Merge pull request #120 from rust-osdev/dev

Merge #119 + necessary fixed into main + multiboot2-0.14.1

Author: phip1611

.github/workflows/rust.yml

@@ -65,7 +65,7 @@ jobs:
     strategy:
       matrix:
         rust:
-          - stable
+          - 1.52.1 # MSVR
     steps:
       - uses: actions/checkout@v2
       # Important preparation step: override the latest default Rust version in GitHub CI

multiboot2-header/src/builder/information_request.rs

@@ -21,6 +21,7 @@ pub struct InformationRequestHeaderTagBuilder {
 #[cfg(feature = "builder")]
 impl InformationRequestHeaderTagBuilder {
     /// New builder.
+    #[allow(clippy::missing_const_for_fn)] // TODO remove once MSRV is higher than 1.52.1
     pub fn new(flag: HeaderTagFlag) -> Self {
         Self {
             irs: BTreeSet::new(),
@@ -30,6 +31,7 @@ impl InformationRequestHeaderTagBuilder {
 
     /// Returns the expected length of the information request tag,
     /// when the `build`-method gets called.
+    #[allow(clippy::missing_const_for_fn)] // TODO remove once MSRV is higher than 1.52.1
     pub fn expected_len(&self) -> usize {
         let basic_header_size = size_of::<InformationRequestHeaderTag<0>>();
         let req_tags_size = self.irs.len() * size_of::<MbiTagType>();

multiboot2/Cargo.toml

@@ -6,7 +6,7 @@ Multiboot2-compliant bootloaders, like GRUB. It supports all tags from the speci
 including full support for the sections of ELF-64. This library is `no_std` and can be
 used in a Multiboot2-kernel.
 """
-version = "0.14.0"
+version = "0.14.1"
 authors = [
     "Philipp Oppermann <[email protected]>",
     "Calvin Lee <[email protected]>",

multiboot2/Changelog.md

@@ -1,5 +1,9 @@
 # CHANGELOG for crate `multiboot2`
 
+## 0.14.1 (2023-03-09)
+- fixed the calculation of the last area of the memory map tag ([#119](https://github.com/rust-osdev/multiboot2/pull/119))
+  (Previously, iterating the EFI Memory map resulted in a superfluous entry as it ran over the next tag)
+
 ## 0.14.0 (2022-06-30)
 - **BREAKING CHANGES** \
   This version includes a few small breaking changes that brings more safety when parsing strings from the

multiboot2/src/framebuffer.rs

@@ -39,6 +39,7 @@ pub enum FramebufferType<'a> {
 
     /// Direct RGB color.
     #[allow(missing_docs)]
+    #[allow(clippy::upper_case_acronyms)]
     RGB {
         red: FramebufferField,
         green: FramebufferField,

multiboot2/src/lib.rs

@@ -1415,13 +1415,23 @@ mod tests {
         assert!(efi_mmap.is_none());
     }
 
+    #[test]
+    /// Compile time test for `MemoryMapTag`.
+    fn e820_memory_map_tag_size() {
+        use super::MemoryMapTag;
+        unsafe {
+            // `MemoryMapTag` is 16 bytes without the 1st entry
+            core::mem::transmute::<[u8; 16], MemoryMapTag>([0u8; 16]);
+        }
+    }
+
     #[test]
     /// Compile time test for `EFIMemoryMapTag`.
     fn efi_memory_map_tag_size() {
         use super::EFIMemoryMapTag;
         unsafe {
-            // `EFIMemoryMapTag` is 16 bytes + `EFIMemoryDesc` is 40 bytes.
-            core::mem::transmute::<[u8; 56], EFIMemoryMapTag>([0u8; 56]);
+            // `EFIMemoryMapTag` is 16 bytes without the 1st entry
+            core::mem::transmute::<[u8; 16], EFIMemoryMapTag>([0u8; 16]);
         }
     }
 }

multiboot2/src/memory_map.rs

@@ -18,7 +18,7 @@ pub struct MemoryMapTag {
     size: u32,
     entry_size: u32,
     entry_version: u32,
-    first_area: MemoryArea,
+    first_area: [MemoryArea; 0],
 }
 
 impl MemoryMapTag {
@@ -31,10 +31,13 @@ impl MemoryMapTag {
     /// Return an iterator over all marked memory areas.
     pub fn all_memory_areas(&self) -> impl Iterator<Item = &MemoryArea> {
         let self_ptr = self as *const MemoryMapTag;
-        let start_area = (&self.first_area) as *const MemoryArea;
+        let start_area = self.first_area.as_ptr();
+
         MemoryAreaIter {
             current_area: start_area as u64,
-            last_area: (self_ptr as u64 + (self.size - self.entry_size) as u64),
+            // NOTE: `last_area` is only a bound, it doesn't necessarily point exactly to the last element
+            last_area: (self_ptr as u64
+                + (self.size as u64 - core::mem::size_of::<MemoryMapTag>() as u64)),
             entry_size: self.entry_size,
             phantom: PhantomData,
         }
@@ -127,7 +130,7 @@ pub struct EFIMemoryMapTag {
     size: u32,
     desc_size: u32,
     desc_version: u32,
-    first_desc: EFIMemoryDesc,
+    first_desc: [EFIMemoryDesc; 0],
 }
 
 impl EFIMemoryMapTag {
@@ -137,10 +140,12 @@ impl EFIMemoryMapTag {
     /// available memory areas for tables and such.
     pub fn memory_areas(&self) -> EFIMemoryAreaIter {
         let self_ptr = self as *const EFIMemoryMapTag;
-        let start_area = (&self.first_desc) as *const EFIMemoryDesc;
+        let start_area = self.first_desc.as_ptr();
         EFIMemoryAreaIter {
             current_area: start_area as u64,
-            last_area: (self_ptr as u64 + self.size as u64),
+            // NOTE: `last_area` is only a bound, it doesn't necessarily point exactly to the last element
+            last_area: (self_ptr as u64
+                + (self.size as u64 - core::mem::size_of::<EFIMemoryMapTag>() as u64)),
             entry_size: self.desc_size,
             phantom: PhantomData,
         }

multiboot2/src/vbe_info.rs

@@ -330,6 +330,7 @@ bitflags! {
 #[derive(Debug, PartialEq, Eq, Copy, Clone)]
 #[repr(u8)]
 #[allow(missing_docs)]
+#[allow(clippy::upper_case_acronyms)]
 pub enum VBEMemoryModel {
     Text = 0x00,
     CGAGraphics = 0x01,