Minimal interrupts, prevent deadlocks

tetros/src/idt/stackframe.rs

@@ -1,9 +1,9 @@
+use bitflags::bitflags;
+use core::arch::asm;
 use core::{fmt, ops::Deref};
 
 use super::VirtAddr;
 
-use bitflags::bitflags;
-
 bitflags! {
 	/// The EFLAGS register. All bit patterns are valid representations for this type.
 	///
@@ -82,6 +82,24 @@ bitflags! {
 	}
 }
 
+impl EFlags {
+	#[inline]
+	pub fn read() -> EFlags {
+		EFlags::from_bits_truncate(EFlags::read_raw())
+	}
+
+	#[inline]
+	fn read_raw() -> u32 {
+		let r: u32;
+
+		unsafe {
+			asm!("pushfd; pop {0:e}", out(reg) r, options(nomem, preserves_flags));
+		}
+
+		r
+	}
+}
+
 /// Wrapper type for the interrupt stack frame pushed by the CPU.
 ///
 /// This type derefs to an [`InterruptStackFrameValue`], which allows reading the actual values.