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wip: multiple pds and switch to kernel pd when needed

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0x35c 2025-02-10 13:25:19 +01:00
parent 8dd5373e7f
commit 5e561bfa15
9 changed files with 41 additions and 27 deletions
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4
headers/memory.h
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@ -46,7 +46,8 @@ extern uint32_t _kernel_end;
extern uint32_t _kernel_start; extern uint32_t _kernel_start;
extern uint32_t boot_page_directory; extern uint32_t boot_page_directory;
extern uint32_t boot_page_table1; extern uint32_t boot_page_table1;
extern uint32_t *page_directory; extern uint32_t *kernel_pd;
extern uint32_t *current_pd;
extern uint32_t page_table_default[1024]; extern uint32_t page_table_default[1024];
extern uint32_t mem_size; extern uint32_t mem_size;
extern multiboot_memory_map_t *mmap_addr; extern multiboot_memory_map_t *mmap_addr;
@ -62,3 +63,4 @@ void *alloc_pages(size_t size, void **phys_addr);
int free_pages(void *page_ptr, size_t size); int free_pages(void *page_ptr, size_t size);
void init_page_table(uint32_t page_table[1024], uint16_t start); void init_page_table(uint32_t page_table[1024], uint16_t start);
int16_t add_page_table(uint16_t pd_index); int16_t add_page_table(uint16_t pd_index);
void switch_pd(uint32_t *pd, uint32_t *cr3);

2
src/kernel.c
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@ -66,7 +66,7 @@ void kernel_main(multiboot_info_t *mbd, uint32_t magic)
*/ */
/* "Martin 03:50, 22 March 2009 (UTC)\n"); */ /* "Martin 03:50, 22 March 2009 (UTC)\n"); */
create_kernel_task(); create_kernel_task();
exec_fn(uwu); exec_fn(owo);
/* exec_fn(owo); */ /* exec_fn(owo); */
/* exec_fn(owo); */ /* exec_fn(owo); */
/* exec_fn(owo); */ /* exec_fn(owo); */

16
src/memory/memory.c
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@ -4,12 +4,19 @@
#include <stdint.h> #include <stdint.h>
uint32_t *page_directory = &boot_page_directory; uint32_t *kernel_pd = &boot_page_directory;
uint32_t *current_pd;
uint32_t page_table_default[1024] __attribute__((aligned(PAGE_SIZE))); uint32_t page_table_default[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t frame_zones_page_table[1024] __attribute__((aligned(PAGE_SIZE))); uint32_t frame_zones_page_table[1024] __attribute__((aligned(PAGE_SIZE)));
uint32_t mem_size; uint32_t mem_size;
struct frame_zone *head; struct frame_zone *head;
void switch_pd(uint32_t *pd, uint32_t *cr3)
{
current_pd = pd;
asm volatile("mov %0, %%cr3" ::"r"(cr3));
}
static void lst_add_back(struct frame_zone **root, struct frame_zone *element) static void lst_add_back(struct frame_zone **root, struct frame_zone *element)
{ {
if (!*root) { if (!*root) {
@ -61,7 +68,7 @@ static void add_frame_node(multiboot_memory_map_t *mmmt)
end_addr = ROUND_CEIL(start_addr + len, PAGE_SIZE); end_addr = ROUND_CEIL(start_addr + len, PAGE_SIZE);
init_page_table(frame_zones_page_table, 0); init_page_table(frame_zones_page_table, 0);
page_directory[1022] = ((uint32_t)frame_zones_page_table - HEAP_END) | 0x03; kernel_pd[1022] = ((uint32_t)frame_zones_page_table - HEAP_END) | 0x03;
frame_zones_page_table[index] = frame_zones_page_table[index] =
((uint32_t)start_addr & PAGE_MASK) | INIT_FLAGS; ((uint32_t)start_addr & PAGE_MASK) | INIT_FLAGS;
@ -107,9 +114,10 @@ static void init_frame_zones(void)
void init_memory(multiboot_info_t *mbd, uint32_t magic) void init_memory(multiboot_info_t *mbd, uint32_t magic)
{ {
for (uint16_t i = 0; i < 0x300; i++) for (uint16_t i = 0; i < 0x300; i++)
page_directory[i] = 0x02; kernel_pd[i] = 0x02;
init_page_table(page_table_default, 0); init_page_table(page_table_default, 0);
page_directory[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03; kernel_pd[0] = ((uint32_t)page_table_default - HEAP_END) | 0x03;
current_pd = kernel_pd;
init_multiboot(mbd, magic); init_multiboot(mbd, magic);
init_frame_zones(); init_frame_zones();
} }

7
src/memory/page.c
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@ -10,10 +10,10 @@
#include "utils.h" #include "utils.h"
static int16_t find_next_block(size_t nb_pages, uint16_t *pd_index_ptr, static int16_t find_next_block(size_t nb_pages, uint16_t *pd_index_ptr,
uint32_t **page_table_ptr) uint32_t **page_table_ptr)
{ {
for (*pd_index_ptr = 1; *pd_index_ptr < 768; (*pd_index_ptr)++) { for (*pd_index_ptr = 1; *pd_index_ptr < 768; (*pd_index_ptr)++) {
if (current_task->heap[(*pd_index_ptr)] == 0x02) { if (current_pd[(*pd_index_ptr)] == 0x02) {
if (add_page_table(*pd_index_ptr) < 0) if (add_page_table(*pd_index_ptr) < 0)
return -2; return -2;
} }
@ -92,7 +92,8 @@ int free_pages(void *page_ptr, size_t size)
kprintf(KERN_WARNING "Invalid number of frames\n"); kprintf(KERN_WARNING "Invalid number of frames\n");
return -1; return -1;
} }
uint32_t *page_table = (uint32_t *)GET_PAGE_ADDR(0, PT_START + pd_index); uint32_t *page_table =
(uint32_t *)GET_PAGE_ADDR(0, PT_START + pd_index);
for (uint16_t i = pt_index; i < pt_index + nb_pages; i++) { for (uint16_t i = pt_index; i < pt_index + nb_pages; i++) {
if (page_table[i] >> 12 == i) { if (page_table[i] >> 12 == i) {
kprintf(KERN_WARNING "Page already free\n"); kprintf(KERN_WARNING "Page already free\n");

2
src/memory/page_table.c
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@ -17,6 +17,6 @@ int16_t add_page_table(uint16_t pd_index)
uint32_t *page_table = uint32_t *page_table =
(uint32_t *)GET_PAGE_ADDR(0, PT_START + pd_index); (uint32_t *)GET_PAGE_ADDR(0, PT_START + pd_index);
init_page_table(page_table, 0); init_page_table(page_table, 0);
page_directory[pd_index] = ((uint32_t)frame & PAGE_MASK) | 0x03; kernel_pd[pd_index] = ((uint32_t)frame & PAGE_MASK) | 0x03;
return 0; return 0;
} }

5
src/multiboot.c
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@ -38,7 +38,7 @@ static void init_vbe(multiboot_info_t *mbd_virt)
((mbd_virt->framebuffer_addr + i * PAGE_SIZE) & PAGE_MASK) | ((mbd_virt->framebuffer_addr + i * PAGE_SIZE) & PAGE_MASK) |
INIT_FLAGS; INIT_FLAGS;
} }
page_directory[800] = ((uint32_t)vbe_page_table - HEAP_END) | 0x03; kernel_pd[800] = ((uint32_t)vbe_page_table - HEAP_END) | 0x03;
display.buff = (uint32_t *)GET_PAGE_ADDR(800, 0) + display.buff = (uint32_t *)GET_PAGE_ADDR(800, 0) +
(mbd_virt->framebuffer_addr % PAGE_SIZE); (mbd_virt->framebuffer_addr % PAGE_SIZE);
display.height = mbd_virt->framebuffer_height; display.height = mbd_virt->framebuffer_height;
@ -53,8 +53,7 @@ void init_multiboot(multiboot_info_t *mbd, uint32_t magic)
kpanic("invalid magic number! (git good skill issue)"); kpanic("invalid magic number! (git good skill issue)");
init_page_table(multiboot_page_table, 0); init_page_table(multiboot_page_table, 0);
page_directory[1023] = kernel_pd[1023] = ((uint32_t)multiboot_page_table - HEAP_END) | 0x03;
((uint32_t)multiboot_page_table - HEAP_END) | 0x03;
size_t pt_index = CEIL( size_t pt_index = CEIL(
(uint32_t)mbd % PAGE_SIZE + sizeof(multiboot_info_t), PAGE_SIZE); (uint32_t)mbd % PAGE_SIZE + sizeof(multiboot_info_t), PAGE_SIZE);

3
src/multitasking/scheduler.c
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@ -19,8 +19,7 @@ void scheduler(void)
if (!current_task) // || current_task->next == current_task) if (!current_task) // || current_task->next == current_task)
return; return;
cli(); cli();
uint32_t *old_pd = current_task->heap; switch_pd(kernel_pd, (uint32_t *)((uint32_t)kernel_pd - HEAP_END));
current_task->heap = page_directory;
struct task *it = current_task->next; struct task *it = current_task->next;
while (it && it->status != RUN) { while (it && it->status != RUN) {
if (it != current_task && func[it->status]) { if (it != current_task && func[it->status]) {

5
src/multitasking/switch_to_task.s
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@ -23,6 +23,11 @@ switch_to_task:
mov esp, [eax+0] // get esp mov esp, [eax+0] // get esp
mov ecx, [eax+12] // get task's pd
mov [current_pd], ecx
mov ecx, [eax+8]
mov cr3, ecx
pop esi pop esi
pop edi pop edi
pop ebp pop ebp

24
src/multitasking/task.c
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@ -15,36 +15,36 @@ uint32_t esp_backup;
struct task *create_task(uint8_t uid) struct task *create_task(uint8_t uid)
{ {
static uint32_t pid = 1; static uint32_t pid = 1;
uint32_t *old_pd = current_task->heap; switch_pd(kernel_pd, (uint32_t *)((uint32_t)kernel_pd - HEAP_END));
current_task->heap = page_directory; // kernel pd
struct task *new_task = vmalloc(sizeof(struct task)); struct task *new_task = vmalloc(sizeof(struct task));
current_task->heap = old_pd; if (!new_task) {
if (!new_task) switch_pd(current_task->heap, current_task->cr3);
return NULL; return NULL;
}
switch_pd(current_task->heap, current_task->cr3);
new_task->status = RUN; new_task->status = RUN;
new_task->uid = uid; new_task->uid = uid;
new_task->esp = new_task->esp0 + STACK_SIZE; new_task->esp = new_task->esp0 + STACK_SIZE;
new_task->pid = pid++; new_task->pid = pid++;
// Allocate new pd // Allocate new pd
old_pd = current_task->heap; new_task->heap = alloc_pages(4096, (void **)&new_task->cr3);
current_task->heap = alloc_pages(4096, (void **)&new_task->cr3);
if (!new_task->heap) { if (!new_task->heap) {
current_task->heap = old_pd;
vfree(new_task); vfree(new_task);
return NULL; return NULL;
} }
new_task->heap = current_task->heap; new_task->heap[768] = ((uint32_t)boot_page_table1 - HEAP_END) | 0x03;
memcpy(new_task->heap, current_task->heap, 4096);
switch_pd(new_task->heap, new_task->cr3);
// Allocate new stack on the newly allocated pd // Allocate new stack on the newly allocated pd
new_task->esp0 = alloc_pages(STACK_SIZE, NULL); new_task->esp0 = alloc_pages(STACK_SIZE, NULL);
current_task->heap = old_pd; switch_pd(current_task->heap, current_task->cr3);
if (!new_task->esp0) { if (!new_task->esp0) {
vfree(new_task); vfree(new_task);
free_pages(new_task->heap, 4096); free_pages(new_task->heap, 4096);
return NULL; return NULL;
} }
new_task->heap[768] = ((uint32_t)boot_page_table1 - HEAP_END) | 0x03;
new_task->next = current_task->next; new_task->next = current_task->next;
new_task->prev = current_task; new_task->prev = current_task;
@ -60,8 +60,8 @@ int8_t create_kernel_task(void)
new_task->status = RUN; new_task->status = RUN;
new_task->uid = 0; new_task->uid = 0;
new_task->pid = 0; new_task->pid = 0;
new_task->heap = page_directory; new_task->heap = kernel_pd;
new_task->cr3 = page_directory - KERNEL_START; new_task->cr3 = (uint32_t *)((uint32_t)kernel_pd - HEAP_END);
new_task->prev = new_task; new_task->prev = new_task;
new_task->next = new_task; new_task->next = new_task;
current_task = new_task; current_task = new_task;