per...@pluto.rain.com wrote:
John Baldwin <j...@freebsd.org> wrote:
On Friday, September 10, 2010 2:55:15 am per...@pluto.rain.com wrote:
...
It is arguably a bug to open O_RDWR when only examining things.
You have to have RDWR permission to issue the ioctl to read config
registers which pciconf does when examining capabilities.
So much for avoiding a reboot for <b...@lordcow.org> (or whatever the
correct address is -- that one bounced), but now it is beginning to
look as if there may be a POLA violation at a lower level. Unless
there are devices out there whose state can be changed by merely
_reading_ (not writing) their configuration registers, I would not
expect to need RDWR permission just to read them.
Umm, not all config registers are standardized and devices are free to
define device-specific registers with device-specific behavior (many
do). Given that, it is quite possible for a device to implement a
register that takes action when read (e.g. resets to 0 or clears status
bits, etc.).
pciconf -l itself does not require RDWR permissions, only -c which does
a good bit more work.
--
John Baldwin
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