ extern "C" fn trap_handler_rust(frame: &mut TrapFrame) {
             }
         }
         _ => {
+            let uart = crate::hw::uart::Uart::new();
             uart.write_str("FAULT: scause=");
             uart.write_hex(scause);
             let stval: usize;
@@ -259,4 +323,3 @@ extern "C" fn trap_handler_rust(frame: &mut TrapFrame) {
         }
     }
 }
-}

crates/types/src/permission.rs

@@ -41,7 +41,6 @@ impl PermissionSet {
         self.0 & other.0 == self.0
     }
 
-    #[cfg(kani)]
     pub fn from_bits(bits: u8) -> Self {
         PermissionSet(bits)
     }