Support configuration of memory size

crates/scheduler/CHANGELOG.md

@@ -8,6 +8,7 @@
 
 ### Minor
 
+- Support configuring the memory size with `WASEFIRE_MEMORY_PAGE_COUNT`
 - Support `platform::update::is_supported()`
 - Support `platform::update`
 - Support `platform` and `platform::reboot()`

crates/scheduler/src/lib.rs

@@ -293,9 +293,10 @@ impl<B: Board> Scheduler<B> {
 
     #[cfg(feature = "wasm")]
     fn load(&mut self, wasm: &'static [u8]) {
+        const MEMORY_SIZE: usize = memory_size();
         #[repr(align(16))]
-        struct Memory([u8; 0x10000]);
-        static mut MEMORY: Memory = Memory([0; 0x10000]);
+        struct Memory([u8; MEMORY_SIZE]);
+        static mut MEMORY: Memory = Memory([0; MEMORY_SIZE]);
         #[cfg(not(feature = "unsafe-skip-validation"))]
         let module = Module::new(wasm).unwrap();
         // SAFETY: The module is valid by the feature invariant.
@@ -421,3 +422,18 @@ impl From<()> for Trap {
         Trap
     }
 }
+
+#[cfg(feature = "wasm")]
+const fn memory_size() -> usize {
+    let page = match option_env!("WASEFIRE_MEMORY_PAGE_COUNT") {
+        Some(x) => {
+            let x = x.as_bytes();
+            assert!(x.len() == 1, "not a single digit");
+            let x = x[0];
+            assert!(x.is_ascii_digit(), "not a single digit");
+            x as usize
+        }
+        None => 1,
+    };
+    page * 0x10000
+}

crates/xtask/src/main.rs

@@ -201,9 +201,16 @@ struct RunnerOptions {
     #[clap(long)]
     measure_bloat: bool,
 
-    /// Show the (top N) stack sizes of the firmware
+    /// Show the (top N) stack sizes of the firmware.
     #[clap(long)]
     stack_sizes: Option<Option<usize>>,
+
+    /// Allocates <MEMORY_PAGE_COUNT> pages for the WASM module.
+    ///
+    /// Supported values are numbers between 0 and 9 inclusive, i.e. single digit. The default when
+    /// missing is 1 page.
+    #[clap(long)]
+    memory_page_count: Option<usize>,
 }
 
 #[derive(Copy, Clone)]
@@ -533,6 +540,10 @@ impl RunnerOptions {
         if !features.is_empty() {
             cargo.arg(format!("--features={}", features.join(",")));
         }
+        if let Some(n) = self.memory_page_count {
+            ensure!((0 ..= 9).contains(&n), "--memory-page-count supports single digit only");
+            cargo.env("WASEFIRE_MEMORY_PAGE_COUNT", format!("{n}"));
+        }
         cargo.env("RUSTFLAGS", rustflags.join(" "));
         cargo.current_dir(format!("crates/runner-{}", self.name));
         fs::touch("target/wasefire/applet.wasm")?;