Messages in this thread | | | Date | Mon, 6 Oct 2008 10:27:39 +0100 | From | Alan Cox <> | Subject | Re: RFC: banning device driver reserved resources from /dev/mem |
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> This patch adds, to the existing config option to restrict /dev/mem, the > reserved regions to the "banned from /dev/mem use" list, so now > both kernel memory and device-exclusive MMIO regions are banned.
This breaks a whole class of diagnostic and debug tools which quite intentionally dump the MMIO register space of devices that are live.
Plus it doesn't actually work - if I have /dev/mem open and mmapped you don't pull the pages from under me....
The problem with the way this is going is the more you take from /dev/mem the sooner someone is forced to add /dev/mem-proper which undoes it all again so they can get work done.
It's certainly a useful debug aid to know about such things but I don't believe it's something you should ban.
Alan
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