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

README.md

@@ -14,8 +14,9 @@ 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
+- MMU ✓
 - SVC instructions
+- Kernel Independent Applications
 - Multi Core
 - Dynamic clock speed
 - Multiprocessing

link.ld

@@ -4,53 +4,43 @@ SECTIONS {
     .text ALIGN(4) : {
         KEEP(*(.text._start))
         *(.text .text.*)
+        . = ALIGN(4K);
+        __text_end = .;
     }
 
     .rodata : {
         *(.rodata .rodata.*)
     }
 
-    .data ALIGN(2M) : {
-        _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 = .;
-    . += 100K; #100kB
-    __heap_end = .;
-    }
-
+    # EL2 Stack
     .stack ALIGN(16): {
     __stack_start = .;
-    . += 10K; #10kB stack
+    . += 100K; #100kB stack
+    . = ALIGN(16);
     __stack_end = .;
     }
 
     . = ALIGN(2M);
 
     __kernel_end = .;
-
-    .stack_el0 : {
-    __stack_start_el0 = .;
-    . += 10K; #10kB stack
-    __stack_end_el0 = .;
-    }
-
-    . = ALIGN(2M);
-    _end = .;
 }
 
 __bss_size = (__bss_end - __bss_start) >> 3;

src/aarch64/mmu.rs

@@ -1,20 +1,23 @@
-use core::{panic, u64::MAX};
-
+use core::mem::size_of;
 use nova_error::NovaError;
 
-unsafe extern "C" {
-    static mut __translation_table_l2_start: u64;
-    static __stack_start_el0: u64;
-    static __kernel_end: u64;
-    static _data: u64;
-}
+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;
@@ -37,114 +40,119 @@ 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 = 1 * 1024 * 1024 * 1024 / 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]);
 
-static mut PAGING_BITMAP: [u64; MAX_PAGE_COUNT / 64] = [0; MAX_PAGE_COUNT / 64];
-
+/// Allocate a memory block of `size` starting at `virtual_address`.
 pub fn allocate_memory(
-    mut virtual_address: usize,
-    mut size: usize,
-    additional_flags: u64,
+    virtual_address: usize,
+    size_bytes: usize,
+    phys: PhysSource,
+    flags: u64,
 ) -> Result<(), NovaError> {
-    if virtual_address % GRANULARITY != 0 {
+    if !virtual_address.is_multiple_of(GRANULARITY) {
         return Err(NovaError::Misalignment);
     }
-
-    let level1_blocks = size / LEVEL1_BLOCK_SIZE;
-    size %= LEVEL1_BLOCK_SIZE;
-    let level2_blocks = size / LEVEL2_BLOCK_SIZE;
-    size %= LEVEL2_BLOCK_SIZE;
-    let level3_pages = size / GRANULARITY;
-    if size % GRANULARITY != 0 {
+    if !size_bytes.is_multiple_of(GRANULARITY) {
         return Err(NovaError::InvalidGranularity);
     }
 
-    if level1_blocks > 0 {
-        todo!("Currently not supported");
+    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)
+        }
+    }
 }
 
-    for _ in 0..level2_blocks {
-        unsafe {
-            alloc_block_l2(
-                virtual_address,
-                &mut TRANSLATIONTABLE_TTBR0,
-                additional_flags,
-            )?;
-        }
-        virtual_address += LEVEL2_BLOCK_SIZE;
-    }
-    for _ in 0..level3_pages {
-        unsafe {
-            alloc_page(
-                virtual_address,
-                &mut TRANSLATIONTABLE_TTBR0,
-                additional_flags,
-            )?;
-        }
-        virtual_address += GRANULARITY;
-    }
-
-    Ok(())
-}
-pub fn allocate_memory_explicit(
-    mut virtual_address: usize,
-    mut size: usize,
-    mut physical_address: usize,
-    additional_flags: u64,
+fn map_range_explicit(
+    mut virt: VirtAddr,
+    mut phys: PhysAddr,
+    size_bytes: usize,
+    base: *mut PageTable,
+    flags: u64,
 ) -> Result<(), NovaError> {
-    if virtual_address % GRANULARITY != 0 {
-        return Err(NovaError::Misalignment);
+    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;
     }
 
-    let level1_blocks = size / LEVEL1_BLOCK_SIZE;
-    size %= LEVEL1_BLOCK_SIZE;
-    let level2_blocks = size / LEVEL2_BLOCK_SIZE;
-    size %= LEVEL2_BLOCK_SIZE;
-    let level3_pages = size / GRANULARITY;
-    if size % GRANULARITY != 0 {
-        return Err(NovaError::InvalidGranularity);
+    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;
     }
 
-    if level1_blocks > 0 {
-        todo!("Currently not supported");
-    }
-
-    for _ in 0..level2_blocks {
-        unsafe {
-            alloc_block_l2_explicit(
-                virtual_address,
-                physical_address,
-                &mut TRANSLATIONTABLE_TTBR0,
-                additional_flags,
-            )?;
-        }
-        virtual_address += LEVEL2_BLOCK_SIZE;
-        physical_address += LEVEL2_BLOCK_SIZE;
-    }
-    for _ in 0..level3_pages {
-        unsafe {
-            alloc_page_explicit(
-                virtual_address,
-                physical_address,
-                &mut TRANSLATIONTABLE_TTBR0,
-                additional_flags,
-            )?;
-        }
-        virtual_address += GRANULARITY;
-        physical_address += GRANULARITY;
+    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,
+    base_table: *mut PageTable,
     additional_flags: u64,
 ) -> Result<(), NovaError> {
     map_page(
@@ -155,10 +163,11 @@ pub fn alloc_page(
     )
 }
 
+/// Allocate a single page at an explicit `physical_address`.
 pub fn alloc_page_explicit(
     virtual_address: usize,
     physical_address: usize,
-    base_table: &mut PageTable,
+    base_table: *mut PageTable,
     additional_flags: u64,
 ) -> Result<(), NovaError> {
     reserve_page_explicit(physical_address)?;
@@ -170,52 +179,59 @@ pub fn alloc_page_explicit(
     )
 }
 
-fn map_page(
+pub fn map_page(
     virtual_address: usize,
     physical_address: usize,
-    base_table: &mut PageTable,
+    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 table = navigate_table(base_table, [l1_off, l2_off, 0], 2)?;
+    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_block_descriptor_entry(physical_address, additional_flags);
+    table.0[l3_off] = create_page_descriptor_entry(physical_address, additional_flags);
 
     Ok(())
 }
 
-pub fn alloc_block_l2(
-    virtual_addr: usize,
-    base_table: &mut PageTable,
-    additional_flags: u64,
-) -> Result<(), NovaError> {
-    map_l2_block(virtual_addr, reserve_block(), base_table, additional_flags)
-}
-
+// Allocate a level 2 block, at a explicit `physical_address`.
 pub fn alloc_block_l2_explicit(
     virtual_addr: usize,
     physical_address: usize,
-    base_table: &mut PageTable,
+    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, additional_flags)
+    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: &mut PageTable,
+    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 = navigate_table(base_table, [l1_off, 0, 0], 1)?;
+    let table = unsafe { &mut *table_ptr };
 
     // Verify virtual address is available.
     if table.0[l2_off] & 0b11 != 0 {
@@ -228,10 +244,11 @@ pub fn map_l2_block(
 
     Ok(())
 }
-pub fn reserve_range_explicit(
-    start_physical_address: usize,
-    end_physical_address: usize,
-) -> Result<(), NovaError> {
+
+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;
@@ -239,7 +256,7 @@ pub fn reserve_range_explicit(
     size %= LEVEL2_BLOCK_SIZE;
     let l3_pages = size / GRANULARITY;
 
-    if size % GRANULARITY != 0 {
+    if !size.is_multiple_of(GRANULARITY) {
         return Err(NovaError::Misalignment);
     }
 
@@ -258,150 +275,92 @@ pub fn reserve_range_explicit(
         addr += GRANULARITY;
     }
 
-    Ok(())
-}
-
-fn reserve_page() -> usize {
-    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!");
-}
-
-fn reserve_page_explicit(physical_address: usize) -> Result<(), 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(())
-}
-
-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] = MAX };
-        }
-        return start * 64 * GRANULARITY;
-    }
-
-    panic!("Out of Memory!");
-}
-
-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] = MAX;
-        };
-    }
-    Ok(())
+    Ok(start_physical_address)
 }
 
 fn create_block_descriptor_entry(physical_address: usize, additional_flags: u64) -> u64 {
-    (physical_address as u64 & 0x0000_FFFF_FFE0_0000)
+    (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 {
-    0 | (addr as u64 & 0x0000_FFFF_FFFF_F000) | TABLE
+    (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 / GRANULARITY;
+    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: &mut PageTable,
-    offsets: [usize; 3],
-    offsets_size: usize,
-) -> Result<&mut PageTable, NovaError> {
-    let root_table_ptr = initial_table as *mut PageTable;
-    let mut table = initial_table;
-    for i in 0..offsets_size {
-        let offset = offsets[i];
-        match table.0[offset] & 0b11 {
-            0 => {
-                let new_table_addr = reserve_page();
-
-                table.0[offset] = create_table_descriptor_entry(new_table_addr);
-                table =
-                    unsafe { &mut *(get_table_entry_address(table.0[offset]) as *mut PageTable) };
-
-                map_page(
-                    new_table_addr,
-                    new_table_addr,
-                    unsafe { &mut *root_table_ptr },
-                    NORMAL_MEM | WRITABLE | PXN | UXN,
-                )?;
-            }
-            1 => return Err(NovaError::Paging),
-            3 => {
-                table =
-                    unsafe { &mut *(get_table_entry_address(table.0[offset]) as *mut PageTable) }
-            }
-            _ => panic!(),
-        };
+    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)
 }
 
-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
-}
+/// 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();
 
-fn find_contiguous_free_bitmap_words(required_words: usize) -> Option<usize> {
-    let mut run_start = 0;
-    let mut run_len = 0;
+            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,
+            )?;
 
-    for (i, entry) in unsafe { PAGING_BITMAP }.iter().enumerate() {
-        if *entry == 0 {
-            if run_len == 0 {
-                run_start = i;
+            Ok(entry_table_addr(table.0[offset] as usize) as *mut PageTable)
         }
-            run_len += 1;
-
-            if run_len == required_words {
-                return Some(run_start);
-            }
-        } else {
-            run_len = 0;
+        1 => Err(NovaError::Paging),
+        3 => Ok(entry_table_addr(table.0[offset] as usize) as *mut PageTable),
+        _ => unreachable!(),
     }
 }
 
-    None
+/// Extracts the physical address out of an table entry.
+#[inline]
+fn entry_phys(entry: usize) -> PhysAddr {
+    entry & 0x0000_FFFF_FFFF_F000
 }
 
 #[inline]
-fn get_table_entry_address(entry: u64) -> u64 {
-    entry & 0x0000_FFFF_FFFF_F000
+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/registers.rs

@@ -50,9 +50,9 @@ psr!(ESR_EL1, u32);
 
 psr!(SPSR_EL1, u32);
 
-psr!(ELR_EL1, u32);
+psr!(ELR_EL1, u64);
 
-psr!(SCTLR_EL1, u32);
+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

@@ -23,72 +23,107 @@ 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 EPD1: u64 = 0b1 << 23; // Trigger translation fault when using TTBR1_EL1
 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 | EPD1 | AS;
+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, map_l2_block, reserve_range_explicit, DEVICE_MEM,
-            EL0_ACCESSIBLE, LEVEL1_BLOCK_SIZE, LEVEL2_BLOCK_SIZE, NORMAL_MEM, PXN, READ_ONLY,
+            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 _data: u64;
-        static _end: u64;
+        static __text_end: u64;
+        static __share_end: u64;
         static __kernel_end: u64;
     }
 
     pub fn initialize_mmu_translation_tables() {
-        let shared_segment_end = unsafe { &_data } as *const _ as usize;
+        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;
-        let user_space_end = unsafe { &_end } as *const _ as usize;
 
-        reserve_range_explicit(0x0, user_space_end).unwrap();
+        reserve_range(0x0, kernel_end).unwrap();
 
-        for addr in (0..shared_segment_end).step_by(LEVEL2_BLOCK_SIZE) {
-            let _ = map_l2_block(
+        for addr in (0..text_end).step_by(GRANULARITY) {
+            map_page(
                 addr,
                 addr,
-                unsafe { &mut TRANSLATIONTABLE_TTBR0 },
+                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) {
-            let _ = map_l2_block(
+            map_l2_block(
                 addr,
                 addr,
-                unsafe { &mut TRANSLATIONTABLE_TTBR0 },
+                core::ptr::addr_of_mut!(TRANSLATIONTABLE_TTBR0),
                 WRITABLE | UXN | NORMAL_MEM,
-            );
-        }
-
-        for addr in (kernel_end..user_space_end).step_by(LEVEL2_BLOCK_SIZE) {
-            let _ = map_l2_block(
-                addr,
-                addr,
-                unsafe { &mut TRANSLATIONTABLE_TTBR0 },
-                EL0_ACCESSIBLE | WRITABLE | PXN | NORMAL_MEM,
-            );
+            )
+            .unwrap();
         }
 
         for addr in (PERIPHERAL_BASE..LEVEL1_BLOCK_SIZE).step_by(LEVEL2_BLOCK_SIZE) {
-            let _ = alloc_block_l2_explicit(
+            alloc_block_l2_explicit(
                 addr,
                 addr,
-                unsafe { &mut TRANSLATIONTABLE_TTBR0 },
+                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

@@ -41,7 +41,7 @@ impl FrameBuffer {
             return;
         }
         unsafe {
-            write_volatile(self.start_addr.byte_add(4 * offset as usize), color);
+            write_volatile(self.start_addr.add(offset as usize), color);
         }
     }
 

src/interrupt_handlers.rs

@@ -82,7 +82,7 @@ unsafe extern "C" fn rust_irq_handler() {
         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)();
@@ -222,7 +222,7 @@ pub fn initialize_interrupt_handler() {
 }
 
 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/lib.rs

@@ -12,24 +12,31 @@ 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: 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]
@@ -46,7 +53,6 @@ pub mod configuration;
 pub mod framebuffer;
 pub mod interrupt_handlers;
 pub mod logger;
-pub mod timer;
 
 pub mod pi3;
 
@@ -73,6 +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

@@ -31,14 +31,12 @@ macro_rules! log {
 }
 
 pub fn log(args: fmt::Arguments) {
-    unsafe {
-        if let Some(logger) = LOGGER.as_mut() {
+    if let Some(logger) = unsafe { &mut *core::ptr::addr_of_mut!(LOGGER) } {
         logger.write_str("\n").unwrap();
         logger.write_fmt(args).unwrap();
         logger.flush();
     }
 }
-}
 
 pub fn set_logger(logger: Box<dyn Logger>) {
     unsafe {

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::{
@@ -10,17 +9,12 @@ use core::{
 
 extern crate alloc;
 
+use alloc::vec::Vec;
 use nova::{
-    aarch64::{
-        mmu::{
-            allocate_memory_explicit, EL0_ACCESSIBLE, LEVEL2_BLOCK_SIZE, NORMAL_MEM, PXN, UXN,
-            WRITABLE,
-        },
-        registers::{daif, read_id_aa64mmfr0_el1},
-    },
+    aarch64::registers::{daif, read_id_aa64mmfr0_el1},
     configuration::mmu::initialize_mmu_translation_tables,
     framebuffer::{FrameBuffer, BLUE, GREEN, RED},
-    get_current_el, init_heap,
+    get_current_el,
     interrupt_handlers::{enable_irq_source, IRQSource},
     peripherals::{
         gpio::{
@@ -29,11 +23,13 @@ use nova::{
         },
         uart::uart_init,
     },
-    pi3::mailbox,
     println,
 };
 
 global_asm!(include_str!("vector.S"));
+global_asm!(include_str!("config.S"));
+
+static mut FRAMEBUFFER: Option<FrameBuffer> = None;
 
 extern "C" {
     fn el2_to_el1();
@@ -69,23 +65,14 @@ pub extern "C" fn main() -> ! {
     println!("Exception level: {}", get_current_el());
 
     unsafe {
-        init_heap();
-
         initialize_mmu_translation_tables();
-        // Frame Buffer memory range
-        // TODO: this is just temporary
-        // TODO: Investigate why the size is off
-        allocate_memory_explicit(
-            0x3c100000,
-            1080 * 1920 * 4 + LEVEL2_BLOCK_SIZE + LEVEL2_BLOCK_SIZE,
-            0x3c100000,
-            NORMAL_MEM | PXN | UXN | WRITABLE | EL0_ACCESSIBLE,
-        )
-        .unwrap();
         configure_mmu_el1();
+        println!("MMU initialized...");
     };
 
-    println!("AA64 {:064b}", read_id_aa64mmfr0_el1());
+    println!("Register: AA64MMFR0_EL1: {:064b}", read_id_aa64mmfr0_el1());
+    println!("Moving El2->EL1");
+    unsafe { FRAMEBUFFER = Some(FrameBuffer::default()) };
 
     unsafe {
         el2_to_el1();
@@ -105,7 +92,14 @@ unsafe fn zero_bss() {
 
 #[no_mangle]
 pub extern "C" fn kernel_main() -> ! {
+    println!("Kernel Start...");
     nova::initialize_kernel();
+    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();
 
@@ -129,10 +123,9 @@ 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, RED);
+            fb.draw_pixel(50, i, BLUE);
         }
         fb.draw_square(500, 500, 600, 700, RED);
         fb.draw_square_fill(800, 800, 900, 900, GREEN);
@@ -141,10 +134,14 @@ pub extern "C" fn el0() -> ! {
         fb.draw_string("Hello World! :D\nTest next Line", 500, 5, 3, BLUE);
 
         fb.draw_function(cos, 0, 101, RED);
+    }
 
     loop {
-        let temp = mailbox::read_soc_temp([0]).unwrap();
-        println!("{} °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);
     }

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/pi3/mod.rs

@@ -1,2 +1,3 @@
 pub mod mailbox;
 pub mod power_management;
+pub mod timer;

src/pi3/power_management.rs

@@ -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 v_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 .
@@ -28,190 +27,3 @@ vector_table:
     ventry .
     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
-
-    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
-
-.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
-    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
-    ldr x0, =__stack_end_el0
-    msr SP_EL0, x0
-
-    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

tools/start_simulator_debug.sh

@@ -11,6 +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) };
@@ -135,14 +135,13 @@ 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();
@@ -162,4 +161,3 @@ fn test_first_fit() {
     let malloc7 = heap.malloc(MIN_BLOCK_SIZE).unwrap();
     assert_eq!(malloc1, malloc7);
 }
-}