make paging more stable

src/arch/amd64/fb.c

@@ -1,11 +1,16 @@
-#include "bindings.h"
+#include <lib.h>
-
+#include <memory.h>
+#include <serial.h>
 #include <stdint.h>
 #include <stddef.h>
 
+#include "bindings.h"
+
 #define INDEX           0x1CE
 #define DATA            0x1CF
 #define FB_ADDR         0xE0000000
+#define FB_MAX		    0xFF000000
+#define FB_LEN			(FB_MAX - FB_ADDR)
 
 #define PREFERRED_VY    4096
 #define PREFERRED_B     32
@@ -44,29 +49,35 @@ int fb_init(uint16_t res_x, uint16_t res_y) {
 	outw(INDEX, 0x04);
 	outw(DATA, 0x41);
 
-	uint32_t * text_vid_mem = (uint32_t *)0xA0000;
+//	uint32_t * text_vid_mem = (uint32_t *)0xA0000;
-	text_vid_mem[0] = 0xA5ADFACE;
+//	text_vid_mem[0] = 0xA5ADFACE;
-
+//
-	for (uintptr_t fb_offset = FB_ADDR; fb_offset < 0xFF000000; fb_offset += 0x01000000) {
+//	void *temp = mmap((void *) FB_ADDR, 0xFF1000);
-		/* Enable the higher memory */
+//
-		for (uintptr_t i = fb_offset; i < fb_offset; i += 0x1000) {
+//	for (uintptr_t fb_offset = FB_ADDR; fb_offset < FB_MAX; fb_offset += 0x01000000) {
-			// todo ident map fb
+//		/* Enable the higher memory */
-		}
+//		remap(temp, (void *)fb_offset, 0xFF1000);
-
+//
-		/* Go find it */
+//		/* Go find it */
-		for (uintptr_t x = fb_offset; x < fb_offset + 0xFF0000; x += 0x1000) {
+//		for (uintptr_t offset = 0; offset < 0xFF0000; offset += 0x1000) {
-			if (((uintptr_t *)x)[0] == 0xA5ADFACE) {
+//			uintptr_t x = (uintptr_t)temp + offset;
-				fb_buffer = (uint8_t *) x;
+//			if (((uintptr_t *)x)[0] == 0xA5ADFACE) {
-				goto mem_found;
+//				fb_buffer = (uint8_t *) (fb_offset + offset);
-			}
+//				goto mem_found;
-		}
+//			}
-	}
+//		}
-
+//	}
-mem_found:
+//
-	
+//	unmap(temp);
-	fb_res_x = res_x;
+//
-	fb_res_y = res_y;
+//mem_found:
-	fb_res_b = PREFERRED_B;
+//	
-
+//	fb_res_x = res_x;
+//	fb_res_y = res_y;
+//	fb_res_b = PREFERRED_B;
+//	
+//	fb_buffer = mmap(fb_buffer, 0xFF0000);
+//	memset(fb_buffer, 7, 0xFF0000);
+//
 	return 0;
 }

src/arch/amd64/mboot.c

@@ -35,13 +35,18 @@ static uint32_t *read_tag(struct mboot_info *info, uint32_t *data) {
         case MBOOT_MEMORYMAP:
             read_memorymap(&tag, tag.size, data + 2);
             break;
+        case MBOOT_SYMBOLS:
+            // TODO:
+            goto done;
         case MBOOT_XSDP:
             read_xsdp(&tag, (char *) (data + 2));
             break;
         default:
-            break;
+            goto done;
     }
 
+done:
+
     info->tags[tag.type] = tag;
 
     if(tag.size % 8 != 0) {

src/arch/amd64/mboot.h

@@ -19,6 +19,7 @@ struct mboot_tag {
 enum mboot_tag_type {
 	MBOOT_CMDLINE = 0,
 	MBOOT_MEMORYMAP = 6,
+	MBOOT_SYMBOLS = 9,
 	MBOOT_XSDP = 14
 };
 

src/arch/amd64/paging.c

@@ -61,172 +61,437 @@ extern struct pte paging_pt[512]; // paging_pt should NEVER be outside of this f
 // paged address to read page tables
 // the structures are not gurenteed to be ident mapped
 // map them here with map_<type>(phys_addr) before useing structures
-static struct pdpte *pdpt_mapped = (void *) (uintptr_t) 0x201000;
-static struct pdpte *pd_mapped = (void *) (uintptr_t) 0x202000;
-static struct pdpte *pt_mapped = (void *) (uintptr_t) 0x203000;
 void                *addr_mapped = (void *) (uintptr_t) 0x204000;
+static struct pml4e *pml4_mapped = (void *) (uintptr_t) 0x200000;
+static struct pdpte *pdpt_mapped = (void *) (uintptr_t) 0x201000;
+static struct pde   *pd_mapped   = (void *) (uintptr_t) 0x202000;
+static struct pte   *pt_mapped   = (void *) (uintptr_t) 0x203000;
 
-static inline void invlpg(void *addr) {
+static inline void
+invlpg(void *addr)
+{
 	__asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
 }
 
-static void map_pdpt(struct pdpte *phys_addr) {
+static void
-	paging_pt[1].address = (((uint64_t)phys_addr) >> 12);
+load_addr(void *phys_addr)
-	paging_pt[1].flags = F_PRESENT | F_WRITEABLE;
+{
-	invlpg(pdpt_mapped);
+	static struct pte *pt = &paging_pt[4];
-}
+	pt->address = (uint64_t)phys_addr >> 12;
-
+	pt->flags = F_PRESENT | F_WRITEABLE;
-static void map_pd(struct pde *phys_addr) {
-	paging_pt[2].address = (((uint64_t)phys_addr) >> 12);
-	paging_pt[2].flags = F_PRESENT | F_WRITEABLE;
-	invlpg(pd_mapped);
-}
-
-static void map_pt(struct pte *phys_addr) {
-	paging_pt[3].address = (((uint64_t)phys_addr) >> 12);
-	paging_pt[3].flags = F_PRESENT | F_WRITEABLE;
-	invlpg(pt_mapped);
-}
-
-static void map_addr(void *phys_addr) {
-	paging_pt[4].address = (((uint64_t)phys_addr) >> 12);
-	paging_pt[4].flags = F_PRESENT | F_WRITEABLE;
 	invlpg(addr_mapped);
 }
 
-//static int get_maxphysaddr() {
+static void
-//	uint32_t eax, ebx, ecx, edx;
+load_pml4(
-//	__cpuid(0x80000008, eax, ebx, ecx, edx);
+		void *phys
-//	return eax & 0xFF;
+) {
-//}
+	static struct pte *pt = &paging_pt[0];
+	pt->address = (uint64_t)phys >> 12;
+	pt->flags = F_PRESENT | F_WRITEABLE;
+	invlpg(pml4_mapped);
+}
 
-//int find_phys_addr(struct pml4e *pml4, void *virt_addr, void **phys_addr) {
+static void
-//	uint64_t pml4_offset =  ((uint64_t)virt_addr) >> 39;
+load_pdpt(
-//	uint64_t pdpt_offset = (((uint64_t)virt_addr) >> 30) & 0x1FF;
+		void *phys
-//	uint64_t pd_offset   = (((uint64_t)virt_addr) >> 21) & 0x1FF;
+) {
-//	uint64_t pt_offset   = (((uint64_t)virt_addr) >> 12) & 0x1FF;
+	static struct pte *pt = &paging_pt[1];
-//	uint64_t page_offset = (((uint64_t)virt_addr)      ) & 0xFFF;
+	pt->address = (uint64_t)phys >> 12;
-//
+	pt->flags = F_PRESENT | F_WRITEABLE;
-//	if (!(pml4[pml4_offset].flags & F_PRESENT))
+	invlpg(pdpt_mapped);
-//		return -1;
+}
-//	struct pdpte *pdpt = (struct pdpte *)(pml4[pml4_offset].address << 12);
-//	if (!(pdpt[pdpt_offset].flags & F_PRESENT))
-//		return -1;
-//	struct pde *pd = (struct pde *)(pdpt[pdpt_offset].address << 12);
-//	if (!(pd[pd_offset].flags & F_PRESENT))
-//		return -1;
-//	struct pte *pt = (struct pte *)(pd[pd_offset].address << 12);
-//	if (!(pt[pt_offset].flags & F_PRESENT))
-//		return -1;
-//	*phys_addr = (void *)((pt[pt_offset].address << 12) + page_offset);
-//	return 0;
-//}
 
-char *curr_alloc = (void *) 0x5000;
+static void
+load_pd(
+		void *phys
+) {
+	static struct pte *pt = &paging_pt[2];
+	pt->address = (uint64_t)phys >> 12;
+	pt->flags = F_PRESENT | F_WRITEABLE;
+	invlpg(pdpt_mapped);
+}
 
-int map_page(struct pml4e *pml4, void *virt_addr, void *phys_addr, unsigned int flags) {
+static void
-	uint64_t pml4_offset =  ((uint64_t)virt_addr) >> 39;
+load_pt(
-	uint64_t pdpt_offset = (((uint64_t)virt_addr) >> 30) & 0x1FF;
+		void *phys
-	uint64_t pd_offset   = (((uint64_t)virt_addr) >> 21) & 0x1FF;
+) {
-	uint64_t pt_offset   = (((uint64_t)virt_addr) >> 12) & 0x1FF;
+	static struct pte *pt = &paging_pt[3];
-	//uint64_t page_offset = (((uint64_t)virt_addr)      ) & 0xFFF;
+	pt->address = (uint64_t)phys >> 12;
+	pt->flags = F_PRESENT | F_WRITEABLE;
+	invlpg(pt_mapped);
+}
 
-	if (!(pml4[pml4_offset].flags & F_PRESENT)) {
+#define PAG_SUCCESS      0
+#define PAG_CANNOT_ALLOC 1
+#define PAG_NOT_PRESENT  2
+
+static int
+select_pdpt(
+		void *virt,
+		unsigned int flags,
+		struct pml4e *root,
+		struct pdpte **res,
+		bool create
+) {
+	load_pml4(root);
+	uint64_t offset = (uint64_t)virt >> 39;
+	struct pml4e *pml4e = &pml4_mapped[offset];
+	if (!(pml4e->flags & F_PRESENT)) {
+		if (!create) {
+			return PAG_NOT_PRESENT;
+		}
 		void *new_page = alloc_phys_page();
-		map_addr(new_page);
+		if (new_page == NULL) {
-		memset(addr_mapped, 0, 4096);
+			return PAG_CANNOT_ALLOC;
-		pml4[pml4_offset].address = ((uint64_t)new_page) >> 12;
+		}
+		load_addr(new_page);
+		memset(addr_mapped, 0, PAGE_SIZE);
+		pml4e->address = ((uint64_t)new_page) >> 12;
+		pml4e->flags = F_PRESENT;
+	}
+	if (flags)
+		pml4e->flags = F_PRESENT | flags;
+	*res = (struct pdpte *)(uintptr_t)(pml4e->address << 12);
+	return PAG_SUCCESS;
 }
-	pml4[pml4_offset].flags = F_PRESENT | flags;
 
-	struct pdpte *__pdpt = (struct pdpte *)(uintptr_t)(pml4[pml4_offset].address << 12);
+static int
-	map_pdpt(__pdpt);
+select_pd(
-	if (!(pdpt_mapped[pdpt_offset].flags & F_PRESENT)) {
+		void *virt,
+		unsigned int flags,
+		struct pdpte *pdpt,
+		struct pde **res,
+		bool create
+) {
+	load_pdpt(pdpt);
+	uint64_t offset = ((uint64_t)virt >> 30) & 0x1ff;
+	struct pdpte *pdpte = &pdpt_mapped[offset];
+	if (!(pdpte->flags & F_PRESENT)) {
+		if (!create) {
+			return PAG_NOT_PRESENT;
+		}
 		void *new_page = alloc_phys_page();
-		map_addr(new_page);
+		if (new_page == NULL) {
-		memset(addr_mapped, 0, 4096);
+			return PAG_CANNOT_ALLOC;
-		pdpt_mapped[pdpt_offset].address = ((uint64_t)new_page) >> 12;
+		}
+		load_addr(new_page);
+		memset(addr_mapped, 0, PAGE_SIZE);
+		pdpte->address = ((uint64_t)new_page) >> 12;
+		pdpte->flags = F_PRESENT;
+	}
+	if (flags)
+		pdpte->flags = F_PRESENT | flags;
+	*res = (struct pde *)(uintptr_t)(pdpte->address << 12);
+	return PAG_SUCCESS;
 }
-	pdpt_mapped[pdpt_offset].flags = F_PRESENT | flags;
 
-	struct pde *__pd = (struct pde *)(uintptr_t)(pdpt_mapped[pdpt_offset].address << 12);
+static int
-	map_pd(__pd);
+select_pt(
-	if (!(pd_mapped[pd_offset].flags & F_PRESENT)) {
+		void *virt,
+		unsigned int flags,
+		struct pde *pd,
+		struct pte **res,
+		bool create
+) {
+	load_pd(pd);
+	uint64_t offset = ((uint64_t)virt >> 21) & 0x1ff;
+	struct pde *pde = &pd_mapped[offset];
+	if (!(pde->flags & F_PRESENT)) {
+		if (!create) {
+			return PAG_NOT_PRESENT;
+		}
 		void *new_page = alloc_phys_page();
-		map_addr(new_page);
+		if (new_page == NULL) {
-		memset(addr_mapped, 0, 4096);
+			return PAG_CANNOT_ALLOC;
-		pd_mapped[pd_offset].address = ((uint64_t)new_page) >> 12;
 		}
-	pd_mapped[pd_offset].flags = F_PRESENT | flags;
+		load_addr(new_page);
-
+		memset(addr_mapped, 0, PAGE_SIZE);
-	struct pte *__pt = (struct pte *)(uintptr_t)(pd_mapped[pd_offset].address << 12);
+		pde->address = ((uint64_t)new_page) >> 12;
-	map_pt(__pt);
+		pde->flags = F_PRESENT;
-	pt_mapped[pt_offset].flags = F_PRESENT | flags;
+	}
-	pt_mapped[pt_offset].address = (((uint64_t)phys_addr) >> 12);
+	if (flags)
-	
+		pde->flags = F_PRESENT | flags;
-	invlpg(virt_addr);
+	*res = (struct pte *)(uintptr_t)(pde->address << 12);
-	return 0;
+	return PAG_SUCCESS;
 }
 
-int unmap_page(struct pml4e *pml4, void *virt_addr) {
+static void
-	uint64_t pml4_offset = ((uint64_t)virt_addr) >> 39;
+select_page(
-	uint64_t pdpt_offset = (((uint64_t)virt_addr) >> 30) & 0x1FF;
+		void *virt,
-	uint64_t pd_offset   = (((uint64_t)virt_addr) >> 21) & 0x1FF;
+		struct pte *pt,
-	uint64_t pt_offset   = (((uint64_t)virt_addr) >> 12) & 0x1FF;
+		struct pte **res
-	//uint64_t page_offset = (((uint64_t)virt_addr)      ) & 0xFFF;
+) {
-
+	load_pt(pt);
-	if (!(pml4[pml4_offset].flags & F_PRESENT))
+	uint64_t offset = ((uint64_t)virt >> 12) & 0x1ff;
-		return -1;
+	struct pte *page = &pt_mapped[offset];
-	struct pdpte *__pdpt = (struct pdpte *)(uintptr_t)(pml4[pml4_offset].address << 12);
+	*res = page;
-	map_pdpt(__pdpt);
+	return;
-	if (!(pdpt_mapped[pdpt_offset].flags & F_PRESENT))
-		return -1;
-	struct pde *__pd = (struct pde *)(uintptr_t)(pdpt_mapped[pdpt_offset].address << 12);
-	map_pd(__pd);
-	if (!(pd_mapped[pd_offset].flags & F_PRESENT))
-		return -1;
-	struct pte *__pt = (struct pte *)(uintptr_t)(pd_mapped[pd_offset].address << 12);
-	map_pt(__pt);
-	if (!(pt_mapped[pt_offset].flags & F_PRESENT))
-		return -1;
-
-	pt_mapped[pt_offset].flags = 0;
-
-	int i = 0;
-	for(; i < 512; i++) {
-		if (pt_mapped[i].flags & F_PRESENT)
-			break;
 }
-	if (i == 512)
-		goto done;
 
-	pd_mapped[pd_offset].flags = 0;
+static inline void
-
+try_unmap_pml4(void) {
-	for(i = 0; i < 512; i++) {
+	for (int i = 0; i < 512; i++) {
-		if (pd_mapped[i].flags & F_PRESENT)
+		if (pml4_mapped[i].flags & F_PRESENT)
-			break;
+			return;
+	}
+	for (int i = 0; i < 512; i++) {
+		if (pml4_mapped[i].address) {
+			void *addr = (void *)(uintptr_t)(pml4_mapped[i].address << 12);
+			free_phys_page(addr);
+		}
+	}
 }
-	if (i == 512)
-		goto done;
 
-	pdpt_mapped[pdpt_offset].flags = 0;
+static inline void
-
+try_unmap_pdpt(void) {
-	for(i = 0; i < 512; i++) {
+	for (int i = 0; i < 512; i++) {
 		if (pdpt_mapped[i].flags & F_PRESENT)
-			break;
+			return;
+	}
+	for (int i = 0; i < 512; i++) {
+		if (pdpt_mapped[i].address) {
+			void *addr = (void *)(uintptr_t)(pdpt_mapped[i].address << 12);
+			free_phys_page(addr);
+		}
+	}
+	try_unmap_pml4();
 }
-	if (i == 512)
-		goto done;
 
-	pml4[pml4_offset].flags = 0;
+static inline void
+try_unmap_pd(void) {
+	for (int i = 0; i < 512; i++) {
+		if (pd_mapped[i].flags & F_PRESENT)
+			return;
+	}
+	for (int i = 0; i < 512; i++) {
+		if (pd_mapped[i].address) {
+			void *addr = (void *)(uintptr_t)(pd_mapped[i].address << 12);
+			free_phys_page(addr);
+		}
+	}
+	try_unmap_pdpt();
+}
 
-	//TODO: Return memory used for page structures
+static inline void
+try_unmap_pt(void) {
+	for (int i = 0; i < 512; i++) {
+		if (pt_mapped[i].flags & F_PRESENT)
+			return;
+	}
+	for (int i = 0; i < 512; i++) {
+		if (pt_mapped[i].address) {
+			void *addr = (void *)(uintptr_t)(pt_mapped[i].address << 12);
+			free_phys_page(addr);
+		}
+	}
+	try_unmap_pd();
+}
+
+static void
+unmap_page(
+		struct pml4e *root,
+		void *virt
+) {
+
+	struct pdpte *pdpt;
+	struct pde   *pd;
+	struct pte   *pt;
+	struct pte   *page;
+
+	unsigned int df = 0;
+
+	if (select_pdpt(virt, df, root, &pdpt, false))
+		return;
+
+	if (select_pd(virt, df, pdpt, &pd, false))
+		return;
+
+	if (select_pt(virt, df, pd, &pt, false))
+		return;
+
+	select_page(virt, pt, &page);
+
+	page->address = 0;
+	page->flags = 0;
+
+	try_unmap_pt();
+
+	invlpg(virt);
+
+	return;
+}
+
+static void
+unmap_pages(
+		struct pml4e *root,
+		void *virt_start,
+		long page_count
+) {
+
+	uint64_t pml4_o = -1,
+			 pdpt_o = -1,
+			 pd_o   = -1;
+
+	uint64_t pml4_n,
+			 pdpt_n,
+			 pd_n;
+
+	struct pdpte *pdpt = NULL;
+	struct pde   *pd   = NULL;
+	struct pte   *pt   = NULL;
+	struct pte   *page = NULL;
+
+	unsigned int df = 0;
+
+	void *virt;
+
+	for (long i = 0; i < page_count; i++) {
+
+		virt = (char *)virt_start + (i * PAGE_SIZE);
+
+		pml4_n = (uint64_t)  virt >> 39;
+		pdpt_n = ((uint64_t) virt >> 30) & 0x1ff;
+		pd_n   = ((uint64_t) virt >> 21) & 0x1ff;
+
+		if (pdpt == NULL || pml4_o != pml4_n) {
+			if (select_pdpt(virt, df, root, &pdpt, false))
+				continue;
+			pml4_o = pml4_n;
+		}
+
+		if (pd == NULL || pdpt_o != pdpt_n) {
+			if (select_pd(virt, df, pdpt, &pd, false))
+				continue;
+			pdpt_o = pdpt_n;
+		}
+
+		if (pt == NULL || pd_o != pd_n) {
+			if (pt) {
+				try_unmap_pt();
+			}
+			if (select_pt(virt, df, pd, &pt, false))
+				continue;
+			pd_o = pd_n;
+		}
+
+		select_page(virt, pt, &page);
+
+		page->address = 0;
+		page->flags = 0;
+
+	}
+
+	if (pt != NULL)
+		try_unmap_pt();
+
+	return;
+}
+
+static int
+map_page(
+		struct pml4e *root,
+		void *virt,
+		void *phys,
+		unsigned int flags
+) {
+
+	struct pdpte *pdpt;
+	struct pde   *pd;
+	struct pte   *pt;
+	struct pte   *page;
+
+	unsigned int df = F_WRITEABLE;
+
+	if (select_pdpt(virt, df, root, &pdpt, true))
+		return 1;
+
+	if (select_pd(virt, df, pdpt, &pd, true))
+		return 1;
+
+	if (select_pt(virt, df, pd, &pt, true))
+		return 1;
+
+	select_page(virt, pt, &page);
+
+	page->address = (uint64_t)phys >> 12;
+	page->flags = F_PRESENT | flags;
+	invlpg(virt);
 
-done:	
-	invlpg(virt_addr);
 	return 0;
 }
 
+static int
+map_pages(
+		struct pml4e *root,
+		void *virt_start,
+		void *phys_start,
+		unsigned int flags,
+		long page_count
+) {
+
+	uint64_t pml4_o = -1,
+			 pdpt_o = -1,
+			 pd_o   = -1;
+
+	uint64_t pml4_n,
+			 pdpt_n,
+			 pd_n;
+
+	struct pdpte *pdpt = NULL;
+	struct pde   *pd   = NULL;
+	struct pte   *pt   = NULL;
+	struct pte   *page = NULL;
+
+	void *virt, *phys;
+
+	unsigned int df = F_WRITEABLE;
+
+	long i;
+	for (i = 0; i < page_count; i++) {
+
+		virt = (char *)virt_start + (i * PAGE_SIZE);
+		phys = (char *)phys_start + (i * PAGE_SIZE);
+
+		pml4_n = (uint64_t)  virt >> 39;
+		pdpt_n = ((uint64_t) virt >> 30) & 0x1ff;
+		pd_n   = ((uint64_t) virt >> 21) & 0x1ff;
+
+		if (pdpt == NULL || pml4_o != pml4_n) {
+			if (select_pdpt(virt, df, root, &pdpt, true))
+				goto failed;
+			pml4_o = pml4_n;
+		}
+
+		if (pd == NULL || pdpt_o != pdpt_n) {
+			if (select_pd(virt, df, pdpt, &pd, true))
+				goto failed;
+			pdpt_o = pdpt_n;
+		}
+
+		if (pt == NULL || pd_o != pd_n) {
+			if (select_pt(virt, df, pd, &pt, true))
+				goto failed;
+			pd_o = pd_n;
+		}
+
+		select_page(virt, pt, &page);
+
+		page->address = (uint64_t)phys >> 12;
+		page->flags = F_PRESENT | flags;
+		invlpg(virt);
+
+	}
+
+	return 0;
+
+failed:
+
+	unmap_pages(root, virt, i);
+
+	return 1;
+}
+
 void paging_init(void) {
 
 	kernel_pml4[0].flags = F_PRESENT | F_WRITEABLE;
@@ -260,21 +525,24 @@ void *mmap(void *addr, size_t len) {
 		return NULL;
 	}
 	void *phys = page_align(addr);
-	for (long i = 0; i < pages; i++) {
+	if (map_pages(
-		void *virt_temp = (char *)virt + (i * PAGE_SIZE);
+			kernel_pml4,
-		void *phys_temp = (char *)phys + (i * PAGE_SIZE);
+			virt,
-		map_page(kernel_pml4, virt_temp, phys_temp, F_WRITEABLE);
+			phys,
+			F_WRITEABLE,
+			pages
+	)) {
+		virtaddr_free(virt);
+		return NULL;
 	}
-	map_page(kernel_pml4, virt, (void*)0x23443, F_WRITEABLE);
 	return virt;
 }
 
 void unmap(void *addr) {
 	long pages = virtaddr_free(addr);
-	for (long i = 0; i < pages; i++) {
+	if (pages < 1)
-		void *virt = (char *)addr + (i * PAGE_SIZE);
+		return;
-		unmap_page(kernel_pml4, virt);
+	unmap_pages(kernel_pml4, addr, pages);
-	}
 }
 
 void *alloc_pages(int count) {
@@ -286,10 +554,15 @@ void *alloc_pages(int count) {
 		virtaddr_free(virt);
 		return NULL;
 	}
-	for (int i = 0; i < count; i++) {
+	if (map_pages(
-		void *virt_temp = (char *)virt + (i * PAGE_SIZE);
+			kernel_pml4,
-		void *phys_temp = (char *)phys + (i * PAGE_SIZE);
+			virt,
-		map_page(kernel_pml4, virt_temp, phys_temp, F_WRITEABLE);
+			phys,
+			F_WRITEABLE,
+			count
+	)) {
+		virtaddr_free(virt);
+		return NULL;
 	}
 	return virt;
 }
@@ -298,10 +571,7 @@ void free_page(void *virt) {
 	long pages = virtaddr_free(virt);
 	if (pages < 1)
 		return;
-	for (long i = 0; i < pages; i++) {
+	unmap_pages(kernel_pml4, virt, pages);
-		void *virt_temp = (char *)virt + (i * PAGE_SIZE);
-		unmap_page(kernel_pml4, virt_temp);
-	}
 }
 
 void memory_lock(void) {
@@ -317,5 +587,6 @@ int kmap_page(void *virt_addr, void *phys_addr, unsigned int flags) {
 }
 
 int kunmap_page(void *virt_addr) {
-	return unmap_page(kernel_pml4, virt_addr);
+	unmap_page(kernel_pml4, virt_addr);
+	return 0;
 }

src/arch/amd64/paging.h

@@ -10,7 +10,6 @@
 #define F_MEGABYTE     0x080
 #define F_GLOBAL       0x100
 
+void paging_init(void);
 int kmap_page(void *virt_addr, void *phys_addr, unsigned int flags);
 int kunmap_page(void *virt_addr);
-
-void paging_init(void);

src/memory/physalloc.c

@@ -26,6 +26,7 @@ static uint64_t total_memory;
 static uint64_t free_memory;
 static uint64_t page_count;
 static uint64_t page_free_start;
+static uint64_t segment_count;
 static struct memory_area *page_start;
 
 static int n_pages(const struct memory_area *m) {
@@ -34,7 +35,8 @@ static int n_pages(const struct memory_area *m) {
 
 static void *page_at(int i) {
 	int cur_page = 0;
-	for (struct memory_area *m = page_start; m != NULL; m++) {
+	for (uint64_t idx = 0; idx < segment_count; idx++) {
+		struct memory_area *m = &page_start[idx];
 		int pages = n_pages(m);
 		if (i - cur_page < pages) {
 			return (void *) (m->addr + (PAGE_SIZE * (i - cur_page)));
@@ -165,7 +167,7 @@ void memory_init(struct memory_map *map) {
 	end += map->size;
 
 	struct memory_segment *segment = &map->entries[0];
-	int segment_count = 0;
+	segment_count = 0;
 	
 	for(; (uintptr_t) segment < end; segment++) {
 		if (segment_invalid(segment))