Implement BlGetMemoryMap() routine

xtldr2/memory.c

@@ -9,6 +9,69 @@
 #include <xtldr.h>
 
 
+/**
+ * Returns the memory descriptors which define a memory map of all the physical memory ranges reserved by the UEFI.
+ *
+ * @param MemoryMap
+ *        Supplies a pointer to the buffer where memory map will be written.
+ *
+ * @return This routine returns a status code.
+ *
+ * @since XT 1.0
+ */
+XTCDECL
+EFI_STATUS
+BlGetMemoryMap(OUT PEFI_MEMORY_MAP MemoryMap)
+{
+    EFI_STATUS Status;
+
+    if(MemoryMap == NULL)
+    {
+        return STATUS_EFI_INVALID_PARAMETER;
+    }
+
+    MemoryMap->Map = NULL;
+    MemoryMap->MapSize = 0;
+
+    /* Get memory map */
+    do
+    {
+        /* Attempt do get EFI memory map */
+        Status = EfiSystemTable->BootServices->GetMemoryMap(&MemoryMap->MapSize, MemoryMap->Map, &MemoryMap->MapKey,
+                                                            &MemoryMap->DescriptorSize, &MemoryMap->DescriptorVersion);
+        if(Status == STATUS_EFI_SUCCESS)
+        {
+            /* Go further if succeeded */
+            break;
+        }
+        else if(Status != STATUS_EFI_BUFFER_TOO_SMALL)
+        {
+            /* Some error occurred */
+            if(MemoryMap->Map)
+            {
+                /* Free allocated memory */
+                BlMemoryFreePool(MemoryMap->Map);
+            }
+            return Status;
+        }
+
+        /* Allocate the desired amount of memory */
+        MemoryMap->MapSize += 2 * MemoryMap->DescriptorSize;
+        BlMemoryAllocatePool(MemoryMap->MapSize, (PVOID *)&MemoryMap->Map);
+    }
+    while(Status == STATUS_EFI_BUFFER_TOO_SMALL);
+
+    /* Make sure memory map is set */
+    if(MemoryMap->Map == NULL)
+    {
+        /* Something went wrong */
+        return STATUS_EFI_NO_MAPPING;
+    }
+
+    /* Return success */
+    return STATUS_EFI_SUCCESS;
+}
+
 /**
  * This routine allocates one or more 4KB pages.
  *