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From: steve@Watt.COM (Steve Watt)
Date: Wed, 19 May 2004 15:29:09 -0700
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Subject: Re: api for sharing memory from kernel to userspace?
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In article <20040519143453.GZ845@darkness.comp.waw.pl> you write:
>
>On Wed, May 19, 2004 at 05:29:07AM -0700, Alfred Perlstein wrote:
>+> I need to share about 100megs of memory between kernel and userspace.
>+>
>+> The memory can not be paged and should appear contig in the process's
>+> address space.  Any suggestions?
>+>
>+> I need a way to either:
>+> map user memory into the kernel's address space.
>+> map kernel memory into the user's address space.
>+>
>+> I was looking at pmap_qenter() but it didn't see attractive because
>+> it's for "short term mappings", this mapping will exist for quite a
>+> while.
>
>In mapping kernel memory into user's address space I am interested as well
>for GEOM Gate and other evil projects.

The way we accomplished this in some other operating system was to
create a shared memory segment with an implementation-reserved
name, and then have the application shm_open the name and mmap it in.

Shouldn't be hard with a device driver.

-- 
Steve Watt KD6GGD  PP-ASEL-IA          ICBM: 121W 56' 57.8" / 37N 20' 14.9"
 Internet: steve @ Watt.COM                         Whois: SW32
   Free time?  There's no such thing.  It just comes in varying prices...