feat: move EL0 stack to virtual space

* feat: Implement a basic MMU configuration

* feat: Enhance MMU by separating sections and configuring permissions

* feat: Update MMU configuration and memory allocation functions

* fix: Level 3 translation fault

* docs: add code documentation

* fix: linter

* feat: map translation tables to kernel space

* feat: move el1 stack to kernel VA space

* feat: use virtual memory for heap allocation

* docs: update Readme

.gitignore

@@ -4,3 +4,4 @@ kernel8.img
 sd.img
 settings.json
 .DS_Store
+.venv

.vscode/launch.json

@@ -33,6 +33,31 @@
       ],
       "preLaunchTask": "Run QEMU"
     },
+    {
+      "name": "Attach to QEMU (AArch64) wo. window",
+      "type": "cppdbg",
+      "request": "launch",
+      "program": "${workspaceFolder}/target/aarch64-unknown-none/debug/nova",
+      "miDebuggerServerAddress": "localhost:1234",
+      "miDebuggerPath": "gdb",
+      "cwd": "${workspaceFolder}",
+      "stopAtEntry": true,
+      "externalConsole": false,
+      "MIMode": "gdb",
+      "setupCommands": [
+        {
+          "description": "Enable pretty-printing for gdb",
+          "text": "-enable-pretty-printing",
+          "ignoreFailures": true
+        },
+        {
+          "description": "Show assembly on stop",
+          "text": "set disassemble-next-line on",
+          "ignoreFailures": true
+        }
+      ],
+      "preLaunchTask": "Run QEMU wo window"
+    },
 
     {
       "name": "Attach LLDB",

.vscode/tasks.json

@@ -14,9 +14,38 @@
     {
       "label": "Run QEMU",
       "type": "shell",
-      "command": "llvm-objcopy -O binary target/aarch64-unknown-none/debug/nova target/aarch64-unknown-none/debug/kernel8.img && qemu-system-aarch64 -M raspi3b -cpu cortex-a53 -serial stdio -sd sd.img -kernel ${workspaceFolder}/target/aarch64-unknown-none/debug/kernel8.img -S -s -m 1024",
+      "command": "llvm-objcopy -O binary target/aarch64-unknown-none/debug/nova target/aarch64-unknown-none/debug/kernel8.img && echo Starting QEMU&qemu-system-aarch64 -M raspi3b -cpu cortex-a53 -serial stdio -sd sd.img -kernel ${workspaceFolder}/target/aarch64-unknown-none/debug/kernel8.img -S -s -m 1024",
       "isBackground": true,
-      "dependsOn": ["Build"]
+      "dependsOn": ["Build"],
+      "problemMatcher": {
+                "pattern": {
+                    "regexp": "^(Starting QEMU)",
+                    "line": 1,
+                },
+                "background": {
+                    "activeOnStart": true,
+                    "beginsPattern": "^(Starting QEMU)",
+                    "endsPattern": "^(Starting QEMU)"
+                }
+            }
+    },
+        {
+      "label": "Run QEMU wo window",
+      "type": "shell",
+      "command": "llvm-objcopy -O binary target/aarch64-unknown-none/debug/nova target/aarch64-unknown-none/debug/kernel8.img && echo Starting QEMU&qemu-system-aarch64 -M raspi3b -cpu cortex-a53 -display none -serial stdio -sd sd.img -kernel ${workspaceFolder}/target/aarch64-unknown-none/debug/kernel8.img -S -s -m 1024",
+      "isBackground": true,
+      "dependsOn": ["Build"],
+      "problemMatcher": {
+                "pattern": {
+                    "regexp": "^(Starting QEMU)",
+                    "line": 1,
+                },
+                "background": {
+                    "activeOnStart": true,
+                    "beginsPattern": "^(Starting QEMU)",
+                    "endsPattern": "^(Starting QEMU)"
+                }
+            }
     }
   ]
 }

Cargo.lock

@@ -47,12 +47,19 @@ dependencies = [
  "heap",
  "libm",
  "nova_error",
+ "paste",
 ]
 
 [[package]]
 name = "nova_error"
 version = "0.1.0"
 
+[[package]]
+name = "paste"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.21"

Cargo.toml

@@ -14,11 +14,13 @@ panic = "abort"
 
 [dependencies]
 libm = "0.2.15"
-heap = {path = "heap"}
-nova_error = {path = "nova_error"}
+heap = {path = "workspace/heap"}
+nova_error = {path = "workspace/nova_error"}
+paste = "1.0.15"
 
 [workspace]
 
-members = [ "nova_error",
-    "heap"
+members = [
+    "workspace/nova_error",
+    "workspace/heap",
 ]

README.md

@@ -14,8 +14,10 @@ NovaOS is a expository project where I build a kernel from scratch for a Raspber
 - Communicate with peripherals via mailboxes ✓
 - Frame Buffer ✓
 - Heap Memory allocation ✓
+- MMU ✓
+- SVC instructions
+- Kernel Independent Applications
 - Multi Core
 - Dynamic clock speed
-- MMU
 - Multiprocessing
 - Basic Terminal over UART

link.ld

@@ -4,52 +4,43 @@ SECTIONS {
     .text ALIGN(4) : {
         KEEP(*(.text._start))
         *(.text .text.*)
+        . = ALIGN(4K);
+        __text_end = .;
     }
 
     .rodata : {
         *(.rodata .rodata.*)
     }
 
-    .data : {
-        _data = .;
+    .data  : {
         *(.data .data.*)
     }
 
-    .bss (NOLOAD) : {
-        . = ALIGN(16);
+    .bss ALIGN(16) (NOLOAD) : {
         __bss_start = .;
         *(.bss .bss.*)
-        *(COMMON)
         __bss_end = .;
     }
 
-    .vector_table ALIGN(2048) : {
+    . = ALIGN(2M);
+
+    __share_end = .;
+
+    .vector_table ALIGN(2K) : {
         KEEP(*(.vector_table))
     }
 
-    .heap : ALIGN(16)
-    {
-    __heap_start = .;
-    . += 0x10000; #10kB
-    __heap_end = .;
-    }
-
-    .stack : ALIGN(16)
-    {
+    # EL2 Stack
+    .stack ALIGN(16): {
     __stack_start = .;
-    . += 0x10000; #10kB stack
+    . += 100K; #100kB stack
+    . = ALIGN(16);
     __stack_end = .;
     }
 
-    .stack_el0 : ALIGN(16)
-    {
-    __stack_start_el0 = .;
-    . += 0x10000; #10kB stack
-    __stack_end_el0 = .;
-    }
+    . = ALIGN(2M);
 
-
-    _end = .;
+    __kernel_end = .;
 }
 
 __bss_size = (__bss_end - __bss_start) >> 3;

src/aarch64/mmu.rs

@@ -0,0 +1,366 @@
+use core::mem::size_of;
+use nova_error::NovaError;
+
+use crate::{
+    aarch64::mmu::physical_mapping::{
+        reserve_block, reserve_block_explicit, reserve_page, reserve_page_explicit,
+    },
+    get_current_el,
+};
+
+const BLOCK: u64 = 0b01;
+const TABLE: u64 = 0b11;
+const PAGE: u64 = 0b11;
+
+/// Allow EL0 to access this section
+pub const EL0_ACCESSIBLE: u64 = 1 << 6;
+
+/// Allow a page or block to be written.
+pub const WRITABLE: u64 = 0 << 7;
+/// Disallow a page or block to be written.
+pub const READ_ONLY: u64 = 1 << 7;
+
+const ACCESS_FLAG: u64 = 1 << 10;
+const INNER_SHAREABILITY: u64 = 0b11 << 8;
+
+pub const NORMAL_MEM: u64 = 0 << 2;
+pub const DEVICE_MEM: u64 = 1 << 2;
+
+/// Disallow EL1 Execution.
+pub const PXN: u64 = 1 << 53;
+
+/// Disallow EL0 Execution.
+pub const UXN: u64 = 1 << 54;
+
+pub const GRANULARITY: usize = 4 * 1024;
+const TABLE_ENTRY_COUNT: usize = GRANULARITY / size_of::<u64>(); // 2MiB
+
+pub const LEVEL1_BLOCK_SIZE: usize = TABLE_ENTRY_COUNT * TABLE_ENTRY_COUNT * GRANULARITY;
+pub const LEVEL2_BLOCK_SIZE: usize = TABLE_ENTRY_COUNT * GRANULARITY;
+
+const L2_BLOCK_BITMAP_WORDS: usize = LEVEL2_BLOCK_SIZE / (64 * GRANULARITY);
+
+const MAX_PAGE_COUNT: usize = 1024 * 1024 * 1024 / GRANULARITY;
+
+const TRANSLATION_TABLE_BASE_ADDR: usize = 0xFFFF_FF82_0000_0000;
+pub const KERNEL_VIRTUAL_MEM_SPACE: usize = 0xFFFF_FF80_0000_0000;
+
+pub const STACK_START_ADDR: usize = !KERNEL_VIRTUAL_MEM_SPACE & (!0xF);
+
+mod physical_mapping;
+
+type VirtAddr = usize;
+type PhysAddr = usize;
+
+pub enum PhysSource {
+    Any,
+    Explicit(PhysAddr),
+}
+
+#[repr(align(4096))]
+pub struct PageTable([u64; TABLE_ENTRY_COUNT]);
+
+#[no_mangle]
+pub static mut TRANSLATIONTABLE_TTBR0: PageTable = PageTable([0; 512]);
+#[no_mangle]
+pub static mut TRANSLATIONTABLE_TTBR1: PageTable = PageTable([0; 512]);
+
+/// Allocate a memory block of `size` starting at `virtual_address`.
+pub fn allocate_memory(
+    virtual_address: usize,
+    size_bytes: usize,
+    phys: PhysSource,
+    flags: u64,
+) -> Result<(), NovaError> {
+    if !virtual_address.is_multiple_of(GRANULARITY) {
+        return Err(NovaError::Misalignment);
+    }
+    if !size_bytes.is_multiple_of(GRANULARITY) {
+        return Err(NovaError::InvalidGranularity);
+    }
+
+    let base_table = if virtual_address & KERNEL_VIRTUAL_MEM_SPACE > 0 {
+        core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR1)
+    } else {
+        core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0)
+    };
+
+    match phys {
+        PhysSource::Any => map_range_dynamic(virtual_address, size_bytes, base_table, flags),
+        PhysSource::Explicit(phys_addr) => {
+            map_range_explicit(virtual_address, phys_addr, size_bytes, base_table, flags)
+        }
+    }
+}
+
+fn map_range_explicit(
+    mut virt: VirtAddr,
+    mut phys: PhysAddr,
+    size_bytes: usize,
+    base: *mut PageTable,
+    flags: u64,
+) -> Result<(), NovaError> {
+    let mut remaining = size_bytes;
+
+    while virt % LEVEL2_BLOCK_SIZE != 0 {
+        map_page(virt, phys, base, flags)?;
+        (virt, _) = virt.overflowing_add(GRANULARITY);
+        phys += GRANULARITY;
+        remaining -= GRANULARITY;
+    }
+
+    while remaining >= LEVEL2_BLOCK_SIZE {
+        map_l2_block(virt, phys, base, flags)?;
+        (virt, _) = virt.overflowing_add(LEVEL2_BLOCK_SIZE);
+        phys += LEVEL2_BLOCK_SIZE;
+        remaining -= LEVEL2_BLOCK_SIZE;
+    }
+
+    while remaining > 0 {
+        map_page(virt, phys, base, flags)?;
+        (virt, _) = virt.overflowing_add(GRANULARITY);
+        phys += GRANULARITY;
+        remaining -= GRANULARITY;
+    }
+
+    Ok(())
+}
+
+fn map_range_dynamic(
+    mut virt: PhysAddr,
+    size_bytes: usize,
+    base: *mut PageTable,
+    flags: u64,
+) -> Result<(), NovaError> {
+    let mut remaining = size_bytes;
+
+    while remaining >= LEVEL2_BLOCK_SIZE {
+        map_l2_block(virt, reserve_block(), base, flags)?;
+        (virt, _) = virt.overflowing_add(LEVEL2_BLOCK_SIZE);
+        remaining -= LEVEL2_BLOCK_SIZE;
+    }
+
+    while remaining > 0 {
+        map_page(virt, reserve_page(), base, flags)?;
+        (virt, _) = virt.overflowing_add(GRANULARITY);
+        remaining -= GRANULARITY;
+    }
+
+    Ok(())
+}
+
+/// Allocate a singe page.
+pub fn alloc_page(
+    virtual_address: usize,
+    base_table: *mut PageTable,
+    additional_flags: u64,
+) -> Result<(), NovaError> {
+    map_page(
+        virtual_address,
+        reserve_page(),
+        base_table,
+        additional_flags,
+    )
+}
+
+/// Allocate a single page at an explicit `physical_address`.
+pub fn alloc_page_explicit(
+    virtual_address: usize,
+    physical_address: usize,
+    base_table: *mut PageTable,
+    additional_flags: u64,
+) -> Result<(), NovaError> {
+    reserve_page_explicit(physical_address)?;
+    map_page(
+        virtual_address,
+        physical_address,
+        base_table,
+        additional_flags,
+    )
+}
+
+pub fn map_page(
+    virtual_address: usize,
+    physical_address: usize,
+    base_table_ptr: *mut PageTable,
+    additional_flags: u64,
+) -> Result<(), NovaError> {
+    let (l1_off, l2_off, l3_off) = virtual_address_to_table_offset(virtual_address);
+
+    let offsets = [l1_off, l2_off];
+
+    let table_ptr = navigate_table(base_table_ptr, &offsets)?;
+    let table = unsafe { &mut *table_ptr };
+
+    if table.0[l3_off] & 0b11 > 0 {
+        return Err(NovaError::Paging);
+    }
+
+    table.0[l3_off] = create_page_descriptor_entry(physical_address, additional_flags);
+
+    Ok(())
+}
+
+// Allocate a level 2 block, at a explicit `physical_address`.
+pub fn alloc_block_l2_explicit(
+    virtual_addr: usize,
+    physical_address: usize,
+    base_table_ptr: *mut PageTable,
+    additional_flags: u64,
+) -> Result<(), NovaError> {
+    if !physical_address.is_multiple_of(LEVEL2_BLOCK_SIZE) {
+        return Err(NovaError::Misalignment);
+    }
+
+    reserve_block_explicit(physical_address)?;
+    map_l2_block(
+        virtual_addr,
+        physical_address,
+        base_table_ptr,
+        additional_flags,
+    )
+}
+
+pub fn map_l2_block(
+    virtual_addr: usize,
+    physical_address: usize,
+    base_table_ptr: *mut PageTable,
+    additional_flags: u64,
+) -> Result<(), NovaError> {
+    let (l1_off, l2_off, _) = virtual_address_to_table_offset(virtual_addr);
+    let offsets = [l1_off];
+    let table_ptr = navigate_table(base_table_ptr, &offsets)?;
+
+    let table = unsafe { &mut *table_ptr };
+
+    // Verify virtual address is available.
+    if table.0[l2_off] & 0b11 != 0 {
+        return Err(NovaError::Paging);
+    }
+
+    let new_entry = create_block_descriptor_entry(physical_address, additional_flags);
+
+    table.0[l2_off] = new_entry;
+
+    Ok(())
+}
+
+pub fn reserve_range(
+    start_physical_address: PhysAddr,
+    end_physical_address: PhysAddr,
+) -> Result<PhysAddr, NovaError> {
+    let mut size = end_physical_address - start_physical_address;
+    let l1_blocks = size / LEVEL1_BLOCK_SIZE;
+    size %= LEVEL1_BLOCK_SIZE;
+    let l2_blocks = size / LEVEL2_BLOCK_SIZE;
+    size %= LEVEL2_BLOCK_SIZE;
+    let l3_pages = size / GRANULARITY;
+
+    if !size.is_multiple_of(GRANULARITY) {
+        return Err(NovaError::Misalignment);
+    }
+
+    if l1_blocks > 0 {
+        todo!();
+    }
+
+    let mut addr = start_physical_address;
+    for _ in 0..l2_blocks {
+        reserve_block_explicit(addr)?;
+        addr += LEVEL2_BLOCK_SIZE;
+    }
+
+    for _ in 0..l3_pages {
+        reserve_page_explicit(addr)?;
+        addr += GRANULARITY;
+    }
+
+    Ok(start_physical_address)
+}
+
+fn create_block_descriptor_entry(physical_address: usize, additional_flags: u64) -> u64 {
+    (physical_address as u64 & 0x0000_FFFF_FFFF_F000)
+        | BLOCK
+        | ACCESS_FLAG
+        | INNER_SHAREABILITY
+        | additional_flags
+}
+
+fn create_page_descriptor_entry(physical_address: usize, additional_flags: u64) -> u64 {
+    (physical_address as u64 & 0x0000_FFFF_FFFF_F000)
+        | PAGE
+        | ACCESS_FLAG
+        | INNER_SHAREABILITY
+        | additional_flags
+}
+
+fn create_table_descriptor_entry(addr: usize) -> u64 {
+    (addr as u64 & 0x0000_FFFF_FFFF_F000) | TABLE
+}
+
+fn virtual_address_to_table_offset(virtual_addr: usize) -> (usize, usize, usize) {
+    let absolute_page_off = (virtual_addr & !KERNEL_VIRTUAL_MEM_SPACE) / GRANULARITY;
+    let l3_off = absolute_page_off % TABLE_ENTRY_COUNT;
+    let l2_off = (absolute_page_off / TABLE_ENTRY_COUNT) % TABLE_ENTRY_COUNT;
+    let l1_off = (absolute_page_off / TABLE_ENTRY_COUNT / TABLE_ENTRY_COUNT) % TABLE_ENTRY_COUNT;
+    (l1_off, l2_off, l3_off)
+}
+
+/// Navigate the table tree, by following given offsets. This function
+/// allocates new tables if required.
+fn navigate_table(
+    initial_table_ptr: *mut PageTable,
+    offsets: &[usize],
+) -> Result<*mut PageTable, NovaError> {
+    let mut table = initial_table_ptr;
+    for offset in offsets {
+        table = next_table(table, *offset)?;
+    }
+    Ok(table)
+}
+
+/// Get the next table one level down.
+///
+/// If table doesn't exit a page will be allocated for it.
+fn next_table(table_ptr: *mut PageTable, offset: usize) -> Result<*mut PageTable, NovaError> {
+    let table = unsafe { &mut *table_ptr };
+    match table.0[offset] & 0b11 {
+        0 => {
+            let new_phys_page_table_address = reserve_page();
+
+            table.0[offset] = create_table_descriptor_entry(new_phys_page_table_address);
+            map_page(
+                phys_table_to_kernel_space(new_phys_page_table_address),
+                new_phys_page_table_address,
+                &raw mut TRANSLATIONTABLE_TTBR1,
+                NORMAL_MEM | WRITABLE | PXN | UXN,
+            )?;
+
+            Ok(entry_table_addr(table.0[offset] as usize) as *mut PageTable)
+        }
+        1 => Err(NovaError::Paging),
+        3 => Ok(entry_table_addr(table.0[offset] as usize) as *mut PageTable),
+        _ => unreachable!(),
+    }
+}
+
+/// Extracts the physical address out of an table entry.
+#[inline]
+fn entry_phys(entry: usize) -> PhysAddr {
+    entry & 0x0000_FFFF_FFFF_F000
+}
+
+#[inline]
+fn entry_table_addr(entry: usize) -> VirtAddr {
+    if get_current_el() == 1 {
+        phys_table_to_kernel_space(entry_phys(entry))
+    } else {
+        entry_phys(entry)
+    }
+}
+
+/// Extracts the physical address out of an table entry.
+#[inline]
+fn phys_table_to_kernel_space(entry: usize) -> VirtAddr {
+    entry | TRANSLATION_TABLE_BASE_ADDR
+}

src/aarch64/mmu/physical_mapping.rs

@@ -0,0 +1,89 @@
+use crate::aarch64::mmu::{PhysAddr, GRANULARITY, L2_BLOCK_BITMAP_WORDS, MAX_PAGE_COUNT};
+use nova_error::NovaError;
+
+static mut PAGING_BITMAP: [u64; MAX_PAGE_COUNT / 64] = [0; MAX_PAGE_COUNT / 64];
+
+pub fn reserve_page() -> PhysAddr {
+    if let Some(address) = find_unallocated_page() {
+        let page = address / GRANULARITY;
+        let word_index = page / 64;
+        unsafe { PAGING_BITMAP[word_index] |= 1 << (page % 64) };
+        return address;
+    }
+    panic!("Out of Memory!");
+}
+
+pub fn reserve_page_explicit(physical_address: usize) -> Result<PhysAddr, NovaError> {
+    let page = physical_address / GRANULARITY;
+    let word_index = page / 64;
+
+    if unsafe { PAGING_BITMAP[word_index] } & (1 << (page % 64)) > 0 {
+        return Err(NovaError::Paging);
+    }
+
+    unsafe { PAGING_BITMAP[word_index] |= 1 << (page % 64) };
+    Ok(physical_address)
+}
+
+pub fn reserve_block() -> usize {
+    if let Some(start) = find_contiguous_free_bitmap_words(L2_BLOCK_BITMAP_WORDS) {
+        for j in 0..L2_BLOCK_BITMAP_WORDS {
+            unsafe { PAGING_BITMAP[start + j] = u64::MAX };
+        }
+        return start * 64 * GRANULARITY;
+    }
+
+    panic!("Out of Memory!");
+}
+
+pub fn reserve_block_explicit(physical_address: usize) -> Result<(), NovaError> {
+    let page = physical_address / GRANULARITY;
+    for i in 0..L2_BLOCK_BITMAP_WORDS {
+        unsafe {
+            if PAGING_BITMAP[(page / 64) + i] != 0 {
+                return Err(NovaError::Paging);
+            }
+        };
+    }
+    for i in 0..L2_BLOCK_BITMAP_WORDS {
+        unsafe {
+            PAGING_BITMAP[(page / 64) + i] = u64::MAX;
+        };
+    }
+    Ok(())
+}
+
+fn find_unallocated_page() -> Option<usize> {
+    for (i, entry) in unsafe { PAGING_BITMAP }.iter().enumerate() {
+        if *entry != u64::MAX {
+            for offset in 0..64 {
+                if entry >> offset & 0b1 == 0 {
+                    return Some((i * 64 + offset) * GRANULARITY);
+                }
+            }
+        }
+    }
+    None
+}
+
+fn find_contiguous_free_bitmap_words(required_words: usize) -> Option<usize> {
+    let mut run_start = 0;
+    let mut run_len = 0;
+
+    for (i, entry) in unsafe { PAGING_BITMAP }.iter().enumerate() {
+        if *entry == 0 {
+            if run_len == 0 {
+                run_start = i;
+            }
+            run_len += 1;
+
+            if run_len == required_words {
+                return Some(run_start);
+            }
+        } else {
+            run_len = 0;
+        }
+    }
+
+    None
+}

src/aarch64/mod.rs

@@ -0,0 +1,2 @@
+pub mod mmu;
+pub mod registers;

src/aarch64/registers.rs

@@ -0,0 +1,59 @@
+use core::arch::asm;
+
+pub mod daif {
+    use core::arch::asm;
+
+    #[inline(always)]
+    pub fn mask_all() {
+        unsafe { asm!("msr DAIFSet, #0xf", options(nomem, nostack)) }
+    }
+
+    #[inline(always)]
+    pub fn unmask_all() {
+        unsafe { asm!("msr DAIFClr, #0xf", options(nomem, nostack)) }
+    }
+
+    #[inline(always)]
+    pub fn mask_irq() {
+        unsafe { asm!("msr DAIFSet, #0x2", options(nomem, nostack)) }
+    }
+
+    #[inline(always)]
+    pub fn unmask_irq() {
+        unsafe { asm!("msr DAIFClr, #0x2", options(nomem, nostack)) }
+    }
+}
+
+#[macro_export]
+macro_rules! psr {
+    ($name:ident, $t:tt) => {
+        paste::item! {
+            pub fn [<read_ $name:lower>]() -> $t {
+                let buf: $t;
+                unsafe {
+                    asm!(
+                        concat!("mrs {0:x}, ", stringify!($name)),
+                        out(reg) buf
+                    );
+                }
+                buf
+            }
+        }
+    };
+}
+
+psr!(TCR_EL1, u64);
+
+psr!(ID_AA64MMFR0_EL1, u64);
+
+psr!(ESR_EL1, u32);
+
+psr!(SPSR_EL1, u32);
+
+psr!(ELR_EL1, u64);
+
+psr!(SCTLR_EL1, u64);
+
+pub fn read_exception_source_el() -> u32 {
+    read_spsr_el1() & 0b1111
+}

src/config.S

@@ -0,0 +1,194 @@
+.section .text.config
+.align 4
+.global el2_to_el1
+el2_to_el1:
+    mov x0, #(1 << 31)
+    msr HCR_EL2, x0
+
+    // Set SPSR_EL2: return to EL1h
+    mov x0, #(0b0101)
+    msr SPSR_EL2, x0
+
+    // Set return address to kernel_main
+    adrp x0, kernel_main
+    add  x0, x0, :lo12:kernel_main
+    msr ELR_EL2, x0
+
+    // Set SP_EL1 to stack base
+    adrp x0, EL1_STACK_TOP
+    ldr  x1, [x0, :lo12:EL1_STACK_TOP]
+    msr SP_EL1, x1
+
+    // Set VBAR_EL1 to vector table
+    adrp x0, vector_table
+    add  x0, x0, :lo12:vector_table
+    msr VBAR_EL1, x0
+
+    isb
+
+    adrp x0, SCTLR_EL1_CONF
+    ldr  x1, [x0, :lo12:SCTLR_EL1_CONF]
+    msr SCTLR_EL1, x1
+
+    isb
+
+    // SIMD should not be trapped
+    mrs x0, CPACR_EL1
+    mov x1, #(0b11<<20)
+    orr x0,x0, x1
+    msr CPACR_EL1,x0
+
+    isb
+
+    // Return to EL1
+    eret
+
+.section .text.config
+.align 4
+.global configure_mmu_el1
+configure_mmu_el1:
+    // Configure MMU
+    adrp x0, TCR_EL1_CONF
+    ldr  x1, [x0, :lo12:TCR_EL1_CONF]
+    msr TCR_EL1, x1
+    isb
+
+    // MAIR0: Normal Mem.
+    // MAIR1: Device Mem.
+    mov x0, #0x04FF
+    msr MAIR_EL1, x0
+    isb
+
+    // Configure translation table
+    adrp x0, TRANSLATIONTABLE_TTBR0
+    add  x1, x0, :lo12:TRANSLATIONTABLE_TTBR0
+    msr TTBR0_EL1, x1
+
+    adrp x0, TRANSLATIONTABLE_TTBR1
+    add  x1, x0, :lo12:TRANSLATIONTABLE_TTBR1
+    msr TTBR1_EL1, x1
+
+    tlbi vmalle1
+    dsb ish
+    isb
+
+    ret
+
+.align 4
+.global el1_to_el0
+el1_to_el0:
+
+    // Set SPSR_EL1: return to EL0t
+    mov x0, #(0b0000)
+    msr SPSR_EL1, x0
+
+    // Set return address to el0
+    ldr x0, =el0
+    msr ELR_EL1, x0
+
+    // Set SP_EL1 to stack base
+    adrp x0, EL0_STACK_TOP
+    ldr  x1, [x0, :lo12:EL0_STACK_TOP]
+    msr SP_EL0, x1
+
+    isb
+
+    // Return to EL0
+    eret
+
+
+.align 4
+irq_handler:
+    sub sp, sp, #176
+    stp x0, x1, [sp, #0]
+    stp x2, x3, [sp, #16]
+    stp x4, x5, [sp, #32]
+    stp x6, x7, [sp, #48]
+    stp x8, x9, [sp, #64]
+    stp x10, x11, [sp, #80]
+    stp x12, x13, [sp, #96]
+    stp x14, x15, [sp, #112]
+    stp x16, x17, [sp, #128]
+    stp x18, x29, [sp, #144]
+    stp x30, xzr, [sp, #160]
+
+    bl rust_irq_handler
+
+    ldp x0, x1, [sp, #0]
+    ldp x2, x3, [sp, #16]
+    ldp x4, x5, [sp, #32]
+    ldp x6, x7, [sp, #48]
+    ldp x8, x9, [sp, #64]
+    ldp x10, x11, [sp, #80]
+    ldp x12, x13, [sp, #96]
+    ldp x14, x15, [sp, #112]
+    ldp x16, x17, [sp, #128]
+    ldp x18, x29, [sp, #144]
+    ldp x30, xzr, [sp, #160]
+    add sp, sp, #176
+
+    eret
+
+.align 4
+synchronous_interrupt_imm_lower_aarch64:
+    sub sp, sp, #176
+    stp x0, x1, [sp, #0]
+    stp x2, x3, [sp, #16]
+    stp x4, x5, [sp, #32]
+    stp x6, x7, [sp, #48]
+    stp x8, x9, [sp, #64]
+    stp x10, x11, [sp, #80]
+    stp x12, x13, [sp, #96]
+    stp x14, x15, [sp, #112]
+    stp x16, x17, [sp, #128]
+    stp x18, x29, [sp, #144]
+    stp x30, xzr, [sp, #160]
+
+    bl rust_synchronous_interrupt_imm_lower_aarch64
+
+    ldp x0, x1, [sp, #0]
+    ldp x2, x3, [sp, #16]
+    ldp x4, x5, [sp, #32]
+    ldp x6, x7, [sp, #48]
+    ldp x8, x9, [sp, #64]
+    ldp x10, x11, [sp, #80]
+    ldp x12, x13, [sp, #96]
+    ldp x14, x15, [sp, #112]
+    ldp x16, x17, [sp, #128]
+    ldp x18, x29, [sp, #144]
+    ldp x30, xzr, [sp, #160]
+    add sp, sp, #176
+
+    eret
+
+.align 4
+synchronous_interrupt_no_el_change:
+    sub sp, sp, #176
+    stp x0, x1, [sp, #0]
+    stp x2, x3, [sp, #16]
+    stp x4, x5, [sp, #32]
+    stp x6, x7, [sp, #48]
+    stp x8, x9, [sp, #64]
+    stp x10, x11, [sp, #80]
+    stp x12, x13, [sp, #96]
+    stp x14, x15, [sp, #112]
+    stp x16, x17, [sp, #128]
+    stp x18, x29, [sp, #144]
+    stp x30, xzr, [sp, #160]
+
+    bl rust_synchronous_interrupt_no_el_change
+
+    ldp x0, x1, [sp, #0]
+    ldp x2, x3, [sp, #16]
+    ldp x4, x5, [sp, #32]
+    ldp x6, x7, [sp, #48]
+    ldp x8, x9, [sp, #64]
+    ldp x10, x11, [sp, #80]
+    ldp x12, x13, [sp, #96]
+    ldp x14, x15, [sp, #112]
+    ldp x16, x17, [sp, #128]
+    ldp x18, x29, [sp, #144]
+    ldp x30, xzr, [sp, #160]
+    add sp, sp, #176
+
+    eret

src/configuration.rs

@@ -1,16 +1,129 @@
-static SCTLR_EL1_MMU_DISABLED: u64 = 0; //M
-static SCTLR_EL1_DATA_CACHE_DISABLED: u64 = 0 << 2; //C
-static SCTLR_EL1_INSTRUCTION_CACHE_DISABLED: u64 = 0 << 12; //I
-static SCTLR_EL1_LITTLE_ENDIAN_EL0: u64 = 0 << 24; //E0E
-static SCTLR_EL1_LITTLE_ENDIAN_EL1: u64 = 0 << 25; //EE
+const SCTLR_EL1_MMU_ENABLED: u64 = 1; //M
+const SCTLR_EL1_DATA_CACHE_DISABLED: u64 = 0 << 2; //C
+const SCTLR_EL1_INSTRUCTION_CACHE_DISABLED: u64 = 0 << 12; //I
+const SCTLR_EL1_LITTLE_ENDIAN_EL0: u64 = 0 << 24; //E0E
+const SCTLR_EL1_LITTLE_ENDIAN_EL1: u64 = 0 << 25; //EE
+const SCTLR_EL1_SPAN: u64 = 1 << 23; //SPAN
 
 #[allow(clippy::identity_op)]
-static SCTLR_EL1_RES: u64 = (0 << 6) | (1 << 11) | (0 << 17) | (1 << 20) | (1 << 22); //Res0 & Res1
+const SCTLR_EL1_RES: u64 = (0 << 6) | (1 << 11) | (0 << 17) | (1 << 20) | (1 << 22); //Res0 & Res1
 
 #[no_mangle]
-pub static SCTLR_EL1_CONF: u64 = SCTLR_EL1_MMU_DISABLED
+pub static SCTLR_EL1_CONF: u64 = SCTLR_EL1_MMU_ENABLED
     | SCTLR_EL1_DATA_CACHE_DISABLED
     | SCTLR_EL1_INSTRUCTION_CACHE_DISABLED
     | SCTLR_EL1_LITTLE_ENDIAN_EL0
     | SCTLR_EL1_LITTLE_ENDIAN_EL1
-    | SCTLR_EL1_RES;
+    | SCTLR_EL1_RES
+    | SCTLR_EL1_SPAN;
+
+const TG0: u64 = 0b00 << 14; // 4KB granularity EL0
+const T0SZ: u64 = 25; // 25 Bits of TTBR select -> 39 Bits of VA
+const SH0: u64 = 0b11 << 12; // Inner shareable
+
+const TG1: u64 = 0b10 << 30; // 4KB granularity EL1
+const T1SZ: u64 = 25 << 16; // 25 Bits of TTBR select -> 39 Bits of VA
+const SH1: u64 = 0b11 << 28; // Inner sharable
+
+const IPS: u64 = 0b000 << 32; // 32 bits of PA space -> up to 4GiB
+const AS: u64 = 0b1 << 36; // configure an ASID size of 16 bits
+
+#[no_mangle]
+pub static TCR_EL1_CONF: u64 = IPS | TG0 | TG1 | T0SZ | T1SZ | SH0 | SH1 | AS;
+
+pub mod mmu {
+    use crate::{
+        aarch64::mmu::{
+            alloc_block_l2_explicit, allocate_memory, map_l2_block, map_page, reserve_range,
+            PhysSource, DEVICE_MEM, EL0_ACCESSIBLE, GRANULARITY, KERNEL_VIRTUAL_MEM_SPACE,
+            LEVEL1_BLOCK_SIZE, LEVEL2_BLOCK_SIZE, NORMAL_MEM, PXN, READ_ONLY, STACK_START_ADDR,
+            TRANSLATIONTABLE_TTBR0, UXN, WRITABLE,
+        },
+        PERIPHERAL_BASE,
+    };
+
+    #[no_mangle]
+    static EL1_STACK_TOP: usize = STACK_START_ADDR | KERNEL_VIRTUAL_MEM_SPACE;
+    const EL1_STACK_SIZE: usize = LEVEL2_BLOCK_SIZE * 2;
+    #[no_mangle]
+    static EL0_STACK_TOP: usize = STACK_START_ADDR;
+    const EL0_STACK_SIZE: usize = LEVEL2_BLOCK_SIZE * 2;
+    extern "C" {
+        static __text_end: u64;
+        static __share_end: u64;
+        static __kernel_end: u64;
+    }
+
+    pub fn initialize_mmu_translation_tables() {
+        let text_end = unsafe { &__text_end } as *const _ as usize;
+        let shared_segment_end = unsafe { &__share_end } as *const _ as usize;
+        let kernel_end = unsafe { &__kernel_end } as *const _ as usize;
+
+        reserve_range(0x0, kernel_end).unwrap();
+
+        for addr in (0..text_end).step_by(GRANULARITY) {
+            map_page(
+                addr,
+                addr,
+                core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0),
+                EL0_ACCESSIBLE | READ_ONLY | NORMAL_MEM,
+            )
+            .unwrap();
+        }
+
+        for addr in (text_end..shared_segment_end).step_by(GRANULARITY) {
+            map_page(
+                addr,
+                addr,
+                core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0),
+                EL0_ACCESSIBLE | WRITABLE | NORMAL_MEM,
+            )
+            .unwrap();
+        }
+
+        for addr in (shared_segment_end..kernel_end).step_by(LEVEL2_BLOCK_SIZE) {
+            map_l2_block(
+                addr,
+                addr,
+                core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0),
+                WRITABLE | UXN | NORMAL_MEM,
+            )
+            .unwrap();
+        }
+
+        for addr in (PERIPHERAL_BASE..LEVEL1_BLOCK_SIZE).step_by(LEVEL2_BLOCK_SIZE) {
+            alloc_block_l2_explicit(
+                addr,
+                addr,
+                core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0),
+                EL0_ACCESSIBLE | WRITABLE | UXN | PXN | DEVICE_MEM,
+            )
+            .unwrap();
+        }
+
+        // Frame Buffer memory range
+        allocate_memory(
+            0x3c100000,
+            1080 * 1920 * 4,
+            PhysSource::Explicit(0x3c100000),
+            NORMAL_MEM | PXN | UXN | WRITABLE | EL0_ACCESSIBLE,
+        )
+        .unwrap();
+
+        allocate_memory(
+            EL1_STACK_TOP - EL1_STACK_SIZE + 0x10,
+            EL1_STACK_SIZE,
+            PhysSource::Any,
+            WRITABLE | NORMAL_MEM,
+        )
+        .unwrap();
+
+        allocate_memory(
+            EL0_STACK_TOP - EL0_STACK_SIZE + 0x10,
+            EL0_STACK_SIZE,
+            PhysSource::Any,
+            WRITABLE | EL0_ACCESSIBLE | NORMAL_MEM,
+        )
+        .unwrap();
+    }
+}

src/framebuffer.rs

@@ -5,7 +5,7 @@ mod bitmaps;
 use bitmaps::BASIC_LEGACY;
 
 use crate::{
-    mailbox::{read_mailbox, write_mailbox},
+    pi3::mailbox::{read_mailbox, write_mailbox},
     println,
 };
 #[repr(align(16))]
@@ -24,8 +24,8 @@ pub struct FrameBuffer {
     pixel_depth: u32, // Bits per pixel
     pitch: u32,       // Pixel per row
     rows: u32,        // Rows
-    start_addr: *mut u32,
-    size: u32, //Bytes
+    pub start_addr: *mut u32,
+    pub size: u32, //Bytes
 }
 
 pub const RED: u32 = 0x00FF0000;
@@ -37,6 +37,9 @@ pub const YELLOW: u32 = 0x00FFFF00;
 impl FrameBuffer {
     pub fn draw_pixel(&self, x: u32, y: u32, color: u32) {
         let offset = x + y * self.pitch;
+        if x >= self.pitch || y >= self.rows {
+            return;
+        }
         unsafe {
             write_volatile(self.start_addr.add(offset as usize), color);
         }

src/interrupt_handlers.rs

@@ -3,8 +3,11 @@ use core::arch::asm;
 use alloc::vec::Vec;
 
 use crate::{
+    aarch64::registers::{
+        daif::{mask_all, unmask_irq},
+        read_elr_el1, read_esr_el1, read_exception_source_el,
+    },
     get_current_el,
-    interrupt_handlers::daif::unmask_irq,
     peripherals::{
         gpio::{read_gpio_event_detect_status, reset_gpio_event_detect_status},
         uart::clear_uart_interrupt_state,
@@ -68,18 +71,18 @@ impl From<u32> for EsrElX {
 
 #[no_mangle]
 unsafe extern "C" fn rust_irq_handler() {
-    daif::mask_all();
+    mask_all();
     let pending_irqs = get_irq_pending_sources();
 
     if pending_irqs & GPIO_PENDING_BIT_OFFSET != 0 {
         handle_gpio_interrupt();
-        let source_el = get_exception_return_exception_level() >> 2;
+        let source_el = read_exception_source_el() >> 2;
         println!("Source EL: {}", source_el);
         println!("Current EL: {}", get_current_el());
-        println!("Return register address: {:#x}", get_elr_el1());
+        println!("Return register address: {:#x}", read_esr_el1());
     }
 
-    if let Some(handler_vec) = unsafe { INTERRUPT_HANDLERS.as_ref() } {
+    if let Some(handler_vec) = unsafe { &*core::ptr::addr_of_mut!(INTERRUPT_HANDLERS) } {
         for handler in handler_vec {
             if (pending_irqs & (1 << (handler.source.clone() as u32))) != 0 {
                 (handler.function)();
@@ -91,14 +94,14 @@ unsafe extern "C" fn rust_irq_handler() {
 
 #[no_mangle]
 unsafe extern "C" fn rust_synchronous_interrupt_no_el_change() {
-    daif::mask_all();
+    mask_all();
 
-    let source_el = get_exception_return_exception_level() >> 2;
+    let source_el = read_exception_source_el() >> 2;
     println!("--------Sync Exception in EL{}--------", source_el);
     println!("No EL change");
     println!("Current EL: {}", get_current_el());
-    println!("{:?}", EsrElX::from(get_esr_el1()));
-    println!("Return register address: {:#x}", get_elr_el1());
+    println!("{:?}", EsrElX::from(read_esr_el1()));
+    println!("Return register address: {:#x}", read_esr_el1());
     println!("-------------------------------------");
 }
 
@@ -109,21 +112,23 @@ unsafe extern "C" fn rust_synchronous_interrupt_no_el_change() {
 /// AArch64.
 #[no_mangle]
 unsafe extern "C" fn rust_synchronous_interrupt_imm_lower_aarch64() {
-    daif::mask_all();
+    mask_all();
 
-    let source_el = get_exception_return_exception_level() >> 2;
+    let source_el = read_exception_source_el() >> 2;
     println!("--------Sync Exception in EL{}--------", source_el);
     println!("Exception escalated to EL {}", get_current_el());
     println!("Current EL: {}", get_current_el());
-    let esr = EsrElX::from(get_esr_el1());
-    println!("{:?}", EsrElX::from(esr));
-    println!("Return register address: {:#x}", get_elr_el1());
+    let esr: EsrElX = EsrElX::from(read_esr_el1());
+    println!("{:?}", esr);
+    println!("Return address: {:#x}", read_elr_el1());
 
     match esr.ec {
         0b100100 => {
             println!("Cause: Data Abort from a lower Exception level");
         }
-        _ => {}
+        _ => {
+            println!("Unknown Error Code: {:b}", esr.ec);
+        }
     }
     println!("-------------------------------------");
 
@@ -133,7 +138,9 @@ unsafe extern "C" fn rust_synchronous_interrupt_imm_lower_aarch64() {
 fn clear_interrupt_for_source(source: IRQSource) {
     match source {
         IRQSource::UartInt => clear_uart_interrupt_state(),
-        _ => {}
+        _ => {
+            todo!()
+        }
     }
 }
 
@@ -144,42 +151,6 @@ fn set_return_to_kernel_main() {
     }
 }
 
-fn get_exception_return_exception_level() -> u32 {
-    let spsr: u32;
-    unsafe {
-        asm!("mrs {0:x}, SPSR_EL1", out(reg) spsr);
-    }
-    spsr & 0b1111
-}
-
-/// Read the syndrome information that caused an exception
-///
-/// ESR = Exception Syndrome Register
-fn get_esr_el1() -> u32 {
-    let esr: u32;
-    unsafe {
-        asm!(
-            "mrs {esr:x}, ESR_EL1",
-            esr = out(reg) esr
-        );
-    }
-    esr
-}
-
-/// Read the return address
-///
-/// ELR = Exception Link Registers
-fn get_elr_el1() -> u32 {
-    let elr: u32;
-    unsafe {
-        asm!(
-            "mrs {esr:x}, ELR_EL1",
-            esr = out(reg) elr
-        );
-    }
-    elr
-}
-
 fn handle_gpio_interrupt() {
     println!("Interrupt");
     for i in 0..=53u32 {
@@ -245,36 +216,13 @@ pub fn get_irq_pending_sources() -> u64 {
     pending
 }
 
-pub mod daif {
-    use core::arch::asm;
-
-    #[inline(always)]
-    pub fn mask_all() {
-        unsafe { asm!("msr DAIFSet, #0xf", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn unmask_all() {
-        unsafe { asm!("msr DAIFClr, #0xf", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn mask_irq() {
-        unsafe { asm!("msr DAIFSet, #0x2", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn unmask_irq() {
-        unsafe { asm!("msr DAIFClr, #0x2", options(nomem, nostack)) }
-    }
-}
-
+#[inline(always)]
 pub fn initialize_interrupt_handler() {
     unsafe { INTERRUPT_HANDLERS = Some(Vec::new()) };
 }
 
 pub fn register_interrupt_handler(source: IRQSource, function: fn()) {
-    if let Some(handler_vec) = unsafe { INTERRUPT_HANDLERS.as_mut() } {
+    if let Some(handler_vec) = unsafe { &mut *core::ptr::addr_of_mut!(INTERRUPT_HANDLERS) } {
         handler_vec.push(InterruptHandlers { source, function });
     }
 }

src/irq_interrupt.rs

@@ -1,227 +0,0 @@
-use core::arch::asm;
-
-use crate::{
-    get_current_el,
-    irq_interrupt::daif::unmask_irq,
-    mmio_read, mmio_write,
-    peripherals::gpio::{read_gpio_event_detect_status, reset_gpio_event_detect_status},
-};
-
-const INTERRUPT_BASE: u32 = 0x3F00_B000;
-const IRQ_PENDING_BASE: u32 = INTERRUPT_BASE + 0x204;
-const ENABLE_IRQ_BASE: u32 = INTERRUPT_BASE + 0x210;
-const DISABLE_IRQ_BASE: u32 = INTERRUPT_BASE + 0x21C;
-
-#[repr(u32)]
-pub enum IRQState {
-    AuxInt = 29,
-    I2cSpiSlvInt = 44,
-    Pwa0 = 45,
-    Pwa1 = 46,
-    Smi = 48,
-    GpioInt0 = 49,
-    GpioInt1 = 50,
-    GpioInt2 = 51,
-    GpioInt3 = 52,
-    I2cInt = 53,
-    SpiInt = 54,
-    PcmInt = 55,
-    UartInt = 57,
-}
-
-/// Representation of the ESR_ELx registers
-///
-///  Reference: D1.10.4
-#[derive(Debug, Clone, Copy)]
-#[allow(dead_code)]
-struct EsrElX {
-    ec: u32,
-    il: u32,
-    iss: u32,
-}
-
-impl From<u32> for EsrElX {
-    fn from(value: u32) -> Self {
-        Self {
-            ec: value >> 26,
-            il: (value >> 25) & 0b1,
-            iss: value & 0x1FFFFFF,
-        }
-    }
-}
-
-#[no_mangle]
-unsafe extern "C" fn rust_irq_handler() {
-    daif::mask_all();
-    handle_gpio_interrupt();
-    let source_el = get_exception_return_exception_level() >> 2;
-    println!("Source EL: {}", source_el);
-    println!("Current EL: {}", get_current_el());
-    println!("Return register address: {:#x}", get_elr_el1());
-}
-
-#[no_mangle]
-unsafe extern "C" fn rust_synchronous_interrupt_no_el_change() {
-    daif::mask_all();
-
-    let source_el = get_exception_return_exception_level() >> 2;
-    println!("--------Sync Exception in EL{}--------", source_el);
-    println!("No EL change");
-    println!("Current EL: {}", get_current_el());
-    println!("{:?}", EsrElX::from(get_esr_el1()));
-    println!("Return register address: {:#x}", get_elr_el1());
-    println!("-------------------------------------");
-}
-
-/// Synchronous Exception Handler
-///
-/// Lower Exception level, where the implemented level
-/// immediately lower than the target level is using
-/// AArch64.
-#[no_mangle]
-unsafe extern "C" fn rust_synchronous_interrupt_imm_lower_aarch64() {
-    daif::mask_all();
-
-    let source_el = get_exception_return_exception_level() >> 2;
-    println!("--------Sync Exception in EL{}--------", source_el);
-    println!("Exception escalated to EL {}", get_current_el());
-    println!("Current EL: {}", get_current_el());
-    let esr = EsrElX::from(get_esr_el1());
-    println!("{:?}", EsrElX::from(esr));
-    println!("Return register address: {:#x}", get_elr_el1());
-
-    match esr.ec {
-        0b100100 => {
-            println!("Cause: Data Abort from a lower Exception level");
-        }
-        _ => {}
-    }
-    println!("-------------------------------------");
-
-    set_return_to_kernel_main();
-}
-
-fn set_return_to_kernel_main() {
-    unsafe {
-        asm!("ldr x0, =kernel_main", "msr ELR_EL1, x0");
-        asm!("mov x0, #(0b0101)", "msr SPSR_EL1, x0");
-    }
-}
-
-fn get_exception_return_exception_level() -> u32 {
-    let spsr: u32;
-    unsafe {
-        asm!("mrs {0:x}, SPSR_EL1", out(reg) spsr);
-    }
-    spsr & 0b1111
-}
-
-/// Read the syndrome information that caused an exception
-///
-/// ESR = Exception Syndrome Register
-fn get_esr_el1() -> u32 {
-    let esr: u32;
-    unsafe {
-        asm!(
-            "mrs {esr:x}, ESR_EL1",
-            esr = out(reg) esr
-        );
-    }
-    esr
-}
-
-/// Read the return address
-///
-/// ELR = Exception Link Registers
-fn get_elr_el1() -> u32 {
-    let elr: u32;
-    unsafe {
-        asm!(
-            "mrs {esr:x}, ELR_EL1",
-            esr = out(reg) elr
-        );
-    }
-    elr
-}
-
-fn handle_gpio_interrupt() {
-    println!("Interrupt");
-    for i in 0..=53u32 {
-        let val = read_gpio_event_detect_status(i);
-
-        if val {
-            #[allow(clippy::single_match)]
-            match i {
-                26 => {
-                    println!("Button Pressed");
-                }
-                _ => {}
-            }
-            // Reset GPIO Interrupt handler by writing a 1
-            reset_gpio_event_detect_status(i);
-        }
-    }
-    unmask_irq();
-}
-
-/// Enables IRQ Source
-pub fn enable_irq_source(state: IRQState) {
-    let nr = state as u32;
-    let register = ENABLE_IRQ_BASE + 4 * (nr / 32);
-    let register_offset = nr % 32;
-    let current = mmio_read(register);
-    let mask = 0b1 << register_offset;
-    let new_val = current | mask;
-    mmio_write(register, new_val);
-}
-
-/// Disable IRQ Source
-pub fn disable_irq_source(state: IRQState) {
-    let nr = state as u32;
-    let register = DISABLE_IRQ_BASE + 4 * (nr / 32);
-    let register_offset = nr % 32;
-    let current = mmio_read(register);
-    let mask = 0b1 << register_offset;
-    let new_val = current | mask;
-    mmio_write(register, new_val);
-}
-
-/// Read current IRQ Source status
-pub fn read_irq_source_status(state: IRQState) -> u32 {
-    let nr = state as u32;
-    let register = ENABLE_IRQ_BASE + 4 * (nr / 32);
-    let register_offset = nr % 32;
-    (mmio_read(register) >> register_offset) & 0b1
-}
-
-/// Status if a IRQ Source is enabled
-pub fn read_irq_pending(state: IRQState) -> bool {
-    let nr = state as u32;
-    let register = IRQ_PENDING_BASE + 4 * (nr / 32);
-    let register_offset = nr % 32;
-    ((mmio_read(register) >> register_offset) & 0b1) != 0
-}
-
-pub mod daif {
-    use core::arch::asm;
-
-    #[inline(always)]
-    pub fn mask_all() {
-        unsafe { asm!("msr DAIFSet, #0xf", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn unmask_all() {
-        unsafe { asm!("msr DAIFClr, #0xf", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn mask_irq() {
-        unsafe { asm!("msr DAIFSet, #0x2", options(nomem, nostack)) }
-    }
-
-    #[inline(always)]
-    pub fn unmask_irq() {
-        unsafe { asm!("msr DAIFClr, #0x2", options(nomem, nostack)) }
-    }
-}

src/lib.rs

@@ -12,42 +12,49 @@ use core::{
 
 use heap::Heap;
 
-use crate::{interrupt_handlers::initialize_interrupt_handler, logger::DefaultLogger};
+use crate::{
+    aarch64::mmu::{
+        allocate_memory, PhysSource, KERNEL_VIRTUAL_MEM_SPACE, LEVEL2_BLOCK_SIZE, NORMAL_MEM, UXN,
+        WRITABLE,
+    },
+    interrupt_handlers::initialize_interrupt_handler,
+    logger::DefaultLogger,
+};
 
-static PERIPHERAL_BASE: u32 = 0x3F00_0000;
+static PERIPHERAL_BASE: usize = 0x3F00_0000;
 
 unsafe extern "C" {
-    unsafe static mut __heap_start: u8;
-    unsafe static mut __heap_end: u8;
+    unsafe static mut __kernel_end: u8;
 }
 
 #[global_allocator]
 pub static mut GLOBAL_ALLOCATOR: Heap = Heap::empty();
 
-pub unsafe fn init_heap() {
-    let start = core::ptr::addr_of_mut!(__heap_start) as usize;
-    let end = core::ptr::addr_of_mut!(__heap_end) as usize;
+pub unsafe fn init_kernel_heap() {
+    let start = core::ptr::addr_of_mut!(__kernel_end) as usize | KERNEL_VIRTUAL_MEM_SPACE;
+    let size = LEVEL2_BLOCK_SIZE * 2;
 
+    allocate_memory(start, size, PhysSource::Any, NORMAL_MEM | UXN | WRITABLE).unwrap();
     let heap = core::ptr::addr_of_mut!(GLOBAL_ALLOCATOR);
-    (*heap).init(start, end);
+    (*heap).init(start, start + size);
 }
 
 #[panic_handler]
 fn panic(_panic: &PanicInfo) -> ! {
     loop {
-        println!("Panic");
+        println!("Panic: {}", _panic.message());
     }
 }
 
 pub mod peripherals;
 
+pub mod aarch64;
 pub mod configuration;
 pub mod framebuffer;
 pub mod interrupt_handlers;
 pub mod logger;
-pub mod mailbox;
-pub mod power_management;
-pub mod timer;
+
+pub mod pi3;
 
 #[inline(always)]
 pub unsafe fn read_address(address: u32) -> u32 {
@@ -72,6 +79,7 @@ pub fn get_current_el() -> u64 {
 }
 
 pub fn initialize_kernel() {
+    unsafe { init_kernel_heap() };
     logger::set_logger(Box::new(DefaultLogger));
     initialize_interrupt_handler();
 }

src/logger.rs

@@ -31,12 +31,10 @@ macro_rules! log {
 }
 
 pub fn log(args: fmt::Arguments) {
-    unsafe {
-        if let Some(logger) = LOGGER.as_mut() {
-            logger.write_str("\n").unwrap();
-            logger.write_fmt(args).unwrap();
-            logger.flush();
-        }
+    if let Some(logger) = unsafe { &mut *core::ptr::addr_of_mut!(LOGGER) } {
+        logger.write_str("\n").unwrap();
+        logger.write_fmt(args).unwrap();
+        logger.flush();
     }
 }
 

src/main.rs

@@ -1,6 +1,5 @@
 #![no_main]
 #![no_std]
-#![feature(asm_experimental_arch)]
 #![allow(static_mut_refs)]
 #![allow(clippy::missing_safety_doc)]
 use core::{
@@ -10,12 +9,13 @@ use core::{
 
 extern crate alloc;
 
-use alloc::boxed::Box;
+use alloc::vec::Vec;
 use nova::{
+    aarch64::registers::{daif, read_id_aa64mmfr0_el1},
+    configuration::mmu::initialize_mmu_translation_tables,
     framebuffer::{FrameBuffer, BLUE, GREEN, RED},
-    get_current_el, init_heap,
-    interrupt_handlers::{daif, enable_irq_source, IRQSource},
-    log, mailbox,
+    get_current_el,
+    interrupt_handlers::{enable_irq_source, IRQSource},
     peripherals::{
         gpio::{
             blink_gpio, gpio_pull_up, set_falling_edge_detect, set_gpio_function, GPIOFunction,
@@ -27,10 +27,14 @@ use nova::{
 };
 
 global_asm!(include_str!("vector.S"));
+global_asm!(include_str!("config.S"));
+
+static mut FRAMEBUFFER: Option<FrameBuffer> = None;
 
 extern "C" {
     fn el2_to_el1();
     fn el1_to_el0();
+    fn configure_mmu_el1();
     static mut __bss_start: u32;
     static mut __bss_end: u32;
 }
@@ -61,7 +65,16 @@ pub extern "C" fn main() -> ! {
     println!("Exception level: {}", get_current_el());
 
     unsafe {
-        asm!("mrs x0, SCTLR_EL1",);
+        initialize_mmu_translation_tables();
+        configure_mmu_el1();
+        println!("MMU initialized...");
+    };
+
+    println!("Register: AA64MMFR0_EL1: {:064b}", read_id_aa64mmfr0_el1());
+    println!("Moving El2->EL1");
+    unsafe { FRAMEBUFFER = Some(FrameBuffer::default()) };
+
+    unsafe {
         el2_to_el1();
     }
 
@@ -79,13 +92,18 @@ unsafe fn zero_bss() {
 
 #[no_mangle]
 pub extern "C" fn kernel_main() -> ! {
+    println!("Kernel Start...");
     nova::initialize_kernel();
-    println!("Kernel Main");
+    let mut test_vector = Vec::new();
+    for i in 0..20 {
+        test_vector.push(i);
+    }
+    println!("heap allocation test: {:?}", test_vector);
+
     println!("Exception Level: {}", get_current_el());
     daif::unmask_all();
 
     unsafe {
-        init_heap();
         el1_to_el0();
     };
 
@@ -105,24 +123,27 @@ pub extern "C" fn el0() -> ! {
 
     enable_irq_source(IRQSource::UartInt);
 
-    let fb = FrameBuffer::default();
+    if let Some(fb) = unsafe { FRAMEBUFFER.as_mut() } {
+        for i in 0..1080 {
+            fb.draw_pixel(50, i, BLUE);
+        }
+        fb.draw_square(500, 500, 600, 700, RED);
+        fb.draw_square_fill(800, 800, 900, 900, GREEN);
+        fb.draw_square_fill(1000, 800, 1200, 700, BLUE);
+        fb.draw_square_fill(900, 100, 800, 150, RED | BLUE);
+        fb.draw_string("Hello World! :D\nTest next Line", 500, 5, 3, BLUE);
 
-    fb.draw_square(500, 500, 600, 700, RED);
-    fb.draw_square_fill(800, 800, 900, 900, GREEN);
-    fb.draw_square_fill(1000, 800, 1200, 700, BLUE);
-    fb.draw_square_fill(900, 100, 800, 150, RED | BLUE);
-    fb.draw_string("Hello World! :D\nTest next Line", 500, 5, 3, BLUE);
-
-    fb.draw_function(cos, 100, 101, RED);
+        fb.draw_function(cos, 0, 101, RED);
+    }
 
     loop {
-        let temp = mailbox::read_soc_temp([0]).unwrap();
-        log!("{} °C", temp[1] / 1000);
+        // TODO: Mailbox requires a physical address. The stack is now in VA space causing an issue.
+        // Fix with SVCs ?
+
+        // let temp = mailbox::read_soc_temp([0]).unwrap();
+        // println!("{} °C", temp[1] / 1000);
 
         blink_gpio(SpecificGpio::OnboardLed as u8, 500);
-
-        let b = Box::new([1, 2, 3, 4]);
-        log!("{:?}", b);
     }
 }
 

src/peripherals/gpio.rs

@@ -2,7 +2,7 @@ use core::result::Result;
 use core::result::Result::Ok;
 use core::sync::atomic::{compiler_fence, Ordering};
 
-use crate::timer::{delay_nops, sleep_ms};
+use crate::pi3::timer::{delay_nops, sleep_ms};
 use crate::{read_address, write_address};
 
 const GPFSEL_BASE: u32 = 0x3F20_0000;

src/peripherals/uart.rs

@@ -3,7 +3,7 @@ use core::{
     fmt::{self, Write},
 };
 
-use crate::{println, read_address, write_address};
+use crate::{read_address, write_address};
 
 const BAUD: u32 = 115200;
 const UART_CLK: u32 = 48_000_000;
@@ -118,11 +118,13 @@ fn uart_fifo_enable(enable: bool) {
     unsafe { write_address(UART0_LCRH, lcrh) };
 }
 
+#[inline(always)]
 fn uart_enable_rx_interrupt() {
     unsafe { write_address(UART0_IMSC, UART0_IMSC_RXIM) };
 }
 
 /// Set UART word length and set FIFO status
+#[inline(always)]
 fn uart_set_lcrh(wlen: u32, enable_fifo: bool) {
     let mut value = (wlen & 0b11) << 5;
     if enable_fifo {
@@ -131,10 +133,12 @@ fn uart_set_lcrh(wlen: u32, enable_fifo: bool) {
     unsafe { write_address(UART0_LCRH, value) };
 }
 
+#[inline(always)]
 pub fn read_uart_data() -> char {
     (unsafe { read_address(UART0_DR) } & 0xFF) as u8 as char
 }
 
+#[inline(always)]
 pub fn clear_uart_interrupt_state() {
     unsafe {
         write_address(UART0_ICR, 1 << 4);

src/pi3/mod.rs

@@ -0,0 +1,3 @@
+pub mod mailbox;
+pub mod power_management;
+pub mod timer;

src/pi3/power_management.rs

@@ -3,7 +3,7 @@ use core::ptr::{read_volatile, write_volatile};
 use crate::PERIPHERAL_BASE;
 
 /// Power Management Base
-static PM_BASE: u32 = PERIPHERAL_BASE + 0x10_0000;
+static PM_BASE: u32 = PERIPHERAL_BASE as u32 + 0x10_0000;
 static PM_RSTC: u32 = PM_BASE + 0x1c;
 static PM_WDOG: u32 = PM_BASE + 0x24;
 
@@ -23,5 +23,6 @@ pub fn reboot_system() {
             PM_PASSWORD | (pm_rstc_val & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET,
         );
     }
+    #[allow(clippy::empty_loop)]
     loop {}
 }

src/vector.S

@@ -1,13 +1,12 @@
-
-.global vector_table
+.section .vector_table  , "ax"
 .extern irq_handler
 
 .macro    ventry    label
-.align    7
+.align    11
 b    \label
 .endm
 
-.section .vector_table, "ax"
+.global vector_table
 vector_table:
     ventry .
     ventry .
@@ -21,156 +20,10 @@ vector_table:
 
     ventry synchronous_interrupt_imm_lower_aarch64
     ventry irq_handler
+    ventry .
+    ventry .
 
-
-.align 4
-.global el2_to_el1
-el2_to_el1:
-
-    mov x0, #(1 << 31)
-    msr HCR_EL2, x0
-
-    // Set SPSR_EL2: return to EL1h
-    mov x0, #(0b0101)
-    msr SPSR_EL2, x0
-
-    // Set return address to kernel_main
-    ldr x0, =kernel_main
-    msr ELR_EL2, x0
-
-    // Set SP_EL1 to stack base
-    ldr x0, =__stack_end
-    msr SP_EL1, x0
-
-    // Set VBAR_EL1 to vector table
-    adr x0, vector_table
-    msr VBAR_EL1, x0
-
-    // Disable MMU
-    ldr x0, =SCTLR_EL1_CONF
-    msr sctlr_el1, x0
-
-    // SIMD should not be trapped
-    mrs x0, CPACR_EL1
-    mov x1, #(0b11<<20)
-    orr x0,x0, x1
-    msr CPACR_EL1,x0
-
-    // Return to EL1
-    eret
-
-.align 4
-.global el1_to_el0
-el1_to_el0:
-
-    // Set SPSR_EL1: return to EL0t
-    mov x0, #(0b0000)
-    msr SPSR_EL1, x0
-
-    // Set return address to el0
-    ldr x0, =el0
-    msr ELR_EL1, x0
-
-    // Set SP_EL1 to stack base
-    ldr x0, =__stack_end_el0
-    msr SP_EL0, x0
-
-    // Return to EL0
-    eret
-
-
-.align 4
-irq_handler:
-    sub sp, sp, #176
-    stp x0, x1, [sp, #0]
-    stp x2, x3, [sp, #16]
-    stp x4, x5, [sp, #32]
-    stp x6, x7, [sp, #48]
-    stp x8, x9, [sp, #64]
-    stp x10, x11, [sp, #80]
-    stp x12, x13, [sp, #96]
-    stp x14, x15, [sp, #112]
-    stp x16, x17, [sp, #128]
-    stp x18, x29, [sp, #144]
-    stp x30, xzr, [sp, #160]
-
-    bl rust_irq_handler
-
-    ldp x0, x1, [sp, #0]
-    ldp x2, x3, [sp, #16]
-    ldp x4, x5, [sp, #32]
-    ldp x6, x7, [sp, #48]
-    ldp x8, x9, [sp, #64]
-    ldp x10, x11, [sp, #80]
-    ldp x12, x13, [sp, #96]
-    ldp x14, x15, [sp, #112]
-    ldp x16, x17, [sp, #128]
-    ldp x18, x29, [sp, #144]
-    ldp x30, xzr, [sp, #160]
-    add sp, sp, #176
-
-    eret
-
-.align 4
-synchronous_interrupt_imm_lower_aarch64:
-    sub sp, sp, #176
-    stp x0, x1, [sp, #0]
-    stp x2, x3, [sp, #16]
-    stp x4, x5, [sp, #32]
-    stp x6, x7, [sp, #48]
-    stp x8, x9, [sp, #64]
-    stp x10, x11, [sp, #80]
-    stp x12, x13, [sp, #96]
-    stp x14, x15, [sp, #112]
-    stp x16, x17, [sp, #128]
-    stp x18, x29, [sp, #144]
-    stp x30, xzr, [sp, #160]
-
-    bl rust_synchronous_interrupt_imm_lower_aarch64
-
-    ldp x0, x1, [sp, #0]
-    ldp x2, x3, [sp, #16]
-    ldp x4, x5, [sp, #32]
-    ldp x6, x7, [sp, #48]
-    ldp x8, x9, [sp, #64]
-    ldp x10, x11, [sp, #80]
-    ldp x12, x13, [sp, #96]
-    ldp x14, x15, [sp, #112]
-    ldp x16, x17, [sp, #128]
-    ldp x18, x29, [sp, #144]
-    ldp x30, xzr, [sp, #160]
-    add sp, sp, #176
-
-    eret
-
-.align 4
-synchronous_interrupt_no_el_change:
-    sub sp, sp, #176
-    stp x0, x1, [sp, #0]
-    stp x2, x3, [sp, #16]
-    stp x4, x5, [sp, #32]
-    stp x6, x7, [sp, #48]
-    stp x8, x9, [sp, #64]
-    stp x10, x11, [sp, #80]
-    stp x12, x13, [sp, #96]
-    stp x14, x15, [sp, #112]
-    stp x16, x17, [sp, #128]
-    stp x18, x29, [sp, #144]
-    stp x30, xzr, [sp, #160]
-
-    bl rust_synchronous_interrupt_no_el_change
-
-    ldp x0, x1, [sp, #0]
-    ldp x2, x3, [sp, #16]
-    ldp x4, x5, [sp, #32]
-    ldp x6, x7, [sp, #48]
-    ldp x8, x9, [sp, #64]
-    ldp x10, x11, [sp, #80]
-    ldp x12, x13, [sp, #96]
-    ldp x14, x15, [sp, #112]
-    ldp x16, x17, [sp, #128]
-    ldp x18, x29, [sp, #144]
-    ldp x30, xzr, [sp, #160]
-    add sp, sp, #176
-
-    eret
+    ventry .
+    ventry .
+    ventry .
+    ventry .

tools/start_simulator.sh

@@ -1,3 +1,5 @@
+set -e
+
 cargo build --target aarch64-unknown-none --release
 cd "$(dirname "$0")"
 

tools/start_simulator_debug.sh

@@ -1,3 +1,5 @@
+set -e
+
 cargo build --target aarch64-unknown-none
 
 cd "$(dirname "$0")"
@@ -9,6 +11,4 @@ qemu-system-aarch64 \
   -cpu cortex-a53 \
   -serial stdio \
   -sd ../sd.img \
-  -display none \
   -kernel ../target/aarch64-unknown-none/debug/kernel8.img \
-  -s -S

workspace/heap/src/tests.rs

@@ -100,7 +100,7 @@ fn test_merging_free_sections() {
     );
 
     let root_header = heap.start_address;
-    let root_header_start_size = unsafe { (*root_header).size };
+    let _root_header_start_size = unsafe { (*root_header).size };
 
     let malloc1 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
     let malloc_header_before = unsafe { *Heap::get_header_ref_from_data_pointer(malloc1) };
@@ -135,31 +135,29 @@ fn test_first_fit() {
     );
 
     let root_header = heap.start_address;
-    let root_header_start_size = unsafe { (*root_header).size };
+    let _root_header_start_size = unsafe { (*root_header).size };
 
     let malloc1 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
-    let malloc2 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
+    let _malloc2 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
     let malloc3 = heap.malloc(MIN_BLOCK_SIZE * 3).unwrap();
     let malloc4 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
 
-    unsafe {
-        assert!(heap.free(malloc1).is_ok());
-        assert!(heap.free(malloc3).is_ok());
-        let malloc5 = heap.malloc(MIN_BLOCK_SIZE * 2).unwrap();
-        let malloc1_header = unsafe { *Heap::get_header_ref_from_data_pointer(malloc1) };
+    assert!(heap.free(malloc1).is_ok());
+    assert!(heap.free(malloc3).is_ok());
+    let malloc5 = heap.malloc(MIN_BLOCK_SIZE * 2).unwrap();
+    let malloc1_header = unsafe { *Heap::get_header_ref_from_data_pointer(malloc1) };
 
-        // First free block stays empty
-        assert!(malloc1_header.free);
+    // First free block stays empty
+    assert!(malloc1_header.free);
 
-        // New allocation takes the first fit aka. malloc3
-        assert_eq!(malloc5, malloc3);
+    // New allocation takes the first fit aka. malloc3
+    assert_eq!(malloc5, malloc3);
 
-        // If no free slot could be found, append to the end
-        let malloc6 = heap.malloc(MIN_BLOCK_SIZE * 2).unwrap();
-        assert!(malloc6 > malloc4);
+    // If no free slot could be found, append to the end
+    let malloc6 = heap.malloc(MIN_BLOCK_SIZE * 2).unwrap();
+    assert!(malloc6 > malloc4);
 
-        // Malloc7 takes slot of Malloc1
-        let malloc7 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
-        assert_eq!(malloc1, malloc7);
-    }
+    // Malloc7 takes slot of Malloc1
+    let malloc7 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
+    assert_eq!(malloc1, malloc7);
 }

workspace/nova_error/src/lib.rs

@@ -8,4 +8,7 @@ pub enum NovaError {
     Mailbox,
     HeapFull,
     EmptyHeapSegmentNotAllowed,
+    Misalignment,
+    InvalidGranularity,
+    Paging,
 }