Hi All, For x86, in arch/x86/kernel/head_32.S, for Initializing page tables, why mapping beyond end by "MAPPING_BEYOND_END": /* * End condition: we must map up to the end + MAPPING_BEYOND_END. */ movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp cmpl %ebp,%eax jb 10b According vmlinux.lds.S, the paging table is between __brk_base and _end. So why map MAPPING_BEYOND_END after _end ? Regards, Jacky