ch05: use stablized naked_functions feature

The `naked_functions` feature was stabilized in
rust-lang/rust#134213. Update the code to
use this stabilized feature. This still requires nightly Rust until
rust-lang/rust#134213 is released in stable
Rust.

Author: sudomateo

ch05/c-fibers/README.md

@@ -14,8 +14,9 @@ run the example just fine.
 
 ## Running the example
 
-This example uses the unstable feature "naked_functions" so we need to run it
-using nightly Rust. There are two ways to do that.
+This example uses the feature "naked_functions" so we need to run it using
+nightly Rust until https://github.com/rust-lang/rust/pull/134213 is released in
+stable Rust. There are two ways to do that.
 
 1. Tell cargo to use the nightly toolchain when you run the program:
 

ch05/c-fibers/src/main.rs

@@ -6,7 +6,6 @@
 ///
 /// See: https://github.com/PacktPublishing/Asynchronous-Programming-in-Rust/issues/31
 /// for more information.
-#![feature(naked_functions)]
 use std::arch::{asm, naked_asm};
 
 const DEFAULT_STACK_SIZE: usize = 1024 * 1024 * 2;
@@ -147,7 +146,7 @@ fn guard() {
     };
 }
 
-#[naked]
+#[unsafe(naked)]
 unsafe extern "C" fn skip() {
     naked_asm!("ret")
 }
@@ -159,7 +158,7 @@ pub fn yield_thread() {
     };
 }
 
-#[naked]
+#[unsafe(naked)]
 #[no_mangle]
 #[cfg_attr(target_os = "macos", export_name = "\x01switch")] // see: How-to-MacOS-M.md for explanation
 unsafe extern "C" fn switch() {
@@ -199,11 +198,16 @@ fn main() {
     runtime.spawn(|| {
         println!("THREAD 2 STARTING");
         let id = 2;
-        for i in 0..15 {
+        for i in 0..7 {
+            println!("thread: {} counter: {}", id, i);
+        }
+        yield_thread();
+        for i in 7..15 {
             println!("thread: {} counter: {}", id, i);
             yield_thread();
         }
         println!("THREAD 2 FINISHED");
     });
+
     runtime.run();
 }

ch05/d-fibers-closure/README.md

@@ -22,8 +22,9 @@ run the example just fine.
 
 ## Running the example
 
-This example uses the unstable feature "naked_functions" so we need to run it
-using nightly Rust. There are two ways to do that.
+This example uses the feature "naked_functions" so we need to run it using
+nightly Rust until https://github.com/rust-lang/rust/pull/134213 is released in
+stable Rust. There are two ways to do that.
 
 1. Tell cargo to use the nightly toolchain when you run the program:
 

ch05/d-fibers-closure/src/main.rs

@@ -6,7 +6,6 @@
 ///
 /// See: https://github.com/PacktPublishing/Asynchronous-Programming-in-Rust/issues/31
 /// for more information.
-#![feature(naked_functions)]
 use std::{arch::{asm, naked_asm}};
 
 const DEFAULT_STACK_SIZE: usize = 1024 * 1024 * 2;
@@ -159,7 +158,7 @@ fn call(thread: u64) {
     }
 }
 
-#[naked]
+#[unsafe(naked)]
 unsafe extern "C" fn skip() {
     naked_asm!("ret")
 }
@@ -180,7 +179,7 @@ pub fn yield_thread() {
         (*rt_ptr).t_yield();
     };
 }
-#[naked]
+#[unsafe(naked)]
 #[no_mangle]
 #[cfg_attr(target_os = "macos", export_name = "\x01switch")]
 unsafe extern "C" fn switch() {

ch05/e-fibers-windows/README.md

@@ -13,8 +13,9 @@ AMD desktop CPU's use this architecture).
 
 ## Running the example
 
-This example uses the unstable feature "naked_functions" so we need to run it
-using nightly Rust. There are two ways to do that.
+This example uses the feature "naked_functions" so we need to run it using
+nightly Rust until https://github.com/rust-lang/rust/pull/134213 is released in
+stable Rust. There are two ways to do that.
 
 1. Tell cargo to use the nightly toolchain when you run the program:
 
@@ -306,4 +307,4 @@ As you see, our code gets just a little bit longer. It's not difficult once you'
 
 ## Conclusion
 
-So this is all we needed to do. As you see we don't really do anything new here, the difficult part is figuring out how Windows works and what it expects, but now that we have done our job properly we should have a pretty complete context switch for both Unix and Windows platforms.
+So this is all we needed to do. As you see we don't really do anything new here, the difficult part is figuring out how Windows works and what it expects, but now that we have done our job properly we should have a pretty complete context switch for both Unix and Windows platforms.

ch05/e-fibers-windows/src/main.rs

@@ -6,7 +6,6 @@
 ///
 /// See: https://github.com/PacktPublishing/Asynchronous-Programming-in-Rust/issues/31
 /// for more information.
-#![feature(naked_functions)]
 use std::arch::{asm, naked_asm};
 
 const DEFAULT_STACK_SIZE: usize = 1024 * 1024 * 2;
@@ -151,7 +150,7 @@ impl Runtime {
     }
 }
 
-#[naked]
+#[unsafe(naked)]
 unsafe extern "C" fn skip() {
     naked_asm!("ret")
 }
@@ -172,7 +171,7 @@ pub fn yield_thread() {
 }
 
 #[cfg(not(target_os = "windows"))]
-#[naked]
+#[unsafe(naked)]
 #[no_mangle]
 #[cfg_attr(target_os = "macos", export_name = "\x01switch")]
 unsafe extern "C" fn switch() {
@@ -278,7 +277,7 @@ impl Runtime {
 // reference: https://probablydance.com/2013/02/20/handmade-coroutines-for-windows/
 // Contents of TIB on Windows: https://en.wikipedia.org/wiki/Win32_Thread_Information_Block
 #[cfg(target_os = "windows")]
-#[naked]
+#[unsafe(naked)]
 #[no_mangle]
 unsafe extern "C" fn switch() {
     asm!(