Query Hard Memory Addresses

[Kenneth Adam Miller]

On Thu, Oct 22, 2015 at 3:38 PM, Jeff Haran <Jeff.Haran at citrix.com> wrote:

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> *From:* kernelnewbies-bounces at kernelnewbies.org [mailto:
> kernelnewbies-bounces at kernelnewbies.org] *On Behalf Of *Kenneth Adam
> Miller
> *Sent:* Thursday, October 22, 2015 12:14 PM
> *To:* Kernelnewbies
> *Subject:* Query Hard Memory Addresses
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> So, previously it was discussed that /dev/mem could be used to mmap a
> specific hardware memory into a process. Now I need to unit test some
> userland code that does exactly that, but I need to make sure that the unit
> test selects a small page that is always free in kernel land. How can I
> query mem to just grab the location of a free page?
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> (my development setup is different from my other deployment; in deployment
> these values are hard coded, in development they occur on a qemu emulator)
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> I suppose it might work to write a kernel module that allocates a page in
> its init routine and then provides the address to user space via a /proc
> entry.
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Well see now we're back to where I was before finding out about /dev/mem.

In any case, I think I can isolate my userland tests with some shared
memory regions at the process level, and then in the production environment
serve up a buffer grabbed by mmap.


> Jeff Haran
>
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