From: Dan Malek <dan@mvista•com>
To: Konstantin Sabodash <konstantin.sabodash@fnc•fujitsu.com>
Cc: linuxppc-embedded@lists•linuxppc.org, wg@world•std.com
Subject: Re: Memory map
Date: Mon, 27 Nov 2000 14:22:44 -0500 [thread overview]
Message-ID: <3A22B484.F4551876@mvista.com> (raw)
In-Reply-To: 3A22B028.6182249F@fnc.fujitsu.com
Konstantin Sabodash wrote:
> "paddr2 = mmap(0,size,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0x50000000);"
>
> But page size is 1K and their start addresses appears in address
> space with increment 0x1000.
No, the Linux page size is 4K.
> So if I put 0x50000400 address it give me segmentation fault. It works
> fine in region 0x50000000 ... 0x500003ff next 0x50001000 ...
> 0x500103ff and so on.
> Question : how can we increase page size to eliminate these holes.
Fix your hardware. I don't know what "size" is in your mmap() example,
but just because you map a large space doesn't mean you necessarily have
access to all of it. If the underlying hardware doesn't respond to
the access, you will get a bus timeout error which is reported to your
program as a segmentation violation (or bus fault violation depending
upon how we map the error today). It looks to me like your hardware
responds to the first 1K of a selected address space, and the memory
controller is programmed to wrap this on 4K boundaries.
What kind of system is this? What kind of device is mapped to this
address?
-- Dan
--
I like MMUs because I don't have a real life.
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2000-11-27 19:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-11-27 19:04 Memory map Konstantin Sabodash
2000-11-27 19:22 ` Dan Malek [this message]
2000-11-27 19:44 ` IBM Walnut 405GP eval board Tom Shaver
2000-11-28 21:04 ` Frank Rowand
-- strict thread matches above, loose matches on Subject: below --
2000-04-25 9:31 Re:Re: memory map zzh
2000-04-25 17:05 ` Dan Malek
2000-04-24 5:11 Shuangjun Zhu
2000-04-24 16:09 ` Dan Malek
2000-04-24 3:24 zzh
2000-04-24 3:54 ` Dan Malek
2000-04-23 22:16 ` Steve Tarr
2000-04-24 16:07 ` Dan Malek
2000-04-21 9:49 zzh
2000-04-21 16:58 ` Dan Malek
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