Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756190AbbLWLMr (ORCPT ); Wed, 23 Dec 2015 06:12:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36074 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751080AbbLWLMo (ORCPT ); Wed, 23 Dec 2015 06:12:44 -0500 From: Xunlei Pang To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Cc: akpm@linux-foundation.org, Eric Biederman , Xunlei Pang Subject: [PATCH 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() Date: Wed, 23 Dec 2015 19:12:26 +0800 Message-Id: <1450869146-6186-2-git-send-email-xlpang@redhat.com> In-Reply-To: <1450869146-6186-1-git-send-email-xlpang@redhat.com> References: <1450869146-6186-1-git-send-email-xlpang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1964 Lines: 69 Implement the protection method for the crash kernel memory reservation for the 64-bit x86 kdump. Signed-off-by: Xunlei Pang --- Only provided x86_64 implementation, as I've only tested on x86_64 so far. arch/x86/kernel/machine_kexec_64.c | 43 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 819ab3f..a3d289c 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -536,3 +536,46 @@ overflow: return -ENOEXEC; } #endif /* CONFIG_KEXEC_FILE */ + +#ifdef CONFIG_KEXEC_CORE +static int +kexec_mark_range(unsigned long start, unsigned long end, bool protect) +{ + struct page *page; + unsigned int nr_pages; + + if (!start || !end || start >= end) + return 0; + + page = pfn_to_page(start >> PAGE_SHIFT); + nr_pages = (end + 1 - start) >> PAGE_SHIFT; + if (protect) + return set_pages_ro(page, nr_pages); + else + return set_pages_rw(page, nr_pages); +} + +static void kexec_mark_crashkres(bool protect) +{ + unsigned long control; + + kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect); + + /* Don't touch the control code page used in crash_kexec().*/ + control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page)); + /* Control code page is located in the 2nd page. */ + control = control + PAGE_SIZE; + kexec_mark_range(crashk_res.start, control - 1, protect); + kexec_mark_range(control + PAGE_SIZE, crashk_res.end, protect); +} + +void arch_kexec_protect_crashkres(void) +{ + kexec_mark_crashkres(true); +} + +void arch_kexec_unprotect_crashkres(void) +{ + kexec_mark_crashkres(false); +} +#endif -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/