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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 B96E7C43603 for ; Mon, 16 Dec 2019 18:14:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 917A5218AC for ; Mon, 16 Dec 2019 18:14:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520049; bh=qONlitSrMg/KdcPLAt0yizWuwMCNALHE+k/dQ5GPIws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ECkpBr6MW8Slxa3yaZulM10Bb/zO+99bofAOrS/rHecbD30Ia6lyRgOV807Li+/Ra CVAZdzW767+pEPoNmr5nge9gY6QENgAddJ1yDkwjgEYFagwT77ro3xIr+6LfkV0DwO RZ/iJ/gb5izcVKNBTUbvEJp65jYzntz+QV/0DyG8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730509AbfLPSOJ (ORCPT ); Mon, 16 Dec 2019 13:14:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:32988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731184AbfLPSOH (ORCPT ); Mon, 16 Dec 2019 13:14:07 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 00D3820CC7; Mon, 16 Dec 2019 18:14:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576520047; bh=qONlitSrMg/KdcPLAt0yizWuwMCNALHE+k/dQ5GPIws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0dBeumuSG4/x3smzfq0z1dm9bJvUsstJtv/dbyo/k3tdy/KxZHgR9QBLXrgvbGvhp J+aFB1ePdGQZ8zHVj0uxQZjY+DhWfgXuVhZuT2spkjRpinMjqnrfUbAXW3mqGJdFIM 76N+A2BiF9eNVxF7qt7LL3eV1ZzCzv5M565ZB2fM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gerald Schaefer , Vasily Gorbik Subject: [PATCH 5.3 176/180] s390/kaslr: store KASLR offset for early dumps Date: Mon, 16 Dec 2019 18:50:16 +0100 Message-Id: <20191216174848.194661636@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174806.018988360@linuxfoundation.org> References: <20191216174806.018988360@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Gerald Schaefer commit a9f2f6865d784477e1c7b59269d3a384abafd9ca upstream. The KASLR offset is added to vmcoreinfo in arch_crash_save_vmcoreinfo(), so that it can be found by crash when processing kernel dumps. However, arch_crash_save_vmcoreinfo() is called during a subsys_initcall, so if the kernel crashes before that, we have no vmcoreinfo and no KASLR offset. Fix this by storing the KASLR offset in the lowcore, where the vmcore_info pointer will be stored, and where it can be found by crash. In order to make it distinguishable from a real vmcore_info pointer, mark it as uneven (KASLR offset itself is aligned to THREAD_SIZE). When arch_crash_save_vmcoreinfo() stores the real vmcore_info pointer in the lowcore, it overwrites the KASLR offset. At that point, the KASLR offset is not yet added to vmcoreinfo, so we also need to move the mem_assign_absolute() behind the vmcoreinfo_append_str(). Fixes: b2d24b97b2a9 ("s390/kernel: add support for kernel address space layout randomization (KASLR)") Cc: # v5.2+ Signed-off-by: Gerald Schaefer Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- arch/s390/boot/startup.c | 5 +++++ arch/s390/kernel/machine_kexec.c | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) --- a/arch/s390/boot/startup.c +++ b/arch/s390/boot/startup.c @@ -164,6 +164,11 @@ void startup_kernel(void) handle_relocs(__kaslr_offset); if (__kaslr_offset) { + /* + * Save KASLR offset for early dumps, before vmcore_info is set. + * Mark as uneven to distinguish from real vmcore_info pointer. + */ + S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL; /* Clear non-relocated kernel */ if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) memset(img, 0, vmlinux.image_size); --- a/arch/s390/kernel/machine_kexec.c +++ b/arch/s390/kernel/machine_kexec.c @@ -254,10 +254,10 @@ void arch_crash_save_vmcoreinfo(void) VMCOREINFO_SYMBOL(lowcore_ptr); VMCOREINFO_SYMBOL(high_memory); VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS); - mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); vmcoreinfo_append_str("SDMA=%lx\n", __sdma); vmcoreinfo_append_str("EDMA=%lx\n", __edma); vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); + mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note()); } void machine_shutdown(void)