Only enable instructions on x86_64

A build on non-x86_64 platforms with the `instructions` feature enabled should not results in lots of inline assembly errors.

Author: phil-opp

src/instructions/mod.rs

@@ -1,4 +1,4 @@
-#![cfg(feature = "instructions")]
+#![cfg(all(feature = "instructions", target_arch = "x86_64"))]
 
 //! Special x86_64 instructions.
 

src/registers/control.rs

@@ -159,7 +159,7 @@ bitflags! {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
     use crate::{

src/registers/debug.rs

@@ -1,6 +1,6 @@
 //! Functions to read and write debug registers.
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 use core::arch::asm;
 use core::ops::Range;
 
@@ -15,11 +15,11 @@ pub trait DebugAddressRegister {
     const NUM: DebugAddressRegisterNumber;
 
     /// Reads the current breakpoint address.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     fn read() -> u64;
 
     /// Writes the provided breakpoint address.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     fn write(addr: u64);
 }
 
@@ -34,7 +34,7 @@ macro_rules! debug_address_register {
         impl DebugAddressRegister for $Dr {
             const NUM: DebugAddressRegisterNumber = DebugAddressRegisterNumber::$Dr;
 
-            #[cfg(feature = "instructions")]
+            #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
             #[inline]
             fn read() -> u64 {
                 let addr;
@@ -44,7 +44,7 @@ macro_rules! debug_address_register {
                 addr
             }
 
-            #[cfg(feature = "instructions")]
+            #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
             #[inline]
             fn write(addr: u64) {
                 unsafe {
@@ -437,7 +437,7 @@ impl Dr7Value {
 #[derive(Debug)]
 pub struct Dr7;
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
 

src/registers/mod.rs

@@ -8,5 +8,5 @@ pub mod rflags;
 pub mod segmentation;
 pub mod xcontrol;
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 pub use crate::instructions::read_rip;

src/registers/model_specific.rs

@@ -6,7 +6,10 @@ use bitflags::bitflags;
 use crate::registers::segmentation::{FS, GS};
 
 /// A model specific register.
-#[cfg_attr(not(feature = "instructions"), allow(dead_code))] // FIXME
+#[cfg_attr(
+    not(all(feature = "instructions", target_arch = "x86_64")),
+    allow(dead_code)
+)] // FIXME
 #[derive(Debug)]
 pub struct Msr(u32);
 
@@ -29,7 +32,7 @@ pub struct FsBase;
 /// [GS].Base Model Specific Register.
 ///
 #[cfg_attr(
-    feature = "instructions",
+    all(feature = "instructions", target_arch = "x86_64"),
     doc = "[`GS::swap`] swaps this register with [`KernelGsBase`]."
 )]
 #[derive(Debug)]
@@ -38,7 +41,7 @@ pub struct GsBase;
 /// KernelGsBase Model Specific Register.
 ///
 #[cfg_attr(
-    feature = "instructions",
+    all(feature = "instructions", target_arch = "x86_64"),
     doc = "[`GS::swap`] swaps this register with [`GsBase`]."
 )]
 #[derive(Debug)]
@@ -158,7 +161,7 @@ bitflags! {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
     use crate::addr::VirtAddr;

src/registers/mxcsr.rs

@@ -1,6 +1,6 @@
 //! Functions to read and write MXCSR register.
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 pub use self::x86_64::*;
 
 use bitflags::bitflags;
@@ -60,7 +60,7 @@ impl Default for MxCsr {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
     use core::arch::asm;

src/registers/rflags.rs

@@ -1,6 +1,6 @@
 //! Processor state stored in the RFLAGS register.
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 pub use self::x86_64::*;
 
 use bitflags::bitflags;
@@ -64,7 +64,7 @@ bitflags! {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
     use core::arch::asm;

src/registers/xcontrol.rs

@@ -50,7 +50,7 @@ bitflags! {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 mod x86_64 {
     use super::*;
     use core::arch::asm;

src/structures/gdt.rs

@@ -10,9 +10,9 @@ use core::fmt;
 #[cfg(doc)]
 use crate::registers::segmentation::{Segment, CS, SS};
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 use core::sync::atomic::{AtomicU64 as EntryValue, Ordering};
-#[cfg(not(feature = "instructions"))]
+#[cfg(not(all(feature = "instructions", target_arch = "x86_64")))]
 use u64 as EntryValue;
 
 /// 8-byte entry in a descriptor table.
@@ -28,7 +28,7 @@ pub struct Entry(EntryValue);
 impl Entry {
     // Create a new Entry from a raw value.
     const fn new(raw: u64) -> Self {
-        #[cfg(feature = "instructions")]
+        #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
         let raw = EntryValue::new(raw);
         Self(raw)
     }
@@ -37,9 +37,9 @@ impl Entry {
     /// bits may correspond to those in [`DescriptorFlags`].
     pub fn raw(&self) -> u64 {
         // TODO: Make this const fn when AtomicU64::load is const.
-        #[cfg(feature = "instructions")]
+        #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
         let raw = self.0.load(Ordering::SeqCst);
-        #[cfg(not(feature = "instructions"))]
+        #[cfg(not(all(feature = "instructions", target_arch = "x86_64")))]
         let raw = self.0;
         raw
     }
@@ -153,7 +153,10 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
     /// * the provided slice has more than `MAX` entries
     /// * the provided slice is empty
     /// * the first entry is not zero
-    #[cfg_attr(not(feature = "instructions"), allow(rustdoc::broken_intra_doc_links))]
+    #[cfg_attr(
+        not(all(feature = "instructions", target_arch = "x86_64")),
+        allow(rustdoc::broken_intra_doc_links)
+    )]
     #[inline]
     pub const fn from_raw_entries(slice: &[u64]) -> Self {
         let len = slice.len();
@@ -215,7 +218,7 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
     /// segment registers; you **must** (re)load them yourself using [the appropriate
     /// functions](crate::instructions::segmentation):
     /// [`SS::set_reg()`] and [`CS::set_reg()`].
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     #[inline]
     pub fn load(&'static self) {
         // SAFETY: static lifetime ensures no modification after loading.
@@ -233,7 +236,7 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
     /// this means its up to the user to ensure that there will be no modifications
     /// after loading and that the GDT will live for as long as it's loaded.
     ///
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     #[inline]
     pub unsafe fn load_unsafe(&self) {
         use crate::instructions::tables::lgdt;
@@ -261,7 +264,7 @@ impl<const MAX: usize> GlobalDescriptorTable<MAX> {
 
     /// Creates the descriptor pointer for this table. This pointer can only be
     /// safely used if the table is never modified or destroyed while in use.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     fn pointer(&self) -> super::DescriptorTablePointer {
         super::DescriptorTablePointer {
             base: crate::VirtAddr::new(self.table.as_ptr() as u64),

src/structures/idt.rs

@@ -489,7 +489,7 @@ impl InterruptDescriptorTable {
     }
 
     /// Loads the IDT in the CPU using the `lidt` command.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     #[inline]
     pub fn load(&'static self) {
         unsafe { self.load_unsafe() }
@@ -505,7 +505,7 @@ impl InterruptDescriptorTable {
     /// - `self` always stays at the same memory location. It is recommended to wrap it in
     /// a `Box`.
     ///
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     #[inline]
     pub unsafe fn load_unsafe(&self) {
         use crate::instructions::tables::lidt;
@@ -516,7 +516,7 @@ impl InterruptDescriptorTable {
 
     /// Creates the descriptor pointer for this table. This pointer can only be
     /// safely used if the table is never modified or destroyed while in use.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     fn pointer(&self) -> crate::structures::DescriptorTablePointer {
         use core::mem::size_of;
         crate::structures::DescriptorTablePointer {
@@ -792,7 +792,7 @@ impl<F> Entry<F> {
     ///
     /// The caller must ensure that `addr` is the address of a valid interrupt handler function,
     /// and the signature of such a function is correct for the entry type.
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     #[inline]
     pub unsafe fn set_handler_addr(&mut self, addr: VirtAddr) -> &mut EntryOptions {
         use crate::instructions::segmentation::{Segment, CS};
@@ -821,7 +821,7 @@ impl<F> Entry<F> {
     }
 }
 
-#[cfg(feature = "instructions")]
+#[cfg(all(feature = "instructions", target_arch = "x86_64"))]
 impl<F: HandlerFuncType> Entry<F> {
     /// Sets the handler function for the IDT entry and sets the following defaults:
     ///   - The code selector is the code segment currently active in the CPU
@@ -1093,7 +1093,7 @@ impl InterruptStackFrameValue {
     /// CS and SS register can all cause undefined behaviour when done incorrectly.
     ///
     #[inline(always)]
-    #[cfg(feature = "instructions")]
+    #[cfg(all(feature = "instructions", target_arch = "x86_64"))]
     pub unsafe fn iretq(&self) -> ! {
         unsafe {
             core::arch::asm!(
@@ -1328,7 +1328,11 @@ pub enum ExceptionVector {
     Security = 0x1E,
 }
 
-#[cfg(all(feature = "instructions", feature = "abi_x86_interrupt"))]
+#[cfg(all(
+    feature = "instructions",
+    feature = "abi_x86_interrupt",
+    target_arch = "x86_64"
+))]
 #[macro_export]
 /// Set a general handler in an [`InterruptDescriptorTable`].
 /// ```
@@ -1390,7 +1394,11 @@ macro_rules! set_general_handler {
     }};
 }
 
-#[cfg(all(feature = "instructions", feature = "abi_x86_interrupt"))]
+#[cfg(all(
+    feature = "instructions",
+    feature = "abi_x86_interrupt",
+    target_arch = "x86_64"
+))]
 #[macro_export]
 #[doc(hidden)]
 /// We can't loop in macros, but we can use recursion.
@@ -1412,7 +1420,11 @@ macro_rules! set_general_handler_recursive_bits {
     };
 }
 
-#[cfg(all(feature = "instructions", feature = "abi_x86_interrupt"))]
+#[cfg(all(
+    feature = "instructions",
+    feature = "abi_x86_interrupt",
+    target_arch = "x86_64"
+))]
 #[macro_export]
 #[doc(hidden)]
 macro_rules! set_general_handler_entry {
@@ -1575,7 +1587,11 @@ mod test {
         assert_eq!(size_of::<InterruptStackFrameValue>(), 40);
     }
 
-    #[cfg(all(feature = "instructions", feature = "abi_x86_interrupt"))]
+    #[cfg(all(
+        feature = "instructions",
+        feature = "abi_x86_interrupt",
+        target_arch = "x86_64"
+    ))]
     // there seems to be a bug in LLVM that causes rustc to crash on windows when compiling this test:
     // https://github.com/rust-osdev/x86_64/pull/285#issuecomment-962642984
     #[cfg(not(windows))]