Initial commit - slab allocator, kmalloc, other re

factors

src/mm/page.c

@@ -0,0 +1,61 @@
+#include "page.h"
+#include <limine.h>
+#include "vmm.h"
+#include <SFB25.h>
+#include <stdatomic.h>
+#include <kprint.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+struct page *pages; // "virtually sparse array", it holds all the pages between the start of the first usable address to the last one.
+
+extern struct limine_memmap_response *memmap_response;
+
+extern uint64_t hhdmoffset;
+
+// Get the page object which is associated with the page that the address `addr` resides in
+struct page *get_page(void *addr){
+    void *canonical_addr = (void*)PAGE_ROUND_DOWN((uint64_t)addr);
+    uint64_t phys_addr = kget_phys_addr(canonical_addr);
+
+    if(phys_addr == 0){
+        return NULL;
+    }
+
+    uint64_t index = phys_addr / PAGE_SIZE;
+    return &pages[index];
+}
+
+void init_page_array(){
+
+    struct limine_memmap_entry **entries = memmap_response->entries;
+
+    size_t firstaddr = 0;
+    size_t lastaddr = 0;
+
+    for(size_t i = 0; i < memmap_response->entry_count; i++){
+        switch(entries[i]->type){
+            case LIMINE_MEMMAP_USABLE:
+                if(firstaddr == 0){
+                    firstaddr = entries[i]->base;
+                    
+                }else{
+                    lastaddr = entries[i]->base + entries[i]->length;
+                }
+        }
+    }
+
+    size_t page_count = (lastaddr - firstaddr) / PAGE_SIZE;
+
+    pages = va_alloc_contigious_pages((page_count * sizeof(struct page)) / PAGE_SIZE);
+
+    if(pages == NULL){
+        klog(__func__, "Couldn't allocate page structure");
+        kkill();
+        return;
+    }
+
+    memset(pages, 0, (page_count * sizeof(struct page)) / PAGE_SIZE);
+
+}