feat: introduced tasking, added paging (no vm), moved malloc, added

syscalls, other stuff

kernel/mem/malloc.c

@@ -0,0 +1,90 @@
+//
+// Created by rick on 23-02-21.
+//
+
+#include <libc/kprintf.h>
+#include <tasks/task.h>
+#include "malloc.h"
+#include "pmm.h"
+
+#define MALLOC_TYPE_FREE 0
+#define MALLOC_TYPE_USED 1
+
+int malloc_entries = 0;
+int malloc_used = 0;
+
+typedef struct malloc_map {
+    struct malloc_map *next;
+    struct malloc_map *prev;
+    uint32_t size;
+    int type;
+} malloc_map;
+
+malloc_map *first_malloc_entry;
+
+void malloc_init() {
+    first_malloc_entry = pmm_get_pages(16);
+    first_malloc_entry->next = first_malloc_entry;
+    first_malloc_entry->prev = first_malloc_entry;
+    first_malloc_entry->size = PAGE_SIZE * 16;
+    first_malloc_entry->type = MALLOC_TYPE_FREE;
+    malloc_entries++;
+}
+
+void split_malloc_map(malloc_map *entry, unsigned int size) {
+    malloc_entries++;
+    malloc_map *new_entry = entry + sizeof(malloc_map) + size;
+    new_entry->size = entry->size - size - sizeof(malloc_map);
+    new_entry->next = entry->next;
+    new_entry->prev = entry;
+    new_entry->type = MALLOC_TYPE_FREE;
+    entry->next->prev = new_entry;
+    entry->next = new_entry;
+    entry->size = size;
+}
+
+void *malloc(size_t size) {
+    // todo replace this horrible mess!
+    // this lacks any page alignment and what so ever
+    void* result = NULL;
+    task_lock_acquire();
+    malloc_map *current_map = first_malloc_entry;
+    // iterate through maps
+    do {
+        if (current_map->type == MALLOC_TYPE_USED) {
+            goto malloc_find_next;
+        }
+        if ((unsigned int) current_map->size < size) {
+            goto malloc_find_next;
+        }
+        if ((unsigned int) current_map->size > (size + sizeof(malloc_map))) {
+            // big enough to split
+            split_malloc_map(current_map, size);
+        }
+        malloc_used++;
+        current_map->type = MALLOC_TYPE_USED;
+        result = ((void *) current_map) + sizeof(malloc_map);
+        break;
+
+        malloc_find_next:
+        current_map = current_map->next;
+    } while (current_map != first_malloc_entry);
+    task_lock_free();
+    return result;
+}
+
+void free(void *mem) {
+    if (mem == NULL) {
+        return;
+    }
+    malloc_used--;
+    malloc_map *map = (mem - sizeof(malloc_map));
+    map->type = MALLOC_TYPE_FREE;
+};
+
+
+void print_malloc_info() {
+    printf("Malloc avail entries: %d\n"
+           "Malloc used entries: %d\n", malloc_entries, malloc_used);
+}
+