Date: Wed, 30 Mar 2005 12:25:06 -0700 From: Scott Long <scottl@samsco.org> To: Rajesh Ghanekar <ghanekar_rajesh@hotmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: physical address to virtual address conversion Message-ID: <424AFD12.7070505@samsco.org> In-Reply-To: <BAY10-F4148A147B94D76669BD6A28A460@phx.gbl> References: <BAY10-F4148A147B94D76669BD6A28A460@phx.gbl>
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Rajesh Ghanekar wrote: > Hi, > > I am trying to convert a physical memory location (address 0x000F0000) > to virtual memory address in kernel module with pmap_map() / pmap_enter(). > Whenever i call these two functions, system hangs. Is this a proper > way for conversion? > > The same physical address can be accessed from the userspace by opening > /dev/mem. The code which does the memory mapping to /dev/mem at kernel > level is in ./sys/i386/i386/mem.c as mmrw() which also uses pmap_enter(). > > kernel = FreeBSD 4.10 > > - Rajesh > pmap_mapdev() is probably what you want. However, what exactly are you trying to do? Why do you need access to a specific physical location? Scott
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