Kernel: Make sure super pages are in the first 16MiB of physical memory

This was broken by recent changes.

Kernel/VM/MemoryManager.cpp

@@ -300,6 +300,9 @@ UNMAP_AFTER_INIT void MemoryManager::parse_memory_map()
         m_user_physical_regions.append(PhysicalRegion::try_create(range.lower, range.upper).release_nonnull());
     }
 
+    // Super pages are guaranteed to be in the first 16MB of physical memory
+    VERIFY(virtual_to_low_physical((FlatPtr)super_pages) + sizeof(super_pages) < 0x1000000);
+
     // Append statically-allocated super physical physical_region.
     m_super_physical_regions.append(PhysicalRegion::try_create(
         PhysicalAddress(virtual_to_low_physical(FlatPtr(super_pages))),

Kernel/linker_amd64.ld

@@ -4,6 +4,7 @@ KERNEL_VIRTUAL_BASE = 0x2000000000;
 
 PHDRS
 {
+  boot_bss PT_LOAD ;
   text PT_LOAD ;
   data PT_LOAD ;
   bss PT_LOAD ;
@@ -16,6 +17,11 @@ SECTIONS
 
     start_of_kernel_image = .;
 
+    .boot_bss ALIGN(4K) (NOLOAD) : AT (ADDR(.boot_bss) - KERNEL_VIRTUAL_BASE)
+    {
+        *(.super_pages)
+    } :boot_bss
+
     .text ALIGN(4K) : AT (ADDR(.text) - KERNEL_VIRTUAL_BASE)
     {
         start_of_kernel_text = .;

Kernel/linker_i386.ld

@@ -4,6 +4,7 @@ KERNEL_VIRTUAL_BASE = 0xc0000000;
 
 PHDRS
 {
+  boot_bss PT_LOAD ;
   text PT_LOAD ;
   data PT_LOAD ;
   bss PT_LOAD ;
@@ -16,6 +17,11 @@ SECTIONS
 
     start_of_kernel_image = .;
 
+    .boot_bss ALIGN(4K) (NOLOAD) : AT (ADDR(.boot_bss) - KERNEL_VIRTUAL_BASE)
+    {
+        *(.super_pages)
+    } :boot_bss
+
     .text ALIGN(4K) : AT (ADDR(.text) - KERNEL_VIRTUAL_BASE)
     {
         start_of_kernel_text = .;