mugenhwcfg -- Could not access file: /dev/mem

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Andre

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Feb 23, 2022, 10:37:52 AM2/23/22
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Hello,

I want to try Muen on two different Systems to see if the Hardware is
compatible.
I used a live Debian 11 ("grml" in persistent-mode) and latest
https://git.codelabs.ch/?p=muen/mugenhwcfg.git to create a .XML
Configuration.

I got multiple Errors like:
** ERROR **: Could not access file: /dev/mem - 0xfed90008

These Errors are in section "Formatting XML document..." which tells me,
that this could be a Script problem. 
The File "/dev/mem" is existing and readable by root:kmem (0640 [also
tried 0666]).

Is my Hardware incompatible or is this a Script issue ?

Regards, 
Andre

Attachments: Script-Output from mugenhwcfg.py from two different Systems
(one is a Lenovo x250 i7-5600U)


dev_mem__fed9xxxx-fail.log
dev_mem__fed900xx-fail_x250.log

Nico Huber

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Feb 23, 2022, 11:26:47 AM2/23/22
to Andre, muen...@googlegroups.com
Hello Andre,

On 23.02.22 16:36, Andre wrote:
> I used a live Debian 11 ("grml" in persistent-mode) and latest
> https://git.codelabs.ch/?p=muen/mugenhwcfg.git to create a .XML
> Configuration.
>
> I got multiple Errors like:
> ** ERROR **: Could not access file: /dev/mem - 0xfed90008

the address looks like MMIO which may be restricted by the GRML kernel.
You can try with the following in your kernel command line (needs to
be added manually during boot):

iomem=relaxed

>
> These Errors are in section "Formatting XML document..." which tells me,
> that this could be a Script problem. 
> The File "/dev/mem" is existing and readable by root:kmem (0640 [also
> tried 0666]).
>
> Is my Hardware incompatible or is this a Script issue ?

That's definitely a software issue. What general-purpose operating
systems gain in security, they lose in convenience for development
purposes like this. /dev/mem is supposed to give a user-space program
like mugenhwcfg direct access to the physical memory space. That can
be a security issue and also cause trouble with kernel drivers, hence
it's restricted by default nowadays.

Nico

Andr'e Dietrich

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Feb 23, 2022, 12:11:57 PM2/23/22
to muen-dev
Hello Nico,
thank you for the fast response and explanation,

iomem=relaxed
 
solved the Problem.

Andre

Reto Buerki

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Feb 23, 2022, 12:39:15 PM2/23/22
to Andr'e Dietrich, muen-dev
Hello Andre,

Welcome to the muen-dev list!
Great! We also provide a Debian Live-based image to collect Muen
configurations from new hardware targets: [1] (thanks to Martin
Lucina/robur.io).

Regards,
- reto

[1] - https://www.codelabs.ch/download/mugenhwcfg-live-amd64.hybrid.iso
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