Return to BSD News archive
Newsgroups: comp.os.386bsd.questions Path: sserve!manuel.anu.edu.au!munnari.oz.au!news.Hawaii.Edu!ames!agate!howland.reston.ans.net!newsserver.jvnc.net!gmd.de!fanoe!veit From: veit@fanoe.gmd.de (Holger Veit) Subject: Re: Equivalent to iopl(3) in 386BSD Message-ID: <1993Mar1.161613.21892@gmd.de> Sender: veit@fanoe (Holger Veit) Nntp-Posting-Host: fanoe Organization: GMD - German National Research Center for Computer Science References: <1993Mar1.140349.12114@lth.se> Date: Mon, 1 Mar 1993 16:16:13 GMT Lines: 31 In article <1993Mar1.140349.12114@lth.se>, jh@efd.lth.se (Joergen Haegg) writes: |> |> Is there any replacement for the linux-function iopl(3)? |> Seems to be support thru the psl.h headerfile, but |> what function should I use? |> |> #define PSL_IOPL 0x00003000 /* i/o priviledge level enable */ |> |> |> -- |> Joergen Haegg jh@efd.lth.se Normal processes run at ring 3, to get I/O access, for instance, you need privilege ring 0. This is implemented for the Xserver as a special hack. With pccons (+Xserver-patches), there are functions CONSOLE_X_MODE_ON/OFF, which do this, but have the disadvantage of switching the keyboard into a probably unwanted mode, codrv has the switcher ioctl CONSOLE_X_MODE (arg=0 => ring 3, arg=1 => ring 0), without influence on the keyboard. There is an intentional protection, which requires the process executing this function to run setuid-root. Holger -- Dr. Holger Veit | INTERNET: Holger.Veit@gmd.de | | / GMD-SET German National Research | Phone: (+49) 2241 14 2448 |__| / Center for Computer Science | Fax: (+49) 2241 14 2342 | | / P.O. Box 13 16 | Three lines Signature space | |/ Schloss Birlinghoven | available for rent. Nearly DW-5205 St. Augustin, Germany | unused, good conditions