feat: 批处理操作系统 (#1)

Reviewed-on: #1

README.md

@@ -0,0 +1,15 @@
+# Rust RISC-V 操作系统
+
+按照[rCore](https://rcore-os.cn/rCore-Tutorial-Book-v3/chapter0/index.html)的教程进行开发。
+
+## 目前进度
+
+- [x] 基本执行环境
+- [x] 批处理系统
+- [ ] 多道程序和分时系统
+- [ ] 地址空间
+- [ ] 文件系统
+- [ ] 进程间通信和I/O重定向
+- [ ] 并发
+- [ ] I/O设备管理
+

os/Cargo.lock

@@ -2,13 +2,72 @@
 # 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"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+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"
@@ -27,8 +86,20 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "spin"
+version = "0.9.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+
 [[package]]
 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

@@ -5,3 +5,5 @@ 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/build.rs

@@ -0,0 +1,56 @@
+use std::fs::{read_dir, File};
+use std::io::{Result, Write};
+
+fn main() {
+    println!("cargo:rerun-if-changed=../user/src/");
+    println!("cargo:rerun-if-changed={}", TARGET_PATH);
+    insert_app_data().unwrap();
+}
+
+static TARGET_PATH: &str = "../user/target/riscv64gc-unknown-none-elf/release/";
+
+fn insert_app_data() -> Result<()> {
+    let mut f = File::create("src/link_app.asm").unwrap();
+    let mut apps: Vec<_> = read_dir("../user/src/bin")
+        .unwrap()
+        .into_iter()
+        .map(|dir_entry| {
+            let mut name_with_ext = dir_entry.unwrap().file_name().into_string().unwrap();
+            name_with_ext.drain(name_with_ext.find('.').unwrap()..name_with_ext.len());
+            name_with_ext
+        })
+        .collect();
+    apps.sort();
+
+    writeln!(
+        f,
+        r#"
+    .align 3
+    .section .data
+    .global _num_app
+_num_app:
+    .quad {}"#,
+        apps.len()
+    )?;
+
+    for i in 0..apps.len() {
+        writeln!(f, r#"    .quad app_{}_start"#, i)?;
+    }
+    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
+
+    for (idx, app) in apps.iter().enumerate() {
+        println!("app_{}: {}", idx, app);
+        writeln!(
+            f,
+            r#"
+    .section .data
+    .global app_{0}_start
+    .global app_{0}_end
+app_{0}_start:
+    .incbin "{2}{1}.bin"
+app_{0}_end:"#,
+            idx, app, TARGET_PATH
+        )?;
+    }
+    Ok(())
+}

os/src/.gitignore

@@ -0,0 +1 @@
+link_app.asm

os/src/batch.rs

@@ -0,0 +1,162 @@
+use core::arch::asm;
+
+use lazy_static::lazy_static;
+
+use crate::log_information;
+use crate::sbi::shutdown;
+use crate::sync::single_cell::SingleCell;
+use crate::trap::context::TrapContext;
+
+const MAX_APP_NUMBER: usize = 32;
+const APP_BASE_ADDRESS: usize = 0x80400000;
+const APP_SIZE_LIMIT: usize = 0x20000;
+
+struct AppManager {
+    app_count: usize,
+    current: usize,
+    start_addresses: [usize; MAX_APP_NUMBER + 1],
+}
+
+lazy_static! {
+    static ref APP_MANAGER: SingleCell<AppManager> = unsafe {
+        SingleCell::new({
+            extern "C" {
+                fn _num_app();
+            }
+
+            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(num_app_ptr.add(1), num_app + 1);
+            start_addresses[..=num_app].copy_from_slice(start_addresses_raw);
+            AppManager {
+                app_count: num_app,
+                current: 0,
+                start_addresses,
+            }
+        })
+    };
+}
+
+impl AppManager {
+    pub fn print_app_information(&self) {
+        log_information!("[kernel] Application count is {}.", self.app_count);
+
+        for i in 0..self.app_count {
+            log_information!(
+                "[kernel] Application_{} ({:#x} -> {:#x})",
+                i,
+                self.start_addresses[i],
+                self.start_addresses[i + 1]
+            );
+        }
+    }
+
+    pub fn get_current_app(&self) -> usize {
+        self.current
+    }
+
+    pub fn move_to_next_app(&mut self) {
+        self.current += 1;
+    }
+
+    unsafe fn load_app(&self, app_id: usize) {
+        if app_id >= self.app_count {
+            panic!("Application id is invalid!");
+        }
+
+        log_information!("[kernel] Loading application_{}...", app_id);
+
+        core::slice::from_raw_parts_mut(APP_BASE_ADDRESS as *mut u8, APP_SIZE_LIMIT).fill(0);
+
+        let app_source = core::slice::from_raw_parts(
+            self.start_addresses[app_id] as *const u8,
+            self.start_addresses[app_id + 1] - self.start_addresses[app_id],
+        );
+        let app_destination =
+            core::slice::from_raw_parts_mut(APP_BASE_ADDRESS as *mut u8, app_source.len());
+        app_destination.copy_from_slice(app_source);
+
+        // 保证指令缓存的更新
+        // 因为上述代码会修改指令数据段
+        asm!("fence.i");
+    }
+}
+
+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();
+    if current_app >= app_manager.app_count {
+        log_information!("Run out of applications, the os will stop!");
+        shutdown(true);
+    }
+
+    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/console.rs

@@ -1,6 +1,6 @@
+use crate::sbi::console_print;
 use core::fmt;
 use core::fmt::Write;
-use crate::sbi::console_print;
 
 struct Stdout;
 

os/src/main.rs

@@ -1,23 +1,25 @@
 #![no_std]
 #![no_main]
 
-use core::arch::global_asm;
 use crate::utils::clear_bss;
+use core::arch::global_asm;
 
-mod utils;
+mod batch;
-mod sbi;
 mod console;
+mod sbi;
+mod sync;
+mod syscall;
+mod trap;
+mod utils;
 
 global_asm!(include_str!("entry.asm"));
+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/sbi.rs

@@ -4,7 +4,7 @@ pub fn console_print(c: usize) {
 }
 
 pub fn shutdown(failure: bool) -> ! {
-    use sbi_rt::{system_reset, Shutdown, NoReason, SystemFailure};
+    use sbi_rt::{system_reset, NoReason, Shutdown, SystemFailure};
 
     if failure {
         system_reset(Shutdown, SystemFailure);

os/src/sync.rs

@@ -0,0 +1 @@
+pub mod single_cell;

os/src/sync/single_cell.rs

@@ -0,0 +1,22 @@
+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/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 +1,65 @@
+.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 +1,53 @@
+use crate::batch::run_next_application;
+use crate::println;
+use crate::syscall::syscall;
+use crate::trap::context::TrapContext;
+use core::arch::global_asm;
+use riscv::register::{
+    mtvec::TrapMode,
+    scause::{self, Exception, Trap},
+    stval, stvec,
+};
+
+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 +1,28 @@
+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;
+    }
+}

os/src/utils.rs

@@ -1,17 +1,19 @@
 use core::panic::PanicInfo;
-use crate::println;
+
+use crate::log_error;
 use crate::sbi::shutdown;
 
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     if let Some(location) = info.location() {
-        println!("Panicked at {}:{} {}.",
+        log_error!(
+            "Panicked at {}:{} {}.",
             location.file(),
             location.line(),
             info.message()
         );
     } else {
-        println!("Panicked: {}.", info.message());
+        log_error!("Panicked: {}.", info.message());
     }
 
     shutdown(true)
@@ -24,8 +26,6 @@ pub fn clear_bss() {
     }
 
     for m in sbss as usize..ebss as usize {
-        unsafe {
+        unsafe { (m as *mut u8).write_volatile(0) }
-            (m as *mut u8).write_volatile(0)
-        }
     }
 }

user/src/console.rs

@@ -1,5 +1,5 @@
-use core::fmt::Write;
 use crate::syscall::sys_write;
+use core::fmt::Write;
 
 struct Stdout;
 

user/src/lib.rs

@@ -3,8 +3,8 @@
 
 use crate::syscall::{sys_exit, sys_write};
 
-mod utils;
 mod syscall;
+mod utils;
 #[macro_use]
 pub mod console;
 
@@ -28,4 +28,3 @@ pub fn write(fd: usize, buf: &[u8]) -> isize {
 pub fn exit(exit_code: i32) -> isize {
     sys_exit(exit_code)
 }
-

user/src/syscall.rs

@@ -4,7 +4,7 @@ const SYSCALL_WRITE: usize = 64;
 const SYSCALL_EXIT: usize = 93;
 
 fn syscall(id: usize, args: [usize; 3]) -> isize {
-    let mut result : isize;
+    let mut result: isize;
 
     unsafe {
         asm!(

user/src/utils.rs

@@ -1,5 +1,5 @@
-use core::panic::PanicInfo;
 use crate::println;
+use core::panic::PanicInfo;
 
 pub fn clear_bss() {
     extern "C" {
@@ -9,9 +9,7 @@ pub fn clear_bss() {
     }
 
     for i in start_bss as usize..end_bss as usize {
-        unsafe {
+        unsafe { (i as *mut u8).write_volatile(0) }
-            (i as *mut u8).write_volatile(0)
-        }
     }
 }
 
@@ -20,7 +18,12 @@ fn panic_handler(info: &PanicInfo) -> ! {
     let message = info.message();
 
     if let Some(location) = info.location() {
-        println!("Panicked at {}:{} {}", location.file(), location.line(), message);
+        println!(
+            "Panicked at {}:{} {}",
+            location.file(),
+            location.line(),
+            message
+        );
     } else {
         println!("Panicked: {}", message);
     }