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From: Lanttor <lanttor.guo@freescale.com>
To: linux-m68k@vger.kernel.org
Subject: why the PAGE_OFFSET is not 0xc0000000 on m68k platform
Date: Thu, 21 May 2009 12:17:41 +0800	[thread overview]
Message-ID: <4A14D5E5.9070103@freescale.com> (raw)

Hi,

I see the definition of PAGE_OFFSET on m68k platform like that:

#define PAGE_OFFSET (PAGE_OFFSET_RAW)

#ifdef CONFIG_MMU
#ifndef CONFIG_SUN3
#define PAGE_OFFSET_RAW         0x00000000
#else
#define PAGE_OFFSET_RAW         0x0E000000
#endif
#else
#define PAGE_OFFSET_RAW         CONFIG_RAMBASE
#endif

In my understanding, the kernel page mapping depends on PAGE_OFFSET.
For example, if PAGE_OFFSET is 0x00000000 (assuming 256M memory), the
kernel virtual address will be at (0x00000000 - 0x10000000), right?

Could this incur some side effect? I see the definition of PAGE_OFFSET
is 0xc0000000 on much platforms.

Thanks,

-- 
Best Regards,
Lanttor



             reply	other threads:[~2009-05-21  4:08 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-21  4:17 Lanttor [this message]
2009-05-21 11:29 ` why the PAGE_OFFSET is not 0xc0000000 on m68k platform Andreas Schwab

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