X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/9fe5e02cf615ad121c4460fbaaac2787d1e09c0e..f4c2f90eddf42f1cc73a2a12ff1435cd4357fa60:/lunaix-os/kernel/mm/dmm.c

diff --git a/lunaix-os/kernel/mm/dmm.c b/lunaix-os/kernel/mm/dmm.c
index 04a0249..edc28ef 100644
--- a/lunaix-os/kernel/mm/dmm.c
+++ b/lunaix-os/kernel/mm/dmm.c
@@ -1,19 +1,99 @@
+/**
+ * @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/page.h>
 #include <lunaix/mm/vmm.h>
+#include <lunaix/status.h>
+
+#include <lunaix/spike.h>
+#include <lunaix/syscall.h>
 
-// This is a temporary design. 
-//  We can do better when we are ready for multitasking
-void
-lxsbrk(void* current, void* next) {
-    // TODO: sbrk 
+__DEFINE_LXSYSCALL1(int, sbrk, size_t, size)
+{
+    heap_context_t* uheap = &__current->mm.u_heap;
+    mutex_lock(&uheap->lock);
+    void* r = lxsbrk(uheap, size, PG_ALLOW_USER);
+    mutex_unlock(&uheap->lock);
+    return r;
 }
 
-void
-lxmalloc(size_t size) {
-    // TODO: Malloc 
+__DEFINE_LXSYSCALL1(void*, brk, void*, addr)
+{
+    heap_context_t* uheap = &__current->mm.u_heap;
+    mutex_lock(&uheap->lock);
+    int r = lxbrk(uheap, addr, PG_ALLOW_USER);
+    mutex_unlock(&uheap->lock);
+    return r;
 }
 
-void
-lxfree(size_t size) {
-    // TODO: Free 
+int
+dmm_init(heap_context_t* heap)
+{
+    assert((uintptr_t)heap->start % BOUNDARY == 0);
+
+    heap->brk = heap->start;
+    mutex_init(&heap->lock);
+
+    return vmm_set_mapping(PD_REFERENCED,
+                           heap->brk,
+                           0,
+                           PG_WRITE | PG_ALLOW_USER,
+                           VMAP_NULL) != NULL;
+}
+
+int
+lxbrk(heap_context_t* heap, void* addr, int user)
+{
+    return -(lxsbrk(heap, addr - heap->brk, user) == (void*)-1);
+}
+
+void*
+lxsbrk(heap_context_t* heap, size_t size, int user)
+{
+    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) {
+        __current->k_status = LXINVLDPTR;
+        return (void*)-1;
+    }
+
+    uintptr_t diff = PG_ALIGN(next) - PG_ALIGN(current_brk);
+    if (diff) {
+        // if next do require new pages to be mapped
+        for (size_t i = 0; i < diff; i += PG_SIZE) {
+            vmm_set_mapping(PD_REFERENCED,
+                            PG_ALIGN(current_brk) + PG_SIZE + i,
+                            0,
+                            PG_WRITE | user,
+                            VMAP_NULL);
+        }
+    }
+
+    heap->brk += size;
+    return current_brk;
 }
\ No newline at end of file