From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 17 Sep 2013 23:21:20 +0200 (CEST) Received: from localhost.localdomain ([127.0.0.1]:47826 "EHLO linux-mips.org" rhost-flags-OK-OK-OK-FAIL) by eddie.linux-mips.org with ESMTP id S6862036Ab3IQVVSYj02w (ORCPT ); Tue, 17 Sep 2013 23:21:18 +0200 Received: from scotty.linux-mips.net (localhost.localdomain [127.0.0.1]) by scotty.linux-mips.net (8.14.7/8.14.4) with ESMTP id r8HLLEVZ005896; Tue, 17 Sep 2013 23:21:14 +0200 Received: (from ralf@localhost) by scotty.linux-mips.net (8.14.7/8.14.7/Submit) id r8HLLDEN005895; Tue, 17 Sep 2013 23:21:13 +0200 Date: Tue, 17 Sep 2013 23:21:13 +0200 From: Ralf Baechle To: Jayachandran C Cc: linux-mips@linux-mips.org Subject: Re: [PATCH 2/2] MIPS: mm: Use scratch for PGD when !CONFIG_MIPS_PGD_C0_CONTEXT Message-ID: <20130917212113.GI22468@linux-mips.org> References: <1376221217-9335-1-git-send-email-jchandra@broadcom.com> <1376221217-9335-3-git-send-email-jchandra@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376221217-9335-3-git-send-email-jchandra@broadcom.com> User-Agent: Mutt/1.5.21 (2010-09-15) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 37839 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Sun, Aug 11, 2013 at 05:10:17PM +0530, Jayachandran C wrote: > Allow usage of scratch register for current pgd even when > MIPS_PGD_C0_CONTEXT is not configured. MIPS_PGD_C0_CONTEXT is set > for 64r2 platforms to indicate availability of Xcontext for saving > cpuid, thus freeing Context to be used for saving PGD. This option > was also tied to using a scratch register for storing PGD. > > This commit will allow usage of scratch register to store the current > pgd if one can be allocated for the platform, even when > MIPS_PGD_C0_CONTEXT is not set. The cpuid will be kept in the CP0 > Context register in this case. > > The code to store the current pgd for the TLB miss handler is now > generated in all cases. When scratch register is available, the PGD > is also stored in the scratch register. This patch breaks the build for almost all platforms. Amusingly it doesn't break Cavium however which is why I didn't notice it right away. The build error is the same for all platforms: [...] LD init/built-in.o arch/mips/built-in.o: In function `per_cpu_trap_init': (.text+0x80e4): undefined reference to `tlbmiss_handler_setup_pgd' arch/mips/built-in.o: In function `build_setup_pgd': tlbex.c:(.text+0xe31c): undefined reference to `tlbmiss_handler_setup_pgd' tlbex.c:(.text+0xe328): undefined reference to `tlbmiss_handler_setup_pgd' tlbex.c:(.text+0xe324): undefined reference to `tlbmiss_handler_setup_pgd_end' tlbex.c:(.text+0xe32c): undefined reference to `tlbmiss_handler_setup_pgd_end' kernel/built-in.o: In function `__schedule': core.c:(.sched.text+0x1b74): undefined reference to `tlbmiss_handler_setup_pgd' mm/built-in.o: In function `use_mm': (.text+0x1a530): undefined reference to `tlbmiss_handler_setup_pgd' fs/built-in.o: In function `flush_old_exec': (.text+0x8da8): undefined reference to `tlbmiss_handler_setup_pgd' make[2]: *** [vmlinux] Error 1 make[1]: *** [sub-make] Error 2 make: *** [all] Error 2 make: Leaving directory `/home/ralf/src/linux/obj/cobalt-build' I'm reverting the patch now. Ralf