Rene, Thanks ! and welcome back (just kidding) ;) On 11/25/07, Rene Herman <rene.herman@xxxxxxxxxxxx> wrote: > On 25-11-07 08:58, Ramagudi Naziir wrote: > > > I read in intel's manual that you can either put interrupt gate > > or a task gate in the IDT. > > Or trap-gate, which is an interrupt-gate minus the automatic interrupt > disabling. > > > So what does Linux put there ? when an int 80 is executed - is > > it via an interrupt gate or task gate ? > > Trap-gate. > > > are task gates used in Linux anyway ? > > Only for a double fault (defined as an exception that occurs while calling > the handler for a previous one and which cannot be handled serially; a page > fault occuring while trying to call the page-fault handler for example) and > only since late 2.5 or early 2.6 or so. > > The most definite advantage of using a task gate for this seems likely to be > that a task switch also switches stacks so that a stack fault won't just > keep recursing upon trying to call the handler and end up as a triple-fault, > meaning an automatic CPU shutdown. > > You can see Linux set up the IDT in trap_init(). > > Rene. > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
