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Merged
merged 1 commit into from
Jul 9, 2025
Merged

FCKED #15

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32 changes: 22 additions & 10 deletions Boot/boot.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ header_start:
dd 0xE85250D6 ; Multiboot2 magic number
dd 0 ; Architecture 0 (protected mode i386)
dd header_end - header_start ; header length
dd -(0xE85250D6 + 0 + (header_end - header_start)) ; checksum
dd 0x17ADAF12 ; checksum (calculated: -(0xE85250D6 + 0 + 24))
; end tag
dw 0 ; type
dw 0 ; flags
Expand All @@ -14,6 +14,13 @@ bits 32

section .text

; Macro for debugging output
%macro debug_print 1
mov dx, 0xE9
mov al, %1
out dx, al
%endmacro

; Enhanced GDT for long mode (keeping your original structure)
gdt64:
dq 0 ; NULL descriptor
Expand All @@ -37,12 +44,14 @@ gdt64:

global start
start:
debug_print '1'
cli
cld

; Save multiboot info for kernel
mov [multiboot_magic], eax
mov [multiboot_info], ebx
debug_print 'B'

; Setup temporary stack
mov esp, stack_top
Expand All @@ -52,15 +61,18 @@ start:

; Load GDT (same as original)
lgdt [gdt64.pointer]
debug_print '2'

; Enable PAE (same as original)
mov eax, cr4
or eax, 1 << 5
mov cr4, eax
debug_print '3'

; Setup paging (keeping your original mapping approach)
mov edi, pml4_table
mov cr3, edi
debug_print '4'

; Initialize the tables by zeroing them out (same as original)
mov edi, pml4_table
Expand Down Expand Up @@ -89,19 +101,23 @@ start:
add edi, 8
add eax, 0x200000 ; Next 2MB
loop .map_loop
debug_print '5'

; Enable long mode (same as original)
mov ecx, 0xC0000080 ; EFER MSR
rdmsr
or eax, 1 << 8 ; LME (Long Mode Enable)
wrmsr
debug_print '6'

; Enable paging (same as original)
mov eax, cr0
or eax, 1 << 31 ; PG (Paging)
mov cr0, eax
debug_print '7'

; Jump to long mode (same as original)
debug_print '8'
jmp 0x08:long_mode

; Check and enable CPU features (non-critical)
Expand Down Expand Up @@ -144,6 +160,7 @@ bits 64
extern KernelMain

long_mode:
debug_print '9'
; Load data segments (same as original)
mov ax, 0x10 ; selector for data segment
mov ss, ax
Expand All @@ -157,18 +174,13 @@ long_mode:

; Clear direction flag
cld

; DEBUG: Write 'BOOT' to VGA before calling C code
mov rax, 0xb8000
mov word [rax], 0x0442 ; Red 'B'
mov word [rax+2], 0x044F ; Red 'O'
mov word [rax+4], 0x044F ; Red 'O'
mov word [rax+6], 0x0454 ; Red 'T'


; Pass multiboot info to kernel
mov rdi, [multiboot_magic]
mov rsi, [multiboot_info]

debug_print 'A'
; Jump to the C kernel (same as original)
call KernelMain

Expand All @@ -179,8 +191,8 @@ long_mode:
jmp .halt_loop

section .data
multiboot_magic: dq 0
multiboot_info: dq 0
multiboot_magic: dd 0
multiboot_info: dd 0

section .bss

Expand Down
24 changes: 21 additions & 3 deletions Kernel/Core/Kernel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@
int CurrentLine = 0;
int CurrentColumn = 0;
void ClearScreen(){
PrintKernel("ClearScreen\n");

char *vidptr = (char*)0xb8000;
for (int j = 0; j < 80 * 25 * 2; j += 2) {
vidptr[j] = ' ';
Expand Down Expand Up @@ -155,7 +157,23 @@ void PrintKernelAt(const char *str, int line, int col) {
}
}

void RemapPIC() {

outb(0x20, 0x11); // Start init
outb(0xA0, 0x11);
outb(0x21, 0x20); // Master offset = 0x20 (32)
outb(0xA1, 0x28); // Slave offset = 0x28 (40)
outb(0x21, 0x04);
outb(0xA1, 0x02);
outb(0x21, 0x01);
outb(0xA1, 0x01);
outb(0x21, 0xFF); // Mask all
outb(0xA1, 0xFF);
}


void KernelMain(uint32_t magic, uint32_t info) {
PrintKernel("KernelMain\n");
ClearScreen();
PrintKernel("[SUCCESS] VoidFrame Kernel - Version 0.0.1-alpha loaded\n");

Expand All @@ -178,19 +196,19 @@ void KernelMain(uint32_t magic, uint32_t info) {

PrintKernel("[SUCCESS] Core system modules loaded\n");

// Timer setup for scheduling
RemapPIC();
outb(0x43, 0x36); // Command: channel 0, lobyte/hibyte, rate generator
outb(0x40, 0x4B); // Low byte of divisor (299 = ~4000Hz)
outb(0x40, 0x01); // High byte of divisor
outb(0x21, inb(0x21) & ~0x03);
outb(0x21, inb(0x21) & ~1);

// Enable interrupts
asm volatile("sti");

PrintKernel("[SUCCESS] Kernel initialization complete - entering main loop\n");
while (1) {
if (ShouldSchedule()) {
Schedule();
RequestSchedule();
}
asm volatile("hlt"); // Wait for the next interrupt
}
Expand Down
25 changes: 20 additions & 5 deletions Kernel/Drivers/Interrupts.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#include "../Core/stdint.h"
#include "../Core/Kernel.h"
#include "Io.h"
#include "../Core/Panic.h"
#include "../Process/Process.h"

#define likely(x) __builtin_expect(!!(x), 1)
Expand Down Expand Up @@ -64,17 +65,31 @@ static void FastDisplayTicks(uint64_t ticks) {
}
}

void PrintStack(uint64_t* ptr, int count) {
for (int i = 0; i < count; i++) {
PrintKernelHex(ptr[i]);
PrintKernel(" ");
}
PrintKernel("\n");
}
Comment on lines +68 to +74
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⚠️ Potential issue

Add bounds checking for stack dump.

The PrintStack function doesn't validate that accessing ptr[i] is safe. Consider adding bounds checking or documenting the safety assumptions.

-void PrintStack(uint64_t* ptr, int count) {
+void PrintStack(uint64_t* ptr, int count) {
+    if (!ptr || count <= 0) return;
     for (int i = 0; i < count; i++) {
         PrintKernelHex(ptr[i]);
         PrintKernel(" ");
     }
     PrintKernel("\n");
 }
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
void PrintStack(uint64_t* ptr, int count) {
for (int i = 0; i < count; i++) {
PrintKernelHex(ptr[i]);
PrintKernel(" ");
}
PrintKernel("\n");
}
void PrintStack(uint64_t* ptr, int count) {
if (!ptr || count <= 0) return;
for (int i = 0; i < count; i++) {
PrintKernelHex(ptr[i]);
PrintKernel(" ");
}
PrintKernel("\n");
}
🤖 Prompt for AI Agents 
In Kernel/Drivers/Interrupts.c around lines 68 to 74, the PrintStack function
accesses ptr[i] without verifying that the pointer is valid or that the index is
within safe bounds. To fix this, add explicit bounds checking to ensure ptr is
not null and that i is less than the actual size of the stack or the accessible
memory region before accessing ptr[i]. Alternatively, document the assumptions
clearly if bounds checking is not feasible here.


// The C-level interrupt handler
void InterruptHandler(struct Registers* regs) {

// Handle timer interrupt (IRQ0, remapped to 32)
if (likely(regs->interrupt_number == 32)) {
PrintKernel("Stack dump: ");
PrintStack((uint64_t*)regs, 20);
PrintKernel("InterruptHandler: interrupt_number=");
PrintKernelInt(regs->interrupt_number);
PrintKernel("\n");
if (regs->interrupt_number == 32) {
tick_count++;
FastDisplayTicks(tick_count); // Re-enabled
outb(0x20, 0x20);
ScheduleFromInterrupt(regs);
ScheduleFromInterrupt(regs); // Re-enabled
return;
}

// if (regs->interrupt_number == 13) {
// Panic("InterruptHandler: Page fault (GPF handler)");
// }
// Send EOI to PICs for other hardware interrupts
if (regs->interrupt_number >= 40) {
outb(0xA0, 0x20); // EOI to slave PIC
Expand Down
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