Date: Thu, 16 Nov 2006 16:53:46 +0100 From: "Attilio Rao" <attilio@freebsd.org> To: "ranjith kumar" <ranjith_kumar_b4u@yahoo.com> Cc: freebsd-ia32@freebsd.org Subject: Re: disabling interrupts Message-ID: <3bbf2fe10611160753q3303d81bw515bffe9af4ee0c9@mail.gmail.com> In-Reply-To: <20061116112749.58242.qmail@web58409.mail.re3.yahoo.com> References: <20061116112749.58242.qmail@web58409.mail.re3.yahoo.com>
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2006/11/16, ranjith kumar <ranjith_kumar_b4u@yahoo.com>: > Hi, > > How to disable interrupts on Pentium 4(or any > i386) machine? > > I tried to include "cli" instruction in kernel module. > But got runtime errors. > > Thanks in advance. Why you want this? Anyway, you can't disable interrupts for long periods of time, since interrupts are required for a lot of vital works (i.e. pagefaults). In this optic, even the "syscall handler" (exception handler of the int 0x80) is implemented through a trap gate more than an interrupt gate. And keep in mind that a lot of kernel routines working on IF, preserve the caller's eflags state (so disabling them would have no results in some cases). Attilio -- Peace can only be achieved by understanding - A. Einstein
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