Switch to usermode

Cargo.lock

@@ -64,7 +64,7 @@ dependencies = [
  "regex",
  "rustc-hash",
  "shlex",
- "syn 2.0.90",
+ "syn 2.0.91",
 ]
 
 [[package]]
@@ -319,7 +319,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "64d1ec885c64d0457d564db4ec299b2dae3f9c02808b8ad9c3a089c591b18033"
 dependencies = [
  "proc-macro2",
- "syn 2.0.90",
+ "syn 2.0.91",
 ]
 
 [[package]]
@@ -453,9 +453,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.90"
+version = "2.0.91"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "919d3b74a5dd0ccd15aeb8f93e7006bd9e14c295087c9896a110f490752bcf31"
+checksum = "d53cbcb5a243bd33b7858b1d7f4aca2153490815872d86d955d6ea29f743c035"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -501,7 +501,7 @@ checksum = "9b24e77d3fc1e617051e630f99da24bcae6328abab37b8f9216bb68d06804f9a"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.90",
+ "syn 2.0.91",
 ]
 
 [[package]]

init/src/main.rs

@@ -1,10 +1,11 @@
 #![no_std]
 #![no_main]
+use core::{arch::global_asm, panic::PanicInfo};
 
-use core::panic::PanicInfo;
+global_asm!(include_str!("start.s"), options(att_syntax));
 
 #[no_mangle]
-extern "C" fn _start() -> ! {
+extern "C" fn main() -> ! {
     loop {}
 }
 

init/src/start.s

@@ -0,0 +1,11 @@
+.text
+
+.global _start
+_start:
+  mov $stack, %rsp
+  call main
+
+.section .bss
+.align 16
+.skip 0x10000
+stack:

kernel/src/cpu/gdt.rs

@@ -55,6 +55,7 @@ pub fn setup_gdt() {
         reserved4: 0,
         iopb_offset: size_of::<TSS>() as u16,
     }));
+    tss.rsp[0] = allocate_stack();
     tss.ist[0] = allocate_stack();
     tss.ist[1] = allocate_stack();
     let gdt = Box::leak(Box::new(GDT {
@@ -113,7 +114,7 @@ pub fn setup_gdt() {
     }));
     let gdt_descriptor = Box::leak(Box::new(GDTDescriptor {
         limit: (size_of::<GDT>() - 1) as u16,
-        base: gdt.entries.as_ptr() as u64,
+        base: gdt as *mut GDT as u64,
     }));
     unsafe {
         asm!("

kernel/src/cpu/isr.rs

@@ -3,13 +3,18 @@ use core::{
     sync::atomic::Ordering,
 };
 
+use kernel_common::instructions::hlt;
 use log::warn;
 
-use crate::sys::{
+use crate::{
+    sys::{
         lapic::{get_current_lapic_id, send_eoi},
         locks::Spinlock,
         scheduler::scheduler,
         sync::{IN_ISR_HANDLER, LOCKS_HELD},
+        task::{terminate_current_task, terminate_tasks},
+    },
+    BROADCASTED_PANIC,
 };
 
 global_asm!(include_str!("isr.s"), options(att_syntax));
@@ -82,8 +87,10 @@ pub static ISR_HANDLERS: Spinlock<[Option<fn()>; 256]> = Spinlock::new([None; 25
 
 #[no_mangle]
 extern "C" fn isr_handler(state: &mut ISRState) {
-    if state.isr < 32 {
-        panic!("Exception: {}", EXCEPTIONS[state.isr as usize]);
+    if BROADCASTED_PANIC.load(Ordering::SeqCst) {
+        loop {
+            hlt();
+        }
     }
     if 32 <= state.isr && state.isr <= 47 {
         return; // Legacy PIC interrupt
@@ -103,6 +110,17 @@ extern "C" fn isr_handler(state: &mut ISRState) {
     }
     let lapic_id = get_current_lapic_id();
     IN_ISR_HANDLER[lapic_id].store(true, Ordering::SeqCst);
+    if state.isr < 32 {
+        if state.cs == 0x1b && state.isr != 2 && state.isr != 8 {
+            warn!("Exception in usermode: {}", EXCEPTIONS[state.isr as usize]);
+            terminate_current_task();
+            state.isr = ISR_SCHEDULER;
+        } else {
+            panic!("Exception: {}", EXCEPTIONS[state.isr as usize]);
+        }
+    } else {
+        terminate_tasks();
+    }
     if state.isr == ISR_SCHEDULER {
         scheduler(state);
         debug_assert_eq!(LOCKS_HELD[lapic_id].load(Ordering::SeqCst), 0);

kernel/src/cpu/usermode.s

@@ -0,0 +1,31 @@
+.text
+
+.global jump_usermode
+jump_usermode:
+  mov $0x23, %ax
+  mov %ax, %ds
+  mov %ax, %es
+  mov %ax, %fs
+  mov %ax, %gs
+  push $0x23
+  push $0
+  pushf
+  push $0x1b
+  push %rdi
+
+  xor %rax, %rax
+  xor %rbx, %rbx
+  xor %rcx, %rcx
+  xor %rdx, %rdx
+  xor %rdi, %rdi
+  xor %rsi, %rsi
+  xor %rbp, %rbp
+  xor %r8, %r8
+  xor %r9, %r9
+  xor %r10, %r10
+  xor %r11, %r11
+  xor %r12, %r12
+  xor %r13, %r13
+  xor %r14, %r14
+  xor %r15, %r15
+  iretq

kernel/src/main.rs

@@ -63,6 +63,7 @@ pub static BROADCASTED_PANIC: AtomicBool = AtomicBool::new(false);
 
 global_asm!(include_str!("cpu/boot.s"), options(att_syntax));
 global_asm!(include_str!("cpu/trampoline.s"), options(att_syntax));
+global_asm!(include_str!("cpu/usermode.s"), options(att_syntax));
 
 #[cfg(debug_assertions)]
 const INIT_BINARY: &[u8] = include_bytes!("../../target/x86_64-unknown-none/debug/init");
@@ -116,10 +117,9 @@ fn main() {
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     cli();
-    if !BROADCASTED_PANIC.load(Ordering::SeqCst) {
     if INTERRUPTS_SETUP.load(Ordering::SeqCst) {
-            smp_broadcast_panic();
         LOCKS_HELD[get_current_lapic_id()].fetch_add(1, Ordering::SeqCst);
+        smp_broadcast_panic();
     }
     error!("{}", info);
     let str = format!("{}", info);
@@ -128,7 +128,6 @@ fn panic(info: &PanicInfo) -> ! {
         display.clear();
         display.print(&str);
     }
-    }
     loop {
         hlt();
     }

kernel/src/misc/elf.rs

@@ -1,4 +1,4 @@
-use core::{mem, ptr};
+use core::ptr;
 
 use elf::{abi::PT_LOAD, endian::LittleEndian, ElfBytes};
 use log::info;
@@ -8,10 +8,13 @@ use crate::{
     sys::{lapic::get_current_lapic_id, task::CURRENT_TASKS},
 };
 
-const USER_END: u64 = 0x800000000000;
+const USER_END: u64 = 0x800000000000 - 0x1000; // Avoid accidentally jumping to non-canonical address
+
+extern "C" {
+    fn jump_usermode(address: u64) -> !;
+}
 
 // TODO: Proper error handling
-// TODO: Verify whether p_offset is within bounds
 pub fn load_binary() {
     let process;
     {
@@ -30,10 +33,11 @@ pub fn load_binary() {
             }
             let write = i.p_flags & 2 != 0;
             let exec = i.p_flags & 1 != 0;
-            assert!(i.p_vaddr < USER_END);
             assert!(i.p_vaddr + i.p_memsz < USER_END);
             assert!(i.p_vaddr + i.p_memsz >= i.p_vaddr);
             assert!(i.p_filesz <= i.p_memsz);
+            assert!(i.p_offset + i.p_filesz <= binary.len() as u64);
+            assert!(i.p_offset + i.p_filesz >= i.p_offset);
             assert!(!write || !exec);
             let start = i.p_vaddr / 0x1000 * 0x1000;
             let end = (i.p_vaddr + i.p_memsz + 0xfff) / 0x1000 * 0x1000;
@@ -48,14 +52,14 @@ pub fn load_binary() {
             }
             disable_user_memory_access();
             unsafe {
-                // TODO: enable user flag
-                process.address_space.update_flags_range(start, size, false, write, exec);
+                process.address_space.update_flags_range(start, size, true, write, exec);
             }
         }
         entry = file.ehdr.e_entry;
+        assert!(entry < USER_END);
     }
     info!("Starting init...");
     unsafe {
-        (mem::transmute::<u64, extern "C" fn() -> !>(entry))();
+        jump_usermode(entry);
     }
 }

kernel/src/sys/task.rs

@@ -49,21 +49,25 @@ static RFLAGS: AtomicU64 = AtomicU64::new(0);
 pub static MULTITASKING_ENABLED: AtomicBool = AtomicBool::new(false);
 pub static STARTING_AP_ID: AtomicI64 = AtomicI64::new(-1);
 pub static ALL_APS_STARTED: AtomicBool = AtomicBool::new(false);
+pub static TERMINATE_STASKS: [Spinlock<Vec<Task>>; 256] = [const { Spinlock::new(Vec::new()) }; 256];
 
 pub fn allocate_stack() -> u64 {
     let stack: Vec<u8> = vec![0; STACK_SIZE];
     stack.leak().as_mut_ptr() as u64 + STACK_SIZE as u64
 }
 pub fn switch_task(current_state: &mut ISRState, new_task: Task) {
+    let lapic_id = get_current_lapic_id();
     let mut current_tasks = CURRENT_TASKS.lock();
-    if let Some(mut current_task) = current_tasks[get_current_lapic_id()].take() {
+    if let Some(mut current_task) = current_tasks[lapic_id].take() {
         current_task.state = *current_state;
         match current_task.task_state {
             TaskState::Ready => {
                 SCHEDULER.lock().add_task(current_task);
             }
             TaskState::Idle => IDLE_TASKS.lock().push(current_task),
-            TaskState::Terminated => {}
+            TaskState::Terminated => {
+                TERMINATE_STASKS[lapic_id].lock().push(current_task);
+            }
             TaskState::Sleeping => sleep_internal(current_task),
             TaskState::SemaphoreBlocked => lock_semaphore_internal(current_task),
         }
@@ -124,6 +128,9 @@ fn create_idle_task() {
         IDLE_TASKS.lock().push(idle_task);
     }
 }
+pub fn terminate_current_task() {
+    CURRENT_TASKS.lock()[get_current_lapic_id()].as_mut().unwrap().task_state = TaskState::Terminated;
+}
 extern "C" fn task_entry() -> ! {
     let func;
     {
@@ -132,7 +139,7 @@ extern "C" fn task_entry() -> ! {
     }
     func();
     {
-        CURRENT_TASKS.lock()[get_current_lapic_id()].as_mut().unwrap().task_state = TaskState::Terminated;
+        terminate_current_task();
     }
     yield_task();
     panic!("Failed to terminate task");
@@ -152,6 +159,9 @@ fn idle_main() {
         hlt();
     }
 }
+pub fn terminate_tasks() {
+    TERMINATE_STASKS[get_current_lapic_id()].lock().clear();
+}
 pub fn setup_multitasking() -> ! {
     let rflags = get_rflags();
     RFLAGS.store(rflags, core::sync::atomic::Ordering::SeqCst);

lib/acpica

@@ -1 +1 @@
-Subproject commit 437f7e1a0039d227d3952677c3f9f5ad9c814395
+Subproject commit 7dae72155bf06b0edda9f3aea713da1d48c1c418