Merge branch 'scheduler_refactor'

Author: Andy-Python-Programmer

src/aero_kernel/src/apic.rs

@@ -108,7 +108,7 @@ impl From<FeatureInfo> for ApicType {
     }
 }
 
-fn lapic_error_handler(stack: &mut InterruptStack) {
+fn lapic_error_handler(_stack: &mut InterruptStack) {
     log::error!("Local apic error");
     log::error!("ESR={:#0x}", self::get_local_apic().get_esr());
 }

src/aero_kernel/src/arch/x86_64/gdt.rs

@@ -63,7 +63,6 @@ bitflags::bitflags! {
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Ring {
     Ring0 = 0b00,
-    Ring3 = 0b11,
 }
 
 const BOOT_GDT_ENTRY_COUNT: usize = 4;
@@ -273,22 +272,22 @@ impl GdtEntry {
 /// mode and its not directly related to task switching mechanism.
 #[repr(C, packed)]
 pub struct Tss {
-    reserved: u32,
+    reserved: u32, // offset 0x00
 
     /// The full 64-bit canonical forms of the stack pointers (RSP) for
     /// privilege levels 0-2.
-    pub rsp: [u64; 3],
-    reserved2: u64,
+    pub rsp: [u64; 3], // offset 0x04
+    reserved2: u64, // offset 0x1C
 
     /// The full 64-bit canonical forms of the interrupt stack table
     /// (IST) pointers.
-    pub ist: [u64; 7],
-    reserved3: u64,
-    reserved4: u16,
+    pub ist: [u64; 7], // offset 0x24
+    reserved3: u64, // offset 0x5c
+    reserved4: u16, // offset 0x64
 
     /// The 16-bit offset to the I/O permission bit map from the 64-bit
     /// TSS base.
-    pub iomap_base: u16,
+    pub iomap_base: u16, // offset 0x66
 }
 
 // Processor Control Region

src/aero_kernel/src/arch/x86_64/interrupts/exceptions.rs

@@ -24,6 +24,7 @@ use crate::mem::paging::PageFaultErrorCode;
 
 use crate::unwind;
 use crate::userland::scheduler;
+use crate::utils::io;
 
 macro interrupt_exception(fn $name:ident() => $message:expr) {
     pub fn $name(stack: &mut InterruptErrorStack) {
@@ -82,6 +83,18 @@ pub(super) fn page_fault(stack: &mut InterruptErrorStack) {
     // a non-mapped memory region while in RPL_3.
     let userland_last_address = super::super::task::userland_last_address();
 
+    // prints out the error information for this page fault.
+    let print_info = || {
+        log::error!("");
+        log::error!("FS={:#x}", unsafe { io::rdmsr(io::IA32_FS_BASE) },);
+        log::error!("GS={:#x}", unsafe { io::rdmsr(io::IA32_GS_BASE) });
+        log::error!("");
+        log::error!("accessed address: {:#x}", accessed_address);
+        log::error!("reason: {:?}", reason);
+        log::error!("");
+        log::error!("stack: {:#x?}", stack);
+    };
+
     if accessed_address < userland_last_address && scheduler::is_initialized() {
         let signal = scheduler::get_scheduler()
             .current_task()
@@ -90,10 +103,7 @@ pub(super) fn page_fault(stack: &mut InterruptErrorStack) {
 
         if !signal && stack.stack.iret.is_user() {
             log::error!("Segmentation fault");
-            log::error!("");
-            log::error!("accessed address: {:#x}", accessed_address);
-            log::error!("reason: {:?}", reason);
-            log::error!("");
+            print_info();
 
             if stack.stack.iret.is_user() {
                 let task = scheduler::get_scheduler().current_task();
@@ -105,8 +115,6 @@ pub(super) fn page_fault(stack: &mut InterruptErrorStack) {
                 );
             }
 
-            log::error!("stack: {:#x?}", stack);
-
             scheduler::get_scheduler().current_task().vm.log();
             scheduler::get_scheduler().current_task().file_table.log();
 
@@ -124,13 +132,8 @@ pub(super) fn page_fault(stack: &mut InterruptErrorStack) {
 
     unwind::prepare_panic();
 
-    log::error!("EXCEPTION: Page Fault");
-    log::error!("");
-    log::error!("Accessed Address: {:#x}", accessed_address);
-    log::error!("Error: {:?}", reason);
-    log::error!("");
-
-    log::error!("Stack: {:#x?}", stack);
+    log::error!("Page fault");
+    print_info();
 
     unwind::unwind_stack_trace();
 

src/aero_kernel/src/arch/x86_64/interrupts/idt.rs

@@ -100,7 +100,7 @@ impl IdtEntry {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Default)]
 #[repr(C)]
 pub struct ScratchRegisters {
     pub r11: u64,
@@ -114,7 +114,7 @@ pub struct ScratchRegisters {
     pub rax: u64,
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Default)]
 #[repr(C)]
 pub struct PreservedRegisters {
     pub r15: u64,
@@ -125,7 +125,7 @@ pub struct PreservedRegisters {
     pub rbx: u64,
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Default)]
 #[repr(C)]
 pub struct IretRegisters {
     pub rip: u64,
@@ -141,7 +141,7 @@ impl IretRegisters {
     }
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone, Copy, Default)]
 #[repr(C)]
 pub struct InterruptStack {
     pub preserved: PreservedRegisters,

src/aero_kernel/src/arch/x86_64/signals.rs

@@ -17,7 +17,6 @@
  * along with Aero. If not, see <https://www.gnu.org/licenses/>.
  */
 
-use crate::syscall::{RegistersFrame, SyscallFrame};
 use crate::userland;
 use crate::userland::scheduler;
 use crate::utils::StackHelper;
@@ -94,20 +93,16 @@ pub fn interrupt_check_signals(stack: &mut InterruptStack) {
 }
 
 /// Helper function to check for any pending signals from a sycall.
-pub fn syscall_check_signals(
-    _syscall_result: isize,
-    _syscall: &mut SyscallFrame,
-    _registers: &mut RegistersFrame,
-) {
+pub fn syscall_check_signals(_syscall_result: isize, _stack: &mut InterruptStack) {
     if let Some((_signal, entry)) = userland::signals::check_for_signals() {
         if let aero_syscall::signal::SignalHandler::Handle(_) = entry.handler() {
             todo!()
         }
     }
 }
 
-pub fn sigreturn(sys: &mut SyscallFrame, regs: &mut RegistersFrame) -> usize {
-    let mut writer = StackHelper::new(&mut sys.rsp);
+pub fn sigreturn(stack: &mut InterruptStack) -> usize {
+    let mut writer = StackHelper::new(&mut stack.iret.rsp);
     let signal_frame = unsafe { writer.get::<SignalFrame>() };
 
     let current_task = scheduler::get_scheduler().current_task();
@@ -121,33 +116,11 @@ pub fn sigreturn(sys: &mut SyscallFrame, regs: &mut RegistersFrame) -> usize {
     writer.get_by(REDZONE_SIZE);
 
     let result = signal_frame.frame.scratch.rax;
-
-    let ret_regs = RegistersFrame {
-        cr2: 0, // TODO: we have to fill up the cr2 as well
-        rax: signal_frame.frame.scratch.rax,
-        rbx: signal_frame.frame.preserved.rbx,
-        rcx: signal_frame.frame.scratch.rcx,
-        rdx: signal_frame.frame.scratch.rdx,
-        rsi: signal_frame.frame.scratch.rsi,
-        rdi: signal_frame.frame.scratch.rdi,
-        rbp: signal_frame.frame.preserved.rbp,
-        r8: signal_frame.frame.scratch.r8,
-        r9: signal_frame.frame.scratch.r9,
-        r10: signal_frame.frame.scratch.r10,
-        r11: signal_frame.frame.scratch.r11,
-        r12: signal_frame.frame.preserved.r12,
-        r13: signal_frame.frame.preserved.r13,
-        r14: signal_frame.frame.preserved.r14,
-        r15: signal_frame.frame.preserved.r15,
-    };
-
-    sys.rflags = signal_frame.frame.iret.rflags;
-    sys.rip = signal_frame.frame.iret.rip;
+    *stack = signal_frame.frame;
 
     if signal_frame.restart_syscall != u64::MAX {
-        sys.rip -= SYSCALL_INSTRUCTION_SIZE;
+        stack.iret.rip -= SYSCALL_INSTRUCTION_SIZE;
     }
 
-    *regs = ret_regs;
     result as usize
 }

src/aero_kernel/src/arch/x86_64/task.asm

@@ -18,100 +18,77 @@
 global jump_userland_exec
 global task_spinup
 global iretq_init
-global sysret_fork_init
-
-extern restore_user_tls
+global fork_init
 
 jump_userland_exec:
     push rdi ; Param: stack
     push rsi ; Param: RIP
     push rdx ; Param: RFLAGS
 
     cli
-    call restore_user_tls
 
     pop r11
     pop rcx
     pop rsp
 
     swapgs
-
     o64 sysret
 
-iretq_init:
-    pop rdi
-    iretq
-
-sysret_fork_init:
-    cli
-    call restore_user_tls
+fork_init:
+    swapgs
+    jmp iretq_init
 
-    pop rax
-    mov cr2, rax
-    pop rax
+iretq_init:
+    ; pop the preserved registers
+    pop r15
+    pop r14
+    pop r13
+    pop r12
+    pop rbp
     pop rbx
-    pop rcx
-    pop rdx
+
+    ; pop the scratch registers
+    pop r11
+    pop r10
+    pop r9
+    pop r8
     pop rsi
     pop rdi
-    pop rbp
-    pop r8
-    pop r9
-    pop r10
-    pop r11
-    pop r12
-    pop r13
-    pop r14
-    pop r15
-
-    pop r11     ; Restore rflags
-    pop rcx     ; Restore rip
-
-    push rdx
-
-    mov rdx, rsp
-    add rdx, 16            ; Skip RDX and user RSP currently on the stack
-    mov [gs:0x04], rdx     ; Stash kernel stack
-
     pop rdx
-    pop rsp                ; Restore user stack
-
-    swapgs
+    pop rcx
+    pop rax
 
-    o64 sysret
+    iretq
 
 ; extern "C" fn task_spinup(prev: &mut Context, next: &mut Context)
 ;
 ; Saves the current context into `prev` and restore the context from `next`.
 task_spinup:
-    pushfq
-
-    cli
-
+    ; save callee-saved registers and this must match
+    ; the ordering of the fields in the `Context` struct.
     push rbp
-    push r15
-    push r14
-    push r13
-    push r12
     push rbx
+    push r12
+    push r13
+    push r14
+    push r15
 
-    mov rax, cr3    ; Save CR3
+    mov rax, cr3    ; save CR3
     push rax
 
-    mov [rdi], rsp	; Update old context pointer with current stack pointer
-    mov rsp, rsi	; Switch to new stack
+    mov [rdi], rsp	; update old context pointer with current stack pointer
+    mov rsp, rsi	; switch to new stack
 
-    pop rax         ; Restore CR3
+    pop rax         ; restore CR3
     mov cr3, rax
 
-    pop rbx
-    pop r12
-    pop r13
-    pop r14
+    ; restore callee-saved registers
     pop r15
+    pop r14
+    pop r13
+    pop r12
+    pop rbx
     pop rbp
 
-    popfq
-
-    ; Resume the next thread.
+    ; resume the next thread
     ret