112 lines
4.0 KiB
Rust
112 lines
4.0 KiB
Rust
use core::arch::asm;
|
|
use lazy_static::*;
|
|
use riscv::register::mcause::Trap;
|
|
use crate::println;
|
|
use crate::sbi::shutdown;
|
|
use crate::sync::UPSafeCell;
|
|
use crate::trap::TrapContext;
|
|
|
|
const USER_STACK_SIZE: usize = 4096 * 2; // 栈大小为8kb
|
|
const KERNEL_STACK_SIZE: usize = 4096 * 2;
|
|
|
|
const MAX_APP_NUM: usize = 16; // 系统最大支持的运行程序数量
|
|
|
|
const APP_BASE_ADDRESS: usize = 0x80400000; // 载入的app的起始的地址
|
|
const APP_SIZE_LIMIT: usize = 0x20000; // app的最大的二进制文件能够使用的大小
|
|
|
|
// 在此之后 应用使用UserStack, 而内核使用KernelStack, entry.asm设置的64k启动栈不再被使用(首次运行run_next_app时被接管了 mv sp, a0)
|
|
// KERNEL_STACK 保存的是 Trap Context
|
|
|
|
static KERNEL_STACK: [u8; KERNEL_STACK_SIZE] = [0; KERNEL_STACK_SIZE];
|
|
static USER_STACK: [u8; USER_STACK_SIZE] = [0; USER_STACK_SIZE];
|
|
|
|
lazy_static! {
|
|
static ref APP_MANAGER: UPSafeCell<AppManager> = unsafe {
|
|
UPSafeCell::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(); // 用户app的总数量
|
|
|
|
let mut app_start_lis: [usize; MAX_APP_NUM + 1] = [0; MAX_APP_NUM + 1]; // 创建一个数组, 用来保存每个app的起始位置
|
|
|
|
// 得到每个app的起始地址
|
|
let mut app_start_lis: [usize; MAX_APP_NUM + 1] = [0; MAX_APP_NUM + 1];
|
|
let app_start_raw: &[usize] =
|
|
core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1);
|
|
app_start_lis[..=num_app].copy_from_slice(app_start_raw);
|
|
|
|
AppManager{
|
|
num_app,
|
|
current_app: 0,
|
|
app_start_lis
|
|
}
|
|
})
|
|
};
|
|
}
|
|
|
|
// 由build.rs 生成的link_app.S, 根据里面的信息生成的结构体
|
|
struct AppManager {
|
|
num_app: usize, // 用户app数量
|
|
current_app: usize, // 当前需要执行的第几个app
|
|
app_start_lis: [usize; MAX_APP_NUM + 1], // 保存了每个app的起始位置, 后面会跳到这里, +1 是因为end的位置也占了一个usize, 需要知道end的位置
|
|
}
|
|
|
|
impl AppManager{
|
|
fn show_app_info(&self){
|
|
println!("[kernel] num_app = {}", self.num_app);
|
|
for i in 0..self.num_app {
|
|
println!(
|
|
"[kernel] app_{} ({:#x}, {:#x})",
|
|
i,
|
|
self.app_start_lis[i],
|
|
self.app_start_lis[i + 1]
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
pub fn init() {
|
|
APP_MANAGER.exclusive_access().show_app_info();
|
|
}
|
|
|
|
pub fn run_next_app() -> ! {
|
|
// 得到下一个需要运行的app的入口地址
|
|
let mut app_manager = APP_MANAGER.exclusive_access();
|
|
let current_app = app_manager.current_app;
|
|
if current_app >= app_manager.num_app {
|
|
shutdown();
|
|
}
|
|
let app_entry_ptr = app_manager.app_start_lis[current_app];
|
|
println!("------------- run_next_app load app {}, {:x}", current_app, app_entry_ptr);
|
|
app_manager.current_app += 1;
|
|
drop(app_manager);
|
|
|
|
|
|
extern "C" {
|
|
fn __restore(trap_context_ptr: usize);
|
|
}
|
|
|
|
unsafe {
|
|
// 得到用户栈的栈顶
|
|
let user_stack_top = USER_STACK.as_ptr() as usize + USER_STACK_SIZE;
|
|
// 得到用户trap的上下文以及寄存器状态
|
|
let user_trap_context = TrapContext::app_init_context(app_entry_ptr, user_stack_top);
|
|
|
|
// 把用户trap copy到内核栈
|
|
let kernel_stack_top = KERNEL_STACK.as_ptr() as usize + KERNEL_STACK_SIZE; // 现在栈顶和栈底都在一个内存位置
|
|
// 为trap context 分配栈空间
|
|
let kernel_trap_context_ptr = (kernel_stack_top - core::mem::size_of::<TrapContext>()) as * mut TrapContext;
|
|
|
|
unsafe {
|
|
// 把user_trap_context copy到内核栈顶
|
|
*kernel_trap_context_ptr = user_trap_context;
|
|
// 返回现在的内核栈顶
|
|
__restore(kernel_trap_context_ptr as *const _ as usize);
|
|
}
|
|
}
|
|
panic!("Unreachable in batch::run_current_app!");
|
|
}
|