From patchwork Wed Jul 17 08:06:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Yan X-Patchwork-Id: 11047399 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 5C5D16C5 for ; Wed, 17 Jul 2019 07:51:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5201F285A4 for ; Wed, 17 Jul 2019 07:51:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4626B286FF; Wed, 17 Jul 2019 07:51:17 +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 59DA9285A4 for ; Wed, 17 Jul 2019 07:51:16 +0000 (UTC) Received: (qmail 1328 invoked by uid 550); 17 Jul 2019 07:49:45 -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 1168 invoked from network); 17 Jul 2019 07:49:40 -0000 From: Jason Yan To: , , , , , , , , CC: , , , , , , Jason Yan Subject: [RFC PATCH 10/10] powerpc/fsl_booke/kaslr: dump out kernel offset information on panic Date: Wed, 17 Jul 2019 16:06:21 +0800 Message-ID: <20190717080621.40424-11-yanaijie@huawei.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190717080621.40424-1-yanaijie@huawei.com> References: <20190717080621.40424-1-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. 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 --- arch/powerpc/include/asm/page.h | 5 +++++ arch/powerpc/kernel/machine_kexec.c | 1 + arch/powerpc/kernel/setup-common.c | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+) diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 60a68d3a54b1..cd3ac530e58d 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 kimage_vaddr; +static inline unsigned long kaslr_offset(void) +{ + return kimage_vaddr - KERNELBASE; +} + #include #endif /* __ASSEMBLY__ */ #include diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c index c4ed328a7b96..078fe3d76feb 100644 --- a/arch/powerpc/kernel/machine_kexec.c +++ b/arch/powerpc/kernel/machine_kexec.c @@ -86,6 +86,7 @@ void arch_crash_save_vmcoreinfo(void) VMCOREINFO_STRUCT_SIZE(mmu_psize_def); VMCOREINFO_OFFSET(mmu_psize_def, shift); #endif + vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset()); } /* diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 1f8db666468d..49e540c0adeb 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -715,12 +715,35 @@ 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) +{ + const unsigned long offset = kaslr_offset(); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) + pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n", + offset, KERNELBASE); + else + pr_emerg("Kernel Offset: disabled\n"); + + return 0; +} + +static struct notifier_block kernel_offset_notifier = { + .notifier_call = dump_kernel_offset +}; + void __init setup_panic(void) { /* PPC64 always does a hard irq disable in its panic handler */ if (!IS_ENABLED(CONFIG_PPC64) && !ppc_md.panic) return; atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block); + atomic_notifier_chain_register(&panic_notifier_list, + &kernel_offset_notifier); } #ifdef CONFIG_CHECK_CACHE_COHERENCY