[MEMORY] Memory pages and paging management

kernel/include/mem.h

@@ -5,6 +5,7 @@
 #ifdef __ASSEMBLER__
   #define V2P(a) ((a) - KERNEL_OFFSET)
   #define P2V(a) ((a) + KERNEL_OFFSET)
+  #define PAGE_OFFSET(p) ((p) & 0xFFF)
   #define P1_OFFSET(p) (((p) >> 12) & 0x1FF)
   #define P2_OFFSET(p) (((p) >> 21) & 0x1FF)
   #define P3_OFFSET(p) (((p) >> 30) & 0x1FF)
@@ -15,8 +16,15 @@
   #define P2V(a) ((void *)((uintptr_t)(a) + KERNEL_OFFSET))
   // returns an address n bytes after the target of pointer p
   #define incptr(p, n) ((void *)(((uintptr_t)(p)) + (n)))
+  #define PAGE_OFFSET(p) (((uintptr_t)(p)) & 0xFFF)
+  #define P1_OFFSET(p) ((((uintptr_t)(p)) >> 12) & 0x1FF)
+  #define P2_OFFSET(p) ((((uintptr_t)(p)) >> 21) & 0x1FF)
+  #define P3_OFFSET(p) ((((uintptr_t)(p)) >> 30) & 0x1FF)
+  #define P4_OFFSET(p) ((((uintptr_t)(p)) >> 39) & 0x1FF)
 #endif
 
+#define PAGE_SIZE 0x1000
+#define PAGE_FLAGS_MASK 0xFFF
 // Paging
 #define   PAGE_PRESENT        0x001
 #define   PAGE_WRITE          0x002
@@ -27,3 +35,23 @@
 #define   PAGE_DIRTY          0x040
 #define   PAGE_HUGE           0x080
 #define   PAGE_GLOBAL         0x100
+
+#ifndef __ASSEMBLER__
+typedef void * page_table;
+extern page_table BootP4;
+
+extern int kernel_start, kernel_end;
+
+void pmm_init();
+uintptr_t pmm_alloc();
+void pmm_free(uintptr_t page);
+
+#define GET_P4() ((page_table)V2P(&BootP4))
+
+void vmm_init();
+page_table *vmm_new_P4();
+void vmm_set_P4(page_table *P4);
+void vmm_free_P4(page_table *P4);
+uintptr_t vmm_get_page(page_table *P4, uintptr_t addr);
+uintptr_t vmm_set_page(page_table *P4, uintptr_t addr, uintptr_t phys, uint32_t flags);
+#endif

kernel/include/multiboot.h

@@ -43,6 +43,15 @@
     uint32_t vbe_interface_len;
   } mboot1_info;
 
+typedef struct {
+  uint32_t size;
+  uint32_t base_lo;
+  uint32_t base_hi;
+  uint32_t len_lo;
+  uint32_t len_hi;
+  uint32_t type;
+} mboot1_mmap_entry;
+
 // MULTIBOOT 2
 
   typedef struct {
@@ -56,9 +65,21 @@
     char data[];
   } mboot2_tag_basic;
 
+  typedef struct {
+    uint64_t base_addr;
+    uint64_t length;
+    uint32_t type;
+    uint32_t reserved;
+  } mboot2_mmap_entry;
+  typedef struct {
+    uint32_t entry_size;
+    uint32_t entry_version;
+    mboot2_mmap_entry entries[];
+  } mboot2_memory_map;
 
   #define MBOOT2_CMDLINE 1
   #define MBOOT2_BOOTLOADER 2
+  #define MBOOT2_MMAP 6
 
   // Multiboot tags are padded to a multiple of 8 bytes
   #define next_tag(tag) ((void *)((((uintptr_t)tag) + tag->size + 7) & ~0x7))
@@ -69,9 +90,15 @@
     void *data;
     char *commandline;
     char *bootloader;
+    void *mmap;
+    uint32_t mmap_size;
   };
   extern struct mboot_data_st mboot_data;
 
+#define MBOOT_MMAP_FREE 1
+
   void multiboot_init(uint64_t magic, void *data);
+  int multiboot_page_used(uintptr_t addr);
+  int multiboot_get_memory_area(uintptr_t *start, uintptr_t *end, uint32_t *type);
 
 #endif

kernel/include/registers.h

@@ -4,4 +4,5 @@ void load_idt(void *);
 uint64_t read_cr0();
 uint64_t read_cr2();
 uint64_t read_cr3();
+void write_cr3(uint64_t);
 uint64_t read_cr4();