feat(riscv): riscv下能够运行hello world用户程序

kernel/Cargo.toml

@@ -65,7 +65,7 @@ x86_64 = "=0.14.10"
 
 # target为riscv64时，使用下面的依赖
 [target.'cfg(target_arch = "riscv64")'.dependencies]
-riscv = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/riscv.git", revision = "cc4d3ea82a", features = [ "s-mode" ] }
+riscv = { git = "https://git.mirrors.dragonos.org.cn/DragonOS-Community/riscv.git", rev = "4241a97", features = [ "s-mode" ] }
 sbi-rt = { version = "=0.0.3", features = ["legacy"] }
 
 

kernel/src/arch/riscv64/driver/of.rs

@@ -3,6 +3,7 @@ use system_error::SystemError;
 use crate::{
     driver::open_firmware::fdt::OpenFirmwareFdtDriver,
     init::boot_params,
+    kdebug,
     libs::align::page_align_up,
     mm::{mmio_buddy::mmio_pool, MemoryManagementArch, PhysAddr},
 };
@@ -28,6 +29,7 @@ impl OpenFirmwareFdtDriver {
 
         // drop the boot params guard in order to avoid deadlock
         drop(bp_guard);
+        // kdebug!("map_fdt: map fdt to {:?}, size: {}", map_paddr, map_size);
         mmio_guard.map_phys(map_paddr, map_size)?;
         let mut bp_guard = boot_params().write();
         let vaddr = mmio_guard.vaddr() + offset;

kernel/src/arch/riscv64/init/mod.rs

@@ -112,7 +112,7 @@ pub fn early_setup_arch() -> Result<(), SystemError> {
     arch_boot_params_guard.arch.fdt_paddr = fdt_paddr;
     arch_boot_params_guard.arch.fdt_size = fdt.total_size();
     arch_boot_params_guard.arch.boot_hartid = ProcessorId::new(hartid);
-
+    // kdebug!("fdt_paddr: {:?}, fdt_size: {}", fdt_paddr, fdt.total_size());
     drop(arch_boot_params_guard);
 
     kinfo!(

kernel/src/arch/riscv64/interrupt/entry.rs

@@ -160,7 +160,8 @@ unsafe extern "C" fn _save_context() -> ! {
         off_cause = const offset_of!(TrapFrame, cause),
         off_tp = const offset_of!(TrapFrame, tp),
         off_epc = const offset_of!(TrapFrame, epc),
-        sr_sum_and_fsvs = const (SR_FS_VS | SR_SUM),
+        sr_sum_and_fsvs = const (0), // 暂时在内核中不禁用FPU和Vector，以及不禁用用户内存访问
+        // sr_sum_and_fsvs = const (SR_FS_VS | SR_SUM),
         csr_status = const CSR_SSTATUS,
         csr_epc = const CSR_SEPC,
         csr_tval = const CSR_STVAL,

kernel/src/arch/riscv64/interrupt/handle.rs

@@ -48,10 +48,6 @@ fn riscv64_do_interrupt(trap_frame: &mut TrapFrame) {
 
 /// 处理异常
 fn riscv64_do_exception(trap_frame: &mut TrapFrame) {
-    kdebug!(
-        "riscv64_do_exception: from_user: {}",
-        trap_frame.is_from_user()
-    );
     let code = trap_frame.cause.code();
 
     if code < EXCEPTION_HANDLERS.len() {
@@ -153,8 +149,16 @@ fn do_trap_user_env_call(trap_frame: &mut TrapFrame) -> Result<(), SystemError>
 // 9-11 reserved
 
 /// 处理指令页错误异常 #12
-fn do_trap_insn_page_fault(_trap_frame: &mut TrapFrame) -> Result<(), SystemError> {
-    kerror!("riscv64_do_irq: do_insn_page_fault");
+fn do_trap_insn_page_fault(trap_frame: &mut TrapFrame) -> Result<(), SystemError> {
+    let vaddr = trap_frame.badaddr;
+    let cause = trap_frame.cause;
+    let epc = trap_frame.epc;
+    kerror!(
+        "riscv64_do_irq: do_insn_page_fault vaddr: {:#x}, cause: {:?} epc: {:#x}",
+        vaddr,
+        cause,
+        epc
+    );
     loop {
         spin_loop();
     }
@@ -179,8 +183,13 @@ fn do_trap_load_page_fault(trap_frame: &mut TrapFrame) -> Result<(), SystemError
 // 14 reserved
 
 /// 处理页存储错误异常 #15
-fn do_trap_store_page_fault(_trap_frame: &mut TrapFrame) -> Result<(), SystemError> {
-    kerror!("riscv64_do_irq: do_trap_store_page_fault");
+fn do_trap_store_page_fault(trap_frame: &mut TrapFrame) -> Result<(), SystemError> {
+    kerror!(
+        "riscv64_do_irq: do_trap_store_page_fault: epc: {:#x}, vaddr={:#x}, cause={:?}",
+        trap_frame.epc,
+        trap_frame.badaddr,
+        trap_frame.cause
+    );
     loop {
         spin_loop();
     }

kernel/src/arch/riscv64/mm/init.rs

@@ -69,14 +69,16 @@ pub(super) unsafe fn riscv_mm_init() -> Result<(), SystemError> {
     mem_block_manager()
         .reserve_block(KERNEL_BEGIN_PA, KERNEL_END_PA - KERNEL_BEGIN_PA)
         .expect("Failed to reserve kernel memory");
+    // 开启S-mode User Memory Access，允许内核访问用户空间
+    riscv::register::sstatus::set_sum();
 
     let mut bump_allocator = BumpAllocator::<RiscV64MMArch>::new(0);
     let _old_page_table = MMArch::table(PageTableKind::Kernel);
     let new_page_table: PhysAddr;
 
     // 使用bump分配器，把所有的内存页都映射到页表
     {
-        kdebug!("to create new page table");
+        // kdebug!("to create new page table");
         // 用bump allocator创建新的页表
         let mut mapper: crate::mm::page::PageMapper<MMArch, &mut BumpAllocator<MMArch>> =
             crate::mm::page::PageMapper::<MMArch, _>::create(
@@ -85,7 +87,7 @@ pub(super) unsafe fn riscv_mm_init() -> Result<(), SystemError> {
             )
             .expect("Failed to create page mapper");
         new_page_table = mapper.table().phys();
-        kdebug!("PageMapper created");
+        // kdebug!("PageMapper created");
 
         // 取消最开始时候，在head.S中指定的映射(暂时不刷新TLB)
         {

kernel/src/arch/riscv64/mm/mod.rs

@@ -105,7 +105,9 @@ impl MemoryManagementArch for RiscV64MMArch {
 
     const ENTRY_FLAG_PRESENT: usize = 1 << 0;
 
-    const ENTRY_FLAG_READONLY: usize = 0;
+    const ENTRY_FLAG_READONLY: usize = (1 << 1);
+
+    const ENTRY_FLAG_WRITEABLE: usize = (1 << 2);
 
     const ENTRY_FLAG_READWRITE: usize = (1 << 2) | (1 << 1);
 

kernel/src/arch/riscv64/process/idle.rs

@@ -15,7 +15,7 @@ impl ProcessManager {
                 spin_loop();
             }
 
-            kdebug!("idle loop");
+            // kdebug!("idle loop");
         }
     }
 }

kernel/src/arch/riscv64/process/kthread.rs

@@ -35,6 +35,7 @@ impl KernelThreadMechanism {
         // 使能中断
         frame.status.update_sie(true);
         frame.status.update_spp(SPP::Supervisor);
+        frame.status.update_sum(true);
 
         frame.ra = kernel_thread_bootstrap_stage1 as usize;
 

kernel/src/arch/riscv64/process/mod.rs

@@ -28,6 +28,7 @@ use crate::{
         PROCESS_SWITCH_RESULT,
     },
     smp::cpu::ProcessorId,
+    syscall::Syscall,
 };
 
 use super::{
@@ -53,7 +54,64 @@ static BSP_IDLE_STACK_SPACE: InitProcUnion = InitProcUnion {
 };
 
 pub unsafe fn arch_switch_to_user(path: String, argv: Vec<String>, envp: Vec<String>) -> ! {
-    unimplemented!("RiscV64 arch_switch_to_user")
+    // 以下代码不能发生中断
+    CurrentIrqArch::interrupt_disable();
+
+    let current_pcb = ProcessManager::current_pcb();
+    let trap_frame_vaddr = VirtAddr::new(
+        current_pcb.kernel_stack().stack_max_address().data() - core::mem::size_of::<TrapFrame>(),
+    );
+    let new_pc = VirtAddr::new(ret_from_exception as usize);
+
+    let mut arch_guard = current_pcb.arch_info_irqsave();
+    arch_guard.ksp = trap_frame_vaddr.data();
+
+    arch_guard.ra = new_pc.data();
+    drop(arch_guard);
+
+    // 删除kthread的标志
+    current_pcb.flags().remove(ProcessFlags::KTHREAD);
+    current_pcb.worker_private().take();
+
+    *current_pcb.sched_info().sched_policy.write_irqsave() = crate::sched::SchedPolicy::CFS;
+
+    let mut trap_frame = TrapFrame::new();
+
+    compiler_fence(Ordering::SeqCst);
+    Syscall::do_execve(path, argv, envp, &mut trap_frame).unwrap_or_else(|e| {
+        panic!(
+            "arch_switch_to_user(): pid: {pid:?}, Failed to execve: , error: {e:?}",
+            pid = current_pcb.pid(),
+            e = e
+        );
+    });
+    compiler_fence(Ordering::SeqCst);
+
+    // 重要！在这里之后，一定要保证上面的引用计数变量、动态申请的变量、锁的守卫都被drop了，否则可能导致内存安全问题！
+
+    drop(current_pcb);
+
+    *(trap_frame_vaddr.data() as *mut TrapFrame) = trap_frame;
+
+    compiler_fence(Ordering::SeqCst);
+    ready_to_switch_to_user(trap_frame_vaddr.data(), new_pc.data());
+}
+
+#[naked]
+unsafe extern "C" fn ready_to_switch_to_user(trap_frame: usize, new_pc: usize) -> ! {
+    asm!(
+        concat!(
+            "
+            // 设置trap frame
+            mv sp, a0
+            // 设置返回地址
+
+            jr a1
+
+            "
+        ),
+        options(noreturn)
+    );
 }
 
 impl ProcessManager {
@@ -98,6 +156,7 @@ impl ProcessManager {
         let current_arch_guard = current_pcb.arch_info_irqsave();
         // 拷贝浮点寄存器的状态
         new_arch_guard.fp_state = current_arch_guard.fp_state;
+        new_arch_guard.sstatus = current_arch_guard.sstatus;
 
         drop(current_arch_guard);
 
@@ -128,11 +187,11 @@ impl ProcessManager {
     /// 参考: https://code.dragonos.org.cn/xref/linux-6.6.21/arch/riscv/include/asm/switch_to.h#76
     pub unsafe fn switch_process(prev: Arc<ProcessControlBlock>, next: Arc<ProcessControlBlock>) {
         assert!(!CurrentIrqArch::is_irq_enabled());
-        kdebug!(
-            "riscv switch process: prev: {:?}, next: {:?}",
-            prev.pid(),
-            next.pid()
-        );
+        // kdebug!(
+        //     "riscv switch process: prev: {:?}, next: {:?}",
+        //     prev.pid(),
+        //     next.pid()
+        // );
         Self::switch_process_fpu(&prev, &next);
         Self::switch_local_context(&prev, &next);
 
@@ -144,6 +203,8 @@ impl ProcessManager {
         drop(next_addr_space);
         compiler_fence(Ordering::SeqCst);
 
+        // kdebug!("current sum={}, prev sum={}, next_sum={}", riscv::register::sstatus::read().sum(), prev.arch_info_irqsave().sstatus.sum(), next.arch_info_irqsave().sstatus.sum());
+
         // 获取arch info的锁，并强制泄露其守卫（切换上下文后，在switch_finish_hook中会释放锁）
         let next_arch = SpinLockGuard::leak(next.arch_info_irqsave()) as *mut ArchPCBInfo;
         let prev_arch = SpinLockGuard::leak(prev.arch_info_irqsave()) as *mut ArchPCBInfo;
@@ -153,7 +214,7 @@ impl ProcessManager {
         ProcessManager::current_pcb().preempt_enable();
         PROCESS_SWITCH_RESULT.as_mut().unwrap().get_mut().prev_pcb = Some(prev);
         PROCESS_SWITCH_RESULT.as_mut().unwrap().get_mut().next_pcb = Some(next);
-        kdebug!("riscv switch process: before to inner");
+        // kdebug!("riscv switch process: before to inner");
         compiler_fence(Ordering::SeqCst);
         // 正式切换上下文
         switch_to_inner(prev_arch, next_arch);
@@ -206,8 +267,8 @@ unsafe extern "C" fn switch_to_inner(prev: *mut ArchPCBInfo, next: *mut ArchPCBI
 
             addi sp , sp, -8
             sd a1, 0(sp)
-            csrr a0, sstatus
-            sd a0, {off_sstatus}(a1)
+            csrr a1, sstatus
+            sd a1, {off_sstatus}(a0)
             ld a1, 0(sp)
             addi sp, sp, 8
 
@@ -271,13 +332,12 @@ unsafe extern "C" fn switch_to_inner(prev: *mut ArchPCBInfo, next: *mut ArchPCBI
 /// 在切换上下文完成后的钩子函数(必须在这里加一个跳转函数，否则会出现relocation truncated to fit: R_RISCV_JAL错误)
 unsafe extern "C" fn before_switch_finish_hook() {
     let pcb = ProcessManager::current_pcb();
-    kdebug!(
-        "before_switch_finish_hook, pid: {:?}, name: {:?}",
-        pcb.pid(),
-        pcb.basic().name()
-    );
+    // kdebug!(
+    //     "before_switch_finish_hook, pid: {:?}, name: {:?}",
+    //     pcb.pid(),
+    //     pcb.basic().name()
+    // );
     switch_finish_hook();
-    kdebug!("after switch_finish_hook");
 }
 
 impl ProcessControlBlock {
@@ -344,6 +404,8 @@ impl ArchPCBInfo {
     ///
     /// 返回一个新的ArchPCBInfo
     pub fn new(kstack: &KernelStack) -> Self {
+        let mut sstatus = Sstatus::from(0);
+        sstatus.update_sum(true);
         Self {
             ra: 0,
             ksp: kstack.stack_max_address().data(),
@@ -359,7 +421,7 @@ impl ArchPCBInfo {
             s9: 0,
             s10: 0,
             s11: 0,
-            sstatus: Sstatus::from(0),
+            sstatus,
             fp_state: FpDExtState::new(),
             local_context: LocalContext::new(ProcessorId::new(0)),
         }