feat(sbi): 封装 mtvec 操作方便管理

Author: YdrMaster

rustsbi-qemu/src/execute/runtime.rs

@@ -20,7 +20,6 @@ impl Runtime {
         use riscv::register::mstatus;
 
         unsafe {
-            asm!("csrw mstatus, {}", in(reg)0);
             mstatus::set_mpp(mstatus::MPP::Supervisor);
             mstatus::set_mie();
         };
@@ -66,7 +65,7 @@ impl Runtime {
 
         clint::get().clear_soft(hart_id());
         unsafe {
-            use riscv::register::{medeleg, mie, mtvec};
+            use riscv::register::{medeleg, mie};
 
             mstatus::clear_mie();
             asm!("csrw     mip, {}", in(reg) 0);
@@ -76,7 +75,7 @@ impl Runtime {
             medeleg::clear_supervisor_env_call();
             medeleg::clear_machine_env_call();
 
-            mtvec::write(from_supervisor_save as usize, mtvec::TrapMode::Direct);
+            crate::set_mtcev(from_supervisor_save as usize);
             mie::set_mext();
             mie::set_msoft();
         }

rustsbi-qemu/src/main.rs

@@ -112,8 +112,7 @@ static HSM: Once<qemu_hsm::QemuHsm> = Once::new();
 
 /// rust 入口。
 extern "C" fn rust_main(_hartid: usize, opaque: usize) {
-    use riscv::register::mtvec;
-    unsafe { mtvec::write(early_trap as _, mtvec::TrapMode::Direct) };
+    unsafe { set_mtcev(early_trap as _) };
 
     #[link_section = ".bss.uninit"]
     static BOARD_INFO: Once<device_tree::BoardInfo> = Once::new();
@@ -294,3 +293,9 @@ impl PmpCfg {
 fn hart_id() -> usize {
     riscv::register::mhartid::read()
 }
+
+#[inline(always)]
+unsafe fn set_mtcev(trap_handler: usize) {
+    use riscv::register::mtvec;
+    mtvec::write(trap_handler, mtvec::TrapMode::Direct);
+}

rustsbi-qemu/src/qemu_hsm.rs

@@ -1,6 +1,6 @@
 //! Hart state monitor designed for QEMU
 
-use crate::{clint::Clint, entry, hart_id, Supervisor, NUM_HART_MAX, SUPERVISOR_ENTRY};
+use crate::{clint::Clint, entry, hart_id, set_mtcev, Supervisor, NUM_HART_MAX, SUPERVISOR_ENTRY};
 use core::{mem::MaybeUninit, sync::atomic::AtomicU8};
 use rustsbi::SbiRet;
 use spin::Mutex;
@@ -35,15 +35,19 @@ impl QemuHsm {
         let mut supervisor = unsafe { supervisor.assume_init() };
         for id in 0..smp {
             state[id] = AtomicU8::new(START_PENDING);
-            // 执行全局初始化的硬件线程将直通特权软件
-            supervisor[id] = Mutex::new(if id == hart_id() {
-                Some(Supervisor {
-                    start_addr: SUPERVISOR_ENTRY,
-                    opaque,
-                })
-            } else {
-                None
-            });
+            supervisor[id] = Mutex::new(
+                // 执行全局初始化的硬件线程将直通特权软件
+                if id == hart_id() {
+                    Some(Supervisor {
+                        start_addr: SUPERVISOR_ENTRY,
+                        opaque,
+                    })
+                }
+                // 否则将在下一个步骤被关闭
+                else {
+                    None
+                },
+            );
         }
 
         Self {
@@ -95,7 +99,7 @@ impl QemuHsm {
     /// 此时核状态必然是不可干预的 Pending 状态，中断业已关闭。
     pub fn finallize_before_stop(&self) {
         use core::sync::atomic::Ordering::{AcqRel, Acquire};
-        use riscv::register::{mie, mip, mtvec};
+        use riscv::register::{mie, mip};
 
         // 检查当前状态是重启前的挂起状态
         let state = &self.state[hart_id()];
@@ -117,7 +121,7 @@ impl QemuHsm {
         unsafe {
             mip::clear_msoft();
             mie::set_msoft();
-            mtvec::write(entry as _, mtvec::TrapMode::Direct);
+            set_mtcev(entry as _);
         }
         if let Err(unexpected) = state.compare_exchange(current, new, AcqRel, Acquire) {
             panic!("failed to reboot for a race {current:?} => {unexpected:?}")