Implement a dynamic virtual memory manager (#7)

* Implement vaddr_t_to_ptr

* vaddr_t should have uint16_t indices

* Add a simple alloc_vpage

* Fix some mistypes

* Revamp to a smarter alloc system + add alloc_vpages

* Format + add free_all_vpages_in_range

* Bugfix + quell some warnings

* Minor readability improvement

* Add free for vpages

* Move the check for pml4 index to free_vpages

* Switch to novel vmm for malloc

* Deprecate try_assign_pt

* Remove now unused 'allocated' flag

* Remove most of init_memmgt

* Don't delete the pdpt even if it is empty

* Format

* Add a message to signify that execution has completed

* Expose the alloc functions just in case

* Make static some file-only functions

* init_memmgt -> __init_memmgt__ to match convention

Author: ryuukumar

include/kernel/memmgt.h

@@ -62,8 +62,7 @@ typedef struct {
 	uint64_t dirty : 1;
 	uint64_t pat : 1;
 	uint64_t global : 1;
-	uint64_t allocated : 1;
-	uint64_t available1 : 2;
+	uint64_t available1 : 3;
 	uint64_t frame_base_address : 40;
 	uint64_t available2 : 11;
 	uint64_t nex : 1;
@@ -77,24 +76,28 @@ typedef struct {
 } memmap_bitmap;
 
 typedef struct {
-	uint8_t pml4_index;
-	uint8_t pdpt_index;
-	uint8_t pd_index;
-	uint8_t pt_index;
+	uint16_t pml4_index;
+	uint16_t pdpt_index;
+	uint16_t pd_index;
+	uint16_t pt_index;
 	uint16_t offset;
 } vaddr_t;
 
 typedef uint64_t* paddr_t;
 
 vaddr_t get_vaddr_t_from_ptr (void* ptr);
 void* get_vaddr_hhdm (uint64_t phys_address);
+void* vaddr_t_to_ptr (vaddr_t* virtual_addr);
+
+void* alloc_vpages (size_t req_count);
+void* alloc_vpage (void);
+void free_vpages (void* ptr, size_t count);
+void free_vpage (void* ptr);
 
-void init_memmgt (uint64_t, struct limine_memmap_response*);
+void __init_memmgt__ (uint64_t, struct limine_memmap_response*);
 void walk_pagetable (void);
 void* get_paddr (void* vaddr);
 
-uint64_t allocate_physical_pageframes (size_t);
-
 // LIBALLOC FUNCTION IMPLEMENTATIONS
 
 void* try_assign_pt (pt_entry_t*, size_t);

src/kernel/entry.c

@@ -72,7 +72,7 @@ void _start (void) {
 		hcf ();
 	}
 
-	init_memmgt (hhdm_base, memmap_req.response);
+	__init_memmgt__ (hhdm_base, memmap_req.response);
 
 	set_color (0x44eeaa);
 
@@ -104,5 +104,6 @@ void _start (void) {
 	printf ("CR3: %lx", cr3);
 
 	// We're done, just hang...
+	printf ("\n\nAll execution completed.");
 	hcf ();
 }