From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH 1/2] arm: Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6 Date: Wed, 23 Jun 2010 09:12:18 +0100 Message-ID: <20100623081218.GA16385@n2100.arm.linux.org.uk> References: <20100621133749.24299.36154.stgit@baageli.muru.com> <20100621135120.24299.98499.stgit@baageli.muru.com> <20100622170020.GF4371@shareable.org> <20100623073912.GA12255@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from caramon.arm.linux.org.uk ([78.32.30.218]:49624 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751209Ab0FWIMb (ORCPT ); Wed, 23 Jun 2010 04:12:31 -0400 Content-Disposition: inline In-Reply-To: <20100623073912.GA12255@atomide.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tony Lindgren Cc: Jamie Lokier , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Wed, Jun 23, 2010 at 10:39:13AM +0300, Tony Lindgren wrote: > Yeah that can be done for __kuser_get_tls if it's always writable. > But __switch_to is trickier because of the CONFIG_MMU ifdefs there. And impossible with XIP kernels. > What if we have optional __switch_to and __kuser_get_tls implementations > in the mm/proc-*.S files that get copied over the current locations > if implemented? Also problematical with XIP - if we go down the route of implementing these by copying code fragments into the kernel, we need to strip out XIP support or implement a second way. Obviously having a second way adds maintainence burden, and the second way will probably lose out on updates.