Date: Wed, 19 May 2004 15:29:09 -0700 From: steve@Watt.COM (Steve Watt) To: pjd@freebsd.org Cc: hackers@freebsd.org Subject: Re: api for sharing memory from kernel to userspace? Message-ID: <200405192229.i4JMT95J087312@wattres.Watt.COM> In-Reply-To: <20040519143453.GZ845@darkness.comp.waw.pl> References: <20040519122907.GO81341@elvis.mu.org>
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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...
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