rust: support for printk_once

Signed-off-by: Gary Guo <[email protected]>
Rust-for-Linux · May 26, 2021 · 765221c · 765221c
1 parent 1173c1f
commit 765221c
Showing 1 changed file with 63 additions and 0 deletions.
diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
@@ -145,6 +145,20 @@ pub fn call_printk_cont(lvl: LogLevel, args: fmt::Arguments<'_>) {
 /// ```
 #[macro_export]
 macro_rules! printk (
+    (once, $($arg:tt)+) => {{
+        use ::core::sync::atomic::{AtomicBool, Ordering};
+
+        #[link_section = ".data.once"]
+        static ONCE: AtomicBool = AtomicBool::new(false);
+
+        if ONCE
+            .compare_exchange(false, true, Ordering::Relaxed, Ordering::Relaxed)
+            .is_ok()
+        {
+            $crate::printk!($($arg)+);
+        }
+    }};
+
     (target: $target:expr, $lvl:expr, $($arg:tt)+) => {{
         $crate::print::call_printk(
             $lvl,
@@ -176,6 +190,13 @@ macro_rules! printk (
 /// ```
 #[macro_export]
 macro_rules! pr_emerg (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::EMERG, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::EMERG, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::EMERG, $($arg)+)
     );
@@ -203,6 +224,13 @@ macro_rules! pr_emerg (
 /// ```
 #[macro_export]
 macro_rules! pr_alert (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::ALERT, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::ALERT, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::ALERT, $($arg)+)
     );
@@ -230,6 +258,13 @@ macro_rules! pr_alert (
 /// ```
 #[macro_export]
 macro_rules! pr_crit (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::CRIT, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::CRIT, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::CRIT, $($arg)+)
     );
@@ -257,6 +292,13 @@ macro_rules! pr_crit (
 /// ```
 #[macro_export]
 macro_rules! pr_err (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::ERR, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::ERR, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::ERR, $($arg)+)
     );
@@ -284,6 +326,13 @@ macro_rules! pr_err (
 /// ```
 #[macro_export]
 macro_rules! pr_warn (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::WARNING, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::WARNING, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::WARNING, $($arg)+)
     );
@@ -311,6 +360,13 @@ macro_rules! pr_warn (
 /// ```
 #[macro_export]
 macro_rules! pr_notice (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::NOTICE, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::NOTICE, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::NOTICE, $($arg)+)
     );
@@ -339,6 +395,13 @@ macro_rules! pr_notice (
 #[macro_export]
 #[doc(alias = "print")]
 macro_rules! pr_info (
+    (once, target: $target:expr, $($arg:tt)+) => (
+        $crate::printk!(once, target: $target, $crate::print::LogLevel::INFO, $($arg)+)
+    );
+    (once, $($arg:tt)+) => (
+        $crate::printk!(once, $crate::print::LogLevel::INFO, $($arg)+)
+    );
+
     (target: $target:expr, $($arg:tt)+) => (
         $crate::printk!(target: $target, $crate::print::LogLevel::INFO, $($arg)+)
     );