Kernel: Add CPU functions in a portable way

moon/src/arch/cpu.rs

@@ -0,0 +1,2 @@
+#![cfg(target_arch = "x86_64")]
+pub use super::x86_64::cpu::*;

moon/src/arch/mod.rs

@@ -0,0 +1,4 @@
+pub mod cpu;
+
+#[cfg(target_arch = "x86_64")]
+mod x86_64;

moon/src/arch/x86_64/cpu.rs

@@ -0,0 +1,27 @@
+#![cfg(target_arch = "x86_64")]
+#![allow(dead_code)]
+
+use core::arch::x86_64::{__cpuid as do_cpuid, CpuidResult};
+use core::arch::asm;
+
+fn safe_cpuid(leaf: u32) -> CpuidResult {
+    return unsafe { do_cpuid(leaf) };
+}
+
+pub fn get_processor_id() -> u32 {
+    let cpuid_result = safe_cpuid(1);
+    return cpuid_result.ebx >> 24;
+}
+
+pub fn halt() -> ! {
+    loop { 
+        unsafe {
+            asm!("cli");
+            asm!("hlt");
+        }
+    }
+}
+
+pub fn wait_for_interrupt() -> () {
+    unsafe { asm!("hlt"); }
+}

moon/src/arch/x86_64/mod.rs

@@ -0,0 +1 @@
+pub mod cpu;

moon/src/init.rs

@@ -1,6 +1,15 @@
 use crate::bootboot::{BOOTBOOT, BOOTBOOT_MAGIC};
 use crate::util::get_bootboot;
 
+use crate::arch::cpu;
+
+pub fn halt_other_cores() -> () {
+    let boot: BOOTBOOT = get_bootboot();
+    if cpu::get_processor_id() != boot.bspid as u32 {
+        cpu::halt();
+    }
+}
+
 pub fn check_magic() -> () {
     let boot: BOOTBOOT = get_bootboot();
     assert_eq!(boot.magic, BOOTBOOT_MAGIC[..4]);

moon/src/main.rs

@@ -6,12 +6,20 @@ mod bootboot;
 mod panic;
 mod util;
 mod init;
+mod arch;
+
+use arch::cpu;
 
 use video::Color;
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
+
+    init::halt_other_cores();
     init::check_magic();
+    
     video::clear(Color::White);
-    loop {}
+    
+    cpu::halt();
+
 }