feat: add heap implementation for embedded alloc

Author: emmanuelm41

bolos-impl/src/lib.rs

@@ -36,6 +36,9 @@ pub use bolos_sys::exit_app;
 pub use bolos_sys::pic;
 pub use bolos_sys::pic::PIC;
 
+pub use bolos_sys::heap;
+pub use bolos_sys::heap::Heap;
+
 pub mod nvm;
 pub use nvm::NVM;
 

bolos-sys/Cargo.toml

@@ -7,6 +7,14 @@ edition = "2018"
 [dependencies]
 cfg-if = "1.0.0"
 
+# Required for the global allocator
+critical-section = { version = "1.1.2" }
+
+# Required for LLHeap
+linked_list_allocator = { version = "0.10.5", default-features = false }
+rlsf = { version = "0.2.1", default-features = false, optional = true }
+const-default = { version = "1.0.0", default-features = false, optional = true }
+
 zeroize = { version = "1", default-features = false }
 
 [dev-dependencies]

bolos-sys/src/heap.rs

@@ -0,0 +1,144 @@
+// Code taken from
+// https://github.com/Zondax/embedded-alloc
+// https://crates.io/crates/embedded-alloc/0.5.1
+
+// LLHeap with PIC on RefCell
+// This was required to PIC the RefCell on the Heap struct. Otherwise, the app will fail with segmentation fault.
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::cell::RefCell;
+use core::ptr::{self, NonNull};
+
+use critical_section::Mutex;
+use linked_list_allocator::Heap as LLHeap;
+
+use crate::pic::PIC;
+
+/// A linked list first fit heap.
+pub struct Heap {
+    pub heap: Mutex<PIC<RefCell<LLHeap>>>,
+}
+
+impl Heap {
+    /// Create a new UNINITIALIZED heap allocator
+    ///
+    /// You must initialize this heap using the
+    /// [`init`](Self::init) method before using the allocator.
+    pub const fn empty() -> Heap {
+        Heap {
+            heap: Mutex::new(PIC::new(RefCell::new(LLHeap::empty()))),
+        }
+    }
+
+    /// Initializes the heap
+    ///
+    /// This function must be called BEFORE you run any code that makes use of the
+    /// allocator.
+    ///
+    /// `start_addr` is the address where the heap will be located.
+    ///
+    /// `size` is the size of the heap in bytes.
+    ///
+    /// Note that:
+    ///
+    /// - The heap grows "upwards", towards larger addresses. Thus `start_addr` will
+    ///   be the smallest address used.
+    ///
+    /// - The largest address used is `start_addr + size - 1`, so if `start_addr` is
+    ///   `0x1000` and `size` is `0x30000` then the allocator won't use memory at
+    ///   addresses `0x31000` and larger.
+    ///
+    /// # Safety
+    ///
+    /// Obey these or Bad Stuff will happen.
+    ///
+    /// - This function must be called exactly ONCE.
+    /// - `size > 0`
+    pub unsafe fn init(&self, start_addr: usize, size: usize) {
+        // zlog("-- init 1 --\x00");
+        critical_section::with(|cs| {
+            self.heap
+                .borrow(cs)
+                .borrow_mut()
+                .init(start_addr as *mut u8, size);
+        });
+    }
+
+    /// Returns an estimate of the amount of bytes in use.
+    pub fn used(&self) -> usize {
+        // zlog("-- used 1 --\x00");
+        critical_section::with(|cs| self.heap.borrow(cs).borrow_mut().used())
+    }
+
+    /// Returns an estimate of the amount of bytes available.
+    pub fn free(&self) -> usize {
+        // zlog("-- free 1 --\x00");
+        critical_section::with(|cs| self.heap.borrow(cs).borrow_mut().free())
+    }
+
+    pub fn alloc(&self, layout: Layout) -> Option<NonNull<u8>> {
+        // zlog("-- alloc 1 --\x00");
+        let res = critical_section::with(|cs| {
+            // zlog("-- alloc 2 --\x00");
+            let heap = &self.heap;
+            // zlog("-- alloc 3 --\x00");
+            let heap2 = heap.borrow(cs);
+            // zlog("-- alloc 4 --\x00");
+            let mut heap3 = heap2.borrow_mut();
+            // zlog("-- alloc 5 --\x00");
+            let result = heap3.allocate_first_fit(layout);
+            // zlog("-- alloc 6 --\x00");
+            result.ok()
+        });
+        // zlog("-- alloc 7 --\x00");
+        res
+    }
+
+    pub unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        // zlog("-- dealloc 1 --\x00");
+        critical_section::with(|cs| {
+            self.heap
+                .borrow(cs)
+                .borrow_mut()
+                .deallocate(NonNull::new_unchecked(ptr), layout)
+        });
+    }
+}
+
+unsafe impl GlobalAlloc for PIC<Heap> {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        // zlog("-- GlobalAlloc alloc 1 --\x00");
+        self.get_ref().alloc(layout)
+            .map_or(ptr::null_mut(), |allocation| allocation.as_ptr())
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        // zlog("-- GlobalAlloc dealloc 1 --\x00");
+        self.get_ref().dealloc(ptr, layout);
+    }
+}
+
+#[cfg(feature = "allocator_api")]
+mod allocator_api {
+    use super::*;
+    use core::alloc::{AllocError, Allocator};
+
+    unsafe impl Allocator for Heap {
+        fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+            zlog("-- Allocator allocate 1 --\x00");
+            match layout.size() {
+                0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
+                size => self.alloc(layout).map_or(Err(AllocError), |allocation| {
+                    Ok(NonNull::slice_from_raw_parts(allocation, size))
+                }),
+            }
+        }
+
+        unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+            zlog("-- Allocator deallocate 1 --\x00");
+            if layout.size() != 0 {
+                self.dealloc(ptr.as_ptr(), layout);
+            }
+        }
+    }
+}

bolos-sys/src/lib.rs

@@ -53,3 +53,4 @@ pub fn exit_app(_status: u8) -> ! {
 mod extra_traits;
 
 pub mod pic;
+pub mod heap;