New Page Map broken

[Andrej123456789]

I finish 8th episode (https://www.youtube.com/watch?v=e47SApmmx44&list=PLxN4E629pPnJxCQCLy7E0SQY_zuumOVyZ&index=8) and Page Map don't work for me:

Code:

Please fix this problem in near future

[Moldytzu]

What doesn't work with the page map?

[Moldytzu]

Be more precise

[Moldytzu]

Does your OS crash or does it do something special?

[Andrej123456789]

Nothing crash

[Andrej123456789]

I clone PonchoOS and works

[Andrej123456789]

Priting text don't work

[Moldytzu]

so it crashes

[Moldytzu]

[Moldytzu]

this is a hint

[Andrej123456789]

I have this

[Moldytzu]

I already told you where you should look in your code

[Moldytzu]

https://media3.giphy.com/media/0owap7cyOBVZO45ZNO/giphy.gif?cid=ecf05e47slxs8asumllxge8nt702pscxel9un1avy9g1k0vk&rid=giphy.gif&ct=g

[Andrej123456789]

I copying Poncho code

[Moldytzu]

no

[Moldytzu]

let me tell you what's the problem

[Andrej123456789]

I will keep my modifications

[Moldytzu]

you're causing a page fault

[Moldytzu]

do you know what is a page fault?

[Andrej123456789]

Problem is I cannot print text using new PageMap

[Moldytzu]

let me explain to you what's happening ok?

[Moldytzu]

you're causing a page fault that's crashing everything

[Moldytzu]

do you know what's a page fault?

[Andrej123456789]

I watch Poncho episode, create new PageMap like Poncho. Poncho print's text using new PageMa, I cannot print text

[Moldytzu]

I asked you something. If you don't listen to me, I won't help you

[Moldytzu]

do you know what's a page fault?

[Moldytzu]

if not: https://wiki.osdev.org/Exceptions

[Andrej123456789]

I don't know where is fault

[Moldytzu]

[Moldytzu]

here

[Moldytzu]

A Page Fault occurs when:

A page directory or table entry is not present in physical memory.
Attempting to load the instruction TLB with a translation for a non-executable page.
A protection check (privileges, read/write) failed. <- that's happening now
A reserved bit in the page directory or table entries is set to 1. 

[Moldytzu]

you're writing to privileged or inexistent memory

[Moldytzu]

if you don't understand what I'm saying let me know

[Moldytzu]

wanna tell you the fix?

[Andrej123456789]

Whatever you say, I can print now

[Moldytzu]

you removed that chunk of code, right?

[Andrej123456789]

#include <stdint.h>
#include "BasicRenderer.h"
#include "cstr.h"
#include "efiMemory.h"
#include "memory.h"
#include "Bitmap.h"
#include "paging/PageFrameAllocator.h"
#include "paging/PageMapIndexer.h"
#include "paging/paging.h"
#include "paging/PageTableManager.h"

struct BootInfo {
	Framebuffer* framebuffer;
	PSF1_FONT* psf1_Font;
	EFI_MEMORY_DESCRIPTOR* mMap;
	uint64_t mMapSize;
	uint64_t mMapDescSize;
} ;

extern uint64_t _KernelStart;
extern uint64_t _KernelEnd;

extern "C" void _start(BootInfo* bootInfo){
    
    BasicRenderer newRenderer = BasicRenderer(bootInfo->framebuffer, bootInfo->psf1_Font); 

    //Welcome
    newRenderer.Colour = 0xff00ffff;
	newRenderer.CursorPosition = {0, 0};
	newRenderer.Print("Welcome to ringOS!!");
	newRenderer.Print(" ");

	//Basic system info
	newRenderer.Colour = 0xffffff00;

	newRenderer.CursorPosition = {0, 16};
	newRenderer.Print("Basic System Info:");
	newRenderer.Print(" ");

	newRenderer.Print("Width: ");
	newRenderer.Print(to_string((uint64_t)bootInfo->framebuffer->Width));
	newRenderer.Print(" | ");

	newRenderer.Print("Height: ");
	newRenderer.Print(to_string((uint64_t)bootInfo->framebuffer->Height));
	newRenderer.Print(" | ");

	newRenderer.Print("PixelsPerScanLine: ");
	newRenderer.Print(to_string((uint64_t)bootInfo->framebuffer->PixelsPerScanLine));
	newRenderer.Print(" | ");
    
    uint64_t mMapEntries = bootInfo->mMapSize / bootInfo->mMapDescSize;

    GlobalAllocator = PageFrameAllocator();
    GlobalAllocator.ReadEFIMemoryMap(bootInfo->mMap, bootInfo->mMapSize, bootInfo->mMapDescSize);

    uint64_t kernelSize = (uint64_t)&_KernelEnd - (uint64_t)&_KernelStart;
    uint64_t kernelPages = (uint64_t)kernelSize / 4096 + 1;

    GlobalAllocator.LockPages(&_KernelStart, kernelPages);

    PageTable* PML4 = (PageTable*)GlobalAllocator.RequestPage();
    memset(PML4, 0, 0x1000);

    PageTableManager pageTableManager = PageTableManager(PML4);

    for (uint64_t t = 0; t < GetMemorySize(bootInfo->mMap, mMapEntries, bootInfo->mMapDescSize); t+= 0x1000){
        pageTableManager.MapMemory((void*)t, (void*)t);
    }

    uint64_t fbBase = (uint64_t)bootInfo->framebuffer->BaseAddress;
    uint64_t fbSize = (uint64_t)bootInfo->framebuffer->BufferSize + 0x1000;
    for (uint64_t t = fbBase; t < fbBase + fbSize; t += 4096){
        pageTableManager.MapMemory((void*)t, (void*)t);
    }

    asm ("mov %0, %%cr3" : : "r" (PML4));

    pageTableManager.MapMemory((void*)0x600000000, (void*)0x80000);

    uint64_t* test = (uint64_t*)0x600000000;
    *test = 26;

    newRenderer.Print(to_string(*test));
    
    return ;
}

[Andrej123456789]

My code

[Moldytzu]

does it work?

[Andrej123456789]

Yes

[Moldytzu]

ok

[Andrej123456789]

[Andrej123456789]

Thanks for help

[Moldytzu]

ur welcome