Add support for multiboot2.

README.md

@@ -3,7 +3,7 @@
 
 An experimental Multiboot 2 crate for ELF-64 kernels. It's still incomplete, so please open an issue if you're missing some functionality. Contributions welcome!
 
-It uses the Multiboot 1.6 specification at http://nongnu.askapache.com/grub/phcoder/multiboot.pdf and the ELF 64 specification at http://www.uclibc.org/docs/elf-64-gen.pdf.
+It uses the Multiboot 2.0 specification at https://www.gnu.org/software/grub/manual/multiboot2/multiboot.html and the ELF 64 specification at http://www.uclibc.org/docs/elf-64-gen.pdf.
 
 Below is the draft for a blog post about this. I don't plan to finish it but maybe it's helpful as documentation.
 

src/lib.rs

@@ -30,9 +30,15 @@ pub use elf_sections::{
 };
 pub use framebuffer::{FramebufferColor, FramebufferField, FramebufferTag, FramebufferType};
 use header::{Tag, TagIter};
-pub use memory_map::{MemoryArea, MemoryAreaIter, MemoryAreaType, MemoryMapTag};
+pub use memory_map::{
+    EFIMemoryAreaType, EFIMemoryMapTag, EFIMemoryDesc, MemoryArea, MemoryAreaIter,
+    MemoryAreaType, MemoryMapTag,
+};
 pub use module::{ModuleIter, ModuleTag};
-pub use rsdp::{RsdpV1Tag, RsdpV2Tag};
+pub use rsdp::{
+    EFIImageHandle32, EFIImageHandle64, EFISdt32, EFISdt64, ImageLoadPhysAddr, 
+    RsdpV1Tag, RsdpV2Tag,
+};
 pub use vbe_info::{
     VBECapabilities, VBEControlInfo, VBEDirectColorAttributes, VBEField, VBEInfoTag,
     VBEMemoryModel, VBEModeAttributes, VBEModeInfo, VBEWindowAttributes,
@@ -170,6 +176,18 @@ impl BootInformation {
         self.get_tag(8).map(|tag| framebuffer::framebuffer_tag(tag))
     }
 
+    /// Search for the EFI 32-bit SDT tag.
+    pub fn efi_sdt_32_tag<'a>(&self) -> Option<&'a EFISdt32> {
+        self.get_tag(11)
+            .map(|tag| unsafe { &*(tag as *const Tag as *const EFISdt32) })
+    }
+
+    /// Search for the EFI 64-bit SDT tag.
+    pub fn efi_sdt_64_tag<'a>(&self) -> Option<&'a EFISdt64> {
+        self.get_tag(12)
+            .map(|tag| unsafe { &*(tag as *const Tag as *const EFISdt64) })
+    }
+
     /// Search for the (ACPI 1.0) RSDP tag.
     pub fn rsdp_v1_tag<'a>(&self) -> Option<&'a RsdpV1Tag> {
         self.get_tag(14)
@@ -182,6 +200,37 @@ impl BootInformation {
             .map(|tag| unsafe { &*(tag as *const Tag as *const RsdpV2Tag) })
     }
 
+    /// Search for the EFI Memory map tag.
+    pub fn efi_memory_map_tag<'a>(&'a self) -> Option<&'a EFIMemoryMapTag> {
+        // If the EFIBootServicesNotExited is present, then we should not use
+        // the memory map, as it could still be in use.
+        match self.get_tag(18) {
+            Some(_tag) => None,
+            None => {
+                self.get_tag(17)
+                    .map(|tag| unsafe { &*(tag as *const Tag as *const EFIMemoryMapTag) })
+            },
+        }
+    }
+
+    /// Search for the EFI 32-bit image handle pointer.
+    pub fn efi_32_ih<'a>(&'a self) -> Option<&'a EFIImageHandle32> {
+        self.get_tag(19)
+            .map(|tag| unsafe { &*(tag as *const Tag as *const EFIImageHandle32) })
+    }
+
+    /// Search for the EFI 64-bit image handle pointer.
+    pub fn efi_64_ih<'a>(&'a self) -> Option<&'a EFIImageHandle64> {
+        self.get_tag(20)
+            .map(|tag| unsafe { &*(tag as *const Tag as *const EFIImageHandle64) })
+    }
+
+    /// Search for the Image Load Base Physical Address.
+    pub fn load_base_addr<'a>(&'a self) -> Option<&'a ImageLoadPhysAddr> {
+        self.get_tag(21)
+            .map(|tag| unsafe { &*(tag as *const Tag as *const ImageLoadPhysAddr) })
+    }
+
     /// Search for the VBE information tag.
     pub fn vbe_info_tag(&self) -> Option<&'static VBEInfoTag> {
         self.get_tag(7)
@@ -1174,4 +1223,71 @@ mod tests {
         assert_eq!(ElfSectionType::StringTable, s1.section_type());
         assert!(s.next().is_none());
     }
+
+    #[test]
+    fn efi_memory_map() {
+        use memory_map::EFIMemoryAreaType;
+        #[repr(C, align(8))]
+        struct Bytes([u8; 72]);
+        // test that the EFI memory map is detected.
+        let bytes: Bytes = Bytes([
+            72, 0, 0, 0, // size
+            0, 0, 0, 0, // reserved
+            17, 0, 0, 0, // EFI memory map type
+            56, 0, 0, 0, // EFI memory map size
+            48, 0, 0, 0, // EFI descriptor size
+            1, 0, 0, 0, // EFI descriptor version, don't think this matters.
+            7, 0, 0, 0, // Type: EfiConventionalMemory
+            0, 0, 0, 0, // Padding
+            0, 0, 16, 0,// Physical Address: should be 0x100000
+            0, 0, 0, 0, // Extension of physical address.
+            0, 0, 16, 0,// Virtual Address: should be 0x100000
+            0, 0, 0, 0, // Extension of virtual address.
+            4, 0, 0, 0, // 4 KiB Pages: 16 KiB
+            0, 0, 0, 0, // Extension of pages
+            0, 0, 0, 0, // Attributes of this memory range.
+            0, 0, 0, 0, // Extension of attributes
+            0, 0, 0, 0, // end tag type.
+            8, 0, 0, 0, // end tag size.
+        ]);
+        let addr = bytes.0.as_ptr() as usize;
+        let boot_info = unsafe { load(addr) };
+        assert_eq!(addr, boot_info.start_address());
+        assert_eq!(addr + bytes.0.len(), boot_info.end_address());
+        assert_eq!(bytes.0.len(), boot_info.total_size() as usize);
+        let efi_memory_map = boot_info.efi_memory_map_tag().unwrap();
+        let mut efi_mmap_iter = efi_memory_map.memory_areas();
+        let desc = efi_mmap_iter.next().unwrap();
+        assert_eq!(desc.physical_address(), 0x100000);
+        assert_eq!(desc.size(), 16384);
+        assert_eq!(desc.typ(), EFIMemoryAreaType::EfiConventionalMemory);
+        // test that the EFI memory map is not detected if the boot services
+        // are not exited.
+        struct Bytes2([u8; 80]);
+        let bytes2: Bytes2 = Bytes2([
+            80, 0, 0, 0, // size
+            0, 0, 0, 0, // reserved
+            17, 0, 0, 0, // EFI memory map type
+            56, 0, 0, 0, // EFI memory map size
+            48, 0, 0, 0, // EFI descriptor size
+            1, 0, 0, 0, // EFI descriptor version, don't think this matters.
+            7, 0, 0, 0, // Type: EfiConventionalMemory
+            0, 0, 0, 0, // Padding
+            0, 0, 16, 0,// Physical Address: should be 0x100000
+            0, 0, 0, 0, // Extension of physical address.
+            0, 0, 16, 0,// Virtual Address: should be 0x100000
+            0, 0, 0, 0, // Extension of virtual address.
+            4, 0, 0, 0, // 4 KiB Pages: 16 KiB
+            0, 0, 0, 0, // Extension of pages
+            0, 0, 0, 0, // Attributes of this memory range.
+            0, 0, 0, 0, // Extension of attributes
+            18, 0, 0, 0, // Tag ExitBootServices not terminated.
+            8, 0, 0, 0, // Tag ExitBootServices size.
+            0, 0, 0, 0, // end tag type.
+            8, 0, 0, 0, // end tag size.
+        ]);
+        let boot_info = unsafe { load(bytes2.0.as_ptr() as usize) };
+        let efi_mmap = boot_info.efi_memory_map_tag();
+        assert!(efi_mmap.is_none());
+    }
 }

src/memory_map.rs

@@ -52,7 +52,7 @@ impl MemoryArea {
 
     /// The end address of the memory region.
     pub fn end_address(&self) -> u64 {
-        (self.base_addr + self.length)
+        self.base_addr + self.length
     }
 
     /// The size, in bytes, of the memory region.
@@ -114,3 +114,169 @@ impl<'a> Iterator for MemoryAreaIter<'a> {
         }
     }
 }
+
+/// EFI memory map as per EFI specification.
+#[derive(Debug)]
+#[repr(C)]
+pub struct EFIMemoryMapTag {
+    typ: u32,
+    size: u32,
+    desc_size: u32,
+    desc_version: u32,
+    first_desc: EFIMemoryDesc,
+}
+
+impl EFIMemoryMapTag {
+    /// Return an iterator over ALL marked memory areas.
+    ///
+    /// This differs from `MemoryMapTag` as for UEFI, the OS needs some non-
+    /// 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;
+        EFIMemoryAreaIter {
+            current_area: start_area as u64,
+            last_area: (self_ptr as u64 + self.size as u64),
+            entry_size: self.desc_size,
+            phantom: PhantomData,
+        }
+    }
+}
+
+/// EFI Boot Memory Map Descriptor
+#[derive(Debug)]
+#[repr(C)]
+pub struct EFIMemoryDesc {
+    typ: u32,
+    _padding: u32,
+    phys_addr: u64,
+    virt_addr: u64,
+    num_pages: u64,
+    attr: u64,
+}
+
+/// An enum of possible reported region types.
+#[derive(Debug, PartialEq, Eq)]
+pub enum EFIMemoryAreaType {
+    /// Unusable.
+    EfiReservedMemoryType,
+    /// Code area of a UEFI application.
+    EfiLoaderCode,
+    /// Data area of a UEFI application.
+    EfiLoaderData,
+    /// Code area of a UEFI Boot Service Driver.
+    EfiBootServicesCode,
+    /// Data area of a UEFI Boot Service Driver.
+    EfiBootServicesData,
+    /// Code area of a UEFI Runtime Driver.
+    ///
+    /// Must be preserved in working and ACPI S1-S3 states.
+    EfiRuntimeServicesCode,
+    /// Data area of a UEFI Runtime Driver.
+    ///
+    /// Must be preserved in working and ACPI S1-S3 states.
+    EfiRuntimeServicesData,
+    /// Available memory.
+    EfiConventionalMemory,
+    /// Memory with errors, treat as unusable.
+    EfiUnusableMemory,
+    /// Memory containing the ACPI tables.
+    ///
+    /// Must be preserved in working and ACPI S1-S3 states.
+    EfiACPIReclaimMemory,
+    /// Memory reserved by firmware.
+    ///
+    /// Must be preserved in working and ACPI S1-S3 states.
+    EfiACPIMemoryNVS,
+    /// Memory used by firmware for requesting memory mapping of IO.
+    ///
+    /// Should not be used by the OS. Use the ACPI tables for memory mapped IO
+    /// information.
+    EfiMemoryMappedIO,
+    /// Memory used to translate memory cycles to IO cycles.
+    ///
+    /// Should not be used by the OS. Use the ACPI tables for memory mapped IO
+    /// information.
+    EfiMemoryMappedIOPortSpace,
+    /// Memory used by the processor.
+    ///
+    /// Must be preserved in working and ACPI S1-S4 states. Processor defined
+    /// otherwise.
+    EfiPalCode,
+    /// Available memory supporting byte-addressable non-volatility.
+    EfiPersistentMemory,
+    /// Unknown region type, treat as unusable.
+    EfiUnknown,
+}
+
+impl EFIMemoryDesc {
+    /// The physical address of the memory region.
+    pub fn physical_address(&self) -> u64 {
+        self.phys_addr
+    }
+
+    /// The virtual address of the memory region.
+    pub fn virtual_address(&self) -> u64 {
+        self.virt_addr
+    }
+
+    /// The size in bytes of the memory region.
+    pub fn size(&self) -> u64 {
+        // Spec says this is number of 4KiB pages.
+        self.num_pages * 4096
+    }
+
+    /// The type of the memory region.
+    pub fn typ(&self) -> EFIMemoryAreaType {
+        match self.typ {
+            0 => EFIMemoryAreaType::EfiReservedMemoryType,
+            1 => EFIMemoryAreaType::EfiLoaderCode,
+            2 => EFIMemoryAreaType::EfiLoaderData,
+            3 => EFIMemoryAreaType::EfiBootServicesCode,
+            4 => EFIMemoryAreaType::EfiBootServicesData,
+            5 => EFIMemoryAreaType::EfiRuntimeServicesCode,
+            6 => EFIMemoryAreaType::EfiRuntimeServicesData,
+            7 => EFIMemoryAreaType::EfiConventionalMemory,
+            8 => EFIMemoryAreaType::EfiUnusableMemory,
+            9 => EFIMemoryAreaType::EfiACPIReclaimMemory,
+            10 => EFIMemoryAreaType::EfiACPIMemoryNVS,
+            11 => EFIMemoryAreaType::EfiMemoryMappedIO,
+            12 => EFIMemoryAreaType::EfiMemoryMappedIOPortSpace,
+            13 => EFIMemoryAreaType::EfiPalCode,
+            14 => EFIMemoryAreaType::EfiPersistentMemory,
+            _ => EFIMemoryAreaType::EfiUnknown,
+        }
+    }
+}
+
+/// EFI ExitBootServices was not called
+#[derive(Debug)]
+#[repr(C)]
+pub struct EFIBootServicesNotExited {
+    typ: u32,
+    size: u32,
+}
+
+
+/// An iterator over ALL EFI memory areas.
+#[derive(Clone, Debug)]
+pub struct EFIMemoryAreaIter<'a> {
+    current_area: u64,
+    last_area: u64,
+    entry_size: u32,
+    phantom: PhantomData<&'a EFIMemoryDesc>,
+}
+
+impl<'a> Iterator for EFIMemoryAreaIter<'a> {
+    type Item = &'a EFIMemoryDesc;
+    fn next(&mut self) -> Option<&'a EFIMemoryDesc> {
+        if self.current_area > self.last_area {
+            None
+        } else {
+            let area = unsafe{&*(self.current_area as *const EFIMemoryDesc)};
+            self.current_area = self.current_area + (self.entry_size as u64);
+            Some(area)
+        }
+    }
+}
+