From 70d78d86be89b7e2651d2b79235eaa43f7552520 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Mon, 31 Oct 2022 16:18:05 +0100
Subject: [PATCH] Kernel: Add CPU functions in a portable way

---
 moon/src/arch/cpu.rs        |  2 ++
 moon/src/arch/mod.rs        |  4 ++++
 moon/src/arch/x86_64/cpu.rs | 27 +++++++++++++++++++++++++++
 moon/src/arch/x86_64/mod.rs |  1 +
 moon/src/init.rs            |  9 +++++++++
 moon/src/main.rs            | 10 +++++++++-
 6 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 moon/src/arch/cpu.rs
 create mode 100644 moon/src/arch/mod.rs
 create mode 100644 moon/src/arch/x86_64/cpu.rs
 create mode 100644 moon/src/arch/x86_64/mod.rs

diff --git a/moon/src/arch/cpu.rs b/moon/src/arch/cpu.rs
new file mode 100644
index 00000000..7f6a1368
--- /dev/null
+++ b/moon/src/arch/cpu.rs
@@ -0,0 +1,2 @@
+#![cfg(target_arch = "x86_64")]
+pub use super::x86_64::cpu::*;
\ No newline at end of file
diff --git a/moon/src/arch/mod.rs b/moon/src/arch/mod.rs
new file mode 100644
index 00000000..a704f875
--- /dev/null
+++ b/moon/src/arch/mod.rs
@@ -0,0 +1,4 @@
+pub mod cpu;
+
+#[cfg(target_arch = "x86_64")]
+mod x86_64;
\ No newline at end of file
diff --git a/moon/src/arch/x86_64/cpu.rs b/moon/src/arch/x86_64/cpu.rs
new file mode 100644
index 00000000..ff8e4f44
--- /dev/null
+++ b/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"); }
+}
\ No newline at end of file
diff --git a/moon/src/arch/x86_64/mod.rs b/moon/src/arch/x86_64/mod.rs
new file mode 100644
index 00000000..374e8ae6
--- /dev/null
+++ b/moon/src/arch/x86_64/mod.rs
@@ -0,0 +1 @@
+pub mod cpu;
\ No newline at end of file
diff --git a/moon/src/init.rs b/moon/src/init.rs
index 2fa10f43..dea50760 100644
--- a/moon/src/init.rs
+++ b/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]);
diff --git a/moon/src/main.rs b/moon/src/main.rs
index 8b2cbc21..c09d2071 100644
--- a/moon/src/main.rs
+++ b/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();
+
 }
\ No newline at end of file