add: finish basic work

os/Cargo.lock

@@ -2,6 +2,28 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "bit_field"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc827186963e592360843fb5ba4b973e145841266c1357f7180c43526f2e5b61"
+
+[[package]]
+name = "critical-section"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7059fff8937831a9ae6f0fe4d658ffabf58f2ca96aa9dec1c889f936f705f216"
+
+[[package]]
+name = "embedded-hal"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "35949884794ad573cf46071e41c9b60efb0cb311e3ca01f7af807af1debc66ff"
+dependencies = [
+ "nb 0.1.3",
+ "void",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -11,14 +33,41 @@ dependencies = [
  "spin",
 ]
 
+[[package]]
+name = "nb"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "801d31da0513b6ec5214e9bf433a77966320625a37860f910be265be6e18d06f"
+dependencies = [
+ "nb 1.1.0",
+]
+
+[[package]]
+name = "nb"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8d5439c4ad607c3c23abf66de8c8bf57ba8adcd1f129e699851a6e43935d339d"
+
 [[package]]
 name = "os"
 version = "0.1.0"
 dependencies = [
  "lazy_static",
+ "riscv",
  "sbi-rt",
 ]
 
+[[package]]
+name = "riscv"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aa3145d2fae3778b1e31ec2e827b228bdc6abd9b74bb5705ba46dcb82069bc4f"
+dependencies = [
+ "bit_field",
+ "critical-section",
+ "embedded-hal",
+]
+
 [[package]]
 name = "sbi-rt"
 version = "0.0.2"
@@ -48,3 +97,9 @@ name = "static_assertions"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
+[[package]]
+name = "void"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"

os/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 [dependencies]
 sbi-rt = { version = "0.0.2", features = ["legacy"] }
 lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
+riscv = { version = "0.10.0" }

os/src/batch.rs

@@ -1,7 +1,10 @@
 use core::arch::asm;
-use core::cell::UnsafeCell;
+
 use lazy_static::lazy_static;
-use crate::println;
+
+use crate::log_information;
+use crate::sync::single_cell::SingleCell;
+use crate::trap::context::TrapContext;
 
 const MAX_APP_NUMBER: usize = 32;
 const APP_BASE_ADDRESS: usize = 0x80400000;
@@ -14,13 +17,13 @@ struct AppManager {
 }
 
 lazy_static! {
-    static ref APP_MANAGER: UnsafeCell<AppManager> = unsafe {
+    static ref APP_MANAGER: SingleCell<AppManager> = unsafe {
-        UnsafeCell::new({
+        SingleCell::new({
             extern "C" {
                 fn _num_app();
             }
 
-            let num_app_ptr = _num_app() as usize as *const usize;
+            let num_app_ptr = _num_app as usize as *const usize;
             let num_app = num_app_ptr.read_volatile();
             let mut start_addresses: [usize; MAX_APP_NUMBER + 1] = [0; MAX_APP_NUMBER + 1];
             let start_addresses_raw: &[usize] = core::slice::from_raw_parts(
@@ -38,10 +41,10 @@ lazy_static! {
 
 impl AppManager {
     pub fn print_app_information(&self) {
-        println!("[kernel] Application count is {}.", self.app_count);
+        log_information!("[kernel] Application count is {}.", self.app_count);
 
         for i in 0..self.app_count {
-            println!("[kernel] Application_{} ({:#x} -> {:#x})",
+            log_information!("[kernel] Application_{} ({:#x} -> {:#x})",
                      i,
                      self.start_addresses[i],
                      self.start_addresses[i + 1]);
@@ -61,7 +64,7 @@ impl AppManager {
             panic!("Application id is invalid!");
         }
 
-        println!("[kernel] Loading application_{}...", app_id);
+        log_information!("[kernel] Loading application_{}...", app_id);
 
         core::slice::from_raw_parts_mut(
             APP_BASE_ADDRESS as *mut u8,
@@ -74,7 +77,7 @@ impl AppManager {
         );
         let app_destination = core::slice::from_raw_parts_mut(
             APP_BASE_ADDRESS as *mut u8,
-            APP_SIZE_LIMIT
+            app_source.len()
         );
         app_destination.copy_from_slice(app_source);
 
@@ -84,3 +87,72 @@ impl AppManager {
     }
 }
 
+const USER_STACK_SIZE: usize = 4096 * 2;
+const KERNEL_STACK_SIZE: usize = 4096 * 2;
+
+#[repr(align(4096))]
+struct UserStack {
+    data: [u8; USER_STACK_SIZE]
+}
+
+impl UserStack {
+    fn get_sp(&self) -> usize {
+        self.data.as_ptr() as usize + USER_STACK_SIZE
+    }
+}
+
+#[repr(align(4096))]
+struct KernelStack {
+    data: [u8; KERNEL_STACK_SIZE]
+}
+
+impl KernelStack {
+    fn get_sp(&self) -> usize {
+        self.data.as_ptr() as usize + KERNEL_STACK_SIZE
+    }
+
+    pub fn push_context(&self, context: TrapContext) -> &'static mut TrapContext {
+        let context_pointer = (self.get_sp() - size_of::<TrapContext>()) as *mut TrapContext;
+        unsafe {
+            *context_pointer = context;
+            context_pointer.as_mut().unwrap()
+        }
+    }
+}
+
+static KERNEL_STACK: KernelStack = KernelStack { data: [0; KERNEL_STACK_SIZE]};
+static USER_STACK: UserStack = UserStack { data: [0; USER_STACK_SIZE]};
+
+pub fn print_app_information() {
+    let app_manager = APP_MANAGER.exclusive_borrow();
+    app_manager.print_app_information();
+}
+
+pub fn run_next_application() -> ! {
+    let mut app_manager = APP_MANAGER.exclusive_borrow();
+    let current_app = app_manager.get_current_app();
+    unsafe {
+        app_manager.load_app(current_app);
+    }
+    app_manager.move_to_next_app();
+
+    // We must drop resource manually
+    // As this function will never return!
+    drop(app_manager);
+
+    extern "C" {
+        fn __restore(context_address: usize);
+    }
+
+    unsafe {
+        let context_address = KERNEL_STACK.push_context(TrapContext::init_application_context(
+            APP_BASE_ADDRESS,
+            USER_STACK.get_sp()
+        )) as *const _ as usize;
+        __restore(context_address);
+
+        unreachable!()
+    }
+}
+
+

os/src/main.rs

@@ -9,6 +9,8 @@ mod sbi;
 mod console;
 mod batch;
 mod sync;
+mod trap;
+mod syscall;
 
 global_asm!(include_str!("entry.asm"));
 global_asm!(include_str!("link_app.asm"));
@@ -17,11 +19,9 @@ global_asm!(include_str!("link_app.asm"));
 #[no_mangle]
 fn rust_main() -> ! {
     clear_bss();
-    log_error!("Hello, rCore!");
+    log_information!("[kernel] Hello, rCore!");
-    log_warning!("Hello, rCore!");
+    trap::init();
-    log_information!("Hello, rCore!");
+    batch::print_app_information();
-    log_debug!("Hello, rCore!");
+    batch::run_next_application();
-    log_trace!("Hello, rCore!");
-    sbi::shutdown(false);
 }
 

os/src/sync.rs

@@ -1 +1 @@
-mod unsafe_cell;
+pub mod single_cell;

os/src/sync/single_cell.rs

@@ -0,0 +1,24 @@
+use core::cell::{RefCell, RefMut};
+
+/// 只能在单核场景下保持安全的屑RefCell
+pub struct SingleCell<T> {
+    inner: RefCell<T>
+}
+
+unsafe impl<T> Sync for SingleCell<T> {
+
+}
+
+impl<T> SingleCell<T> {
+    pub unsafe fn new(value: T) -> SingleCell<T> {
+        SingleCell {
+            inner: RefCell::new(value)
+        }
+    }
+
+    /// 独占访问
+    /// 当已被借用时访问会Panic
+    pub fn exclusive_borrow(&self) -> RefMut<'_, T> {
+        self.inner.borrow_mut()
+    }
+}

os/src/sync/unsafe_cell.rs

@@ -1,24 +0,0 @@
-use core::cell::{RefCell, RefMut};
-
-/// 只能在单核场景下保持安全的屑RefCell
-struct UnsafeCell<T> {
-    inner_cell: RefCell<T>
-}
-
-unsafe impl<T> Sync for UnsafeCell<T> {
-
-}
-
-impl<T> UnsafeCell<T> {
-    pub unsafe fn new(value: T) -> UnsafeCell<T> {
-        Self {
-            inner_cell: RefCell::new(value)
-        }
-    }
-
-    /// 独占访问
-    /// 当已被借用时访问会Panic
-    pub fn exclusive_access(&self) -> RefMut<'_, T> {
-        self.inner_cell.borrow_mut()
-    }
-}

os/src/syscall.rs

@@ -0,0 +1,18 @@
+use crate::syscall::fs::sys_write;
+use crate::syscall::process::sys_exit;
+
+mod fs;
+mod process;
+
+const SYSCALL_WRITE: usize = 64;
+const SYSCALL_EXIT: usize = 93;
+
+pub fn syscall(syscall_id: usize, args: [usize; 3]) -> usize {
+    match syscall_id {
+        SYSCALL_WRITE => sys_write(args[0], args[1] as *const u8, args[2]),
+        SYSCALL_EXIT => sys_exit(args[0] as i32),
+        _ => {
+            panic!("Unsupported syscall: {}", syscall_id)
+        }
+    }
+}

os/src/syscall/fs.rs

@@ -0,0 +1,17 @@
+use crate::print;
+
+const STDOUT_FD: usize = 1;
+
+pub fn sys_write(fd: usize, buffer: *const u8, len: usize) -> usize {
+    match fd {
+        STDOUT_FD => {
+            let slice = unsafe { core::slice::from_raw_parts(buffer, len) };
+            let str = core::str::from_utf8(slice).unwrap();
+            print!("{}", str);
+            len as usize
+        }
+        _ => {
+            panic!("Unsupported file descriptor in sys_write");
+        }
+    }
+}

os/src/syscall/process.rs

@@ -0,0 +1,7 @@
+use crate::batch::run_next_application;
+use crate::println;
+
+pub fn sys_exit(exit_state: i32) -> ! {
+    println!("[kernel] Application exited with code {}.", exit_state);
+    run_next_application()
+}

os/src/trap.asm

@@ -0,0 +1,67 @@
+.altmacro
+.macro SAVE_GP n
+    sd x\n, \n*8(sp)
+.endm
+.macro LOAD_GP n
+    ld x\n, \n*8(sp)
+.endm
+
+    .section .text
+    .global __alltraps
+    .global __restore
+    .align 2
+__alltraps:
+    csrrw sp, sscratch, sp
+    # now sp->kernel stack, sscratch->user stack
+    # allocate a TrapContext on kernel stack
+    addi sp, sp, -34*8
+    # save general-purpose registers
+    sd x1, 1*8(sp)
+    # skip sp(x2), we will save it later
+    sd x3, 3*8(sp)
+    # skip tp(x4), application does not use it
+    # save x5~x31
+    .set n, 5
+    .rept 27
+        SAVE_GP %n
+        .set n, n+1
+    .endr
+    # we can use t0/t1/t2 freely, because they were saved on kernel stack
+    csrr t0, sstatus
+    csrr t1, sepc
+    sd t0, 32*8(sp)
+    sd t1, 33*8(sp)
+    # read user stack from sscratch and save it on the kernel stack
+    csrr t2, sscratch
+    sd t2, 2*8(sp)
+    # set input argument of trap_handler(cx: &mut TrapContext)
+    mv a0, sp
+    call trap_handler
+
+
+
+__restore:
+    # case1: start running app by __restore
+    # case2: back to U after handling trap
+    mv sp, a0
+    # now sp->kernel stack(after allocated), sscratch->user stack
+    # restore sstatus/sepc
+    ld t0, 32*8(sp)
+    ld t1, 33*8(sp)
+    ld t2, 2*8(sp)
+    csrw sstatus, t0
+    csrw sepc, t1
+    csrw sscratch, t2
+    # restore general-purpuse registers except sp/tp
+    ld x1, 1*8(sp)
+    ld x3, 3*8(sp)
+    .set n, 5
+    .rept 27
+        LOAD_GP %n
+        .set n, n+1
+    .endr
+    # release TrapContext on kernel stack
+    addi sp, sp, 34*8
+    # now sp->kernel stack, sscratch->user stack
+    csrrw sp, sscratch, sp
+    sret

os/src/trap.rs

@@ -0,0 +1,47 @@
+use core::arch::global_asm;
+use riscv::register::{
+    mtvec::TrapMode,
+    scause::{self, Exception, Trap},
+    stval, stvec
+};
+use crate::batch::run_next_application;
+use crate::println;
+use crate::syscall::syscall;
+use crate::trap::context::TrapContext;
+
+pub mod context;
+
+global_asm!(include_str!("trap.asm"));
+
+pub fn init() {
+    extern "C" { fn __alltraps(); }
+    unsafe {
+        stvec::write(__alltraps as usize, TrapMode::Direct);
+    }
+}
+
+#[no_mangle]
+pub fn trap_handler(context: &mut TrapContext) -> &mut TrapContext {
+    let scause = scause::read();
+    let stval = stval::read();
+
+    match scause.cause() {
+        Trap::Exception(Exception::UserEnvCall) => {
+            context.sepc += 4;
+            context.x[10] = syscall(context.x[17], [context.x[10], context.x[11], context.x[12]]);
+        },
+        Trap::Exception(Exception::StoreFault) | Trap::Exception(Exception::StorePageFault) => {
+            println!("[kernel] PageFault in application, kernel will kill it.");
+            run_next_application();
+        },
+        Trap::Exception(Exception::IllegalInstruction) => {
+            println!("[kernel] Illegal instruction in application, kernel will kill it.");
+            run_next_application();
+        },
+        _ => {
+            panic!("[Kernel] Unsupported trap: {:?}, stval = {:#x}!", scause.cause(), stval);
+        }
+    }
+
+    context
+}

os/src/trap/context.rs

@@ -0,0 +1,29 @@
+use riscv::register::sstatus::{self, Sstatus, SPP};
+
+#[repr(C)]
+pub struct TrapContext {
+    pub x: [usize; 32],
+    pub s_status: Sstatus,
+    pub sepc: usize
+}
+
+impl TrapContext {
+    pub unsafe fn init_application_context(entry: usize, sp: usize) -> Self {
+        let sstatus = sstatus::read();
+        sstatus::set_spp(SPP::User);
+        let mut context = Self {
+            x: [0; 32],
+            s_status: sstatus,
+            sepc: entry
+        };
+
+        context.set_sp(sp);
+        context
+    }
+
+    pub fn set_sp(&mut self, sp: usize) {
+        // x2 is stack pointer register
+        self.x[2] = sp;
+    }
+}
+