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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AFFEFECAAA1 for ; Sun, 30 Oct 2022 18:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229719AbiJ3SWU (ORCPT ); Sun, 30 Oct 2022 14:22:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229574AbiJ3SWT (ORCPT ); Sun, 30 Oct 2022 14:22:19 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AB6A5B854 for ; Sun, 30 Oct 2022 11:22:18 -0700 (PDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 29UDkg35004578; Sun, 30 Oct 2022 18:22:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=zIoTWuen4ZrZqY3T64H1KYNmxzw5GiUs2dPpkzdesP8=; b=kUAfCh/DGCm4gs3qW97kAfaFoKvr5oK2mgEvkA9BQ0aJwaJKw+qaK9bGPnd/59OJMMIx yGsaH9YSsEgkkamBu8/DE/z1EsBTHtB67evvsRhq6HxoaNBB0N9YVSn10DXV9oY0JSeL Hhp4czwoc7u+ooh1dJF4QNux7HQc3lmwjTwVke/u3CAwQMaHih+EDH4l5s21H+OACZTZ 5DmqIexGLpX0CnWPo1m43AhsGbdxF3KbMRPFTnFoPZRPv++gHvNr1vJhSIhk0fX6Avs7 LY9AHNSQ7h31H1NVrutzvpGI42qk6W42HCX0HXX/fhPTDNiHfP/KXCzICHKum9IoeObT lA== Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3khe6ug925-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 30 Oct 2022 18:22:09 +0000 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 29UIM1dh031753; Sun, 30 Oct 2022 18:22:07 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma03ams.nl.ibm.com with ESMTP id 3kgut8su3y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 30 Oct 2022 18:22:07 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 29UIM2jH31588964 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 30 Oct 2022 18:22:02 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7E888AE051; Sun, 30 Oct 2022 18:22:02 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 34A4AAE045; Sun, 30 Oct 2022 18:22:02 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Sun, 30 Oct 2022 18:22:02 +0000 (GMT) From: Heiko Carstens To: Vasily Gorbik , Alexander Gordeev , Nathan Chancellor Cc: Sven Schnelle , Christian Borntraeger , Ulrich Weigand , Gerald Schaefer , linux-s390@vger.kernel.org Subject: [PATCH] s390: always build relocatable kernel Date: Sun, 30 Oct 2022 19:22:02 +0100 Message-Id: <20221030182202.2062705-1-hca@linux.ibm.com> X-Mailer: git-send-email 2.34.1 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Guc8KgieGb6L9boNQKfHfaoF-5nuT6np X-Proofpoint-GUID: Guc8KgieGb6L9boNQKfHfaoF-5nuT6np Content-Transfer-Encoding: 8bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-30_11,2022-10-27_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 adultscore=0 spamscore=0 mlxlogscore=999 clxscore=1011 phishscore=0 mlxscore=0 suspectscore=0 priorityscore=1501 bulkscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2210170000 definitions=main-2210300116 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org Nathan Chancellor reported several link errors on s390 with CONFIG_RELOCATABLE disabled, after binutils commit 906f69cf65da ("IBM zSystems: Issue error for *DBL relocs on misaligned symbols"). The binutils commit reveals potential miscompiles that might have happened already before with linker script defined symbols at odd addresses. A similar bug was recently fixed in the kernel with commit c9305b6c1f52 ("s390: fix nospec table alignments"). See https://github.com/ClangBuiltLinux/linux/issues/1747 for an analysis from Ulich Weigand. Therefore always build a relocatable kernel to avoid this problem. There is hardly any use-case for non-relocatable kernels, so this shouldn't be controversial. Link: https://github.com/ClangBuiltLinux/linux/issues/1747 Signed-off-by: Heiko Carstens --- arch/s390/Kconfig | 6 +++--- arch/s390/Makefile | 2 -- arch/s390/boot/Makefile | 3 +-- arch/s390/boot/startup.c | 3 +-- 4 files changed, 5 insertions(+), 9 deletions(-) diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 318fce77601d..de575af02ffe 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -568,8 +568,7 @@ config EXPOLINE_FULL endchoice config RELOCATABLE - bool "Build a relocatable kernel" - default y + def_bool y help This builds a kernel image that retains relocation information so it can be loaded at an arbitrary address. @@ -578,10 +577,11 @@ config RELOCATABLE bootup process. The relocations make the kernel image about 15% larger (compressed 10%), but are discarded at runtime. + Note: this option exists only for documentation purposes, please do + not remove it. config RANDOMIZE_BASE bool "Randomize the address of the kernel image (KASLR)" - depends on RELOCATABLE default y help In support of Kernel Address Space Layout Randomization (KASLR), diff --git a/arch/s390/Makefile b/arch/s390/Makefile index de6d8b2ea4d8..b3235ab0ace8 100644 --- a/arch/s390/Makefile +++ b/arch/s390/Makefile @@ -14,10 +14,8 @@ KBUILD_AFLAGS_MODULE += -fPIC KBUILD_CFLAGS_MODULE += -fPIC KBUILD_AFLAGS += -m64 KBUILD_CFLAGS += -m64 -ifeq ($(CONFIG_RELOCATABLE),y) KBUILD_CFLAGS += -fPIE LDFLAGS_vmlinux := -pie -endif aflags_dwarf := -Wa,-gdwarf-2 KBUILD_AFLAGS_DECOMPRESSOR := $(CLANG_FLAGS) -m64 -D__ASSEMBLY__ ifndef CONFIG_AS_IS_LLVM diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile index 883357a211a3..d52c3e2e16bc 100644 --- a/arch/s390/boot/Makefile +++ b/arch/s390/boot/Makefile @@ -37,9 +37,8 @@ CFLAGS_sclp_early_core.o += -I$(srctree)/drivers/s390/char obj-y := head.o als.o startup.o mem_detect.o ipl_parm.o ipl_report.o obj-y += string.o ebcdic.o sclp_early_core.o mem.o ipl_vmparm.o cmdline.o -obj-y += version.o pgm_check_info.o ctype.o ipl_data.o +obj-y += version.o pgm_check_info.o ctype.o ipl_data.o machine_kexec_reloc.o obj-$(findstring y, $(CONFIG_PROTECTED_VIRTUALIZATION_GUEST) $(CONFIG_PGSTE)) += uv.o -obj-$(CONFIG_RELOCATABLE) += machine_kexec_reloc.o obj-$(CONFIG_RANDOMIZE_BASE) += kaslr.o obj-y += $(if $(CONFIG_KERNEL_UNCOMPRESSED),,decompressor.o) info.o obj-$(CONFIG_KERNEL_ZSTD) += clz_ctz.o diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c index 6e7f01ca53e6..47ca3264c023 100644 --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -291,8 +291,7 @@ void startup_kernel(void) clear_bss_section(); copy_bootdata(); - if (IS_ENABLED(CONFIG_RELOCATABLE)) - handle_relocs(__kaslr_offset); + handle_relocs(__kaslr_offset); if (__kaslr_offset) { /* -- 2.34.1