From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 456AF67A04 for ; Sat, 15 Apr 2006 08:57:45 +1000 (EST) Subject: Re: 7447A strange problem with MSR:POW (WAS: can't boot 2.6.17-rc1) From: Benjamin Herrenschmidt To: Becky Bruce In-Reply-To: References: <1144408805.30891.42.camel@localhost.localdomain> <17463.9759.442768.685153@cargo.ozlabs.ibm.com> <1144923633.4935.11.camel@localhost.localdomain> <21F7D7D8-B9BC-44EB-B07B-F888D89DCF25@freescale.com> <17471.62187.774127.783000@cargo.ozlabs.ibm.com> <20060414195436.GC24769@pb15.lixom.net> Content-Type: text/plain Date: Sat, 15 Apr 2006 08:57:31 +1000 Message-Id: <1145055451.4223.40.camel@localhost.localdomain> Mime-Version: 1.0 Cc: Olof Johansson , linuxppc-dev list , Michael Schmitz , debian-powerpc@lists.debian.org, Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, 2006-04-14 at 15:00 -0500, Becky Bruce wrote: > He's being sneaky - there's a copy of HID0 in the CR at this point > from the caller, and bit 9 is the position for NAP. It's a trick I learned from Darwin :) They do that regulary when code is very cpu-feature dependant, like cache code for example, they put the cpu features bitmask in CR and do branches based on individual bits of it here or there. Ben.