From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752583AbcAFJvr (ORCPT ); Wed, 6 Jan 2016 04:51:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752182AbcAFJvM (ORCPT ); Wed, 6 Jan 2016 04:51:12 -0500 From: Xunlei Pang To: linux-kernel@vger.kernel.org, kexec@lists.infradead.org Cc: akpm@linux-foundation.org, ebiederm@xmission.com, Minfei Huang , Vivek Goyal , Dave Young , Xunlei Pang Subject: [PATCH v2 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() Date: Wed, 6 Jan 2016 17:50:45 +0800 Message-Id: <1452073845-1474-2-git-send-email-xlpang@redhat.com> In-Reply-To: <1452073845-1474-1-git-send-email-xlpang@redhat.com> References: <1452073845-1474-1-git-send-email-xlpang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Implement the protection method for the crash kernel memory reservation for the 64-bit x86 kdump. Signed-off-by: Xunlei Pang --- arch/x86/kernel/machine_kexec_64.c | 41 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 819ab3f..cda867d 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -536,3 +536,44 @@ overflow: return -ENOEXEC; } #endif /* CONFIG_KEXEC_FILE */ + +static int +kexec_mark_range(unsigned long start, unsigned long end, bool protect) +{ + struct page *page; + unsigned int nr_pages; + + /* For physical range: [start, end] */ + if (!start || !end || start > end) + return 0; + + page = pfn_to_page(start >> PAGE_SHIFT); + nr_pages = (end + PAGE_SIZE - 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. */ + kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect); + kexec_mark_range(control + 2 * 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); +} -- 2.5.0