Create memory module (#690)

* Improve memory counting at boot

* Allow interrupts during heap init

* Load keyboard module after memory module

* Mask keyword interrupt instead of loading the module later

* Remove newline

* Create sys::mem module

* Refactor module

* Fix tests

* Add paging file in mem module

* Improve comment about keyboard interrupt masking

* Rename max_memory to heap_max

src/sys/fs/block_device.rs

@@ -86,7 +86,7 @@ impl BlockDeviceIO for MemBlockDevice {
 }
 
 pub fn mount_mem() {
-    let mem = sys::allocator::memory_size() / 2; // Half the allocatable memory
+    let mem = sys::mem::memory_free() / 2;
     let len = mem / super::BLOCK_SIZE; // TODO: take a size argument
     let dev = MemBlockDevice::new(len);
     *BLOCK_DEVICE.lock() = Some(BlockDevice::Mem(dev));

src/sys/idt.rs

@@ -138,7 +138,7 @@ extern "x86-interrupt" fn page_fault_handler(
     };
 
     if error_code.contains(PageFaultErrorCode::CAUSED_BY_WRITE) {
-        if sys::allocator::alloc_pages(&mut mapper, addr, 1).is_err() {
+        if sys::mem::alloc_pages(&mut mapper, addr, 1).is_err() {
             printk!(
                 "{}Error:{} Could not allocate page at {:#X}\n",
                 csi_color, csi_reset, addr
@@ -154,7 +154,7 @@ extern "x86-interrupt" fn page_fault_handler(
         // longer a simple clone of the kernel page table. Currently a process
         // is executed from its kernel address that is shared with the process.
         let start = (addr / 4096) * 4096;
-        if sys::allocator::alloc_pages(&mut mapper, start, 4096).is_ok() {
+        if sys::mem::alloc_pages(&mut mapper, start, 4096).is_ok() {
             if sys::process::is_userspace(start) {
                 let code_addr = sys::process::code_addr();
                 let src = (code_addr + start) as *mut u8;