About init_heap

[PinoTsao]

In chapter "First steps in the kernel setup", section "Heap initialization" :

Then there is the heap_end calculation:

heap_end = (char *)((size_t)boot_params.hdr.heap_end_ptr + 0x200);

which means heap_end_ptr or _end + 512 (0x200h)

which is a little bit obscure, How about:

The definition of heap_end_ptr would minus 0x200, so make it up.

Check heap_end_ptr in Documentation/x86/boot.txt. Although I don't understand the "minus 0x200" in the definition