Merge #619

619: chore: create the process loader r=toku-sa-n a=toku-sa-n

- fix: the order of registers to be pushed
- chore: create a process loader

Fixes: #618 
bors r+


Co-authored-by: toku-sa-n <[email protected]>

Author: bors[bot]

kernel/src/process/manager.rs

@@ -44,6 +44,10 @@ fn add_process(p: Process) {
     collections::process::add(p);
 }
 
+pub(super) fn loader(f: fn() -> !) -> ! {
+    f()
+}
+
 enum Message {
     Add(fn() -> !, Privilege),
 }

kernel/src/process/stack_frame.rs

@@ -1,5 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 
+use core::convert::TryInto;
+
 use crate::gdt::GDT;
 use rflags::RFlags;
 use x86_64::{
@@ -15,18 +17,21 @@ pub struct StackFrame {
     interrupt: InterruptStackFrameValue,
 }
 impl StackFrame {
-    pub fn kernel(instruction_pointer: VirtAddr, stack_pointer: VirtAddr) -> Self {
-        Self::new(instruction_pointer, stack_pointer, &Selectors::kernel())
+    pub fn kernel(f: fn() -> !, stack_pointer: VirtAddr) -> Self {
+        Self::new(f, stack_pointer, &Selectors::kernel())
     }
 
-    pub fn user(instruction_pointer: VirtAddr, stack_pointer: VirtAddr) -> Self {
-        Self::new(instruction_pointer, stack_pointer, &Selectors::user())
+    pub fn user(f: fn() -> !, stack_pointer: VirtAddr) -> Self {
+        Self::new(f, stack_pointer, &Selectors::user())
     }
 
-    fn new(instruction_pointer: VirtAddr, stack_pointer: VirtAddr, segs: &Selectors) -> Self {
+    fn new(f: fn() -> !, stack_pointer: VirtAddr, segs: &Selectors) -> Self {
         let cpu_flags = (rflags::read() | RFlags::INTERRUPT_FLAG).bits();
+        let instruction_pointer =
+            VirtAddr::new((super::manager::loader as usize).try_into().unwrap());
+
         Self {
-            regs: GeneralRegisters::default(),
+            regs: GeneralRegisters::new(f),
             interrupt: InterruptStackFrameValue {
                 instruction_pointer,
                 code_segment: segs.code.0.into(),
@@ -59,13 +64,12 @@ impl Selectors {
 #[repr(C)]
 #[derive(Default, Debug)]
 struct GeneralRegisters {
-    _rbp: u64,
     _rax: u64,
     _rbx: u64,
     _rcx: u64,
     _rdx: u64,
     _rsi: u64,
-    _rdi: u64,
+    rdi: u64,
     _r8: u64,
     _r9: u64,
     _r10: u64,
@@ -74,4 +78,13 @@ struct GeneralRegisters {
     _r13: u64,
     _r14: u64,
     _r15: u64,
+    _rbp: u64,
+}
+impl GeneralRegisters {
+    fn new(f: fn() -> !) -> Self {
+        Self {
+            rdi: (f as usize).try_into().unwrap(),
+            ..Self::default()
+        }
+    }
 }

kernel/src/process/switch.rs

@@ -92,13 +92,10 @@ impl<'a> StackCreator<'a> {
 
         match self.process.stack {
             Some(ref s) => {
-                let instruction_pointer =
-                    VirtAddr::new((self.process.f as usize).try_into().unwrap());
                 let stack_bottom = s.virt_addr() + s.bytes().as_usize();
-
                 let stack_frame = PageBox::kernel(match self.process.privilege {
-                    Privilege::Kernel => StackFrame::kernel(instruction_pointer, stack_bottom),
-                    Privilege::User => StackFrame::user(instruction_pointer, stack_bottom),
+                    Privilege::Kernel => StackFrame::kernel(self.process.f, stack_bottom),
+                    Privilege::User => StackFrame::user(self.process.f, stack_bottom),
                 });
 
                 self.process.stack_frame = Some(stack_frame);