multiboot: make sure heap ends up after cmdline

Author: alfreb

src/kernel/multiboot.cpp

@@ -25,7 +25,7 @@ extern "C" {
 
   extern uintptr_t _end;
 
-  // Function to deterimine the end of multiboot provided data
+  // Deterimine the end of multiboot provided data
   // (e.g. multiboot's data area as offset to the _end symbol)
   uintptr_t _multiboot_free_begin(uintptr_t boot_addr){
 
@@ -34,8 +34,12 @@ extern "C" {
 
     if (bootinfo->flags & MULTIBOOT_INFO_CMDLINE
         and bootinfo->cmdline > multi_end) {
-      debug("* Multiboot cmdline end: 0x%x \n", bootinfo->cmdline);
-      multi_end = bootinfo->cmdline;
+
+      debug("* Multiboot cmdline @ 0x%x: %s \n", bootinfo->cmdline, (char*)bootinfo->cmdline);
+
+      // Set free begin to after the cmdline string
+      multi_end = bootinfo->cmdline +
+        strlen(reinterpret_cast<const char*>(bootinfo->cmdline)) + 1;
     }
 
     debug("* Multiboot end: 0x%x \n", multi_end);