physical address to virtual address conversion
Scott Long
scottl at samsco.org
Wed Mar 30 11:27:13 PST 2005
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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