增加x87FPU支持 (#212)

* remove `ret_from_syscall`
*修复ps2键盘驱动程序inode在进程fork的时候导致死锁的问题.
*更新: VFS每次拷贝文件描述符的时候,都会去调用inode的open函数

---------

Co-authored-by: longjin <longjin@RinGoTek.cn>

kernel/src/ipc/signal.rs

@@ -1,8 +1,14 @@
-use core::{ffi::c_void, intrinsics::size_of, ptr::read_volatile, sync::atomic::compiler_fence};
+use core::{
+    ffi::c_void,
+    intrinsics::size_of,
+    ptr::{null_mut, read_volatile},
+    sync::atomic::compiler_fence,
+};
 
 use crate::{
     arch::{
         asm::{bitops::ffz, current::current_pcb, ptrace::user_mode},
+        fpu::FpState,
         interrupt::sti,
     },
     include::bindings::bindings::{
@@ -658,6 +664,17 @@ fn setup_frame(
         (*frame).handler = ka._u._sa_handler as usize as *mut c_void;
     }
 
+    // 将当前进程的fp_state拷贝到用户栈
+    if current_pcb().fp_state != null_mut() {
+        unsafe {
+            let fp_state: &mut FpState = (current_pcb().fp_state as usize as *mut FpState)
+                .as_mut()
+                .unwrap();
+            (*frame).context.sc_stack.fpstate = *fp_state;
+            // 保存完毕后，清空fp_state，以免下次save的时候，出现SIMD exception
+            fp_state.clear();
+        }
+    }
     // 将siginfo拷贝到用户栈
     err |= copy_siginfo_to_user(unsafe { &mut (*frame).info }, info).unwrap_or(1);
 
@@ -768,7 +785,11 @@ fn restore_sigcontext(context: *const sigcontext, regs: &mut pt_regs) -> bool {
         (*current_thread).trap_num = (*context).trap_num;
         (*current_thread).cr2 = (*context).cr2;
         (*current_thread).err_code = (*context).err_code;
+
+        // 如果当前进程有fpstate，则将其恢复到pcb的fp_state中
+        *(current_pcb().fp_state as usize as *mut FpState) = (*context).sc_stack.fpstate;
     }
+
     return true;
 }
 

kernel/src/ipc/signal_types.rs

@@ -6,6 +6,7 @@ use core::fmt::Debug;
 
 use alloc::vec::Vec;
 
+use crate::arch::fpu::FpState;
 use crate::include::bindings::bindings::NULL;
 // todo: 将这里更换为手动编写的ffi绑定
 use crate::include::bindings::bindings::atomic_t;
@@ -664,4 +665,5 @@ pub struct signal_stack {
     pub sp: *mut c_void,
     pub flags: u32,
     pub size: u32,
+    pub fpstate:FpState,
 }