From: Wang Baisheng <baisheng.wang.cn@gmail.com>
To: linux-newbie@vger.kernel.org
Subject: why mapping beyond end "MAPPING_BEYOND_END"?
Date: Fri, 21 Dec 2012 14:50:57 +0800 [thread overview]
Message-ID: <CABymN7aq6zs47MKVuijcvRg5yggNkg_jUT_UJfOguUg2xv2f5A@mail.gmail.com> (raw)
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
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reply other threads:[~2012-12-21 6:50 UTC|newest]
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