Fix stack trace, WIP usermode

arch/x86_64/src/interrupt/exception.rs

@@ -1,7 +1,8 @@
-use super::halt;
+use super::{halt, stack_trace};
 
 interrupt!(divide_by_zero, {
     print!("Divide by zero fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
@@ -23,75 +24,90 @@ interrupt!(overflow, {
 
 interrupt!(bound_range, {
     print!("Bound range exceeded fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(invalid_opcode, {
     print!("Invalid opcode fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(device_not_available, {
     print!("Device not available fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(double_fault, {
     print!("Double fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(invalid_tss, {
     print!("Invalid TSS fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(segment_not_present, {
     print!("Segment not present fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(stack_segment, {
     print!("Stack segment fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(protection, {
     print!("Protection fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(page, {
     print!("Page fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(fpu, {
     print!("FPU floating point fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(alignment_check, {
     print!("Alignment check fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(machine_check, {
     print!("Machine check fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(simd, {
     print!("SIMD floating point fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt!(virtualization, {
     print!("Virtualization fault\n");
+    stack_trace();
     loop { halt(); }
 });
 
 interrupt_error!(security, {
     print!("Security exception\n");
+    stack_trace();
     loop { halt(); }
 });

arch/x86_64/src/interrupt/mod.rs

@@ -1,5 +1,9 @@
 //! Interrupt instructions
 
+use core::mem;
+
+use paging::{ActivePageTable, VirtualAddress};
+
 pub mod exception;
 pub mod irq;
 pub mod syscall;
@@ -46,12 +50,15 @@ pub unsafe fn stack_trace() {
 
     println!("TRACE: {:>016X}", rbp);
     //Maximum 64 frames
+    let active_table = ActivePageTable::new();
     for _frame in 0..64 {
-        let rip = *(rbp as *const usize).offset(1);
-        println!("  {:>016X}: {:>016X}", rbp, rip);
-        if rip == 0 {
+        if active_table.translate(VirtualAddress::new(rbp)).is_some() && active_table.translate(VirtualAddress::new(rbp + mem::size_of::<usize>())).is_some() {
+            let rip = *(rbp as *const usize).offset(1);
+            println!("  {:>016X}: {:>016X}", rbp, rip);
+            rbp = *(rbp as *const usize);
+        } else {
+            println!("  {:>016X}: GUARD PAGE", rbp);
             break;
         }
-        rbp = *(rbp as *const usize);
     }
 }

arch/x86_64/src/lib.rs

@@ -48,7 +48,8 @@ macro_rules! interrupt {
             }
 
             // Push scratch registers
-            asm!("push rax
+            asm!("xchg bx, bx
+                push rax
                 push rcx
                 push rdx
                 push rdi
@@ -63,7 +64,8 @@ macro_rules! interrupt {
             inner();
 
             // Pop scratch registers and return
-            asm!("pop r11
+            asm!("xchg bx,bx
+                pop r11
                 pop r10
                 pop r9
                 pop r8
@@ -89,7 +91,8 @@ macro_rules! interrupt_error {
             }
 
             // Push scratch registers
-            asm!("push rax
+            asm!("xchg bx, bx
+                push rax
                 push rcx
                 push rdx
                 push rdi
@@ -104,7 +107,8 @@ macro_rules! interrupt_error {
             inner();
 
             // Pop scratch registers, error code, and return
-            asm!("pop r11
+            asm!("xchg bx, bx
+                pop r11
                 pop r10
                 pop r9
                 pop r8

arch/x86_64/src/paging/mod.rs

@@ -180,7 +180,7 @@ impl DerefMut for ActivePageTable {
 }
 
 impl ActivePageTable {
-    unsafe fn new() -> ActivePageTable {
+    pub unsafe fn new() -> ActivePageTable {
         ActivePageTable {
             mapper: Mapper::new(),
         }

arch/x86_64/src/start.rs

@@ -137,6 +137,28 @@ pub unsafe extern fn kstart() -> ! {
     kmain();
 }
 
+unsafe fn usermode(ip: usize, sp: usize) {
+    // Test usermode
+    asm!("xchg bx, bx
+        mov rax, 0x2B
+        mov ds, ax
+        mov es, ax
+        mov fs, ax
+        mov gs, ax
+
+        push rax
+        push rbx
+        pushfq
+        mov rax, 0x23
+        push rax
+        push rcx
+        iretq"
+        :
+        : "{rbx}"(sp), "{rcx}"(ip)
+        : "rax", "rbx", "rcx", "sp"
+        : "intel", "volatile");
+}
+
 /// Entry to rust for an AP
 pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
     {