From patchwork Fri Aug 9 10:07:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Yan X-Patchwork-Id: 11086151 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8C5E6112C for ; Fri, 9 Aug 2019 09:53:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7B43928C2B for ; Fri, 9 Aug 2019 09:53:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6EEAA28C5E; Fri, 9 Aug 2019 09:53:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 85F8E28C2B for ; Fri, 9 Aug 2019 09:53:47 +0000 (UTC) Received: (qmail 13666 invoked by uid 550); 9 Aug 2019 09:52:21 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 13377 invoked from network); 9 Aug 2019 09:52:15 -0000 From: Jason Yan To: , , , , , , , , CC: , , , , , , , Jason Yan Subject: [PATCH v6 10/12] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Date: Fri, 9 Aug 2019 18:07:58 +0800 Message-ID: <20190809100800.5426-11-yanaijie@huawei.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190809100800.5426-1-yanaijie@huawei.com> References: <20190809100800.5426-1-yanaijie@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.28] X-CFilter-Loop: Reflected X-Virus-Scanned: ClamAV using ClamSMTP When kaslr is enabled, the kernel offset is different for every boot. This brings some difficult to debug the kernel. Dump out the kernel offset when panic so that we can easily debug the kernel. This code is derived from x86/arm64 which has similar functionality. Signed-off-by: Jason Yan Cc: Diana Craciun Cc: Michael Ellerman Cc: Christophe Leroy Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Nicholas Piggin Cc: Kees Cook Reviewed-by: Christophe Leroy Reviewed-by: Diana Craciun Tested-by: Diana Craciun --- arch/powerpc/include/asm/page.h | 5 +++++ arch/powerpc/kernel/setup-common.c | 20 ++++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 4d32d1b561d6..b34b9cdd91f1 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -317,6 +317,11 @@ struct vm_area_struct; extern unsigned long kernstart_virt_addr; +static inline unsigned long kaslr_offset(void) +{ + return kernstart_virt_addr - KERNELBASE; +} + #include #endif /* __ASSEMBLY__ */ #include diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 1f8db666468d..ba1a34ab218a 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -715,8 +715,28 @@ static struct notifier_block ppc_panic_block = { .priority = INT_MIN /* may not return; must be done last */ }; +/* + * Dump out kernel offset information on panic. + */ +static int dump_kernel_offset(struct notifier_block *self, unsigned long v, + void *p) +{ + pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n", + kaslr_offset(), KERNELBASE); + + return 0; +} + +static struct notifier_block kernel_offset_notifier = { + .notifier_call = dump_kernel_offset +}; + void __init setup_panic(void) { + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_offset() > 0) + atomic_notifier_chain_register(&panic_notifier_list, + &kernel_offset_notifier); + /* PPC64 always does a hard irq disable in its panic handler */ if (!IS_ENABLED(CONFIG_PPC64) && !ppc_md.panic) return;