From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0F6CC28CC2 for ; Thu, 30 May 2019 14:16:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4F0A25A58 for ; Thu, 30 May 2019 14:16:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727269AbfE3OQD (ORCPT ); Thu, 30 May 2019 10:16:03 -0400 Received: from foss.arm.com ([217.140.101.70]:36514 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726250AbfE3OQC (ORCPT ); Thu, 30 May 2019 10:16:02 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4BF231684; Thu, 30 May 2019 07:16:02 -0700 (PDT) Received: from e119884-lin.cambridge.arm.com (e119884-lin.cambridge.arm.com [10.1.196.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 10BDC3F59C; Thu, 30 May 2019 07:15:58 -0700 (PDT) From: Vincenzo Frascino To: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Catalin Marinas , Will Deacon , Arnd Bergmann , Russell King , Ralf Baechle , Paul Burton , Daniel Lezcano , Thomas Gleixner , Mark Salyzyn , Peter Collingbourne , Shuah Khan , Dmitry Safonov <0x7f454c46@gmail.com>, Rasmus Villemoes , Huw Davies , Mark Salyzyn Subject: [PATCH v6 05/19] arm64: Build vDSO with -ffixed-x18 Date: Thu, 30 May 2019 15:15:17 +0100 Message-Id: <20190530141531.43462-6-vincenzo.frascino@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190530141531.43462-1-vincenzo.frascino@arm.com> References: <20190530141531.43462-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org From: Peter Collingbourne The vDSO needs to be build with x18 reserved in order to accommodate userspace platform ABIs built on top of Linux that use the register to carry inter-procedural state, as provided for by the AAPCS. An example of such a platform ABI is the one that will be used by an upcoming version of Android. Although this change is currently a no-op due to the fact that the vDSO is currently implemented in pure assembly on arm64, it is necessary in order to prepare for another change [1] that will add C code to the vDSO. [1] https://patchwork.kernel.org/patch/10044501/ Signed-off-by: Peter Collingbourne Signed-off-by: Vincenzo Frascino Cc: Mark Salyzyn Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org --- arch/arm64/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 00bcfd2672cf..d98230f70caf 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -20,7 +20,7 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \ --build-id -n -T -ccflags-y := -fno-common -fno-builtin -fno-stack-protector +ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18 ccflags-y += -DDISABLE_BRANCH_PROFILING VDSO_LDFLAGS := -Bsymbolic -- 2.21.0