Would it be smart to map all physical addresses to virtua...

[Ycep]

...l while boot? If not, why? What would be pros and cons of it?

[BrightLight]

It makes perfect sense to map all physical addresses to virtual address during booting. It makes some things (e.g. ACPI table access, PCIe configuration, ...) easier to do. For 64-bit systems, it makes sense to leave the lower half of the 48-bit address space for general purpose use, and the upper half to map all physical addresses.

[Ycep]

What is wrong with this then...

Code: Select all

PageDir* d=(PageDir*)AllocBlock(12288);
memclr(d,sizeof(PageDir));
uint page=0, frame=0;
for(uint j=0;j<SystemBootInfo->memoryLo/4096;j++)
{
	PageTable* t=new PageTable;
	for(uint i=0;i<1024;i++,frame+=4096)
	{
		AddAtrib(&page,pteUser);
		SetFrame(&page,(uint)frame);
		AddAtrib(&page,ptePresent);
		t->entries[pteIndex(frame)]=frame;
	}
	AddAtrib(&d->entries[j], pdeWritable);
	AddAtrib(&d->entries[j], pdePresent);
	SetFrame(&d->entries[j], (uint)t);
}

AddAtrib(), SetFrame() and pteIndex() are checked to be working.

[iansjack]

What makes you think anything is wrong with it? Have you checked the generated page table to make sure it is correct?

[Ycep]

Finally I finished the skeleton of my memory managament. ( I sound nerdy)