Update rust, use redox branch to prepare for libstd

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "rust"]
 	path = rust
-	url = https://github.com/rust-lang/rust.git
+	url = https://github.com/redox-os/rust.git

Makefile

@@ -82,4 +82,5 @@ qemu: build/harddrive.bin
 endif
 
 clean:
-	rm -rf build/* target/*
+	cargo clean
+	rm -rf build/*

arch/x86_64/src/start.rs

@@ -202,23 +202,26 @@ pub unsafe extern fn kstart_ap(stack_start: usize, stack_end: usize) -> ! {
     kmain_ap(ap_number);
 }
 
-pub unsafe fn usermode(ip: usize, sp: usize) {
-    // Test usermode
-    asm!("mov rax, 0x2B
+pub unsafe fn usermode(ip: usize, sp: usize) -> ! {
+    // Go to usermode
+    asm!("mov rax, 0x2B # Set segment pointers
         mov ds, ax
         mov es, ax
         mov fs, ax
         mov gs, ax
 
-        push rax
-        push rbx
-        pushfq
+        push rax # Push stack segment
+        push rbx # Push stack pointer
+        mov rax, 3 << 12 | 1 << 9 # Set IOPL and interrupt enable flag
+        push rax # Push rflags
         mov rax, 0x23
-        push rax
-        push rcx
+        push rax # Push code segment
+        push rcx # Push rip
+        xchg bx, bx
         iretq"
         :
         : "{rbx}"(sp), "{rcx}"(ip)
-        : "rax", "rbx", "rcx", "sp"
+        : "rax", "sp"
         : "intel", "volatile");
+    unreachable!();
 }

init/src/lib.rs

@@ -11,7 +11,7 @@ use syscall::{exit, write};
 pub unsafe extern fn _start() {
     let string = b"Hello, World!\n";
     write(1, string);
-    exit(1);
+    exit(0);
 }
 
 #[cfg(not(test))]
@@ -22,6 +22,8 @@ extern "C" fn eh_personality() {}
 /// Required to handle panics
 #[lang = "panic_fmt"]
 extern "C" fn panic_fmt(_fmt: ::core::fmt::Arguments, _file: &str, _line: u32) -> ! {
+    write(2, b"panic\n");
+    exit(127);
     loop {}
 }
 

rust

@@ -1 +1 @@
-Subproject commit a23064af5ec7f52b287e2c60823fed92a4763502
+Subproject commit 46a90c60ab79d65a09330448becd01c78511ea77