From: "Sébastien Chrétien" <chretien@enseirb.fr>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: ioremap and vmalloc
Date: Fri, 19 Sep 2008 19:47:43 +0200 [thread overview]
Message-ID: <48D3E5BF.6000809@enseirb.fr> (raw)
In-Reply-To: <fa686aa40809191012q76d1c450ye12094ac63bc68a7@mail.gmail.com>
I made a mistake. The right code is :
ioremap(0x20000000,0x40000) and ioremap(0x80000000,0x50000)
Grant Likely a écrit :
> On Fri, Sep 19, 2008 at 10:58 AM, Josh Boyer <jwboyer@gmail.com> wrote:
>
>> On Fri, Sep 19, 2008 at 06:45:01PM +0200, =?ISO-8859-1?Q?S=E9bastien_Chr=E9tien_ wrote:
>>
>>> if I write :
>>> ioremap(0x20000000,0x40000) and ioremap(0x20000000,0x50000)
>>>
>>> Will it crash ?
>>>
>> I have no idea. You haven't given us enough information to really answer
>> that.
>>
>
> But I can say that the second ioremap() call makes the first ioremap()
> both redundant and inefficient. You're using exactly the same base
> address so the same region is getting mapped twice. Since the second
> call uses a bigger region than the first then the kernel will probably
> need to allocate another chunk of virtual address space to map it
> instead of reusing the first mapping.
>
> g.
>
>
>
next prev parent reply other threads:[~2008-09-19 17:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-19 11:15 ioremap and vmalloc Sébastien Chrétien
2008-09-19 13:49 ` Grant Likely
2008-09-19 16:34 ` Sébastien Chrétien
2008-09-19 16:38 ` Josh Boyer
2008-09-19 16:45 ` Sébastien Chrétien
2008-09-19 16:58 ` Josh Boyer
2008-09-19 17:12 ` Grant Likely
2008-09-19 17:47 ` Sébastien Chrétien [this message]
2008-09-19 17:52 ` Sébastien Chrétien
2008-09-22 5:28 ` Benjamin Herrenschmidt
2008-09-19 16:43 ` Grant Likely
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