X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/9fe5e02cf615ad121c4460fbaaac2787d1e09c0e..ae23ad2227bd97df4b464937b1dd54a0f3702148:/lunaix-os/kernel/mm/dmm.c

diff --git a/lunaix-os/kernel/mm/dmm.c b/lunaix-os/kernel/mm/dmm.c
index 04a0249..ae89908 100644
--- a/lunaix-os/kernel/mm/dmm.c
+++ b/lunaix-os/kernel/mm/dmm.c
@@ -1,19 +1,71 @@
+/**
+ * @file dmm.c
+ * @author Lunaixsky
+ * @brief Dynamic memory manager for heap. This design do not incorporate any\
+ * specific implementation of malloc family. The main purpose of this routines is to
+ * provide handy method to initialize & grow the heap as needed by upstream implementation.
+ * 
+ * This is designed to be portable, so it can serve as syscalls to malloc/free in the c std lib. 
+ * 
+ * @version 0.2
+ * @date 2022-03-3
+ *
+ * @copyright Copyright (c) Lunaixsky 2022
+ *
+ */
+
 #include <lunaix/mm/dmm.h>
 #include <lunaix/mm/vmm.h>
+#include <lunaix/mm/page.h>
+
+#include <lunaix/spike.h>
+
+int
+dmm_init(heap_context_t* heap)
+{
+    assert((uintptr_t)heap->start % BOUNDARY == 0);
 
-// This is a temporary design. 
-//  We can do better when we are ready for multitasking
-void
-lxsbrk(void* current, void* next) {
-    // TODO: sbrk 
+    heap->brk = heap->start;
+
+    return vmm_alloc_page(heap->brk, PG_PREM_RW) != NULL;
 }
 
-void
-lxmalloc(size_t size) {
-    // TODO: Malloc 
+int
+lxsbrk(heap_context_t* heap, void* addr)
+{
+    return lxbrk(heap, addr - heap->brk) != NULL;
 }
 
-void
-lxfree(size_t size) {
-    // TODO: Free 
+void*
+lxbrk(heap_context_t* heap, size_t size)
+{
+    if (size == 0) {
+        return heap->brk;
+    }
+
+    void* current_brk = heap->brk;
+
+    // The upper bound of our next brk of heap given the size.
+    // This will be used to calculate the page we need to allocate.
+    void* next = current_brk + ROUNDUP(size, BOUNDARY);
+
+    // any invalid situations
+    if (next >= heap->max_addr || next < current_brk) {
+        return NULL;
+    }
+
+    uintptr_t diff = PG_ALIGN(next) - PG_ALIGN(current_brk);
+    if (diff) {
+        // if next do require new pages to be allocated
+        if (!vmm_alloc_pages((void*)(PG_ALIGN(current_brk) + PG_SIZE),
+                             diff,
+                             PG_PREM_RW)) {
+            // for debugging
+            assert_msg(0, "unable to brk");
+            return NULL;
+        }
+    }
+
+    heap->brk += size;
+    return current_brk;
 }
\ No newline at end of file