create kmalloc and km_init

2 files changed, 35 insertions, 5 deletions

diff --git a/kernel/kernel.c b/kernel/kernel.c
index 568d8a3..3952f8f 100644
--- a/kernel/kernel.c
+++ b/kernel/kernel.c
@@ -20,11 +20,12 @@ void kernel_main(size_t hart, void *fdt) {
     struct dt_node *head = dt_parse(fdt);
     struct mem_info *info = km_find_memory(head);
 
-    if (info) {
-        print_string("found memory!\n");
-    } else {
-        print_string("could not find memory!\n");
+    if (!info) {
+        print_string("failed to get memory!\n");
+        while (1);
     }
 
+    km_init(info);
+
     while(1);
 }
diff --git a/kernel/mem.c b/kernel/mem.c
index 3a0b19b..840a3b7 100644
--- a/kernel/mem.c
+++ b/kernel/mem.c
@@ -3,10 +3,31 @@
 #include <dtb.h>
 #include <common.h>
 
+static struct page *free_list;
+
 void* kmalloc(size_t size) {
-    return (void*)size;
+    struct page *page = free_list;
+    while (page != NULL && page->size < size && page->status != MEMPAGE_FREE) {
+        page = page->next;
+    }
+    if (page == NULL)
+        return NULL;
+
+    size_t combined_size = size + sizeof(struct page);
+    struct page *next = (struct page *)((void *)page + combined_size);
+    next->next = page->next;
+    next->size = page->size - combined_size;
+    next->status = MEMPAGE_FREE;
+
+    page->status = MEMPAGE_USED;
+    next->size = combined_size;
+    next->next = NULL;
+
+    return (void *)page + sizeof(struct page);
 }
 
+
+
 void* memcpy(void *to, const void *from, size_t size) {
     char *dest = (char *)to;
     const char *src = (const char *)from;
@@ -18,3 +39,11 @@ void* memcpy(void *to, const void *from, size_t size) {
     return dest;
 }
 
+void km_init(struct mem_info *info) {
+    struct page *base = (struct page *)info->start;
+    base->next = NULL;
+    base->size = info->size - sizeof(struct page);
+    base->status = MEMPAGE_FREE;
+
+    free_list = base;
+}