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bugfix: Putting fence.i after loading apps

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This commit is contained in:
Yifan Wu 2024-02-19 22:34:20 +08:00
parent d27f835f3e
commit 8afce1c1a1
1 changed files with 9 additions and 4 deletions
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13
os/src/loader.rs
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@ -70,10 +70,6 @@ pub fn load_apps() {
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 = get_num_app(); let num_app = get_num_app();
let app_start = unsafe { core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1) }; let app_start = unsafe { core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1) };
// clear i-cache first
unsafe {
asm!("fence.i");
}
// load apps // load apps
for i in 0..num_app { for i in 0..num_app {
let base_i = get_base_i(i); let base_i = get_base_i(i);
@ -87,6 +83,15 @@ pub fn load_apps() {
let dst = unsafe { core::slice::from_raw_parts_mut(base_i as *mut u8, src.len()) }; let dst = unsafe { core::slice::from_raw_parts_mut(base_i as *mut u8, src.len()) };
dst.copy_from_slice(src); dst.copy_from_slice(src);
} }
// Memory fence about fetching the instruction memory
// It is guaranteed that a subsequent instruction fetch must
// observes all previous writes to the instruction memory.
// Therefore, fence.i must be executed after we have loaded
// the code of the next app into the instruction memory.
// See also: riscv non-priv spec chapter 3, 'Zifencei' extension.
unsafe {
asm!("fence.i");
}
} }
/// get app info with entry and sp and save `TrapContext` in kernel stack /// get app info with entry and sp and save `TrapContext` in kernel stack