wip: switch current_pcb and cr3 in switch_thread

fix: copy child to the current_pcb

headers/alloc.h

@@ -75,10 +75,10 @@ int new_vzone(block_type_t type, size_t size);
 int new_kzone(block_type_t type, size_t size);
 /*----------------------------*/
 
-void *vmalloc(size_t size);
-void vfree(void *ptr);
+void *umalloc(size_t size);
+void ufree(void *ptr);
 void *vrealloc(void *ptr, size_t size);
-void show_valloc_mem(void);
+void show_ualloc_mem(void);
 size_t vsize(void *virt_addr);
 void *kmalloc(size_t size);
 void kfree(void *ptr);

headers/memory.h

@@ -21,14 +21,21 @@
 #define KERNEL_END      ((uint32_t)&_kernel_end - VIRT_OFFSET)
 #define KERNEL_PT_END   1020
 #define KERNEL_PT_START 769
+#define USER_PT_START   1
+#define USER_PT_END     768
 
 #define PDE_VBE         1021
 #define PDE_FRAME_ZONES 1022
-#define PDE_MULTIBOOT   1023
+#define PDE_MULTIBOOT   1020
+
+#define GET_PTE(pd_index, pt_index)                                            \
+	((uint32_t *)(VIRT_PT_BASE + ((uint32_t)pd_index) * 4096 +             \
+	              ((uint32_t)pt_index) * 4))
 
 #define PTE2VA(pd_index, pt_index)                                             \
-	((uint32_t *)((((uint32_t)pd_index * 1024) + (uint32_t)pt_index) *     \
-	              4096))
+	((uint32_t *)((                                                        \
+	    ((((uint32_t)pd_index) * 1024) + ((uint32_t)pt_index)) * 4096)))
+
 static inline uint32_t *VA2PTE(uint32_t va)
 {
 	uint32_t pde = va >> 22;
@@ -64,10 +71,11 @@ extern multiboot_memory_map_t *mmap_addr;
 extern multiboot_uint32_t mmap_length;
 extern struct frame_zone *head;
 
-void init_memory(multiboot_info_t *mbd, uint32_t magic);
+void init_multiboot(multiboot_info_t *mbd, uint32_t magic);
+void init_memory(void);
 void *alloc_frame(void);
 int free_frame(void *frame_ptr);
 void *kalloc_pages(size_t nb_pages);
-void *valloc_pages(size_t size, void **phys_addr);
-int kfree_pages(void *page_ptr, size_t size);
-int vfree_pages(void *page_ptr, size_t size);
+void *ualloc_pages(size_t nb_pages);
+int kfree_pages(void *page_ptr, size_t nb_pages);
+int ufree_pages(void *page_ptr, size_t nb_pages);

headers/process.h

@@ -28,5 +28,5 @@ struct pcb {
 
 void switch_process(struct pcb *next_pcb);
 struct pcb *create_process(uid_t uid);
-// int8_t create_kernel_process(void);
 void remove_process(struct pcb *pcb);
+pid_t fork(void);

headers/thread.h

@@ -24,4 +24,4 @@ struct tcb {
 
 struct tcb *create_thread(struct pcb *process, void (*entry)(void));
 void delete_thread(struct tcb *thread);
-void switch_thread(uint32_t *esp);
+void switch_thread(struct tcb *thread_to_switch);

src/drivers/clock.c

@@ -40,7 +40,7 @@ static void clock_handler(struct registers *regs)
 {
 	scheduler_counter++;
 	sleep_counter--;
-	if (scheduler_counter % 100 == 0)
+	if (scheduler_counter % 30 == 0)
 		scheduler((uint32_t *)regs);
 }
 

src/kernel.c

@@ -33,9 +33,11 @@
 
 static void uwu(void)
 {
+	pid_t pid = fork();
+	kprintf("pid: %d\n", pid);
 	while (1) {
 		// sleep(1000);
-		kprintf("uwu\n");
+		// kprintf("%d\n", current_pcb->pid);
 	}
 }
 
@@ -50,13 +52,13 @@ void kernel_main(multiboot_info_t *mbd, uint32_t magic)
 	cli();
 	init_gdt();
 	init_idt();
-	init_memory(mbd, magic);
+	init_multiboot(mbd, magic);
+	init_memory();
 	load_drivers();
 	terminal_initialize();
 	create_process(1);
-	create_thread(current_pcb, shell_init);
-	create_process(2);
-	create_thread(current_pcb->next, uwu);
+	// create_thread(current_pcb, shell_init);
+	create_thread(current_pcb, uwu);
 	toris();
 	while (true)
 		;

src/kpanic.c

@@ -27,10 +27,13 @@ __attribute__((noreturn)) void kpanic(const char *format, ...)
 	kprintf("fault at address: %p\n", faulting_address);
 	// for (int i = 16; i < 32; i++)
 	// 	kprintf("%p\n", page_table1[i]);
-	// show_valloc_mem();
+	// show_ualloc_mem();
 	/* kprintf("\n\n"); */
 	/* print_stack(); */
 	/* kprintf("\n\n"); */
-	/* kprintf("PRESS SPACE TO REBOOT"); */
-	__asm__ __volatile__("jmp panic");
+	kprintf("PRESS SPACE TO REBOOT");
+	while (terminal_getkey().c != ' ')
+		;
+	reboot();
+	// __asm__ __volatile__("jmp panic");
 }

src/memory/kern/allocator.c

@@ -3,6 +3,7 @@
 #include "kprintf.h"
 #include "memory.h"
 #include "string.h"
+#include "utils.h"
 
 Zone *kzones[3];
 
@@ -49,7 +50,7 @@ static void new_block(Zone *zone, uint32_t zone_size)
 int new_kzone(block_type_t type, uint32_t size)
 {
 	// assert(current_task->pid);
-	void *heap = kalloc_pages(size);
+	void *heap = kalloc_pages(CEIL(size, PAGE_SIZE));
 	if (heap == NULL) {
 		kprintf(KERN_ERR "error: alloc_frame failed\n");
 		return (-1);

src/memory/kern/page.c

@@ -12,14 +12,15 @@
 static uint32_t *find_next_block(size_t nb_pages)
 {
 	uint32_t count = 0;
-	for (uint32_t *pte = PTE2VA(1023, 0); pte < PTE2VA(1023, 1023); pte++) {
-		if (!*pte) {
+	for (uint32_t *pte = PTE2VA(1023, KERNEL_PT_START);
+	     pte < PTE2VA(1023, KERNEL_PT_END); pte++) {
+		if (*pte) {
 			count = 0;
 			continue;
 		}
 		count++;
 		if (count == nb_pages)
-			return pte - count;
+			return pte - (count - 1);
 	}
 	return NULL;
 }
@@ -27,6 +28,8 @@ static uint32_t *find_next_block(size_t nb_pages)
 void *kalloc_pages(size_t nb_pages)
 {
 	uint32_t *start = find_next_block(nb_pages);
+	if (!start)
+		return NULL;
 	for (uint32_t i = 0; i < nb_pages; i++) {
 		void *frame = alloc_frame();
 		if (!frame) {
@@ -35,7 +38,7 @@ void *kalloc_pages(size_t nb_pages)
 				                    PAGE_MASK));
 			return NULL;
 		}
-		assert(!((uint32_t)frame & PAGE_MASK));
+		assert((uint32_t)frame & PAGE_MASK);
 		start[i] = (uint32_t)frame | INIT_FLAGS;
 	}
 	uint32_t page_index = start - PTE2VA(1023, 0);

src/memory/memory.c

@@ -21,7 +21,6 @@ static void lst_add_back(struct frame_zone **root, struct frame_zone *element)
 	it->next = element;
 }
 
-
 static void add_frame_node(multiboot_memory_map_t *mmmt)
 {
 	static uint32_t index = 0;
@@ -64,33 +63,40 @@ static void add_frame_node(multiboot_memory_map_t *mmmt)
 	    ((uint32_t)frame_zones_page_table - VIRT_OFFSET) | INIT_FLAGS;
 
 	/** We need to determine how many frames are available
-		to save how many frame the blocks contain etc we need some meta data
-		1 struct frame_zone and a frame_table, the size of the frame_table is 1 bit per frame
-		the frame_table is a uint8_t so 8 bit, so its size must be CEIL(max_frames, 8)
-		But we don't have max_frames.
-		We can determine max_frame = (block_len - sizeof(struct frame_zone)) / (PAGE_SIZE + 1 / 8) (1 / 8 because size is in byte but we only need one bit)
-		Because we don't use float we can't have 1 / 8
-		So we will multiplicate every members of this equation by 8 to have only complet number
-		So... max_frame = (block_len - sizeof(struct frame_zone)) * 8 / (PAGE_SIZE * 8 + 1)
+	        to save how many frame the blocks contain etc we need some meta
+	   data 1 struct frame_zone and a frame_table, the size of the
+	   frame_table is 1 bit per frame the frame_table is a uint8_t so 8 bit,
+	   so its size must be CEIL(max_frames, 8) But we don't have max_frames.
+	        We can determine max_frame = (block_len - sizeof(struct
+	   frame_zone)) / (PAGE_SIZE + 1 / 8) (1 / 8 because size is in byte but
+	   we only need one bit) Because we don't use float we can't have 1 / 8
+	        So we will multiplicate every members of this equation by 8 to
+	   have only complet number So... max_frame = (block_len - sizeof(struct
+	   frame_zone)) * 8 / (PAGE_SIZE * 8 + 1)
 	*/
-	const uint32_t nb_frame =  (len - sizeof(struct frame_zone)) * 8 / (PAGE_SIZE * 8 + 1);
+	const uint32_t nb_frame =
+	    (len - sizeof(struct frame_zone)) * 8 / (PAGE_SIZE * 8 + 1);
 
 	const uint32_t frame_table_size = CEIL(nb_frame, (sizeof(uint8_t) * 8));
-	uint32_t page_needed = CEIL(frame_table_size + sizeof(struct frame_zone), PAGE_SIZE);
+	uint32_t page_needed =
+	    CEIL(frame_table_size + sizeof(struct frame_zone), PAGE_SIZE);
 	uint32_t i = 0;
 	for (; i < page_needed; i++)
-		frame_zones_page_table[index + i] = (((uint32_t)start_addr + i * PAGE_SIZE) & PAGE_MASK) | INIT_FLAGS;
+		frame_zones_page_table[index + i] =
+		    (((uint32_t)start_addr + i * PAGE_SIZE) & PAGE_MASK) |
+		    INIT_FLAGS;
 
 	struct frame_zone *current =
 	    (struct frame_zone *)PTE2VA(PDE_FRAME_ZONES, index);
 
-	current->frame_table = (uint8_t*) ((uint32_t) current + sizeof(struct frame_zone));
+	current->frame_table =
+	    (uint8_t *)((uint32_t)current + sizeof(struct frame_zone));
 
 	current->first_free_frame = 0;
 	current->next = NULL;
 	current->remaining_frames = nb_frame;
 	current->total_frames = nb_frame;
-	current->addr = (void*)(uint32_t)start_addr + page_needed * PAGE_SIZE;
+	current->addr = (void *)(uint32_t)start_addr + page_needed * PAGE_SIZE;
 
 	bzero(current->frame_table, frame_table_size);
 
@@ -98,15 +104,12 @@ static void add_frame_node(multiboot_memory_map_t *mmmt)
 	lst_add_back(&head, current);
 }
 
-
 static void init_frame_zones(void)
 {
-    for(uint32_t i = 0; i < mmap_length; 
-        i += sizeof(multiboot_memory_map_t)) 
-    {
-        multiboot_memory_map_t* mmmt = 
-            (multiboot_memory_map_t*) ((uint32_t)mmap_addr + i);
-
+	for (uint32_t i = 0; i < mmap_length;
+	     i += sizeof(multiboot_memory_map_t)) {
+		multiboot_memory_map_t *mmmt =
+		    (multiboot_memory_map_t *)((uint32_t)mmap_addr + i);
 		if (mmmt->type == MULTIBOOT_MEMORY_AVAILABLE)
 			add_frame_node(mmmt);
 	}
@@ -120,7 +123,8 @@ void init_memory()
 		uint32_t frame = (uint32_t)alloc_frame();
 		if (!frame)
 			kpanic("Couldn't initialize kernel PTs\n");
-		PD[i] = frame | RW;
+		PD[i] = frame | INIT_FLAGS;
+		bzero(PTE2VA(1023, i), PAGE_SIZE);
 	}
 	// kalash kalash kalash sur la mélodie chez nous pas de félonie ça vient
 	// de Sevran les R

src/memory/user/allocator.c

@@ -4,6 +4,7 @@
 #include "kprintf.h"
 #include "memory.h"
 #include "string.h"
+#include "utils.h"
 
 Zone *vzones[3];
 
@@ -50,7 +51,7 @@ static void new_block(Zone *zone, uint32_t zone_size)
 int new_vzone(block_type_t type, uint32_t size)
 {
 	// assert(current_task->pid);
-	void *heap = valloc_pages(size, NULL);
+	void *heap = ualloc_pages(CEIL(size, PAGE_SIZE));
 	if (heap == NULL) {
 		kprintf(KERN_ERR "error: alloc_pages failed\n");
 		return (-1);

src/memory/user/info.c

@@ -5,7 +5,7 @@
 // FULL_INFO is to display (or not) both used and unused blocks
 #define FULL_INFO 1
 
-void show_valloc_mem(void)
+void show_ualloc_mem(void)
 {
 	char *const zones_name[3] = {"TINY", "SMALL", "LARGE"};
 	uint32_t total_size = 0;

src/memory/user/page.c

@@ -0,0 +1,77 @@
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "assert.h"
+#include "kprintf.h"
+#include "memory.h"
+#include "process.h"
+#include "string.h"
+#include "utils.h"
+
+static int8_t alloc_pagetable(uint16_t pd_index)
+{
+	uint32_t *pt = alloc_frame();
+	if (!pt)
+		return -1;
+	PD[pd_index] = (uint32_t)pt | INIT_FLAGS;
+	bzero(PTE2VA(1023, pd_index), PAGE_SIZE);
+	return 0;
+}
+
+static uint32_t *find_next_block(size_t nb_pages)
+{
+	size_t count = 0;
+	for (size_t i = USER_PT_START; i < USER_PT_END; i++) {
+		if (!PD[i])
+			if (alloc_pagetable(i) < 0)
+				return NULL;
+		for (size_t j = 0; j < 1024; j++) {
+			if (*GET_PTE(i, j)) {
+				count = 0;
+				continue;
+			}
+			count++;
+			if (count == nb_pages) {
+				return GET_PTE(i, j) - (count - 1);
+			}
+		}
+	}
+	return NULL;
+}
+
+void *ualloc_pages(size_t nb_pages)
+{
+	uint32_t *start = find_next_block(nb_pages);
+	if (!start)
+		return NULL;
+	for (uint32_t i = 0; i < nb_pages; i++) {
+		void *frame = alloc_frame();
+		if (!frame) {
+			for (uint32_t j = 0; j < i; j++)
+				free_frame((void *)(((uint32_t)(start + j)) &
+				                    PAGE_MASK));
+			return NULL;
+		}
+		assert((uint32_t)frame & PAGE_MASK);
+		start[i] = (uint32_t)frame | INIT_FLAGS;
+	}
+	uint32_t page_index = start - PTE2VA(1023, 0);
+	return PTE2VA(page_index / 1024, page_index % 1024);
+}
+
+int ufree_pages(void *page_ptr, size_t nb_pages)
+{
+	const uint32_t page_addr = (uint32_t)page_ptr;
+	if (page_addr % PAGE_SIZE) {
+		kprintf(KERN_WARNING "Invalid address\n");
+		return -1;
+	}
+
+	for (uint32_t *pte = VA2PTE(page_addr);
+	     pte < VA2PTE(page_addr) + nb_pages; pte++) {
+		free_frame((void *)(*pte & PAGE_MASK));
+		*pte = 0;
+	}
+	return 0;
+}

src/memory/user/vfree.c

@@ -47,7 +47,7 @@ static int unmap_zone(Zone *zone)
 	if (right)
 		right->prev = left;
 unmap:
-	err = vfree_pages((void *)zone, zone->size);
+	err = ufree_pages((void *)zone, zone->size);
 	if (err)
 		kprintf(KERN_ERR "error: munmap failed\n");
 	return (err);
@@ -94,7 +94,7 @@ static int add_available(Block *available, Block *merged)
  * newly merged block
  * Finally, we add the block to the list of available blocks
  */
-void vfree(void *ptr)
+void ufree(void *ptr)
 {
 	if (ptr == NULL)
 		return;

src/memory/user/vmalloc.c

@@ -33,7 +33,7 @@ static Block *find_block(Zone *head, uint32_t size)
  * After the allocation, this will become
  * ... -> [5] -> [new] -> [6] -> ...
  *
- * For an example of [5].size = 32 and requiring a vmalloc of 10
+ * For an example of [5].size = 32 and requiring a umalloc of 10
  * Let's say the metadata takes a size of 2:
  * ... -> [metadata][data][remaining size] -> [6]
  *            ^        ^         ^
@@ -126,12 +126,12 @@ static void save_block(Zone *head, Block *block, Zone *zone)
  *
  * ptr: returns the aligned pointer of the block (after the metadata)
  */
-void *vmalloc(uint32_t size)
+void *umalloc(uint32_t size)
 {
 	void *ptr = NULL;
 
 	if (size == 0) {
-		kprintf(KERN_WARNING "vmalloc: can't vmalloc(0)\n");
+		kprintf(KERN_WARNING "umalloc: can't umalloc(0)\n");
 		return NULL;
 	}
 

src/memory/user/vrealloc.c

@@ -2,9 +2,9 @@
 #include "string.h"
 #include <stdint.h>
 
-// Prototype for kfree and vmalloc
+// Prototype for kfree and umalloc
 void kfree(void *ptr);
-void *vmalloc(uint32_t size);
+void *umalloc(uint32_t size);
 
 /*
  * ptr: block to resize (undefined behavior if invalid)
@@ -28,10 +28,10 @@ void *vrealloc(void *ptr, uint32_t size)
 		block->sub_size = size;
 		return (ptr);
 	}
-	new_ptr = vmalloc(size);
+	new_ptr = umalloc(size);
 	if (new_ptr == NULL)
 		return NULL;
 	memmove(new_ptr, ptr, block->size);
-	vfree(ptr);
+	ufree(ptr);
 	return (new_ptr);
 }

src/memory/virt/page.c

@@ -1,90 +0,0 @@
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdint.h>
-
-#include "assert.h"
-#include "kprintf.h"
-#include "memory.h"
-#include "process.h"
-#include "string.h"
-#include "utils.h"
-
-static int16_t find_next_block(size_t nb_pages, uint16_t *pd_index_ptr,
-                               uint32_t **page_table_ptr)
-{
-	for (*pd_index_ptr = 2; *pd_index_ptr < 768; (*pd_index_ptr)++) {
-		// if (current_pd[(*pd_index_ptr)] == 0x02) {
-		// if (add_page_table(*pd_index_ptr, 1) < 0)
-		// 	return -2;
-		// }
-		*page_table_ptr = (uint32_t *)PTE2VA(1, *pd_index_ptr);
-		for (uint16_t i = 0; i + nb_pages - 1 < 1024; i++) {
-			uint16_t j;
-			for (j = 0; (*page_table_ptr)[i + j] >> 12 == i + j &&
-			            j < nb_pages;
-			     j++)
-				;
-			if (j == nb_pages)
-				return i;
-			i += j;
-		}
-	}
-	return -1;
-}
-
-void *valloc_pages(size_t size, void **phys_addr)
-{
-	const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
-	uint16_t pd_index;
-	uint32_t *page_table;
-	const int16_t index = find_next_block(nb_pages, &pd_index, &page_table);
-
-	if (index < 0) {
-		kprintf(KERN_CRIT "%d: Not enough pages (max: %d)\n", index,
-		        1024);
-		return NULL;
-	}
-	for (size_t i = index; i - (size_t)index < nb_pages; i++) {
-		void *frame = alloc_frame();
-		if (!frame) {
-			for (size_t j = index; j < i; j++)
-				free_frame((void *)(page_table[j] & PAGE_MASK));
-			return NULL;
-		}
-		if (phys_addr)
-			*phys_addr = frame;
-		page_table[i] = ((uint32_t)frame & PAGE_MASK) | INIT_FLAGS;
-	}
-	return (void *)PTE2VA(pd_index, index);
-}
-
-int vfree_pages(void *page_ptr, size_t size)
-{
-	const uint32_t page_addr = (uint32_t)page_ptr;
-	const uint32_t nb_pages = CEIL(size, PAGE_SIZE);
-	const uint32_t page_index = page_addr / PAGE_SIZE;
-	const uint32_t pd_index = page_index / 1024;
-	const uint32_t pt_index = page_index % 1024;
-
-	if ((uint32_t)pd_index > 0x300) {
-		kprintf(KERN_WARNING "Address out of range\n");
-		return -1;
-	} else if (page_addr % PAGE_SIZE) {
-		kprintf(KERN_WARNING "Invalid address\n");
-		return -1;
-	} else if (pt_index + nb_pages > 1024) {
-		kprintf(KERN_WARNING "Invalid number of frames\n");
-		return -1;
-	}
-	uint32_t *page_table = (uint32_t *)PTE2VA(1, pd_index);
-	for (uint16_t i = pt_index; i < pt_index + nb_pages; i++) {
-		if (page_table[i] >> 12 == i) {
-			kprintf(KERN_WARNING "Page already freed\n");
-			return -2;
-		}
-		free_frame((void *)(page_table[i] & PAGE_MASK));
-		page_table[i] = i << 12;
-	}
-
-	return 0;
-}

src/multiboot.c

@@ -16,15 +16,15 @@ static void init_mmap(multiboot_info_t *mbd_virt, size_t *pt_index)
 {
 	// Index mbd->mmap_addr pointers
 	uint32_t i = 0;
-	for (; i < mbd_virt->mmap_length; i++)
+	for (; i < CEIL(mbd_virt->mmap_length, PAGE_SIZE); i++)
 		multiboot_page_table[i + *pt_index] =
 		    ((mbd_virt->mmap_addr + i * PAGE_SIZE) & PAGE_MASK) |
 		    INIT_FLAGS;
 	mmap_addr =
-	    (multiboot_memory_map_t *)(PTE2VA(PDE_MULTIBOOT, *pt_index) +
-	                               (uint32_t)mbd_virt->mmap_addr %
-	                                   PAGE_SIZE);
-	mmap_length = mbd_virt->mmap_length / sizeof(multiboot_memory_map_t);
+	    (multiboot_memory_map_t *)((uint32_t)PTE2VA(PDE_MULTIBOOT, *pt_index) +
+	                               (mbd_virt->mmap_addr %
+	                                   PAGE_SIZE));
+	mmap_length = mbd_virt->mmap_length;
 	*pt_index += i;
 }
 
@@ -52,8 +52,7 @@ void init_multiboot(multiboot_info_t *mbd, uint32_t magic)
 	if (magic != MULTIBOOT_BOOTLOADER_MAGIC)
 		kpanic("invalid magic number! (git gud skill issue)");
 
-	uint32_t *pd = &boot_page_directory;
-	pd[PDE_MULTIBOOT] =
+	PD[PDE_MULTIBOOT] =
 	    ((uint32_t)multiboot_page_table - VIRT_OFFSET) | INIT_FLAGS;
 	size_t pt_index = CEIL(
 	    (uint32_t)mbd % PAGE_SIZE + sizeof(multiboot_info_t), PAGE_SIZE);

src/multitasking/fork.c

@@ -4,19 +4,85 @@
 #include "string.h"
 #include "thread.h"
 
-static struct tcb *thread_clone(struct tcb *thread)
+static void free_pts(void)
 {
-	struct tcb *new_tcb = vmalloc(sizeof(struct tcb));
-	if (!new_tcb)
-		return NULL;
-	new_tcb->tid = thread->tid;
-	new_tcb->esp0 = kalloc_pages(STACK_SIZE);
-	if (!new_tcb->esp0) {
-		delete_thread(new_tcb);
-		return NULL;
+	for (size_t i = USER_PT_END / 2; PD[i]; i++) {
+		uint32_t *pt = PTE2VA(1023, i);
+		for (size_t j = 0; j < 1024; j++)
+			if (pt[j])
+				ufree_pages(PTE2VA(i, j), 1);
+		ufree_pages(pt, 1);
 	}
-	memcpy(new_tcb->esp0, thread->esp0, STACK_SIZE);
-	return new_tcb;
+}
+
+static int copy_pt(uint32_t *pt_src, uint32_t *pt_dest, size_t pd_index)
+{
+	for (size_t i = 0; i < 1024; i++) {
+		if (pt_src[i]) {
+			pt_dest[i] = (uint32_t)alloc_frame() | INIT_FLAGS;
+			if (pt_dest[i] == INIT_FLAGS) {
+				for (size_t j = 0; j < i; j++)
+					free_frame(
+					    (void *)(pt_dest[j] & PAGE_MASK));
+				return -1;
+			}
+			void *src_page = PTE2VA(pd_index, i);
+			void *dest_page = PTE2VA(pd_index + USER_PT_END / 2, i);
+			memcpy(dest_page, src_page, PAGE_SIZE);
+		}
+	}
+	return 0;
+}
+
+static int copy_thread_list(struct pcb *new_pcb)
+{
+	struct list *e;
+	struct list *prev = NULL;
+	for (struct list *it = current_pcb->thread_list; it; it = it->next) {
+		e = kmalloc(sizeof(struct list));
+		if (!e)
+			return -1;
+		if (prev)
+			prev->next = e;
+		else
+			new_pcb->thread_list = e;
+		struct tcb *new_content = kmalloc(sizeof(struct tcb));
+		if (!new_content) {
+			kfree(e);
+			return -1;
+		}
+		memcpy(new_content, it->content, sizeof(struct tcb));
+		new_content->process = new_pcb;
+		e->next = NULL;
+		e->content = new_content;
+		prev = e;
+	}
+	return 0;
+}
+
+static int deep_copy(struct pcb *new_pcb)
+{
+	if (PD[USER_PT_END / 2])
+		return -2;
+	size_t i;
+	for (i = USER_PT_START; PD[i]; i++) {
+		void *new_pt = alloc_frame();
+		if (!new_pt) {
+			free_pts();
+			return -1;
+		}
+		PD[i + USER_PT_END / 2] = (uint32_t)new_pt | INIT_FLAGS;
+		if (copy_pt(PTE2VA(1023, i), PTE2VA(1023, i + USER_PT_END / 2),
+		            i) < 0) {
+			free_pts();
+			return -1;
+		}
+		new_pcb->heap[i] = (uint32_t)new_pt | INIT_FLAGS;
+	}
+	bzero(PD + USER_PT_END / 2, i * sizeof(uint32_t));
+	if (copy_thread_list(new_pcb) < 0)
+		return -1;
+	return 0;
 }
 
 pid_t fork(void)
@@ -24,15 +90,18 @@ pid_t fork(void)
 	struct pcb *new_pcb = create_process(current_pcb->uid);
 	if (!new_pcb)
 		return -1;
-	struct list *new_node = vmalloc(sizeof(struct list));
+	struct list *new_node = kmalloc(sizeof(struct list));
 	if (!new_node) {
 		remove_process(new_pcb);
 		return -1;
 	}
 	new_pcb->daddy = current_pcb;
-	lst_add_back(&new_pcb->children, new_node);
-	// loop on threads clone
-	thread_clone(current_pcb->thread_list->content);
+	lst_add_back(&current_pcb->children, new_node);
 
-	return new_pcb->pid;
+	if (deep_copy(new_pcb) < 0) {
+		remove_process(new_pcb);
+		return -1;
+	}
+
+	return current_pcb == new_pcb ? 0 : new_pcb->pid;
 }

src/multitasking/process.c

@@ -5,6 +5,7 @@
 #include "thread.h"
 
 #include "string.h"
+#include <stdint.h>
 
 struct pcb *create_process(uid_t uid)
 {
@@ -22,8 +23,10 @@ struct pcb *create_process(uid_t uid)
 		return NULL;
 	}
 	new_pcb->cr3 =
-	    (void *)((uint32_t)VA2PTE((uint32_t)new_pcb->heap) & PAGE_MASK);
-	memcpy(new_pcb->heap, PD, 4096);
+	    (void *)((uint32_t)*VA2PTE((uint32_t)new_pcb->heap) & PAGE_MASK);
+	memcpy(new_pcb->heap, PD,
+	       4096); // TODO optimize to copy only used bytes
+	new_pcb->heap[1023] = (uint32_t)new_pcb->cr3 | INIT_FLAGS;
 
 	new_pcb->daddy = NULL;
 	new_pcb->children = NULL;

src/multitasking/scheduler.c

@@ -20,7 +20,8 @@ static struct list *get_thread_to_switch(void)
 	it_t = current_tcb == NULL ? NULL : current_tcb->next;
 	while (it_p) {
 		while (it_t != NULL) {
-			if (it_t != NULL && CURRENT_TCB->state != WAITING)
+			if (it_t != NULL &&
+			    ((struct tcb *)it_t->content)->state != WAITING)
 				return it_t;
 			it_t = it_t->next;
 		}
@@ -38,8 +39,6 @@ void scheduler(uint32_t *esp)
 	struct tcb *thread_to_switch = (struct tcb *)list_node->content;
 	if (current_tcb)
 		CURRENT_TCB->esp = esp;
-	if (thread_to_switch->process != current_pcb)
-		switch_process(thread_to_switch->process);
 	current_tcb = list_node;
-	switch_thread(thread_to_switch->esp);
+	switch_thread(thread_to_switch);
 }

src/multitasking/switch_process.s

@@ -1,16 +0,0 @@
-.intel_syntax noprefix
-.extern current_pcb
-
-.section .text
-	.global switch_process
-
-switch_process:
-	// change current_pcb global
-	mov eax, [esp + 4]
-	mov [current_pcb], eax
-	
-	// reload cr3 with the new heap
-	mov edx, [eax + 0]
-	mov cr3, edx
-
-	ret

src/multitasking/switch_to_thread.s

@@ -7,8 +7,20 @@
 switch_thread:
 	
 	mov eax, [esp + 4]
-	mov esp, eax	
+	mov esp, [eax]
 
+	mov edx, [eax + 16]
+	cmp [current_pcb], edx
+	je LABEL1
+	
+	// change current_pcb
+	mov [current_pcb], edx
+	
+	// reload cr3 with the new heap
+	mov edx, [edx]
+	mov cr3, edx
+
+LABEL1:
 	pop eax
 	mov ds, eax
 

src/multitasking/thread.c

@@ -7,6 +7,7 @@
 #include "process.h"
 #include "string.h"
 #include "thread.h"
+#include "utils.h"
 
 struct tcb *create_thread(struct pcb *process, void (*entry)(void))
 {
@@ -15,11 +16,15 @@ struct tcb *create_thread(struct pcb *process, void (*entry)(void))
 		return NULL;
 	new_tcb->tid = process->tid++;
 
-	new_tcb->esp0 = valloc_pages(STACK_SIZE, NULL);
+	memcpy(PD, process->heap,
+	       (USER_PT_END - USER_PT_START) * sizeof(uint32_t));
+	new_tcb->esp0 = ualloc_pages(CEIL(STACK_SIZE, PAGE_SIZE));
 	if (!new_tcb->esp0) {
-		vfree(new_tcb);
+		ufree(new_tcb);
 		return NULL;
 	}
+	memcpy(process->heap, PD,
+	       (USER_PT_END - USER_PT_START) * sizeof(uint32_t));
 	uint32_t *stack = (uint32_t *)((uint8_t *)new_tcb->esp0 + STACK_SIZE);
 	uint32_t *esp = stack;
 
@@ -49,7 +54,7 @@ struct tcb *create_thread(struct pcb *process, void (*entry)(void))
 	struct list *new_node = kmalloc(sizeof(struct list));
 	if (!new_node) {
 		kfree_pages(new_tcb->esp0, STACK_SIZE);
-		vfree(new_tcb);
+		ufree(new_tcb);
 		return NULL;
 	}
 	new_node->content = new_tcb;

src/shell/commands/heap_cmd.c

@@ -5,5 +5,5 @@
 void heap_cmd(char *arg)
 {
 	(void)arg;
-	show_valloc_mem();
+	show_ualloc_mem();
 }