feat: realize paging, add page, frame allocator and change kfree, kmalloc, krealloc

Author: alexeev-prog

CHANGELOG.md

@@ -1,3 +1,9 @@
+commit ffe676bbcd462e3e7d7c8bd82ca1683361ba3bf6
+Author: Alexeev Bronislav <[email protected]>
+Date:   Sun Aug 24 04:06:51 2025 +0700
+
+    docs: add paging docs
+
 commit 14696be1af1db0eb9fd795677785047285ee7277
 Author: Alexeev Bronislav <[email protected]>
 Date:   Sun Aug 24 03:27:10 2025 +0700

Makefile

@@ -17,11 +17,12 @@ LDFLAGS = -Ttext 0x1000 --oformat binary
 
 KERNEL_ENTRY = $(BIN_DIR)/bootloader/kernel_entry.o
 INTERRUPT_OBJ = $(BIN_DIR)/kernel/cpu/interrupt.o
+PAGING_OBJ = $(BIN_DIR)/bootloader/paging.o
 
 C_SOURCES = $(shell find $(SRC_DIR) -name '*.c')
 C_OBJS = $(C_SOURCES:$(SRC_DIR)/%.c=$(BIN_DIR)/%.o)
 
-OBJS = $(KERNEL_ENTRY) $(INTERRUPT_OBJ) $(C_OBJS)
+OBJS = $(KERNEL_ENTRY) $(INTERRUPT_OBJ) $(PAGING_OBJ) $(C_OBJS)
 
 RED=\033[0;31m
 GREEN=\033[0;32m
@@ -77,7 +78,7 @@ debug: $(DISKIMG_DIR)/$(DISKIMG_NAME)
 	@qemu-system-i386 -fda $< -boot a -s -S
 
 clean:
-	@printf "$(RED)[RM]   Clean bin %-50s$(RESET)\n" "$(BIN_DIR)"
+	@printf "$(RED)[RM]   Clean $(BIN_DIR) and $(DISKIMG_DIR)$(RESET)\n"
 	@rm -rf $(BIN_DIR)/* $(DISKIMG_DIR)/*
 
 .PHONY: all diskimg run run_bin debug clean clean_all

src/bootloader/paging.asm

@@ -0,0 +1,14 @@
+[bits 32]
+[global load_page_dir]
+[global enable_paging]
+
+load_page_dir:
+    mov eax, [esp+4]  ; аргумент из стека
+    mov cr3, eax      ; и суем в CR3
+    ret
+
+enable_paging:
+    mov eax, cr0
+    or eax, 0x80000000
+    mov cr0, eax
+    ret

src/kernel/cpu/isr.c

@@ -5,6 +5,8 @@
 #include "../kklibc/stdlib.h"
 #include "timer.h"
 #include "../drivers/lowlevel_io.h"
+#include "../kklibc/stdio.h"
+#include "../kklibc/paging/paging.h"
 
 isr_t interrupt_handlers[256];
 
@@ -116,14 +118,47 @@ char *exception_messages[] = {
     "Reserved"
 };
 
+void page_fault_handler(registers_t r) {
+    u32 fault_addr;
+    asm volatile("mov %%cr2, %0" : "=r" (fault_addr));
+
+    int present = !(r.err_code & 0x1); // Bit 0: 0 if not present
+    int rw = r.err_code & 0x2;         // Bit 1: 1 if write
+    int us = r.err_code & 0x4;         // Bit 2: 1 if user mode
+    int reserved = r.err_code & 0x8;   // Bit 3: 1 if reserved bit overwritten
+
+    kprintf("Page fault at %x: %s %s in %s mode\n",
+            fault_addr,
+            present ? "protection fault" : "not present",
+            rw ? "write" : "read",
+            us ? "user" : "kernel");
+
+    debug_page_fault(fault_addr);
+
+    if (us) {
+        kprintf("Killing process.\n");
+        asm volatile("hlt");
+        return;
+    }
+
+    kprintf("Kernel page fault! Halting.\n");
+    for(;;);
+}
+
 void isr_handler(registers_t r) {
+    if (r.int_no == 14) {
+        page_fault_handler(r);
+    }
+
     kprint("received interrupt: ");
     char s[3];
     int_to_ascii(r.int_no, s);
+
     kprint(s);
     kprint("\n");
     kprint(exception_messages[r.int_no]);
     kprint("\n");
+    asm volatile("hlt");
 }
 
 void register_interrupt_handler(u8 n, isr_t handler) {
@@ -148,6 +183,7 @@ void irq_install() {
     asm volatile("sti");
     /* IRQ0: таймер */
     init_timer(50);
+
     /* IRQ1: клавиатура */
     init_keyboard();
 }

src/kernel/cpu/isr.h

@@ -81,7 +81,6 @@ typedef struct {
 void isr_install();
 void isr_handler(registers_t r);
 void irq_install();
-
 typedef void (*isr_t)(registers_t);
 void register_interrupt_handler(u8 n, isr_t handler);
 

src/kernel/kernel/kernel.c

@@ -24,15 +24,15 @@ void kmain() {
 	irq_install();
 	kprint("IRQ Installed\n");
 
+	init_paging();
+
 	heap_init();
 
 	// Приглашение
-	kprint("Success loaded! Welcome to Kintsugi OS\n");
-	kprint("Copyright (C) alexeev-prog\nRepository: https://github.com/alexeev-prog/KintsugiOS\n");
+	kprint("\nKintsugi OS (C) 2025\nRepository: https://github.com/alexeev-prog/KintsugiOS\n");
 
 	// Уведомление о старте оболочки командной строки
 	kprint("\nKeramika Shell v0.1.0 "
-	        "Type END to halt the CPU\n"
 	        "Type HELP to view commands\n\n!#> ");
 }
 

src/kernel/kklibc/kklibc.h

@@ -7,5 +7,6 @@
 #include "stdlib.h"
 #include "function.h"
 #include "math.h"
+#include "paging/paging.h"
 
 #endif