Messages in this thread | | | From | Jesse Barnes <> | Subject | Re: [PATCH] x86: introduce /dev/mem restrictions with a config option | Date | Thu, 31 Jan 2008 14:02:46 -0800 |
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On Thursday, January 31, 2008 9:42 am H. Peter Anvin wrote: > Arjan van de Ven wrote: > > On Thu, 31 Jan 2008 17:53:04 +0100 (CET) > > > > Jan Engelhardt <jengelh@computergmbh.de> wrote: > >> On Jan 30 2008 12:48, Arjan van de Ven wrote: > >>> Subject: [PATCH] x86: introduce /dev/mem restrictions with a > >>> config option > >>> > >>> This patch introduces a restriction on /dev/mem: Only non-memory > >>> can be read or written unless the newly introduced config option > >>> is set. > >> > >> Would not it be nicer to add a /dev/pcimem that implements the > >> given restrictive semantics? > >> > >> Maybe it's just wishful thinking, but I am dreaming of an > >> unprivileged X, and /dev/pcimem (owned by an 'x11' user or so) > >> would be a step in that direction. > > > > /dev/pcimem is wrong; X can use the exact bar in sysfs already. > > This is more for compatibility with legacy X > > Legacy X, and non-BAR X memory (originally ISA, of course; now > probably more often "stolen system memory").
For legacy memory, we actually have /sys/bus/pci/<busno>/legacy_mem (though ia64 may be the only supported platform). It's actually required on some arches due to the way this space is allocated across the system.
Jesse
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