feature: both physical and virtual allocators should be done

headers/alloc.h

@@ -18,7 +18,7 @@ enum { BPZ = 128, PAGES_TINY = 16, PAGES_SMALL = 64, MEM_ALIGN = 8 };
 typedef enum { TINY, SMALL, LARGE } block_type_t;
 
 /* METADATA:
- * ptr: the ptr to return with kalloc (aligned)
+ * ptr: the ptr to return with kmalloc (aligned)
  * size: the actual size
  * sub_size: the size asked by the user (different
  * from size only if krealloc and krealloc size < size)
@@ -67,7 +67,8 @@ typedef struct Zone {
  * For TINY and SMALL, the zone will be divided in blocks.
  * For LARGE, it will be entire page(s).
  */
-extern Zone *zones[3];
+extern Zone *kzones[3];
+extern Zone *vzones[3];
 
 /*----------- UTILS ----------*/
 block_type_t get_type(size_t size);
@@ -76,10 +77,15 @@ size_t align_mem(size_t addr);
 /*----------------------------*/
 
 /*-------- ALLOCATOR ---------*/
-int new_zone(block_type_t type, size_t size);
+int new_kzone(block_type_t type, size_t size);
+int new_vzone(block_type_t type, size_t size);
 /*----------------------------*/
 
-void *kalloc(size_t size);
+void *kmalloc(size_t size);
 void kfree(void *ptr);
 void *krealloc(void *ptr, size_t size);
-void show_alloc_mem(void);
+void *vmalloc(size_t size);
+void vfree(void *ptr);
+void *vrealloc(void *ptr, size_t size);
+void show_kalloc_mem(void);
+void show_valloc_mem(void);

headers/memory.h

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <stdint.h>
+#include <stddef.h>
 
 #define PRESENT    (1 << 0)
 #define RW         (1 << 1)
@@ -10,5 +10,7 @@
 #define PAGE_SIZE  4096
 
 void init_memory(void);
-void *kalloc_frame(uint32_t nb_frames);
-int kfree_frame(void *frame, uint32_t nb_frames);
+void *alloc_frames(size_t size);
+int free_frames(void *frame_ptr, size_t size);
+void *alloc_pages(size_t size);
+int free_pages(void *page_ptr, size_t size);

src/kernel.c

@@ -1,5 +1,6 @@
 #include "alloc.h"
 #include "gdt.h"
+#include "kpanic.h"
 #include "kprintf.h"
 #include "memory.h"
 #include "shell.h"
@@ -32,5 +33,6 @@ void kernel_main(void)
 	kprintf(KERN_NOTICE "KERN_NOTICE\n");
 	kprintf(KERN_INFO "KERN_INFO\n");
 	kprintf(KERN_DEBUG "KERN_DEBUG\n");
+	vmalloc(10);
 	shell_init();
 }

src/kpanic.c

@@ -20,4 +20,4 @@ void kpanic(const char *format, ...)
 	while (terminal_getkey().scan_code != KEY_SPACE)
 		;
 	reboot();
-}
+}

src/memory/frame.c

@@ -4,9 +4,9 @@
 
 #include "kprintf.h"
 #include "memory.h"
+#include "utils.h"
 
 #define MAX_FRAMES   1048319
-#define CEIL(x, y)   (((x) + (y) - 1) / (y))
 #define GET_FRAME(i) (frame_table[i / 8] & (1 << (i % 8)))
 #define SET_FRAME(i, used)                                                     \
 	do {                                                                   \
@@ -21,7 +21,7 @@ extern uint32_t end_kernel;
 static uint8_t frame_table[CEIL(MAX_FRAMES, 8)];
 static uint32_t remaining_frames = MAX_FRAMES;
 
-void *kalloc_frame(size_t size)
+void *alloc_frames(size_t size)
 {
 	const uint32_t nb_frames = CEIL(size, PAGE_SIZE);
 	if (nb_frames > remaining_frames) {
@@ -50,15 +50,15 @@ end:
 	return NULL;
 }
 
-int kfree_frame(void *frame, size_t size)
+int free_frames(void *frame_ptr, size_t size)
 {
 	const uint32_t nb_frames = CEIL(size, PAGE_SIZE);
-	const uint32_t start = (frame - (void *)&end_kernel) / PAGE_SIZE;
+	const uint32_t start = (frame_ptr - (void *)&end_kernel) / PAGE_SIZE;
 
-	if (start > MAX_FRAMES || frame < (void *)&end_kernel) {
+	if (start > MAX_FRAMES || frame_ptr < (void *)&end_kernel) {
 		kprintf(KERN_WARNING "Address out of range\n");
 		return -1;
-	} else if ((uint32_t)frame % PAGE_SIZE) {
+	} else if ((uint32_t)frame_ptr % PAGE_SIZE) {
 		kprintf(KERN_WARNING "Invalid address\n");
 		return -1;
 	} else if (start + nb_frames > MAX_FRAMES) {

src/memory/memory.c

@@ -1,5 +1,6 @@
 #include "memory.h"
 #include "string.h"
+#include <stdint.h>
 
 extern void load_page_directory(uint32_t *);
 extern void enable_paging(void);

src/memory/page.c

@@ -0,0 +1,73 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "kprintf.h"
+#include "memory.h"
+#include "utils.h"
+
+#define PT_SIZE         1024
+#define MAX_TLB_ENTRIES 32
+
+extern uint32_t page_table_entries[PT_SIZE] __attribute__((aligned(4096)));
+
+static int16_t find_next_block(size_t nb_pages)
+{
+	for (size_t i = 0; i < PT_SIZE; i++) {
+		if (page_table_entries[i] >> 12 == i) {
+			size_t j = i + 1;
+			for (; j - i < nb_pages && j < PT_SIZE; j++)
+				if (page_table_entries[j] >> 12 != j)
+					break;
+			if (j - i == nb_pages)
+				return i;
+			i = j - 1;
+		}
+	}
+	return -1;
+}
+
+void *alloc_pages(size_t size)
+{
+	const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
+	const int16_t index = find_next_block(nb_pages);
+
+	if (index < 0) {
+		kprintf(KERN_CRIT "Not enough pages (max: %d)\n", PT_SIZE);
+		return NULL;
+	}
+	for (size_t i = index; i - (size_t)index < nb_pages; i++) {
+		void *frame = alloc_frames(PAGE_SIZE);
+		if (!frame) {
+			for (size_t j = index; j < i; j++)
+				free_frames(
+				    (void *)(page_table_entries[j] >> 12),
+				    PAGE_SIZE);
+			return NULL;
+		}
+		page_table_entries[i] = (uint32_t)frame << 12;
+	}
+	return (void *)(page_table_entries[index] >> 12);
+}
+
+int free_pages(void *page_ptr, size_t size)
+{
+	const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
+	const uint32_t page_index = (uint32_t)page_ptr / PAGE_SIZE;
+
+	if ((uint32_t)page_ptr > PT_SIZE * PAGE_SIZE) {
+		kprintf(KERN_WARNING "Address out of range\n");
+		return -1;
+	} else if ((uint32_t)page_ptr % PAGE_SIZE) {
+		kprintf(KERN_WARNING "Invalid address\n");
+		return -1;
+	} else if (page_index + nb_pages > PT_SIZE) {
+		kprintf(KERN_WARNING "Invalid number of frames\n");
+		return -1;
+	}
+	for (size_t i = page_index; i < page_index + nb_pages; i++) {
+		free_frames((void *)(page_table_entries[i] >> 12), PAGE_SIZE);
+		page_table_entries[i] = (i >> 12) | INIT_FLAGS;
+	}
+	return 0;
+}

src/memory/phys/allocator.c

@@ -0,0 +1,64 @@
+#include "alloc.h"
+#include "kprintf.h"
+#include "memory.h"
+
+Zone *kzones[3];
+
+static void add_zone(Zone *zone, block_type_t type)
+{
+	// We put the zone at the beginning of the list
+	if (kzones[type]) {
+		zone->next = kzones[type];
+		kzones[type]->prev = zone;
+	}
+	kzones[type] = zone;
+}
+
+static void new_block(Zone *zone, size_t zone_size)
+{
+	Block *new_block = (Block *)align_mem((size_t)zone + sizeof(Zone));
+
+	// Metadata
+	new_block->in_use = false;
+	new_block->size = zone_size - sizeof(Zone) - sizeof(Block);
+	new_block->sub_size = new_block->size;
+	new_block->ptr = (Block *)((size_t)new_block + sizeof(Block));
+	new_block->zone = zone;
+
+	// Init future linked lists
+	new_block->prev = NULL;
+	new_block->prev_free = NULL;
+	new_block->prev_used = NULL;
+	new_block->next = NULL;
+	new_block->next_free = NULL;
+	new_block->next_used = NULL;
+
+	if (zone->free) {
+		zone->free->prev = new_block;
+		zone->free->prev_free = new_block;
+		new_block->next = zone->free;
+		new_block->next_free = zone->free;
+	}
+	zone->free = new_block;
+}
+
+int new_kzone(block_type_t type, size_t size)
+{
+	void *heap = alloc_frames(size);
+	if (heap == NULL) {
+		kprintf(KERN_ERR "error: alloc_frames failed\n");
+		return (-1);
+	}
+
+	Zone *zone = (Zone *)heap;
+	zone->type = type;
+	zone->size = size;
+	zone->used = NULL;
+	zone->next = NULL;
+	zone->prev = NULL;
+
+	new_block(zone, size);
+	add_zone(heap, type);
+
+	return (0);
+}

src/memory/phys/info.c

@@ -4,20 +4,20 @@
 // FULL_INFO is to display (or not) both used and unused blocks
 #define FULL_INFO 1
 
-void show_alloc_mem(void)
+void show_kalloc_mem(void)
 {
-	char *const zones_name[3] = {"TINY", "SMALL", "LARGE"};
+	char *const kzones_name[3] = {"TINY", "SMALL", "LARGE"};
 	size_t total_size = 0;
 
 	for (block_type_t type = 0; type < 3; ++type) {
 		int count = 0;
-		for (Zone *zone_it = zones[type]; zone_it != NULL;
+		for (Zone *zone_it = kzones[type]; zone_it != NULL;
 		     zone_it = zone_it->next) {
 #if FULL_INFO
 			if (zone_it->free)
 				kprintf("---------- AVAILABLE %s [n°%d - %p] "
 				        "----------\n",
-				        zones_name[type], count, zone_it);
+				        kzones_name[type], count, zone_it);
 			for (Block *block_it = zone_it->free; block_it != NULL;
 			     block_it = block_it->next_free) {
 				kprintf("%p - %p : %u bytes\n", block_it->ptr,
@@ -31,7 +31,7 @@ void show_alloc_mem(void)
 			if (zone_it->used)
 				kprintf("---------- IN_USE %s [n°%d - %p] "
 				        "----------\n",
-				        zones_name[type], count, zone_it);
+				        kzones_name[type], count, zone_it);
 			for (Block *block_it = zone_it->used; block_it != NULL;
 			     block_it = block_it->next_used) {
 				kprintf("%p - %p : %u bytes\n", block_it->ptr,

src/memory/phys/kfree.c

@@ -2,20 +2,20 @@
 #include "kprintf.h"
 #include "memory.h"
 
-static void remove_used(Block *to_kfree)
+static void remove_used(Block *to_free)
 {
-	Block *left = to_kfree->prev_used;
-	Block *right = to_kfree->next_used;
+	Block *left = to_free->prev_used;
+	Block *right = to_free->next_used;
 
-	to_kfree->next_used = NULL;
-	to_kfree->prev_used = NULL;
+	to_free->next_used = NULL;
+	to_free->prev_used = NULL;
 
 	if (!left && !right) {
-		to_kfree->zone->used = NULL;
+		to_free->zone->used = NULL;
 		return;
 	}
 	if (!left)
-		to_kfree->zone->used = right;
+		to_free->zone->used = right;
 	else
 		left->next_used = right;
 	if (right)
@@ -24,7 +24,7 @@ static void remove_used(Block *to_kfree)
 
 /*
  * If all the blocks of the zone have been kfreed,
- * we can unmap the zone and delete it from the list of zones
+ * we can unmap the zone and delete it from the list of kzones
  */
 static int unmap_zone(Zone *zone)
 {
@@ -36,17 +36,17 @@ static int unmap_zone(Zone *zone)
 	zone->next = NULL;
 
 	if (!left && !right) {
-		zones[type] = NULL;
+		kzones[type] = NULL;
 		goto unmap;
 	}
 	if (!left)
-		zones[type] = right;
+		kzones[type] = right;
 	else
 		left->next = right;
 	if (right)
 		right->prev = left;
 unmap:
-	err = kfree_frame((void *)zone, zone->size);
+	err = free_frames((void *)zone, zone->size);
 	if (err)
 		kprintf(KERN_ERR "error: munmap failed\n");
 	return (err);
@@ -97,19 +97,19 @@ void kfree(void *ptr)
 {
 	if (ptr == NULL)
 		return;
-	Block *to_kfree = (Block *)((size_t)ptr - sizeof(Block));
+	Block *to_free = (Block *)((size_t)ptr - sizeof(Block));
 	Block *to_merge = NULL;
-	to_kfree->in_use = false;
-	remove_used(to_kfree);
-	if (to_kfree->prev && !to_kfree->prev->in_use) {
-		to_merge = to_kfree;
-		to_kfree = merge_blocks(to_kfree->prev, to_kfree);
+	to_free->in_use = false;
+	remove_used(to_free);
+	if (to_free->prev && !to_free->prev->in_use) {
+		to_merge = to_free;
+		to_free = merge_blocks(to_free->prev, to_free);
 	}
-	if (to_kfree->next && !to_kfree->next->in_use) {
-		to_merge = to_kfree->next;
-		to_kfree = merge_blocks(to_kfree, to_kfree->next);
+	if (to_free->next && !to_free->next->in_use) {
+		to_merge = to_free->next;
+		to_free = merge_blocks(to_free, to_free->next);
 	}
-	int err = add_available(to_kfree, to_merge);
+	int err = add_available(to_free, to_merge);
 	if (err)
 		kprintf(KERN_ERR "kfree: fatal error\n");
 }

src/memory/phys/kmalloc.c

@@ -29,7 +29,7 @@ static Block *find_block(Zone *head, size_t size)
  * After the allocation, this will become
  * ... -> [5] -> [new] -> [6] -> ...
  *
- * For an example of [5].size = 32 and requiring a kalloc of 10
+ * For an example of [5].size = 32 and requiring a kmalloc of 10
  * Let's say the metadata takes a size of 2:
  * ... -> [metadata][data][remaining size] -> [6]
  *            ^        ^         ^
@@ -105,7 +105,7 @@ static void save_block(Zone *head, Block *block, Zone *zone)
  *
  * First, we init the allocator if it's the first time
  * Then we search if there is an available block in all
- * the zones currently mapped
+ * the kzones currently mapped
  * If no block has been found (NULL), we create 1 new zone of
  * the corresponding type
  * We then search again for an available block (should not be NULL)
@@ -114,18 +114,18 @@ static void save_block(Zone *head, Block *block, Zone *zone)
  *
  * ptr: returns the aligned pointer of the block (after the metadata)
  */
-void *kalloc(size_t size)
+void *kmalloc(size_t size)
 {
 	void *ptr = NULL;
 
 	if (size == 0) {
-		kprintf(KERN_WARNING "kalloc: can't kalloc(0)\n");
+		kprintf(KERN_WARNING "kmalloc: can't kmalloc(0)\n");
 		return NULL;
 	}
 
 	// Find the zone we need to search
 	block_type_t type = get_type(size);
-	Zone *head = zones[type];
+	Zone *head = kzones[type];
 
 	// Find an available block in a zone of type "type"
 	Block *available = find_block(head, size);
@@ -135,9 +135,9 @@ void *kalloc(size_t size)
 			full_size = size + sizeof(Block) + sizeof(Zone);
 		else
 			full_size = get_zone_size(type);
-		if (new_zone(type, full_size) == -1)
+		if (new_kzone(type, full_size) == -1)
 			return NULL;
-		head = zones[type];
+		head = kzones[type];
 		available = find_block(head, size);
 	}
 	assert(available != NULL);

src/memory/phys/krealloc.c

@@ -1,9 +1,9 @@
 #include "alloc.h"
 #include "string.h"
 
-// Prototype for kfree and kalloc
+// Prototype for kfree and kmalloc
 void kfree(void *ptr);
-void *kalloc(size_t size);
+void *kmalloc(size_t size);
 
 /*
  * ptr: block to resize (undefined behavior if invalid)
@@ -27,7 +27,7 @@ void *krealloc(void *ptr, size_t size)
 		block->sub_size = size;
 		return (ptr);
 	}
-	new_ptr = kalloc(size);
+	new_ptr = kmalloc(size);
 	if (new_ptr == NULL)
 		return NULL;
 	memmove(new_ptr, ptr, block->size);

src/memory/virt/allocator.c

@@ -2,16 +2,16 @@
 #include "kprintf.h"
 #include "memory.h"
 
-Zone *zones[3];
+Zone *vzones[3];
 
 static void add_zone(Zone *zone, block_type_t type)
 {
 	// We put the zone at the beginning of the list
-	if (zones[type]) {
-		zone->next = zones[type];
-		zones[type]->prev = zone;
+	if (vzones[type]) {
+		zone->next = vzones[type];
+		vzones[type]->prev = zone;
 	}
-	zones[type] = zone;
+	vzones[type] = zone;
 }
 
 static void new_block(Zone *zone, size_t zone_size)
@@ -42,11 +42,11 @@ static void new_block(Zone *zone, size_t zone_size)
 	zone->free = new_block;
 }
 
-int new_zone(block_type_t type, size_t size)
+int new_vzone(block_type_t type, size_t size)
 {
-	void *heap = kalloc_frame(size);
+	void *heap = alloc_pages(size);
 	if (heap == NULL) {
-		kprintf(KERN_ERR "error: syscall mmap failed\n");
+		kprintf(KERN_ERR "error: alloc_pages failed\n");
 		return (-1);
 	}
 

src/memory/virt/info.c

@@ -0,0 +1,49 @@
+#include "alloc.h"
+#include "kprintf.h"
+
+// FULL_INFO is to display (or not) both used and unused blocks
+#define FULL_INFO 1
+
+void show_valloc_mem(void)
+{
+	char *const vzones_name[3] = {"TINY", "SMALL", "LARGE"};
+	size_t total_size = 0;
+
+	for (block_type_t type = 0; type < 3; ++type) {
+		int count = 0;
+		for (Zone *zone_it = vzones[type]; zone_it != NULL;
+		     zone_it = zone_it->next) {
+#if FULL_INFO
+			if (zone_it->free)
+				kprintf("---------- AVAILABLE %s [n°%d - %p] "
+				        "----------\n",
+				        vzones_name[type], count, zone_it);
+			for (Block *block_it = zone_it->free; block_it != NULL;
+			     block_it = block_it->next_free) {
+				kprintf("%p - %p : %u bytes\n", block_it->ptr,
+				        (size_t)block_it->ptr +
+				            block_it->sub_size + sizeof(Block),
+				        block_it->sub_size);
+			}
+			if (zone_it->free)
+				kprintf("\n");
+#endif
+			if (zone_it->used)
+				kprintf("---------- IN_USE %s [n°%d - %p] "
+				        "----------\n",
+				        vzones_name[type], count, zone_it);
+			for (Block *block_it = zone_it->used; block_it != NULL;
+			     block_it = block_it->next_used) {
+				kprintf("%p - %p : %u bytes\n", block_it->ptr,
+				        (size_t)block_it->ptr +
+				            block_it->sub_size + sizeof(Block),
+				        block_it->sub_size);
+				total_size += block_it->sub_size;
+			}
+			if (zone_it->used)
+				kprintf("\n");
+			count++;
+		}
+	}
+	kprintf("Total: %u\n", total_size);
+}

src/memory/virt/vfree.c

@@ -0,0 +1,115 @@
+#include "alloc.h"
+#include "kprintf.h"
+#include "memory.h"
+
+static void remove_used(Block *to_free)
+{
+	Block *left = to_free->prev_used;
+	Block *right = to_free->next_used;
+
+	to_free->next_used = NULL;
+	to_free->prev_used = NULL;
+
+	if (!left && !right) {
+		to_free->zone->used = NULL;
+		return;
+	}
+	if (!left)
+		to_free->zone->used = right;
+	else
+		left->next_used = right;
+	if (right)
+		right->prev_used = left;
+}
+
+/*
+ * If all the blocks of the zone have been kfreed,
+ * we can unmap the zone and delete it from the list of vzones
+ */
+static int unmap_zone(Zone *zone)
+{
+	int err = 0;
+	block_type_t type = zone->type;
+	Zone *left = zone->prev;
+	Zone *right = zone->next;
+	zone->prev = NULL;
+	zone->next = NULL;
+
+	if (!left && !right) {
+		vzones[type] = NULL;
+		goto unmap;
+	}
+	if (!left)
+		vzones[type] = right;
+	else
+		left->next = right;
+	if (right)
+		right->prev = left;
+unmap:
+	err = free_pages((void *)zone, zone->size);
+	if (err)
+		kprintf(KERN_ERR "error: munmap failed\n");
+	return (err);
+}
+
+/*
+ * If the newly kfreed block is next to another previously
+ * kfreed block, merge both of these and update the size
+ */
+static Block *merge_blocks(Block *left, Block *right)
+{
+	if (right->next)
+		right->next->prev = left;
+	if (right->next_free) {
+		right->next_free->prev_free = left;
+		left->next_free = right->next_free;
+	}
+	left->next = right->next;
+	left->size += right->size + sizeof(Block);
+	return (left);
+}
+
+// Simply add the new block to the list of available blocks
+static int add_available(Block *available, Block *merged)
+{
+	Zone *zone = available->zone;
+	if (merged != zone->free && available != zone->free)
+		available->next_free = zone->free;
+	if (zone->free)
+		zone->free->prev_free = available;
+	zone->free = available;
+	if (zone->type == LARGE)
+		return (unmap_zone(zone));
+	return (0);
+}
+
+/*
+ * ptr: pointer to kfree, if the pointer is invalid the kfree()
+ * function will have an undefined behavior (most likely segfault)
+ *
+ * First, we remove the block from the list of in_use blocks
+ * Then, we check if the block needs to be merged with another
+ * neighboring block, if so we replace the previous block by the
+ * newly merged block
+ * Finally, we add the block to the list of available blocks
+ */
+void vfree(void *ptr)
+{
+	if (ptr == NULL)
+		return;
+	Block *to_free = (Block *)((size_t)ptr - sizeof(Block));
+	Block *to_merge = NULL;
+	to_free->in_use = false;
+	remove_used(to_free);
+	if (to_free->prev && !to_free->prev->in_use) {
+		to_merge = to_free;
+		to_free = merge_blocks(to_free->prev, to_free);
+	}
+	if (to_free->next && !to_free->next->in_use) {
+		to_merge = to_free->next;
+		to_free = merge_blocks(to_free, to_free->next);
+	}
+	int err = add_available(to_free, to_merge);
+	if (err)
+		kprintf(KERN_ERR "kfree: fatal error\n");
+}

src/memory/virt/vmalloc.c

@@ -0,0 +1,152 @@
+#include "alloc.h"
+#include "kprintf.h"
+
+int new_zone(block_type_t type, size_t size);
+
+/*
+ * Find first available (not in_use) block
+ * in a zone matching the size we need
+ */
+static Block *find_block(Zone *head, size_t size)
+{
+	for (Zone *zone_it = head; zone_it != NULL; zone_it = zone_it->next) {
+		for (Block *block_it = zone_it->free; block_it != NULL;
+		     block_it = block_it->next_free) {
+			assert(!block_it->in_use);
+			if (size <= block_it->size) {
+				assert(block_it->zone == zone_it);
+				return (block_it);
+			}
+		}
+	}
+	return (NULL);
+}
+
+// PARTIALLY DEPRECATED
+/*
+ * This will split the newly allocated block to use
+ * the remaining bytes for a new block
+ * This is our linked list of blocks
+ * ... -> [5] -> [6] -> ...
+ * After the allocation, this will become
+ * ... -> [5] -> [new] -> [6] -> ...
+ *
+ * For an example of [5].size = 32 and requiring a vmalloc of 10
+ * Let's say the metadata takes a size of 2:
+ * ... -> [metadata][data][remaining size] -> [6]
+ *            ^        ^         ^
+ *            2       10        20
+ *
+ * So now our block [new] will become:
+ * [5] -> [metadata][available data] -> [6]
+ *             ^           ^
+ *             2          18
+ * We can see that it now has its own metadata and available
+ * data and it points towards [6]
+ */
+static void frag_block(Zone *zone, Block *old_block, size_t size)
+{
+	Block *new_block = (Block *)align_mem((size_t)old_block + size);
+	assert(!(new_block >=
+	         (Block *)((size_t)zone + get_zone_size(zone->type))));
+
+	// Newly created block metadata
+	new_block->size = old_block->size - size;
+	new_block->sub_size = new_block->size;
+	new_block->in_use = false;
+	new_block->ptr = (void *)((size_t)new_block + sizeof(Block));
+	new_block->zone = zone;
+
+	new_block->prev = old_block;
+	new_block->next = old_block->next;
+	old_block->next = new_block;
+
+	new_block->prev_used = NULL;
+	new_block->next_used = NULL;
+
+	new_block->prev_free = old_block->prev_free;
+	new_block->next_free = old_block->next_free;
+
+	if (zone->free == old_block)
+		zone->free = new_block;
+
+	old_block->next_free = NULL;
+	old_block->prev_free = NULL;
+
+	// Newly in_use block metadata
+	old_block->in_use = true;
+	old_block->size = size - sizeof(Block);
+	old_block->sub_size = old_block->size;
+
+	if (zone->used == NULL) {
+		zone->used = old_block;
+		return;
+	}
+	old_block->prev_used = NULL;
+	old_block->next_used = zone->used;
+	zone->used->prev_used = old_block;
+	zone->used = old_block;
+}
+
+// Set the block to use and unset free
+static void save_block(Zone *head, Block *block, Zone *zone)
+{
+	zone->free = NULL;
+	block->in_use = true;
+	if (head->used) {
+		head->used->prev_used = block;
+		head->used->prev = block;
+		block->next = head->used;
+		block->next_used = head->used;
+	}
+	head->used = block;
+}
+
+/*
+ * size: size needed by the user to get allocated
+ *
+ * First, we init the allocator if it's the first time
+ * Then we search if there is an available block in all
+ * the vzones currently mapped
+ * If no block has been found (NULL), we create 1 new zone of
+ * the corresponding type
+ * We then search again for an available block (should not be NULL)
+ * Finally, if type == LARGE, we just have to change the block to used
+ * else, we frag the block to use just what's needed
+ *
+ * ptr: returns the aligned pointer of the block (after the metadata)
+ */
+void *vmalloc(size_t size)
+{
+	void *ptr = NULL;
+
+	if (size == 0) {
+		kprintf(KERN_WARNING "vmalloc: can't vmalloc(0)\n");
+		return NULL;
+	}
+
+	// Find the zone we need to search
+	block_type_t type = get_type(size);
+	Zone *head = vzones[type];
+
+	// Find an available block in a zone of type "type"
+	Block *available = find_block(head, size);
+	if (available == NULL) {
+		size_t full_size;
+		if (type == LARGE)
+			full_size = size + sizeof(Block) + sizeof(Zone);
+		else
+			full_size = get_zone_size(type);
+		if (new_vzone(type, full_size) == -1)
+			return NULL;
+		head = vzones[type];
+		available = find_block(head, size);
+	}
+	assert(available != NULL);
+	if (type == LARGE)
+		save_block(head, available, available->zone);
+	else
+		frag_block(available->zone, available, size + sizeof(Block));
+	ptr = available->ptr;
+	return ptr;
+}

src/memory/virt/vrealloc.c

@@ -0,0 +1,36 @@
+#include "alloc.h"
+#include "string.h"
+
+// Prototype for kfree and vmalloc
+void kfree(void *ptr);
+void *vmalloc(size_t size);
+
+/*
+ * ptr: block to resize (undefined behavior if invalid)
+ * size: size needed by the user to get vreallocated
+ *
+ * If we have a size <= to the previous size, we don't have
+ * to do anything, we just change sub_size for info purposes
+ * and return the same pointer
+ * Else, we allocate a new block and copy the content of
+ * the previous block in the new one and kfree the old block
+ *
+ * ptr: returns the aligned pointer of the vreallocated block
+ */
+void *vrealloc(void *ptr, size_t size)
+{
+	void *new_ptr = NULL;
+	if (ptr == NULL)
+		return NULL;
+	Block *block = (Block *)((size_t)ptr - sizeof(Block));
+	if (block->size >= size) {
+		block->sub_size = size;
+		return (ptr);
+	}
+	new_ptr = vmalloc(size);
+	if (new_ptr == NULL)
+		return NULL;
+	memmove(new_ptr, ptr, block->size);
+	kfree(ptr);
+	return (new_ptr);
+}

src/shell/commands/heap_cmd.c

@@ -1,7 +1,16 @@
 #include "alloc.h"
+#include "kprintf.h"
+#include "string.h"
 
 void heap_cmd(char *arg)
 {
-	(void)arg;
-	show_alloc_mem();
-}
+	if (!arg)
+		kprintf(KERN_INFO "You must specify an argument (phys/virt)\n");
+	else if (!strcmp(arg, "phys"))
+		show_kalloc_mem();
+	else if (!strcmp(arg, "virt"))
+		show_valloc_mem();
+	else
+		kprintf(KERN_INFO "%s: invalid argument to heap (phys/virt)\n",
+		        arg);
+}