Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752955Ab3FDJYa (ORCPT ); Tue, 4 Jun 2013 05:24:30 -0400 Received: from smtp.eu.citrix.com ([46.33.159.39]:31344 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751703Ab3FDJY3 (ORCPT ); Tue, 4 Jun 2013 05:24:29 -0400 X-IronPort-AV: E=Sophos;i="4.87,798,1363132800"; d="scan'208";a="5292384" Message-ID: <1370337866.24512.90.camel@zakaz.uk.xensource.com> Subject: Re: [PATCH v2 2/5] arm64/xen: introduce asm/xen header files on arm64 From: Ian Campbell To: Stefano Stabellini CC: , , , , , Date: Tue, 4 Jun 2013 10:24:26 +0100 In-Reply-To: <1370273624-26976-2-git-send-email-stefano.stabellini@eu.citrix.com> References: <1370273624-26976-2-git-send-email-stefano.stabellini@eu.citrix.com> Organization: Citrix Systems, Inc. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.30.203.1] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1585 Lines: 42 On Mon, 2013-06-03 at 16:33 +0100, Stefano Stabellini wrote: > asm/xen/hypercall.h, asm/xen/hypervisor.h, asm/xen/interface.h and > asm/xen/page.h are indentical so to avoid code duplication we are just "identical" > including the original arm header files here. > > asm/xen/events.h is slightly different, so introduce a different file > here (use xchg to implement xchg_xen_ulong and pass regs->pstate to > raw_irqs_disabled_flags). > > Also introduce asm/hypervisor.h and asm/sync_bitops.h. > > Signed-off-by: Stefano Stabellini Acked-by: Ian Campbell [...] > +/* sync_bitops functions are equivalent to the SMP implementation of the > + * original functions, independently from CONFIG_SMP being defined. > + * > + * We need them because _set_bit etc are not SMP safe if !CONFIG_SMP. But > + * under Xen you might be communicating with a completely external entity > + * who might be on another CPU (e.g. two uniprocessor guests communicating > + * via event channels and grant tables). So we need a variant of the bit > + * ops which are SMP safe even on a UP kernel. > + */ > + > +#define sync_set_bit(nr, p) set_bit(nr, p) Oh, arm64 seems to have optimised bitops now, which means I can ditch the skanky versions in Xen in favour of these. Nice. Ian. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/