From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from db8outboundpool.messaging.microsoft.com (mail-db8lp0189.outbound.messaging.microsoft.com [213.199.154.189]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id A5FC02C00A4 for ; Wed, 23 Oct 2013 21:15:32 +1100 (EST) Message-ID: <1382523314.3926.21.camel@aoeu.buserror.net> Subject: Re: [PATCH] [RFC] Emulate "lwsync" to run standard user land on e500 cores From: Scott Wood To: Kumar Gala Date: Wed, 23 Oct 2013 11:15:14 +0100 In-Reply-To: <39CCEB38-1D9B-4918-B8F4-148D4E90FE21@kernel.crashing.org> References: <1382081880-6666-1-git-send-email-wd@denx.de> <39CCEB38-1D9B-4918-B8F4-148D4E90FE21@kernel.crashing.org> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, Wolfgang Denk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2013-10-23 at 00:07 -0500, Kumar Gala wrote: > On Oct 18, 2013, at 2:38 AM, Wolfgang Denk wrote: > > diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c > > index f783c93..f330374 100644 > > --- a/arch/powerpc/kernel/traps.c > > +++ b/arch/powerpc/kernel/traps.c > > @@ -986,6 +986,13 @@ static int emulate_instruction(struct pt_regs *regs) > > return 0; > > } > > > > + /* Emulating the lwsync insn as a sync insn */ > > + if (instword == PPC_INST_LWSYNC) { > > + PPC_WARN_EMULATED(lwsync, regs); > > + asm volatile("sync" : : : "memory"); > > Do we really need the inline asm? Doesn't the fact of just taking an exception and returning from it equate to a sync. No, it doesn't equate to a sync. See the discussion here: http://patchwork.ozlabs.org/patch/256747/ -Scott