feat: start application via application_manager

.gitignore

@@ -6,3 +6,6 @@ settings.json
 .DS_Store
 .venv
 .nvimlog
+__pycache__
+.pytest_cache
+

.vscode/launch.json

@@ -66,6 +66,16 @@
       "preLaunchTask": "Run QEMU",
       "stopOnEntry": true,
       "processCreateCommands": ["gdb-remote localhost:1234"]
+    },
+
+    {
+      "name": "NVIM LLDB",
+      "type": "codelldb",
+      "request": "attach",
+      "program": "${workspaceFolder}/target/aarch64-unknown-none/debug/nova",
+      "preLaunchTask": "Run QEMU",
+      "stopOnEntry": true,
+      "processCreateCommands": ["gdb-remote localhost:1234"]
     }
   ]
 }

Cargo.lock

@@ -40,6 +40,15 @@ version = "0.2.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f9fbbcab51052fe104eb5e5d351cf728d30a5be1fe14d9be8a3b097481fb97de"
 
+[[package]]
+name = "lock_api"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "224399e74b87b5f3557511d98dff8b14089b3dadafcab6bb93eab67d3aace965"
+dependencies = [
+ "scopeguard",
+]
+
 [[package]]
 name = "log"
 version = "0.4.29"
@@ -55,6 +64,7 @@ dependencies = [
  "log",
  "nova_error",
  "paste",
+ "spin",
 ]
 
 [[package]]
@@ -129,6 +139,21 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
+[[package]]
+name = "spin"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d5fe4ccb98d9c292d56fec89a5e07da7fc4cf0dc11e156b41793132775d3e591"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.111"

Cargo.toml

@@ -18,6 +18,7 @@ heap = {path = "workspace/heap"}
 nova_error = {path = "workspace/nova_error"}
 paste = "1.0.15"
 log = "0.4.29"
+spin = "0.10.0"
 
 [workspace]
 

src/aarch64/mmu.rs

@@ -105,7 +105,7 @@ pub enum PhysSource {
 }
 
 #[repr(align(4096))]
-pub struct PageTable([TableEntry; TABLE_ENTRY_COUNT]);
+pub struct PageTable(pub [TableEntry; TABLE_ENTRY_COUNT]);
 
 impl Iterator for PageTable {
     type Item = VirtAddr;
@@ -204,7 +204,6 @@ fn map_range_dynamic(
         (virt, _) = virt.overflowing_add(GRANULARITY);
         remaining -= GRANULARITY;
     }
-
     Ok(())
 }
 
@@ -224,7 +223,7 @@ pub fn alloc_page(
 
 /// Allocate a singe page in one block.
 pub fn find_free_kerne_page_in_block(start: VirtAddr) -> Result<VirtAddr, NovaError> {
-    if !start.is_multiple_of(GRANULARITY) {
+    if !start.is_multiple_of(LEVEL2_BLOCK_SIZE) {
         return Err(NovaError::Misalignment);
     }
 
@@ -238,8 +237,8 @@ pub fn find_free_kerne_page_in_block(start: VirtAddr) -> Result<VirtAddr, NovaEr
         )?
     };
 
-    if let Some(virt_addr) = table.next() {
-        return Ok(virt_addr);
+    if let Some(offset) = table.next() {
+        return Ok(start + (offset * GRANULARITY));
     }
     Err(NovaError::OutOfMeomory)
 }

src/application_manager.rs

@@ -1,24 +1,21 @@
-use alloc::vec::Vec;
-
 use crate::{
     aarch64::mmu::{
-        find_free_kerne_page_in_block, map_page, physical_mapping::reserve_page, TableEntry,
-        NORMAL_MEM, TRANSLATIONTABLE_TTBR1, WRITABLE,
+        find_free_kerne_page_in_block, map_page, physical_mapping::reserve_page, PageTable,
+        TableEntry, VirtAddr, NORMAL_MEM, TRANSLATIONTABLE_TTBR0, TRANSLATIONTABLE_TTBR1, WRITABLE,
     },
-    configuration::memory_mapping::APPLICATION_TRANSLATION_TABLE_VA,
+    configuration::memory_mapping::{APPLICATION_TRANSLATION_TABLE_VA, EL0_STACK_TOP},
 };
+use alloc::vec::Vec;
+use core::arch::asm;
+use spin::Mutex;
+
 pub struct Application {
     pub table_ptr: *mut TableEntry,
-}
-
-impl Default for Application {
-    fn default() -> Self {
-        Self::new()
-    }
+    pub start_addr: usize,
 }
 
 impl Application {
-    pub fn new() -> Self {
+    pub fn new(start_addr: VirtAddr) -> Self {
         let physical_addr = reserve_page();
         let virtual_address =
             find_free_kerne_page_in_block(APPLICATION_TRANSLATION_TABLE_VA).unwrap();
@@ -31,14 +28,55 @@ impl Application {
         )
         .unwrap();
 
+        // TODO: Temporary fix, while kernel and app share some memory regions
+        #[allow(static_mut_refs)]
+        unsafe {
+            let table = &mut *(virtual_address as *mut PageTable);
+            table.0 = TRANSLATIONTABLE_TTBR0.0;
+        }
+
         Self {
             table_ptr: physical_addr as *mut TableEntry,
+            start_addr,
+        }
+    }
+    pub fn start(&self) {
+        unsafe {
+            asm!("msr ELR_EL1, {}", in(reg) self.start_addr);
+            asm!("msr SPSR_EL1, {0:x}", in(reg) 0);
+            asm!("msr SP_EL0, {0:x}", in(reg) EL0_STACK_TOP);
+            asm!("msr TTBR0_EL1, {}", in(reg) self.table_ptr as usize);
+            asm!("eret");
         }
     }
 }
 
-pub static mut APPLICATION_LIST: Option<Vec<Application>> = None;
+struct AppManager {
+    apps: Option<Vec<Application>>,
+}
+
+impl AppManager {
+    const fn new() -> Self {
+        Self { apps: None }
+    }
+}
+
+unsafe impl Send for AppManager {}
+
+static APP_MANAGER: Mutex<AppManager> = Mutex::new(AppManager::new());
 
 pub fn initialize_app_manager() {
-    unsafe { APPLICATION_LIST = Some(Vec::new()) }
+    let mut guard = APP_MANAGER.lock();
+    guard.apps = Some(Vec::new());
+}
+pub fn add_app(app: Application) {
+    if let Some(app_list) = APP_MANAGER.lock().apps.as_mut() {
+        app_list.push(app);
+    }
+}
+
+pub fn start_app(index: usize) {
+    if let Some(app_list) = APP_MANAGER.lock().apps.as_mut() {
+        app_list[index].start();
+    }
 }

src/config.S

@@ -78,25 +78,3 @@ configure_mmu_el1:
 
     ret
 
-.align 4
-.global el1_to_el0
-el1_to_el0:
-    mov x8, x0
-    // 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
-
-    mov x0, x8
-    // Return to EL0
-    eret

src/configuration/memory_mapping.rs

@@ -18,6 +18,8 @@ pub const EL0_STACK_SIZE: usize = LEVEL2_BLOCK_SIZE * 2;
 pub const MAILBOX_VIRTUAL_ADDRESS: VirtAddr = 0xFFFF_FF81_FFFF_E000;
 pub static mut MAILBOX_PHYSICAL_ADDRESS: Option<PhysAddr> = None;
 
+// TODO: Currently limited to 512 applications, more than enough, but has to be kept
+// in mind
 pub const APPLICATION_TRANSLATION_TABLE_VA: VirtAddr = 0xFFFF_FF81_FE00_0000;
 
 extern "C" {

src/main.rs

@@ -13,6 +13,7 @@ extern crate alloc;
 use alloc::vec::Vec;
 use nova::{
     aarch64::registers::{daif, read_id_aa64mmfr0_el1},
+    application_manager::{add_app, Application},
     configuration::memory_mapping::initialize_mmu_translation_tables,
     framebuffer::{FrameBuffer, BLUE, GREEN, RED},
     get_current_el, init_logger,
@@ -77,7 +78,6 @@ pub extern "C" fn main() -> ! {
     unsafe {
         el2_to_el1();
     }
-
     #[allow(clippy::empty_loop)]
     loop {}
 }
@@ -104,6 +104,9 @@ pub extern "C" fn kernel_main() {
 
     enable_irq_source(IRQSource::UartInt);
 
+    let app = Application::new(el0 as *const () as usize);
+    add_app(app);
+
     kernel_loop();
 }
 

src/terminal.rs

@@ -3,6 +3,7 @@ use core::arch::asm;
 use alloc::string::String;
 
 use crate::{
+    application_manager::start_app,
     interrupt_handlers::irq::{register_interrupt_handler, IRQSource},
     peripherals::uart::read_uart_data,
     pi3::mailbox::read_soc_temp,
@@ -15,10 +16,6 @@ pub struct Terminal {
     input: String,
 }
 
-extern "C" {
-    fn el1_to_el0();
-}
-
 impl Default for Terminal {
     fn default() -> Self {
         Self::new()
@@ -48,7 +45,7 @@ impl Terminal {
             "el0" => unsafe {
                 let i = 69;
                 asm!("", in("x0") i);
-                el1_to_el0();
+                start_app(0);
             },
             _ => {
                 println!("Unknown command: \"{}\"", self.input);

tools/start_simulator_debug.sh

@@ -11,4 +11,4 @@ qemu-system-aarch64 \
   -cpu cortex-a53 \
   -serial stdio \
   -sd ../sd.img \
-  -kernel ../target/aarch64-unknown-none/debug/kernel8.img \
+  -kernel ../target/aarch64-unknown-none/debug/kernel8.img -S -s

workspace/heap/src/tests.rs

@@ -29,7 +29,7 @@ fn test_heap_allocation() {
         assert_eq!(actual_alloc_size % MIN_BLOCK_SIZE, 0);
 
         // Verify section is occupied
-        assert!((*malloc_header).free == false);
+        assert!(!(*malloc_header).free);
 
         // Verify next header has been created
         let next = (*malloc_header).next.unwrap();
@@ -55,7 +55,7 @@ fn test_full_heap() {
     let malloc = heap.malloc(malloc_size).unwrap();
     let malloc_header = Heap::get_header_ref_from_data_pointer(malloc);
     unsafe {
-        assert_eq!((*malloc_header).free, false);
+        assert!(!(*malloc_header).free);
         assert!((*malloc_header).next.is_none());
     }
 
@@ -79,7 +79,7 @@ fn test_freeing_root() {
     let malloc = heap.malloc(malloc_size).unwrap();
     let malloc_header = Heap::get_header_ref_from_data_pointer(malloc);
     unsafe {
-        assert_eq!((*malloc_header).free, false);
+        assert!(!(*malloc_header).free);
         assert!((*malloc_header).size >= malloc_size);
         assert!((*root_header).next.is_some());