Update README

use python script instead of system exe

.dockerignore

@@ -0,0 +1 @@
+*/*

.gitignore

@@ -1,6 +1,10 @@
 .idea/*
 os/target/*
 os/.idea/*
+os/Cargo.lock
 os/src/link_app.S
+os/last-*
 user/target/*
-user/.idea/*
+user/.idea/*
+user/Cargo.lock
+tools/

Dockerfile

@@ -0,0 +1,40 @@
+FROM ubuntu:18.04
+LABEL maintainer="dinghao188" \
+      version="1.1" \
+      description="ubuntu 18.04 with tools for tsinghua's rCore-Tutorial-V3"
+
+#install some deps
+RUN set -x \
+    && apt-get update \
+    && apt-get install -y curl wget autoconf automake autotools-dev curl libmpc-dev libmpfr-dev libgmp-dev \
+              gawk build-essential bison flex texinfo gperf libtool patchutils bc xz-utils \
+              zlib1g-dev libexpat-dev pkg-config  libglib2.0-dev libpixman-1-dev git tmux python3 
+
+#install rust and qemu
+RUN set -x; \
+    RUSTUP='/root/rustup.sh' \
+    && cd $HOME \
+    #install rust
+    && curl https://sh.rustup.rs -sSf > $RUSTUP && chmod +x $RUSTUP \
+    && $RUSTUP -y --default-toolchain nightly --profile minimal \
+
+    #compile qemu
+    && wget https://ftp.osuosl.org/pub/blfs/conglomeration/qemu/qemu-5.0.0.tar.xz \
+    && tar xvJf qemu-5.0.0.tar.xz \
+    && cd qemu-5.0.0 \
+    && ./configure --target-list=riscv64-softmmu,riscv64-linux-user \
+    && make -j$(nproc) install \
+    && cd $HOME && rm -rf qemu-5.0.0 qemu-5.0.0.tar.xz
+
+#for chinese network
+RUN set -x; \
+    APT_CONF='/etc/apt/sources.list'; \
+    CARGO_CONF='/root/.cargo/config'; \
+    BASHRC='/root/.bashrc' \
+    && echo 'export RUSTUP_DIST_SERVER=https://mirrors.ustc.edu.cn/rust-static' >> $BASHRC \
+    && echo 'export RUSTUP_UPDATE_ROOT=https://mirrors.ustc.edu.cn/rust-static/rustup' >> $BASHRC \
+    && touch $CARGO_CONF \
+    && echo '[source.crates-io]' > $CARGO_CONF \
+    && echo "replace-with = 'ustc'" >> $CARGO_CONF \
+    && echo '[source.ustc]' >> $CARGO_CONF \
+    && echo 'registry = "git://mirrors.ustc.edu.cn/crates.io-index"' >> $CARGO_CONF

Makefile

@@ -0,0 +1,8 @@
+DOCKER_NAME ?= dinghao188/rcore-tutorial
+.PHONY: docker build_docker
+
+docker:
+	docker run --rm -it --mount type=bind,source=$(shell pwd),destination=/mnt ${DOCKER_NAME}
+
+build_docker: 
+	docker build -t ${DOCKER_NAME} .

README.md

@@ -1,2 +1,12 @@
 # rCore-Tutorial-v3
-rCore-Tutorial version 3.
+rCore-Tutorial version 3.x
+
+## Dependency
+
+### Binaries
+
+* rustc 1.56.0-nightly (b03ccace5 2021-08-24)
+
+* qemu: 5.0.0
+
+* rustsbi: qemu[7d71bfb7] k210[563144b0]

os/Cargo.lock

@@ -1,132 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-[[package]]
-name = "aho-corasick"
-version = "0.7.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
-dependencies = [
- "memchr",
-]
-
-[[package]]
-name = "bare-metal"
-version = "0.2.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5deb64efa5bd81e31fcd1938615a6d98c82eafcbcd787162b6f63b91d6bac5b3"
-dependencies = [
- "rustc_version",
-]
-
-[[package]]
-name = "bit_field"
-version = "0.10.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dcb6dd1c2376d2e096796e234a70e17e94cc2d5d54ff8ce42b28cef1d0d359a4"
-
-[[package]]
-name = "bitflags"
-version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
-
-[[package]]
-name = "lazy_static"
-version = "1.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
-dependencies = [
- "spin",
-]
-
-[[package]]
-name = "memchr"
-version = "2.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
-
-[[package]]
-name = "os"
-version = "0.1.0"
-dependencies = [
- "lazy_static",
- "riscv",
-]
-
-[[package]]
-name = "regex"
-version = "1.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
- "thread_local",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.6.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b181ba2dcf07aaccad5448e8ead58db5b742cf85dfe035e2227f137a539a189"
-
-[[package]]
-name = "riscv"
-version = "0.6.0"
-source = "git+https://github.com/rcore-os/riscv#21e32ee1dc786cc0d5006ceee0040ce4f8398575"
-dependencies = [
- "bare-metal",
- "bit_field",
- "bitflags",
- "riscv-target",
-]
-
-[[package]]
-name = "riscv-target"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88aa938cda42a0cf62a20cfe8d139ff1af20c2e681212b5b34adb5a58333f222"
-dependencies = [
- "lazy_static",
- "regex",
-]
-
-[[package]]
-name = "rustc_version"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
-dependencies = [
- "semver",
-]
-
-[[package]]
-name = "semver"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
-dependencies = [
- "semver-parser",
-]
-
-[[package]]
-name = "semver-parser"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-
-[[package]]
-name = "spin"
-version = "0.5.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
-
-[[package]]
-name = "thread_local"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
-dependencies = [
- "lazy_static",
-]

os/Makefile

@@ -3,13 +3,20 @@ TARGET := riscv64gc-unknown-none-elf
 MODE := release
 KERNEL_ELF := target/$(TARGET)/$(MODE)/os
 KERNEL_BIN := $(KERNEL_ELF).bin
-KERNEL_ENTRY_PA := 0x80020000
 DISASM_TMP := target/$(TARGET)/$(MODE)/asm
 
 # BOARD
 BOARD		?= qemu
 SBI			?= rustsbi
 BOOTLOADER	:= ../bootloader/$(SBI)-$(BOARD).bin
+K210_BOOTLOADER_SIZE := 131072
+
+# KERNEL ENTRY
+ifeq ($(BOARD), qemu)
+	KERNEL_ENTRY_PA := 0x80200000
+else ifeq ($(BOARD), k210)
+	KERNEL_ENTRY_PA := 0x80020000
+endif
 
 # Run K210
 K210-SERIALPORT	= /dev/ttyUSB0
@@ -22,14 +29,30 @@ OBJCOPY := rust-objcopy --binary-architecture=riscv64
 # Disassembly
 DISASM ?= -x
 
-build: $(KERNEL_BIN)
+build: env switch-check $(KERNEL_BIN)
+
+switch-check:
+ifeq ($(BOARD), qemu)
+	(which last-qemu) || (rm last-k210 -f && touch last-qemu && make clean)
+else ifeq ($(BOARD), k210)
+	(which last-k210) || (rm last-qemu -f && touch last-k210 && make clean)
+endif
+
+env:
+	rustup component add rust-src
+	rustup component add llvm-tools-preview
+	cargo install cargo-binutils --vers ~0.2
+	rustup target add riscv64gc-unknown-none-elf
 
 $(KERNEL_BIN): kernel
 	@$(OBJCOPY) $(KERNEL_ELF) --strip-all -O binary $@
 
 kernel:
 	@cd ../user && make build
+	@echo Platform: $(BOARD)
+	@cp src/linker-$(BOARD).ld src/linker.ld
 	@cargo build --release
+	@rm src/linker.ld
 
 clean:
 	@cargo clean
@@ -44,6 +67,8 @@ disasm-vim: kernel
 
 run: run-inner
 
+	
+
 run-inner: build
 ifeq ($(BOARD),qemu)
 	@qemu-system-riscv64 \
@@ -52,12 +77,13 @@ ifeq ($(BOARD),qemu)
 		-bios $(BOOTLOADER) \
 		-device loader,file=$(KERNEL_BIN),addr=$(KERNEL_ENTRY_PA)
 else
+	(which $(K210-BURNER)) || (cd .. && git clone https://github.com/sipeed/kflash.py.git && mv kflash.py tools)
 	@cp $(BOOTLOADER) $(BOOTLOADER).copy
-	@dd if=$(KERNEL_BIN) of=$(BOOTLOADER).copy bs=128K seek=1
+	@dd if=$(KERNEL_BIN) of=$(BOOTLOADER).copy bs=$(K210_BOOTLOADER_SIZE) seek=1
 	@mv $(BOOTLOADER).copy $(KERNEL_BIN)
 	@sudo chmod 777 $(K210-SERIALPORT)
 	python3 $(K210-BURNER) -p $(K210-SERIALPORT) -b 1500000 $(KERNEL_BIN)
-	miniterm --eol LF --dtr 0 --rts 0 --filter direct $(K210-SERIALPORT) 115200
+	python3 -m serial.tools.miniterm  --eol LF --dtr 0 --rts 0 --filter direct $(K210-SERIALPORT) 115200
 endif
 
 debug: build
@@ -66,4 +92,4 @@ debug: build
 		tmux split-window -h "riscv64-unknown-elf-gdb -ex 'file $(KERNEL_ELF)' -ex 'set arch riscv:rv64' -ex 'target remote localhost:1234'" && \
 		tmux -2 attach-session -d
 
-.PHONY: build kernel clean disasm disasm-vim run-inner
+.PHONY: build env kernel clean disasm disasm-vim run-inner switch-check

os/build.rs

@@ -2,11 +2,12 @@ use std::io::{Result, Write};
 use std::fs::{File, read_dir};
 
 fn main() {
-    println!("cargo:rerun-if-changed=../user/src/bin/");
+    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/debug/";
+static TARGET_PATH: &str = "../user/target/riscv64gc-unknown-none-elf/release/";
 
 fn insert_app_data() -> Result<()> {
     let mut f = File::create("src/link_app.S").unwrap();
@@ -22,21 +23,16 @@ fn insert_app_data() -> Result<()> {
     apps.sort();
 
     writeln!(f, r#"
-    .align 4
+    .align 3
     .section .data
     .global _num_app
 _num_app:
-    .quad {}
-    "#, apps.len())?;
+    .quad {}"#, apps.len())?;
 
     for i in 0..apps.len() {
-        writeln!(f, r#"
-    .quad app_{}_start
-        "#, i)?;
+        writeln!(f, r#"    .quad app_{}_start"#, i)?;
     }
-    writeln!(f, r#"
-    .quad app_{}_end
-    "#, apps.len() - 1)?;
+    writeln!(f, r#"    .quad app_{}_end"#, apps.len() - 1)?;
 
     for (idx, app) in apps.iter().enumerate() {
         println!("app_{}: {}", idx, app);
@@ -46,8 +42,7 @@ _num_app:
     .global app_{0}_end
 app_{0}_start:
     .incbin "{2}{1}.bin"
-app_{0}_end:
-        "#, idx, app, TARGET_PATH)?;
+app_{0}_end:"#, idx, app, TARGET_PATH)?;
     }
     Ok(())
 }

os/src/config.rs

@@ -1,5 +1,5 @@
 pub const USER_STACK_SIZE: usize = 4096 * 2;
 pub const KERNEL_STACK_SIZE: usize = 4096 * 2;
 pub const MAX_APP_NUM: usize = 4;
-pub const APP_BASE_ADDRESS: usize = 0x80100000;
+pub const APP_BASE_ADDRESS: usize = 0x80400000;
 pub const APP_SIZE_LIMIT: usize = 0x20000;

os/src/linker-k210.ld

@@ -18,6 +18,7 @@ SECTIONS
     srodata = .;
     .rodata : {
         *(.rodata .rodata.*)
+        *(.srodata .srodata.*)
     }
 
     . = ALIGN(4K);
@@ -25,6 +26,7 @@ SECTIONS
     sdata = .;
     .data : {
         *(.data .data.*)
+        *(.sdata .sdata.*)
     }
 
     . = ALIGN(4K);
@@ -33,6 +35,7 @@ SECTIONS
         *(.bss.stack)
         sbss = .;
         *(.bss .bss.*)
+        *(.sbss .sbss.*)
     }
 
     . = ALIGN(4K);

os/src/linker-qemu.ld

@@ -0,0 +1,48 @@
+OUTPUT_ARCH(riscv)
+ENTRY(_start)
+BASE_ADDRESS = 0x80200000;
+
+SECTIONS
+{
+    . = BASE_ADDRESS;
+    skernel = .;
+
+    stext = .;
+    .text : {
+        *(.text.entry)
+        *(.text .text.*)
+    }
+
+    . = ALIGN(4K);
+    etext = .;
+    srodata = .;
+    .rodata : {
+        *(.rodata .rodata.*)
+        *(.srodata .srodata.*)
+    }
+
+    . = ALIGN(4K);
+    erodata = .;
+    sdata = .;
+    .data : {
+        *(.data .data.*)
+        *(.sdata .sdata.*)
+    }
+
+    . = ALIGN(4K);
+    edata = .;
+    .bss : {
+        *(.bss.stack)
+        sbss = .;
+        *(.bss .bss.*)
+        *(.sbss .sbss.*)
+    }
+
+    . = ALIGN(4K);
+    ebss = .;
+    ekernel = .;
+
+    /DISCARD/ : {
+        *(.eh_frame)
+    }
+}

os/src/loader.rs

@@ -1,13 +1,14 @@
 use crate::trap::TrapContext;
-use crate::task::TaskContext;
 use crate::config::*;
 
 #[repr(align(4096))]
+#[derive(Copy, Clone)]
 struct KernelStack {
     data: [u8; KERNEL_STACK_SIZE],
 }
 
 #[repr(align(4096))]
+#[derive(Copy, Clone)]
 struct UserStack {
     data: [u8; USER_STACK_SIZE],
 }
@@ -26,14 +27,10 @@ impl KernelStack {
     fn get_sp(&self) -> usize {
         self.data.as_ptr() as usize + KERNEL_STACK_SIZE
     }
-    pub fn push_context(&self, trap_cx: TrapContext, task_cx: TaskContext) -> &'static mut TaskContext {
-        unsafe {
-            let trap_cx_ptr = (self.get_sp() - core::mem::size_of::<TrapContext>()) as *mut TrapContext;
-            *trap_cx_ptr = trap_cx;
-            let task_cx_ptr = (trap_cx_ptr as usize - core::mem::size_of::<TaskContext>()) as *mut TaskContext;
-            *task_cx_ptr = task_cx;
-            task_cx_ptr.as_mut().unwrap()
-        }
+    pub fn push_context(&self, trap_cx: TrapContext) -> usize {
+        let trap_cx_ptr = (self.get_sp() - core::mem::size_of::<TrapContext>()) as *mut TrapContext;
+        unsafe { *trap_cx_ptr = trap_cx; }
+        trap_cx_ptr as usize
     }
 }
 
@@ -60,7 +57,7 @@ pub fn load_apps() {
         core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1)
     };
     // clear i-cache first
-    unsafe { llvm_asm!("fence.i" :::: "volatile"); }
+    unsafe { asm!("fence.i"); }
     // load apps
     for i in 0..num_app {
         let base_i = get_base_i(i);
@@ -79,9 +76,8 @@ pub fn load_apps() {
     }
 }
 
-pub fn init_app_cx(app_id: usize) -> &'static TaskContext {
+pub fn init_app_cx(app_id: usize) -> usize {
     KERNEL_STACK[app_id].push_context(
         TrapContext::app_init_context(get_base_i(app_id), USER_STACK[app_id].get_sp()),
-        TaskContext::goto_restore(),
     )
 }

os/src/main.rs

@@ -1,9 +1,8 @@
 #![no_std]
 #![no_main]
 #![feature(global_asm)]
-#![feature(llvm_asm)]
+#![feature(asm)]
 #![feature(panic_info_message)]
-#![feature(const_in_array_repeat_expressions)]
 
 #[macro_use]
 mod console;
@@ -14,6 +13,7 @@ mod trap;
 mod loader;
 mod config;
 mod task;
+mod sync;
 
 global_asm!(include_str!("entry.asm"));
 global_asm!(include_str!("link_app.S"));
@@ -23,9 +23,12 @@ fn clear_bss() {
         fn sbss();
         fn ebss();
     }
-    (sbss as usize..ebss as usize).for_each(|a| {
-        unsafe { (a as *mut u8).write_volatile(0) }
-    });
+    unsafe {
+        core::slice::from_raw_parts_mut(
+            sbss as usize as *mut u8,
+            ebss as usize - sbss as usize,
+        ).fill(0);
+    }
 }
 
 #[no_mangle]

os/src/sbi.rs

@@ -14,11 +14,12 @@ const SBI_SHUTDOWN: usize = 8;
 fn sbi_call(which: usize, arg0: usize, arg1: usize, arg2: usize) -> usize {
     let mut ret;
     unsafe {
-        llvm_asm!("ecall"
-            : "={x10}" (ret)
-            : "{x10}" (arg0), "{x11}" (arg1), "{x12}" (arg2), "{x17}" (which)
-            : "memory"
-            : "volatile"
+        asm!(
+            "ecall",
+            inlateout("x10") arg0 => ret,
+            in("x11") arg1,
+            in("x12") arg2,
+            in("x17") which,
         );
     }
     ret

os/src/sync/mod.rs

@@ -0,0 +1,3 @@
+mod up;
+
+pub use up::UPSafeCell;

os/src/sync/up.rs

@@ -0,0 +1,27 @@
+use core::cell::{RefCell, RefMut};
+
+/// Wrap a static data structure inside it so that we are
+/// able to access it without any `unsafe`.
+///
+/// We should only use it in uniprocessor.
+///
+/// In order to get mutable reference of inner data, call
+/// `exclusive_access`.
+pub struct UPSafeCell<T> {
+    /// inner data
+    inner: RefCell<T>,
+}
+
+unsafe impl<T> Sync for UPSafeCell<T> {}
+
+impl<T> UPSafeCell<T> {
+    /// User is responsible to guarantee that inner struct is only used in
+    /// uniprocessor.
+    pub unsafe fn new(value: T) -> Self {
+        Self { inner: RefCell::new(value) }
+    }
+    /// Panic if the data has been borrowed.
+    pub fn exclusive_access(&self) -> RefMut<'_, T> {
+        self.inner.borrow_mut()
+    }
+}

os/src/syscall/process.rs

@@ -1,18 +1,15 @@
 use crate::task::{
-    mark_current_suspended,
-    mark_current_exited,
-    run_next_task
+    suspend_current_and_run_next,
+    exit_current_and_run_next,
 };
 
-pub fn sys_exit(xstate: i32) -> ! {
-    println!("[kernel] Application exited with code {}", xstate);
-    mark_current_exited();
-    run_next_task();
+pub fn sys_exit(exit_code: i32) -> ! {
+    println!("[kernel] Application exited with code {}", exit_code);
+    exit_current_and_run_next();
     panic!("Unreachable in sys_exit!");
 }
 
 pub fn sys_yield() -> isize {
-    mark_current_suspended();
-    run_next_task();
+    suspend_current_and_run_next();
     0
 }

os/src/task/context.rs

@@ -1,14 +1,24 @@
+#[derive(Copy, Clone)]
 #[repr(C)]
 pub struct TaskContext {
     ra: usize,
+    sp: usize,
     s: [usize; 12],
 }
 
 impl TaskContext {
-    pub fn goto_restore() -> Self {
+    pub fn zero_init() -> Self {
+        Self {
+            ra: 0,
+            sp: 0,
+            s: [0; 12],
+        }
+    }
+    pub fn goto_restore(kstack_ptr: usize) -> Self {
         extern "C" { fn __restore(); }
         Self {
             ra: __restore as usize,
+            sp: kstack_ptr,
             s: [0; 12],
         }
     }

os/src/task/mod.rs

@@ -4,16 +4,16 @@ mod task;
 
 use crate::config::MAX_APP_NUM;
 use crate::loader::{get_num_app, init_app_cx};
-use core::cell::RefCell;
 use lazy_static::*;
 use switch::__switch;
 use task::{TaskControlBlock, TaskStatus};
+use crate::sync::UPSafeCell;
 
 pub use context::TaskContext;
 
 pub struct TaskManager {
     num_app: usize,
-    inner: RefCell<TaskManagerInner>,
+    inner: UPSafeCell<TaskManagerInner>,
 }
 
 struct TaskManagerInner {
@@ -21,55 +21,62 @@ struct TaskManagerInner {
     current_task: usize,
 }
 
-unsafe impl Sync for TaskManager {}
-
 lazy_static! {
     pub static ref TASK_MANAGER: TaskManager = {
         let num_app = get_num_app();
         let mut tasks = [
-            TaskControlBlock { task_cx_ptr: 0, task_status: TaskStatus::UnInit };
+            TaskControlBlock {
+                task_cx: TaskContext::zero_init(),
+                task_status: TaskStatus::UnInit
+            };
             MAX_APP_NUM
         ];
         for i in 0..num_app {
-            tasks[i].task_cx_ptr = init_app_cx(i) as * const _ as usize;
+            tasks[i].task_cx = TaskContext::goto_restore(init_app_cx(i));
             tasks[i].task_status = TaskStatus::Ready;
         }
         TaskManager {
             num_app,
-            inner: RefCell::new(TaskManagerInner {
+            inner: unsafe { UPSafeCell::new(TaskManagerInner {
                 tasks,
                 current_task: 0,
-            }),
+            })},
         }
     };
 }
 
 impl TaskManager {
-    fn run_first_task(&self) {
-        self.inner.borrow_mut().tasks[0].task_status = TaskStatus::Running;
-        let next_task_cx = self.inner.borrow().tasks[0].get_task_cx_ptr2();
+    fn run_first_task(&self) -> ! {
+        let mut inner = self.inner.exclusive_access();
+        let task0 = &mut inner.tasks[0];
+        task0.task_status = TaskStatus::Running;
+        let next_task_cx_ptr = &task0.task_cx as *const TaskContext;
+        drop(inner);
+        let mut _unused = TaskContext::zero_init();
+        // before this, we should drop local variables that must be dropped manually
         unsafe {
             __switch(
-                &0usize as *const _,
-                next_task_cx,
+                &mut _unused as *mut TaskContext,
+                next_task_cx_ptr,
             );
         }
+        panic!("unreachable in run_first_task!");
     }
 
     fn mark_current_suspended(&self) {
-        let mut inner = self.inner.borrow_mut();
+        let mut inner = self.inner.exclusive_access();
         let current = inner.current_task;
         inner.tasks[current].task_status = TaskStatus::Ready;
     }
 
     fn mark_current_exited(&self) {
-        let mut inner = self.inner.borrow_mut();
+        let mut inner = self.inner.exclusive_access();
         let current = inner.current_task;
         inner.tasks[current].task_status = TaskStatus::Exited;
     }
 
     fn find_next_task(&self) -> Option<usize> {
-        let inner = self.inner.borrow();
+        let inner = self.inner.exclusive_access();
         let current = inner.current_task;
         (current + 1..current + self.num_app + 1)
             .map(|id| id % self.num_app)
@@ -80,21 +87,23 @@ impl TaskManager {
 
     fn run_next_task(&self) {
         if let Some(next) = self.find_next_task() {
-            let mut inner = self.inner.borrow_mut();
+            let mut inner = self.inner.exclusive_access();
             let current = inner.current_task;
             inner.tasks[next].task_status = TaskStatus::Running;
             inner.current_task = next;
-            let current_task_cx = inner.tasks[current].get_task_cx_ptr2();
-            let next_task_cx = inner.tasks[next].get_task_cx_ptr2();
-            core::mem::drop(inner);
+            let current_task_cx_ptr = &mut inner.tasks[current].task_cx as *mut TaskContext;
+            let next_task_cx_ptr = &inner.tasks[next].task_cx as *const TaskContext;
+            drop(inner);
+            // before this, we should drop local variables that must be dropped manually
             unsafe {
                 __switch(
-                    current_task_cx,
-                    next_task_cx,
+                    current_task_cx_ptr,
+                    next_task_cx_ptr,
                 );
             }
+            // go back to user mode
         } else {
-            panic!("[kernel] All applications completed!");
+            panic!("All applications completed!");
         }
     }
 }
@@ -103,14 +112,24 @@ pub fn run_first_task() {
     TASK_MANAGER.run_first_task();
 }
 
-pub fn run_next_task() {
+fn run_next_task() {
     TASK_MANAGER.run_next_task();
 }
 
-pub fn mark_current_suspended() {
+fn mark_current_suspended() {
     TASK_MANAGER.mark_current_suspended();
 }
 
-pub fn mark_current_exited() {
+fn mark_current_exited() {
     TASK_MANAGER.mark_current_exited();
+}
+
+pub fn suspend_current_and_run_next() {
+    mark_current_suspended();
+    run_next_task();
+}
+
+pub fn exit_current_and_run_next() {
+    mark_current_exited();
+    run_next_task();
 }

os/src/task/switch.S

@@ -1,34 +1,34 @@
 .altmacro
 .macro SAVE_SN n
-    sd s\n, (\n+1)*8(sp)
+    sd s\n, (\n+2)*8(a0)
 .endm
 .macro LOAD_SN n
-    ld s\n, (\n+1)*8(sp)
+    ld s\n, (\n+2)*8(a1)
 .endm
     .section .text
     .globl __switch
 __switch:
-    # __switch(current_task_cx: &*const TaskContext, next_task_cx: &*const TaskContext)
-    # push TaskContext to current sp and save its address to where a0 points to
-    addi sp, sp, -13*8
-    sd sp, 0(a0)
-    # fill TaskContext with ra & s0-s11
-    sd ra, 0(sp)
+    # __switch(
+    #     current_task_cx_ptr: *mut TaskContext,
+    #     next_task_cx_ptr: *const TaskContext
+    # )
+    # save kernel stack of current task
+    sd sp, 8(a0)
+    # save ra & s0~s11 of current execution
+    sd ra, 0(a0)
     .set n, 0
     .rept 12
         SAVE_SN %n
         .set n, n + 1
     .endr
-    # ready for loading TaskContext a1 points to
-    ld sp, 0(a1)
-    # load registers in the TaskContext
-    ld ra, 0(sp)
+    # restore ra & s0~s11 of next execution
+    ld ra, 0(a1)
     .set n, 0
     .rept 12
         LOAD_SN %n
         .set n, n + 1
     .endr
-    # pop TaskContext
-    addi sp, sp, 13*8
+    # restore kernel stack of next task
+    ld sp, 8(a1)
     ret
 

os/src/task/switch.rs

@@ -1,5 +1,10 @@
 global_asm!(include_str!("switch.S"));
 
+use super::TaskContext;
+
 extern "C" {
-    pub fn __switch(current_task_cx: *const usize, next_task_cx: *const usize);
+    pub fn __switch(
+        current_task_cx_ptr: *mut TaskContext,
+        next_task_cx_ptr: *const TaskContext
+    );
 }

os/src/task/task.rs

@@ -1,12 +1,9 @@
+use super::TaskContext;
+
+#[derive(Copy, Clone)]
 pub struct TaskControlBlock {
-    pub task_cx_ptr: usize,
     pub task_status: TaskStatus,
-}
-
-impl TaskControlBlock {
-    pub fn get_task_cx_ptr2(&self) -> *const usize {
-        &self.task_cx_ptr as *const usize
-    }
+    pub task_cx: TaskContext,
 }
 
 #[derive(Copy, Clone, PartialEq)]

rust-toolchain

@@ -1 +1 @@
-nightly-2020-11-01
+nightly-2021-08-25

user/Cargo.lock

@@ -1,5 +0,0 @@
-# This file is automatically @generated by Cargo.
-# It is not intended for manual editing.
-[[package]]
-name = "user_lib"
-version = "0.1.0"

user/Makefile

@@ -1,5 +1,5 @@
 TARGET := riscv64gc-unknown-none-elf
-MODE := debug
+MODE := release
 APP_DIR := src/bin
 TARGET_DIR := target/$(TARGET)/$(MODE)
 APPS := $(wildcard $(APP_DIR)/*.rs)

user/build.py

@@ -1,6 +1,6 @@
 import os
 
-base_address = 0x80100000
+base_address = 0x80400000
 step = 0x20000
 linker = 'src/linker.ld'
 
@@ -18,7 +18,7 @@ for app in apps:
             lines.append(line)
     with open(linker, 'w+') as f:
         f.writelines(lines)
-    os.system('cargo build --bin %s' % app)
+    os.system('cargo build --bin %s --release' % app)
     print('[build.py] application %s start with address %s' %(app, hex(base_address+step*app_id)))
     with open(linker, 'w+') as f:
         f.writelines(lines_before)

user/src/bin/00write_a.rs

@@ -4,7 +4,7 @@
 #[macro_use]
 extern crate user_lib;
 
-use user_lib::sys_yield;
+use user_lib::yield_;
 
 const WIDTH: usize = 10;
 const HEIGHT: usize = 5;
@@ -14,7 +14,7 @@ fn main() -> i32 {
     for i in 0..HEIGHT {
         for _ in 0..WIDTH { print!("A"); }
         println!(" [{}/{}]", i + 1, HEIGHT);
-        sys_yield();
+        yield_();
     }
     println!("Test write_a OK!");
     0

user/src/bin/01write_b.rs

@@ -4,7 +4,7 @@
 #[macro_use]
 extern crate user_lib;
 
-use user_lib::sys_yield;
+use user_lib::yield_;
 
 const WIDTH: usize = 10;
 const HEIGHT: usize = 2;
@@ -14,7 +14,7 @@ fn main() -> i32 {
     for i in 0..HEIGHT {
         for _ in 0..WIDTH { print!("B"); }
         println!(" [{}/{}]", i + 1, HEIGHT);
-        sys_yield();
+        yield_();
     }
     println!("Test write_b OK!");
     0

user/src/bin/02write_c.rs

@@ -4,7 +4,7 @@
 #[macro_use]
 extern crate user_lib;
 
-use user_lib::sys_yield;
+use user_lib::yield_;
 
 const WIDTH: usize = 10;
 const HEIGHT: usize = 3;
@@ -14,7 +14,7 @@ fn main() -> i32 {
     for i in 0..HEIGHT {
         for _ in 0..WIDTH { print!("C"); }
         println!(" [{}/{}]", i + 1, HEIGHT);
-        sys_yield();
+        yield_();
     }
     println!("Test write_c OK!");
     0

user/src/console.rs

@@ -1,11 +1,13 @@
 use core::fmt::{self, Write};
-use crate::syscall::{STDOUT, sys_write};
+use super::write;
 
 struct Stdout;
 
+const STDOUT: usize = 1;
+
 impl Write for Stdout {
     fn write_str(&mut self, s: &str) -> fmt::Result {
-        sys_write(STDOUT, s.as_bytes());
+        write(STDOUT, s.as_bytes());
         Ok(())
     }
 }

user/src/lib.rs

@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(llvm_asm)]
+#![feature(asm)]
 #![feature(linkage)]
 #![feature(panic_info_message)]
 
@@ -12,7 +12,7 @@ mod lang_items;
 #[link_section = ".text.entry"]
 pub extern "C" fn _start() -> ! {
     clear_bss();
-    syscall::sys_exit(main());
+    exit(main());
     panic!("unreachable after sys_exit!");
 }
 
@@ -32,4 +32,8 @@ fn clear_bss() {
     });
 }
 
-pub use syscall::*;
+use syscall::*;
+
+pub fn write(fd: usize, buf: &[u8]) -> isize { sys_write(fd, buf) }
+pub fn exit(exit_code: i32) -> isize { sys_exit(exit_code) }
+pub fn yield_() -> isize { sys_yield() }

user/src/linker.ld

@@ -2,7 +2,7 @@
 OUTPUT_ARCH(riscv)
 ENTRY(_start)
 
-BASE_ADDRESS = 0x80100000;
+BASE_ADDRESS = 0x80400000;
 
 SECTIONS
 {
@@ -13,13 +13,16 @@ SECTIONS
     }
     .rodata : {
         *(.rodata .rodata.*)
+        *(.srodata .srodata.*)
     }
     .data : {
         *(.data .data.*)
+        *(.sdata .sdata.*)
     }
     .bss : {
         start_bss = .;
         *(.bss .bss.*)
+        *(.sbss .sbss.*)
         end_bss = .;
     }
     /DISCARD/ : {

user/src/syscall.rs

@@ -1,18 +1,16 @@
-pub const STDOUT: usize = 1;
-
 const SYSCALL_WRITE: usize = 64;
 const SYSCALL_EXIT: usize = 93;
 const SYSCALL_YIELD: usize = 124;
-const SYSCALL_GET_TIME: usize = 169;
 
 fn syscall(id: usize, args: [usize; 3]) -> isize {
     let mut ret: isize;
     unsafe {
-        llvm_asm!("ecall"
-            : "={x10}" (ret)
-            : "{x10}" (args[0]), "{x11}" (args[1]), "{x12}" (args[2]), "{x17}" (id)
-            : "memory"
-            : "volatile"
+        asm!(
+            "ecall",
+            inlateout("x10") args[0] => ret,
+            in("x11") args[1],
+            in("x12") args[2],
+            in("x17") id
         );
     }
     ret
@@ -22,14 +20,10 @@ pub fn sys_write(fd: usize, buffer: &[u8]) -> isize {
     syscall(SYSCALL_WRITE, [fd, buffer.as_ptr() as usize, buffer.len()])
 }
 
-pub fn sys_exit(xstate: i32) -> isize {
-    syscall(SYSCALL_EXIT, [xstate as usize, 0, 0])
+pub fn sys_exit(exit_code: i32) -> isize {
+    syscall(SYSCALL_EXIT, [exit_code as usize, 0, 0])
 }
 
 pub fn sys_yield() -> isize {
     syscall(SYSCALL_YIELD, [0, 0, 0])
 }
-
-pub fn sys_get_time() -> isize {
-    syscall(SYSCALL_GET_TIME, [0, 0, 0])
-}