From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wright Subject: Re: [RFC PATCH 01/11] Add basic support for gcc profiler instrumentation Date: Thu, 3 Jan 2008 10:16:51 -0800 Message-ID: <20080103181651.GC3627@sequoia.sous-sol.org> References: <20080103071609.478486470@goodmis.org> <20080103072226.776141236@goodmis.org> <20080103092104.GE10813@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Steven Rostedt Cc: Chris Wright , Mathieu Desnoyers , Peter Zijlstra , Gregory Haskins , LKML , virtualization@lists.linux-foundation.org, Christoph Hellwig , Steven Rostedt , Arnaldo Carvalho de Melo , "William L. Irwin" , Ingo Molnar , Linus Torvalds , Andrew Morton List-Id: virtualization@lists.linuxfoundation.org * Steven Rostedt (rostedt@goodmis.org) wrote: > Hmm, I know paravirt-ops had an issue with mcount in the RT tree. I can't > remember the exact issues, but it did have something to do with the way > parameters were passed in. > > Chris, do you remember what the issues were? Yes, paravirt ops have a well-specified calling convention (register based). There was a cleanup that Andi did that caused the problem because it removed all the "fastcall" annotations since -mregparm=3 is now always on for i386. Since MCOUNT disables REGPARM the calling convention changes (caller pushes to stack, callee expects register) chaos ensues. I sent a patch to fix that quite some months back, but it went stale and I neglected to update it. Would you like me to dig it up refresh and resend? thanks, -chris