Began the process of moving XnoeOS to using more OOP constructs. Added PageDirectory class. Added PageTable class. Added tuple data type. Added beginnings of the skeleton for Allocator and Process.

Makefile

@@ -5,7 +5,7 @@ LDFLAGS =
 DISK_IMG_FILES = build/kernel/kernel.bin
 KERNEL_OBJS = build/kernel/entry.o build/kernel/screenstuff.o build/kernel/io.o build/kernel/idt.o build/kernel/keyboard.o \
 							build/kernel/strings.o build/kernel/atapio.o build/kernel/kernel.o build/kernel/paging.o build/kernel/allocate.o \
-							build/kernel/gdt.o
+							build/kernel/gdt.o build/kernel/memory.o
 STAGE2_OBS = build/c_code_entry.o build/boot_stage2/io.o build/boot_stage2/atapio.o build/boot_stage2/strings.o build/boot_stage2/screenstuff.o build/boot_stage2/stage2.o build/boot_stage2/paging.o
 
 run: disk.img
@@ -26,6 +26,7 @@ prepare:
 	mkdir -p build/boot
 	mkdir -p build/boot_stage2
 	mkdir -p build/kernel
+	mkdir -p build/kernel/datatypes
 	mountpoint img.d | grep not || umount img.d
 
 clean:

src/boot_stage2/main.c

@@ -108,6 +108,7 @@ void main() {
 
   // Page Directory
   PDE* kernel_page_directory = bitmap + 0x20000;
+
   // Clear the PD 
   memset((uint8_t*)kernel_page_directory, 4096, 0);
 
@@ -121,6 +122,23 @@ void main() {
 
   PTE** kernel_page_tables = 0x521000;
 
+  for (int i = 0; i < 1023; i++) {
+    kernel_page_directory[i] = (PDE){
+      .address = (uint32_t)(kernel_page_tables[i]) >> 12,
+      .available = 0,
+      .page_4mb = 0,
+      .accessed = 0,
+      .disable_cache = 0,
+      .write_through_cache = 0,
+      .privilege = 0,
+      .present = 1,
+      .read_write = 1,
+
+      .ignored = 0,
+      .ignored2 = 0
+    };
+  }
+
   // Mark unavailable bitmap to 0x522000
   mark_unavailble(bitmap, 0x4000000);
 

src/kernel/allocate.cpp

@@ -69,3 +69,15 @@ void* dumb_alloc(uint32_t size) {
 
   return (void*)ptr;
 }
+
+xnoe::tuple<uint32_t, void*> alloc_page_with_phys() {
+  uint32_t ptr = kernel_allocate_area;
+
+  for (; get_bit(last_free_page, bitmap) == 0; last_free_page++);
+  uint32_t phys_addr = last_free_page * 4096;
+  mark_unavailble(phys_addr, 4096);
+  map_4k_phys_to_virt(phys_addr, kernel_allocate_area, kernel_page_directory, kernel_page_tables);
+  kernel_allocate_area += 4096;
+
+  return xnoe::tuple<uint32_t, void*>(phys_addr, (void*)ptr);
+}

src/kernel/allocate.h

@@ -2,6 +2,7 @@
 #define ALLOCATE_H
 
 #include "paging.h"
+#include "datatypes/tuple.h"
 //void init_allocator();
 
 extern uint8_t* bitmap;
@@ -16,4 +17,6 @@ void mark_unavailble(uint32_t address, uint32_t size);
 
 void* dumb_alloc(uint32_t size);
 
+xnoe::tuple<uint32_t, void*> alloc_page_with_phys();
+
 #endif 

src/kernel/datatypes/tuple.h

@@ -0,0 +1,45 @@
+#ifndef TUPLE_H
+#define TUPLE_H
+
+#include "../types.h"
+
+namespace xnoe {
+  template<int index, typename T>
+  class tupleGetHelper;
+
+  template<typename ... T>
+  class tuple {};
+
+  template<typename T, typename ... Tail>
+  class tuple<T, Tail ...> {
+  public:
+    T head;
+    tuple<Tail...> tail;
+
+    tuple(const T& head, const Tail& ... tail)
+      : head(head), tail(tail...) {}
+
+    template<int index>
+    auto get() {
+      return tupleGetHelper<index, tuple<T, Tail...>>::get(*this);
+    }
+  };
+
+  template<typename T, typename ... Tail>
+  class tupleGetHelper<0, tuple<T, Tail...>> {
+  public:
+    static T get(tuple<T, Tail...>& t) {
+      return t.head;
+    }
+  };
+
+  template<int index, typename T, typename ... Tail>
+  class tupleGetHelper<index, tuple<T, Tail...>> {
+  public:
+    static auto get(tuple<T, Tail...>& t) {
+      return tupleGetHelper<index - 1, tuple<Tail ...>>::get(t.tail);
+    }
+  };
+}
+
+#endif

src/kernel/kernel.cpp

@@ -8,9 +8,16 @@
 #include "gdt.h"
 #include "paging.h"
 #include "allocate.h"
+#include "memory.h"
 
 int main() {
   init_gdt();
+
+  PageDirectory kernel_pd = PageDirectory(0xc0100000, 0x120000, 0xbffe0000);
+  kernel_pd.select();
+  kernel_pd.map(0x0, 0x400000);
+  //kernel_pd.unmap(0x8000);
+
   init_idt();
   init_term();
 
@@ -18,8 +25,6 @@ int main() {
   
   printf("KERNEL OK!\n");
 
-  unmap_4k_virt(0x8000, kernel_page_directory, kernel_page_tables);
-
   init_keyboard();
   
   enable_idt();

src/kernel/kernel.ld

@@ -10,5 +10,6 @@ SECTIONS {
     build/kernel/entry.o(.text)
     build/kernel/kernel.o(.text)
     build/kernel/*(.text)
+    build/kernel/datatypes/*(.text)
   }
 }

src/kernel/memory.cpp

@@ -0,0 +1,91 @@
+#include "memory.h"
+
+void memset(uint8_t* address, uint32_t count, uint8_t value) {
+  for (int i=0; i<count; i++)
+    address[i] = value;
+}
+
+void memcpy(uint8_t* src, uint8_t* dst, uint32_t count) {
+  for (int i = 0; i<count; i++)
+    dst[i] = src[i];
+}
+
+PageTable::PageTable(uint32_t phys, uint32_t virt) {
+  phys_addr = phys;
+  virt_addr = virt;
+
+  page_table = (PTE*)virt;
+}
+
+PageTable::PageTable(){}
+
+void PageTable::map_table(uint32_t index, uint32_t addr) {
+  page_table[index] = (PTE){
+    .present = 1,
+    .read_write = 1,
+    .privilege = 0,
+    .write_through_cache = 0,
+    .disable_cache = 0,
+    .accessed = 0,
+    .dirty = 0,
+    .ignored = 0,
+    .global = 0,
+    .available = 0,
+    .address = addr
+  };
+}
+
+void PageTable::unmap_table(uint32_t index) {
+  page_table[index] = (PTE){
+    .present = 0,
+    .read_write = 0,
+    .privilege = 0,
+    .write_through_cache = 0,
+    .disable_cache = 0,
+    .accessed = 0,
+    .dirty = 0,
+    .ignored = 0,
+    .global = 0,
+    .available = 0,
+    .address = 0
+  };
+}
+
+PageDirectory::PageDirectory(PDE* page_directory, uint32_t phys_addr, uint32_t offset) {
+  this->page_directory = page_directory;
+  this->phys_addr = phys_addr;
+
+  for (int i=0; i<1024; i++) {
+    uint32_t table_phys_addr = page_directory[i].getPhysicalPTAddress();
+    page_tables[i] = PageTable(table_phys_addr >> 12, table_phys_addr + offset);
+  }
+}
+
+void PageDirectory::map(uint32_t phys, uint32_t virt) {
+  split_addr* split = (split_addr*)&virt;
+
+  page_directory[split->pd_index] = (PDE){
+    .present = 1,
+    .read_write = 1,
+    .privilege = 0,
+    .write_through_cache = 0,
+    .disable_cache = 0,
+    .accessed = 0,
+    .ignored2 = 0,
+    .page_4mb = 0,
+    .ignored = 0,
+    .available = 0,
+    .address = page_tables[split->pd_index].phys_addr
+  };
+
+  page_tables[split->pd_index].map_table(split->pt_index, phys >> 12);
+}
+
+void PageDirectory::unmap(uint32_t virt) {
+  split_addr* split = (split_addr*)&virt;
+  page_tables[split->pd_index].unmap_table(split->pt_index);
+}
+
+void PageDirectory::select() {
+  asm volatile("mov %0, %%eax; mov %%eax, %%cr3" : : "m" (phys_addr));
+}

src/kernel/memory.h

@@ -0,0 +1,80 @@
+#ifndef MEMORY_H
+#define MEMORY_H
+
+#include "datatypes/tuple.h"
+#include "paging.h"
+#include "allocate.h"
+#include "screenstuff.h"
+
+void memset(uint8_t* address, uint32_t count, uint8_t value);
+void memcpy(uint8_t* src, uint8_t* dst, uint32_t count);
+
+class __attribute__((packed)) PageMap {
+private:
+  uint8_t pagemap[1024^2 / 8];
+
+  void set_bit(uint32_t index);
+  void unset_bit(uint32_t index);
+
+public:
+  PageMap(uint8_t* map);
+
+  void mark_unavailble(uint32_t page);
+  void mark_available(uint32_t page);
+};
+
+struct PageTable {
+  PTE* page_table;
+
+  uint32_t phys_addr;
+  uint32_t virt_addr;
+
+  PageTable(uint32_t phys, uint32_t virt);
+  PageTable();
+
+  void map_table(uint32_t index, uint32_t addr);
+  void unmap_table(uint32_t index);
+};
+
+class PageDirectory {
+private:
+  PDE* page_directory;
+  PageTable page_tables[1024];
+
+  uint32_t phys_addr;
+
+public:
+  PageDirectory(PDE* page_directories, uint32_t phys_addr, uint32_t offset);
+
+  void map(uint32_t phys, uint32_t virt);
+
+  void unmap(uint32_t virt);
+
+  void select();
+};
+
+class Allocator {
+protected:
+  static PageMap phys;
+  PageMap virt;
+
+  PageDirectory PD;
+
+  uint32_t current_page_index;
+  uint32_t remaining;
+public:
+  Allocator();
+  Allocator(PageDirectory page_directory, PageMap phys, PageMap virt);
+  void* allocate();
+  void deallocate();
+};
+
+class Process : protected Allocator {
+private:
+  uint32_t PID;
+
+public:
+  Process(uint32_t PID);
+};
+
+#endif

src/kernel/paging.cpp

@@ -1,11 +1,5 @@
 #include "paging.h"
 
-struct __attribute__((packed)) split_addr {
-  uint32_t page_offset : 12;
-  uint32_t pt_index : 10;
-  uint32_t pd_index : 10;
-};
-
 void map_4k_phys_to_virt(uint32_t physical, uint32_t virt, PDE* page_directory, PTE** page_tables) {
   split_addr* split = (split_addr*)&virt;
 
@@ -60,3 +54,7 @@ void unmap_4k_virt(uint32_t virt, PDE* page_directory, PTE** page_tables) {
     .address = 0
   };
 }
+
+uint32_t PDE::getPhysicalPTAddress() {
+  return this->address << 12;
+}

src/kernel/paging.h

@@ -4,18 +4,10 @@
 #include <stdbool.h>
 #include "types.h"
 
-struct __attribute__((packed)) PDE {
+struct __attribute__((packed)) split_addr {
-  uint32_t present : 1;
+  uint32_t page_offset : 12;
-  uint32_t read_write : 1;
+  uint32_t pt_index : 10;
-  uint32_t privilege : 1;
+  uint32_t pd_index : 10;
-  uint32_t write_through_cache : 1;
-  uint32_t disable_cache : 1;
-  uint32_t accessed : 1;
-  uint32_t ignored2 : 1;
-  uint32_t page_4mb : 1;
-  uint32_t ignored : 1;
-  uint32_t available : 3;
-  uint32_t address : 20;
 };
 
 struct __attribute__((packed)) PTE {
@@ -32,6 +24,22 @@ struct __attribute__((packed)) PTE {
   uint32_t address : 20;
 };
 
+struct __attribute__((packed)) PDE {
+  uint32_t present : 1;
+  uint32_t read_write : 1;
+  uint32_t privilege : 1;
+  uint32_t write_through_cache : 1;
+  uint32_t disable_cache : 1;
+  uint32_t accessed : 1;
+  uint32_t ignored2 : 1;
+  uint32_t page_4mb : 1;
+  uint32_t ignored : 1;
+  uint32_t available : 3;
+  uint32_t address : 20;
+
+  uint32_t getPhysicalPTAddress();
+};
+
 void map_4k_phys_to_virt(uint32_t physical, uint32_t virt, PDE* page_directory, PTE** page_tables);
 void map_many_4k_phys_to_virt(uint32_t physical, uint32_t virt, PDE* page_directory, PTE** page_tables, uint32_t count);