physical.c

/*  
    This file is part of VK.
    Copyright (C) 2017 Valentin Haudiquet

    VK is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, version 2.

    VK is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with VK.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "system.h"
#include "mem.h"
#include "error/error.h"

/*
* This file has the goal to trace the physical memory and to gets avaible blocks of it
*/

p_block_t* first_block = 0;
u64 detected_memory = 0;
u32 detected_memory_below32;

void physmem_get(multiboot_info_t* mbt)
{
    //Parse memory map from GRUB
    memory_map_t* mmap = (memory_map_t*) (mbt->mmap_addr+KERNEL_VIRTUAL_BASE);
    p_block_t* prev = 0;
    p_block_t* current_block = first_block = 
    #ifdef MEMLEAK_DBG
    kmalloc(sizeof(p_block_t), "Physical memory block struct");
    #else
    kmalloc(sizeof(p_block_t));
    #endif
    
    unsigned int i = 0;
    while(i < mbt->mmap_length)
    {
        if(first_block == 0) first_block = current_block;
        detected_memory += mmap->length;
        if(mmap->base_addr < U32_MAX)
        {
            current_block->base_addr = (u32) mmap->base_addr;
            if(mmap->length < U32_MAX)
                current_block->size = (u32) mmap->length;
            else
                current_block->size = U32_MAX-1;
            detected_memory_below32 += current_block->size;
            current_block->type = mmap->type;
            current_block->prev = prev;
            i+= (sizeof(memory_map_t));
            if(i < mbt->mmap_length)
            {
                current_block->next = 
                #ifdef MEMLEAK_DBG
                kmalloc(sizeof(p_block_t), "Physical memory block");
                #else
                kmalloc(sizeof(p_block_t));
                #endif
                prev = current_block;
                current_block = current_block->next;
                mmap = (memory_map_t*) ((u32) mmap + mmap->size + sizeof(mmap->size));
            }
        }
        else
        {
            i+= (sizeof(memory_map_t));
            if(i < mbt->mmap_length)
                mmap = (memory_map_t*) ((u32) mmap + mmap->size + sizeof(mmap->size));
        }
    }
    //Mark the kernel page as used (except the first 1 mib that are mapped but free/used by hardware)
    reserve_specific(0x100000, 0x300000, PHYS_KERNEL_BLOCK_TYPE);
    //Mark the kernel heap page as used
    reserve_specific(KHEAP_PHYS_START, KHEAP_BASE_SIZE, PHYS_KERNEL_BLOCK_TYPE);
}

u32 get_free_mem()
{
    u32 tr = 0;
    p_block_t* curr = first_block;
    while(curr)
    {
        if(curr->type == 1 && curr->base_addr > 0x100000) tr+= curr->size;
        curr = curr->next;
    }
    return tr;
}

u32 reserve_block(u32 size, u8 type)
{
    alignup(size, 4096);
    p_block_t* curr = first_block;
    while(curr)
    {
        if(curr->base_addr >= 0x100000 && curr->type == PHYS_FREE_BLOCK_TYPE)
        {
            if(curr->size < size) {curr = curr->next; continue;}
            p_block_t* newblock = 
            #ifdef MEMLEAK_DBG
            kmalloc(sizeof(p_block_t), "physical memory new block (reserve_block)");
            #else
            kmalloc(sizeof(p_block_t));
            #endif
            p_block_t* next = curr->next;
            newblock->base_addr = curr->base_addr+size;
            newblock->size = curr->size-size;
            newblock->type = 1;
            newblock->next = next;
            newblock->prev = curr;
            if(next) next->prev = newblock;
            curr->size = size;
            curr->next = newblock;
            curr->type = type;
            return curr->base_addr;
        }
        curr = curr->next;
    }
    fatal_kernel_error("Trying to reserve more physical memory than available", "RESERVE_BLOCK");
    return 0;
}

//CARE : UNSAFE
u32 reserve_specific(u32 addr, u32 size, u8 type)
{
    p_block_t* curr = first_block;
    while(curr)
    {
        if(curr->base_addr == addr && curr->type == PHYS_FREE_BLOCK_TYPE)
        {
            if(curr->type != PHYS_FREE_BLOCK_TYPE) break;
            if(curr->size < size) {break;}
            p_block_t* newblock = 
            #ifdef MEMLEAK_DBG
            kmalloc(sizeof(p_block_t), "physical memory new block (reserve_specific)");
            #else
            kmalloc(sizeof(p_block_t));
            #endif
            p_block_t* next = curr->next;
            newblock->base_addr = curr->base_addr+size;
            newblock->size = curr->size-size;
            newblock->type = PHYS_FREE_BLOCK_TYPE;
            newblock->next = next;
            newblock->prev = curr;
            next->prev = newblock;
            curr->size = size;
            curr->next = newblock;
            curr->type = type;
            return curr->base_addr;
        }
        else if(curr->base_addr < addr && curr->base_addr+curr->size > addr)
        {
            if(curr->type != PHYS_FREE_BLOCK_TYPE) break;
            if(curr->size < size) {break;}
            p_block_t* beforeblock = 
            #ifdef MEMLEAK_DBG
            kmalloc(sizeof(p_block_t), "physical memory new block (reserve_specific)");
            #else
            kmalloc(sizeof(p_block_t));
            #endif
            beforeblock->base_addr = curr->base_addr;
            beforeblock->size = addr - size;
            beforeblock->next = curr;
            beforeblock->prev = curr->prev;
            beforeblock->type = PHYS_FREE_BLOCK_TYPE; 
            curr->prev->next = beforeblock;

            curr->prev = beforeblock;
            curr->base_addr = addr;
            curr->size -= beforeblock->size;

            p_block_t* afterblock = 
            #ifdef MEMLEAK_DBG
            kmalloc(sizeof(p_block_t), "physical memory new block (reserve_specific)");
            #else
            kmalloc(sizeof(p_block_t));
            #endif
            p_block_t* next = curr->next;
            afterblock->base_addr = curr->base_addr+size;
            afterblock->size = curr->size-size;
            afterblock->type = PHYS_FREE_BLOCK_TYPE;
            afterblock->next = next;
            afterblock->prev = curr;

            curr->next = afterblock;
            curr->size = size;
            curr->type = type;
            return curr->base_addr;
        }
        curr = curr->next;
    }
    fatal_kernel_error("Trying to reserve specific failed", "RESERVE_SPECIFIC");
    return 0;
}

void free_block(u32 base_addr)
{
    p_block_t* curr = first_block;
    while(curr)
    {
        if(curr->base_addr == base_addr)
        {
            if((curr->type != PHYS_KERNELF_BLOCK_TYPE) && (curr->type != PHYS_USER_BLOCK_TYPE))
            {
                kprintf("%lPHYSICAL FREE_BLOCK() ERROR\n", 2);
                kprintf("Block address (physical) : 0x%X\n", curr->base_addr);
                fatal_kernel_error("Trying to free a non-freeable block", "FREE_BLOCK");
            }
            curr->type = PHYS_FREE_BLOCK_TYPE;
            //block merging before and after
            p_block_t* m = curr->prev;
            while(m && m->type == PHYS_FREE_BLOCK_TYPE)
            {
                m->size += curr->size;
                m->next = curr->next;
                if(m->next) m->next->prev = m;
                kfree(curr);
                curr = m;
                m = m->prev;
            }
            m = curr->next;
            while(m && m->type == PHYS_FREE_BLOCK_TYPE)
            {
                curr->size += m->size;
                curr->next = m->next;
                if(curr->next) curr->next->prev = curr;
                kfree(m);
                m = curr->next;
            }
            return;
        }
        curr = curr->next;
    }
    fatal_kernel_error("Trying to free an unknown block", "FREE_BLOCK");
}

p_block_t* get_block(u32 some_addr)
{
    p_block_t* curr = first_block;
    while(curr)
    {
        if(curr->base_addr < some_addr && curr->base_addr+curr->size > some_addr)
            return curr;
        curr = curr->next;
    }
    fatal_kernel_error("This address is not present in memory", "GET_BLOCK");
    return 0;
}