From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1aBz2b-0002C2-LD for kexec@lists.infradead.org; Thu, 24 Dec 2015 06:06:22 +0000 Subject: Re: [PATCH 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() References: <1450869146-6186-1-git-send-email-xlpang@redhat.com> <1450869146-6186-2-git-send-email-xlpang@redhat.com> <20151224055425.GC3480@dhcp-128-65.nay.redhat.com> From: Xunlei Pang Message-ID: <567B8B44.9070807@redhat.com> Date: Thu, 24 Dec 2015 14:05:56 +0800 MIME-Version: 1.0 In-Reply-To: <20151224055425.GC3480@dhcp-128-65.nay.redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Young Cc: akpm@linux-foundation.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, vgoyal@redhat.com, Eric Biederman On 12/24/2015 at 01:54 PM, Dave Young wrote: > Ccing Vivek > > On 12/23/15 at 07:12pm, Xunlei Pang wrote: >> 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 > The file is only compiled when CONFIG_KEXEC_CORE=y so #ifdef is not necessary Yes, indeed. I'll remove this macro and send v2 later. > >> +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); > May use set_memory_ro/rw to avoid converting to *page? on x86 it just a wrapper of set_memory_ro/rw, I think both are ok. > >> +} >> + >> +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); > X86 kexec will copy the page while kexecing, could you check if we can move > that copying to earliyer while kexec loading, maybe machine_kexec_prepare so > that we can make a arch-independent implementation. For some arch, may use huge tlb directly to do the kernel mapping, in such cases, we can't implement this function. So I think it should be arch-dependent. Regards, Xunlei > >> +} >> + >> +void arch_kexec_protect_crashkres(void) >> +{ >> + kexec_mark_crashkres(true); >> +} >> + >> +void arch_kexec_unprotect_crashkres(void) >> +{ >> + kexec_mark_crashkres(false); >> +} >> +#endif >> -- >> 2.5.0 >> >> >> _______________________________________________ >> kexec mailing list >> kexec@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/kexec _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932516AbbLXGGD (ORCPT ); Thu, 24 Dec 2015 01:06:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38966 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932394AbbLXGGA (ORCPT ); Thu, 24 Dec 2015 01:06:00 -0500 Subject: Re: [PATCH 2/2] kexec: Provide arch_kexec_protect(unprotect)_crashkres() To: Dave Young References: <1450869146-6186-1-git-send-email-xlpang@redhat.com> <1450869146-6186-2-git-send-email-xlpang@redhat.com> <20151224055425.GC3480@dhcp-128-65.nay.redhat.com> Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, akpm@linux-foundation.org, Eric Biederman , vgoyal@redhat.com From: Xunlei Pang Message-ID: <567B8B44.9070807@redhat.com> Date: Thu, 24 Dec 2015 14:05:56 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151224055425.GC3480@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/24/2015 at 01:54 PM, Dave Young wrote: > Ccing Vivek > > On 12/23/15 at 07:12pm, Xunlei Pang wrote: >> 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 > The file is only compiled when CONFIG_KEXEC_CORE=y so #ifdef is not necessary Yes, indeed. I'll remove this macro and send v2 later. > >> +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); > May use set_memory_ro/rw to avoid converting to *page? on x86 it just a wrapper of set_memory_ro/rw, I think both are ok. > >> +} >> + >> +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); > X86 kexec will copy the page while kexecing, could you check if we can move > that copying to earliyer while kexec loading, maybe machine_kexec_prepare so > that we can make a arch-independent implementation. For some arch, may use huge tlb directly to do the kernel mapping, in such cases, we can't implement this function. So I think it should be arch-dependent. Regards, Xunlei > >> +} >> + >> +void arch_kexec_protect_crashkres(void) >> +{ >> + kexec_mark_crashkres(true); >> +} >> + >> +void arch_kexec_unprotect_crashkres(void) >> +{ >> + kexec_mark_crashkres(false); >> +} >> +#endif >> -- >> 2.5.0 >> >> >> _______________________________________________ >> kexec mailing list >> kexec@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/kexec