Messages in this thread | | | Date | Mon, 20 Jun 2011 09:31:22 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 00/10] Enhance /dev/mem to allow read/write of arbitrary physical addresses |
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* Ryan Mallon <rmallon@gmail.com> wrote:
> On 17/06/11 19:30, Ingo Molnar wrote: > >* Petr Tesarik<ptesarik@suse.cz> wrote: > > > >>This patch series enhances /dev/mem, so that read and write is > >>possible at any address. The patchset includes actual > >>implementation for x86. > >This series lacks a description of why this is desired. > > > >My strong opinion is that it's not desired at all: /dev/mem never > >worked beyond 4G addresses so by today it has become largely obsolete > >and is on the way out really. > > > >I'm aware of these current /dev/mem uses: > > > > - Xorg maps below 4G non-RAM addresses and the video BIOS > > > > - It used to have some debugging role but these days kexec and kgdb > > has largely taken over that role - partly due to the 4G limit. > > > > - there's some really horrible out-of-tree drivers that do mmap()s > > via /dev/mem, those should be fixed if they want to move beyond > > 4G: their char device should be mmap()able. > > There are drivers where this makes sense. For example an FPGA > device with a proprietary register layout on the memory bus can be > done this way. [...]
So you want us to help vendors screw users with insane, proprietary, user-space drivers with sekrit binary blobs?
Wow.
Thanks,
Ingo
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