From 0722bf8d15a637051cc4ae79d9c916bec781c219 Mon Sep 17 00:00:00 2001
From: Per Lindgren <per.lindgren@ltu.se>
Date: Wed, 20 Oct 2021 10:34:39 +0200
Subject: [PATCH] multilock relock workaround

---
 examples/multilock_problem.rs            | 79 ++++++++++++++++++++++++
 examples/multilock_problem_workaround.rs | 79 ++++++++++++++++++++++++
 2 files changed, 158 insertions(+)
 create mode 100644 examples/multilock_problem.rs
 create mode 100644 examples/multilock_problem_workaround.rs

diff --git a/examples/multilock_problem.rs b/examples/multilock_problem.rs
new file mode 100644
index 0000000000..5fd86ef7a1
--- /dev/null
+++ b/examples/multilock_problem.rs
@@ -0,0 +1,79 @@
+//! examples/multilock_vs_lockall.rs
+
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use panic_semihosting as _;
+
+#[rtic::app(device = lm3s6965, dispatchers = [GPIOA])]
+mod app {
+    use cortex_m_semihosting::{debug, hprintln};
+
+    #[shared]
+    struct Shared {
+        shared1: u32,
+        shared2: u32,
+        shared3: u32,
+    }
+
+    #[local]
+    struct Local {}
+
+    #[init]
+    fn init(_: init::Context) -> (Shared, Local, init::Monotonics) {
+        locks::spawn().unwrap();
+
+        (
+            Shared {
+                shared1: 0,
+                shared2: 0,
+                shared3: 0,
+            },
+            Local {},
+            init::Monotonics(),
+        )
+    }
+
+    // when omitted priority is assumed to be `1`
+    #[task(shared = [shared1, shared2, shared3])]
+    fn locks(c: locks::Context) {
+        // nested multi-lock
+        let s1 = c.shared.shared1;
+        let s2 = c.shared.shared2;
+        let s3 = c.shared.shared3;
+
+        (s1, s2, s3).lock(|s1, s2, s3| {
+            *s1 += 1;
+            *s2 += 2;
+            *s3 += 3;
+
+            hprintln!("Multiple locks, s1: {}, s2: {}, s3: {}", s1, s2, s3).ok();
+        });
+
+        // re-construct gives error (consumed by above lock)
+        let s = locks::SharedResources {
+            shared1: s1,
+            shared2: s2,
+            shared3: s3,
+        };
+
+        // nested multi-lock destruct
+        let locks::SharedResources {
+            shared1,
+            shared2,
+            shared3,
+        } = s;
+
+        (shared1, shared2, shared3).lock(|s1, s2, s3| {
+            *s1 += 1;
+            *s2 += 2;
+            *s3 += 3;
+
+            hprintln!("Multiple locks, s1: {}, s2: {}, s3: {}", s1, s2, s3).ok();
+        });
+
+        debug::exit(debug::EXIT_SUCCESS); // Exit QEMU simulator
+    }
+}
diff --git a/examples/multilock_problem_workaround.rs b/examples/multilock_problem_workaround.rs
new file mode 100644
index 0000000000..652d568241
--- /dev/null
+++ b/examples/multilock_problem_workaround.rs
@@ -0,0 +1,79 @@
+//! examples/multilock_vs_lockall.rs
+
+#![deny(unsafe_code)]
+#![deny(warnings)]
+#![no_main]
+#![no_std]
+
+use panic_semihosting as _;
+
+#[rtic::app(device = lm3s6965, dispatchers = [GPIOA])]
+mod app {
+    use cortex_m_semihosting::{debug, hprintln};
+
+    #[shared]
+    struct Shared {
+        shared1: u32,
+        shared2: u32,
+        shared3: u32,
+    }
+
+    #[local]
+    struct Local {}
+
+    #[init]
+    fn init(_: init::Context) -> (Shared, Local, init::Monotonics) {
+        locks::spawn().unwrap();
+
+        (
+            Shared {
+                shared1: 0,
+                shared2: 0,
+                shared3: 0,
+            },
+            Local {},
+            init::Monotonics(),
+        )
+    }
+
+    // when omitted priority is assumed to be `1`
+    #[task(shared = [shared1, shared2, shared3])]
+    fn locks(c: locks::Context) {
+        // nested multi-lock
+        let mut s1 = c.shared.shared1;
+        let mut s2 = c.shared.shared2;
+        let mut s3 = c.shared.shared3;
+
+        (&mut s1, &mut s2, &mut s3).lock(|s1, s2, s3| {
+            *s1 += 1;
+            *s2 += 2;
+            *s3 += 3;
+
+            hprintln!("Multiple locks, s1: {}, s2: {}, s3: {}", s1, s2, s3).ok();
+        });
+
+        // re-construct gives error (consumed by above lock)
+        let s = locks::SharedResources {
+            shared1: s1,
+            shared2: s2,
+            shared3: s3,
+        };
+
+        // nested multi-lock destruct
+        let locks::SharedResources {
+            shared1,
+            shared2,
+            shared3,
+        } = s;
+
+        (shared1, shared2, shared3).lock(|s1, s2, s3| {
+            *s1 += 1;
+            *s2 += 2;
+            *s3 += 3;
+
+            hprintln!("Multiple locks, s1: {}, s2: {}, s3: {}", s1, s2, s3).ok();
+        });
+
+        debug::exit(debug::EXIT_SUCCESS); // Exit QEMU simulator
+    }
+}