Update to latest bit_field version

(cherry picked from commit 46100ba24b)

.travis.yml

@@ -3,6 +3,15 @@ language: rust
 rust:
     - nightly
 
+cache: cargo
+
+before_script:
+  - curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain=$TRAVIS_RUST_VERSION -y
+  - source ~/.cargo/env
+  - rustup component add rust-src
+  - (test -x $HOME/.cargo/bin/rustfmt || cargo install rustfmt)
+  - (test -x $HOME/.cargo/bin/xargo || cargo install xargo)
+
 sudo: false
 
 notifications:

Cargo.toml

@@ -7,7 +7,7 @@ version = "0.1.0"
 bit_field = "0.7.0"
 bitflags = "0.7.0"
 multiboot2 = "0.1.0"
-once = "0.2.1"
+once = "0.3.2"
 rlibc = "0.1.4"
 spin = "0.3.4"
 volatile = "0.1.0"
@@ -19,6 +19,10 @@ path = "libs/hole_list_allocator"
 default-features = false
 version = "0.8.0"
 
+[dependencies.lazy_static]
+version = "0.2.1"
+features = ["spin_no_std"]
+
 [lib]
 crate-type = ["staticlib"]
 

Makefile

@@ -8,7 +8,7 @@
 # except according to those terms.
 
 arch ?= x86_64
-target ?= $(arch)-unknown-linux-gnu
+target ?= $(arch)-blog_os
 kernel := build/kernel-$(arch).bin
 iso := build/os-$(arch).iso
 
@@ -49,7 +49,7 @@ $(kernel): cargo $(rust_os) $(assembly_object_files) $(linker_script)
 	@ld -n --gc-sections -T $(linker_script) -o $(kernel) $(assembly_object_files) $(rust_os)
 
 cargo:
-	@cargo build --target $(target)
+	@xargo build --target $(target)
 
 # compile assembly files
 build/arch/$(arch)/%.o: src/arch/$(arch)/%.asm

README.md

@@ -1,12 +1,14 @@
-# Blog OS (Better Exception Messages)
-[![Build Status](https://travis-ci.org/phil-opp/blog_os.svg?branch=better_exception_messages)](https://travis-ci.org/phil-opp/blog_os/branches)
+# Blog OS (Returning from Exceptions)
+[![Build Status](https://travis-ci.org/phil-opp/blog_os.svg?branch=returning_from_exceptions)](https://travis-ci.org/phil-opp/blog_os/branches)
 
-This repository contains the source code for the [Better Exception Messages](http://os.phil-opp.com/better-exception-messages.html) post of the [Writing an OS in Rust](http://os.phil-opp.com) series.
+This repository contains the source code for the [Returning from Exceptions](http://os.phil-opp.com/returning-from-exceptions.html) post of the [Writing an OS in Rust](http://os.phil-opp.com) series.
 
 **Check out the [master branch](https://github.com/phil-opp/blog_os) for more information.**
 
 ## Building
-You need to have `nasm`, `grub-mkrescue`, `xorriso`, `qemu`, and a nightly Rust compiler installed. Then you can run it using `make run`.
+You need to have `nasm`, `grub-mkrescue`, `xorriso`, `qemu`, a nightly Rust compiler, and [xargo] installed. Then you can run it using `make run`.
+
+[xargo]: https://github.com/japaric/xargo
 
 Please file an issue if you have any problems.
 

Xargo.toml

@@ -0,0 +1,2 @@
+[target.x86_64-blog_os.dependencies]
+collections = {}

src/interrupts/mod.rs

@@ -9,17 +9,51 @@
 
 mod idt;
 
+macro_rules! save_scratch_registers {
+    () => {
+        asm!("push rax
+              push rcx
+              push rdx
+              push rsi
+              push rdi
+              push r8
+              push r9
+              push r10
+              push r11
+        " :::: "intel", "volatile");
+    }
+}
+
+macro_rules! restore_scratch_registers {
+    () => {
+        asm!("pop r11
+              pop r10
+              pop r9
+              pop r8
+              pop rdi
+              pop rsi
+              pop rdx
+              pop rcx
+              pop rax
+            " :::: "intel", "volatile");
+    }
+}
+
 macro_rules! handler {
     ($name: ident) => {{
         #[naked]
         extern "C" fn wrapper() -> ! {
             unsafe {
+                save_scratch_registers!();
                 asm!("mov rdi, rsp
-                      sub rsp, 8 // align the stack pointer
+                      add rdi, 9*8 // calculate exception stack frame pointer
                       call $0"
                       :: "i"($name as extern "C" fn(
-                          &ExceptionStackFrame) -> !)
+                          &ExceptionStackFrame))
                       : "rdi" : "intel");
+
+                restore_scratch_registers!();
+                asm!("iretq" :::: "intel", "volatile");
                 ::core::intrinsics::unreachable();
             }
         }
@@ -32,13 +66,19 @@ macro_rules! handler_with_error_code {
         #[naked]
         extern "C" fn wrapper() -> ! {
             unsafe {
-                asm!("pop rsi // pop error code into rsi
+                save_scratch_registers!();
+                asm!("mov rsi, [rsp + 9*8] // load error code into rsi
                       mov rdi, rsp
+                      add rdi, 10*8 // calculate exception stack frame pointer
                       sub rsp, 8 // align the stack pointer
-                      call $0"
-                      :: "i"($name as extern "C" fn(
-                          &ExceptionStackFrame, u64) -> !)
+                      call $0
+                      add rsp, 8 // undo stack pointer alignment
+                      " :: "i"($name as extern "C" fn(
+                          &ExceptionStackFrame, u64))
                       : "rdi","rsi" : "intel");
+                restore_scratch_registers!();
+                asm!("add rsp, 8 // pop error code
+                      iretq" :::: "intel", "volatile");
                 ::core::intrinsics::unreachable();
             }
         }
@@ -51,6 +91,7 @@ lazy_static! {
         let mut idt = idt::Idt::new();
 
         idt.set_handler(0, handler!(divide_by_zero_handler));
+        idt.set_handler(3, handler!(breakpoint_handler));
         idt.set_handler(6, handler!(invalid_opcode_handler));
         idt.set_handler(14, handler_with_error_code!(page_fault_handler));
 
@@ -72,12 +113,18 @@ struct ExceptionStackFrame {
     stack_segment: u64,
 }
 
-extern "C" fn divide_by_zero_handler(stack_frame: &ExceptionStackFrame) -> ! {
+extern "C" fn divide_by_zero_handler(stack_frame: &ExceptionStackFrame) {
     println!("\nEXCEPTION: DIVIDE BY ZERO\n{:#?}", stack_frame);
     loop {}
 }
 
-extern "C" fn invalid_opcode_handler(stack_frame: &ExceptionStackFrame) -> ! {
+extern "C" fn breakpoint_handler(stack_frame: &ExceptionStackFrame) {
+    println!("\nEXCEPTION: BREAKPOINT at {:#x}\n{:#?}",
+             stack_frame.instruction_pointer,
+             stack_frame);
+}
+
+extern "C" fn invalid_opcode_handler(stack_frame: &ExceptionStackFrame) {
     println!("\nEXCEPTION: INVALID OPCODE at {:#x}\n{:#?}",
              stack_frame.instruction_pointer,
              stack_frame);
@@ -94,7 +141,7 @@ bitflags! {
     }
 }
 
-extern "C" fn page_fault_handler(stack_frame: &ExceptionStackFrame, error_code: u64) -> ! {
+extern "C" fn page_fault_handler(stack_frame: &ExceptionStackFrame, error_code: u64) {
     use x86::shared::control_regs;
     println!("\nEXCEPTION: PAGE FAULT while accessing {:#x}\nerror code: \
                                   {:?}\n{:#?}",

src/lib.rs

@@ -21,10 +21,13 @@ extern crate spin;
 extern crate multiboot2;
 #[macro_use]
 extern crate bitflags;
+#[macro_use]
 extern crate x86;
 #[macro_use]
 extern crate once;
 extern crate bit_field;
+#[macro_use]
+extern crate lazy_static;
 
 extern crate hole_list_allocator;
 extern crate alloc;
@@ -53,9 +56,8 @@ pub extern "C" fn rust_main(multiboot_information_address: usize) {
     // initialize our IDT
     interrupts::init();
 
-    // provoke a page fault
-    unsafe { *(0xdeadbeaf as *mut u64) = 42 };
-
+    // trigger a breakpoint exception
+    unsafe { int!(3) };
 
     println!("It did not crash!");
     loop {}

x86_64-blog_os.json

@@ -0,0 +1,10 @@
+{
+  "llvm-target": "x86_64-unknown-linux-gnu",
+  "data-layout": "e-m:e-i64:64-f80:128-n8:16:32:64-S128",
+  "target-endian": "little",
+  "target-pointer-width": "64",
+  "arch": "x86_64",
+  "os": "none",
+  "features": "-mmx,-sse,+soft-float",
+  "disable-redzone": true
+}