From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13790C43219 for ; Sat, 27 Apr 2019 16:11:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4951206BB for ; Sat, 27 Apr 2019 16:11:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="hKG4NwvR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726189AbfD0QL2 (ORCPT ); Sat, 27 Apr 2019 12:11:28 -0400 Received: from mail.skyhub.de ([5.9.137.197]:39334 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726067AbfD0QL2 (ORCPT ); Sat, 27 Apr 2019 12:11:28 -0400 Received: from zn.tnic (p200300EC2F1D4200C9F1D41AFD83C4FB.dip0.t-ipconnect.de [IPv6:2003:ec:2f1d:4200:c9f1:d41a:fd83:c4fb]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 131F41EC0469; Sat, 27 Apr 2019 18:11:26 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1556381486; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=92Adu0xBHOyqjn2w5IOR2ZooSb46MP+b89bte9Cxr78=; b=hKG4NwvRBlwmA400X7xEqiTvin+5/dluvFmljDMM1Re2DWytUulHrirZ3jGId97ccLE7U0 /eSkMDDqxhFB9qbm8lc/ZFH8R9oIaRCWanEEaAh14FxrqcY95KIcoNAQDCY8pidl2/Ou1y DRr1aitNioZiReR8A1q/L/ecpkheOE0= Date: Sat, 27 Apr 2019 18:11:21 +0200 From: Borislav Petkov To: Baoquan He Cc: j-nomura@ce.jp.nec.com, kasong@redhat.com, dyoung@redhat.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, fanc.fnst@cn.fujitsu.com, x86@kernel.org, kexec@lists.infradead.org, hpa@zytor.com Subject: Re: [PATCH v5 1/2] x86/kexec: Build identity mapping for EFI systab and ACPI tables Message-ID: <20190427161121.GC12360@zn.tnic> References: <20190424092944.30481-1-bhe@redhat.com> <20190424092944.30481-2-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190424092944.30481-2-bhe@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 24, 2019 at 05:29:43PM +0800, Baoquan He wrote: > From: Kairui Song > > The current code only builds identity mapping for physical memory during > kexec-type loading. The regions reserved by firmware are not covered. > In the next patch, the boot decompressing code of kexec-ed kernel tries There's no guarantee that when this patch gets applied, the next patch will be the one you mean. So explain what you mean here instead. > to access EFI systab and ACPI tables, lacking identity mapping for them > will cause error and reset system to firmware. > > This error doesn't happen on all systems. Because kexec enables gbpages > to build identity mapping, the EFI systab and ACPI tables could have been > covered if they share the same 1 GB area with physical memory. To make > sure, we should map them always. > > So here add mapping for them. > > Signed-off-by: Kairui Song When you send someone else's patch, you need to add your SOB. Lemme point you to Documentation/process/submitting-patches.rst again. Please have a deeper look. > --- > arch/x86/kernel/machine_kexec_64.c | 86 ++++++++++++++++++++++++++++++ > 1 file changed, 86 insertions(+) > > diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c > index ceba408ea982..77b40c3e28d7 100644 > --- a/arch/x86/kernel/machine_kexec_64.c > +++ b/arch/x86/kernel/machine_kexec_64.c > @@ -18,6 +18,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -29,6 +30,48 @@ > #include > #include > > +#ifdef CONFIG_ACPI > +/** Two stars '**' are kernel-doc style but this comment is implementation detail and is irrelevant for kernel-doc ouput. > + * Used while adding mapping for ACPI tables. > + * Can be reused when other iomem regions need be mapped > + */ > +struct init_pgtable_data { > + struct x86_mapping_info *info; > + pgd_t *level4p; > +}; > + > +static int mem_region_callback(struct resource *res, void *arg) > +{ > + struct init_pgtable_data *data = arg; > + unsigned long mstart, mend; > + > + mstart = res->start; > + mend = mstart + resource_size(res) - 1; > + > + return kernel_ident_mapping_init(data->info, > + data->level4p, mstart, mend); Do not break that line. > +} > + > +static int init_acpi_pgtable(struct x86_mapping_info *info, > + pgd_t *level4p) static int map_acpi_tables(...) > +{ > + unsigned long flags = IORESOURCE_MEM | IORESOURCE_BUSY; > + struct init_pgtable_data data; > + > + data.info = info; > + data.level4p = level4p; > + flags = IORESOURCE_MEM | IORESOURCE_BUSY; > + return walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, > + &data, mem_region_callback); > +} > +#else > +static int init_acpi_pgtable(struct x86_mapping_info *info, > + pgd_t *level4p) > +{ > + return 0; > +} > +#endif > + > #ifdef CONFIG_KEXEC_FILE > const struct kexec_file_ops * const kexec_file_loaders[] = { > &kexec_bzImage64_ops, > @@ -36,6 +79,37 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { > }; > #endif > > +#ifdef CONFIG_EFI > +static int init_efi_systab_pgtable(struct x86_mapping_info *info, > + pgd_t *level4p) This function's name is wrong. Make it like this: static int map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p) { #ifdef CONFIG_EFI ... #endif return 0; } and drop the #else ifdeffery. > +{ > + unsigned long mstart, mend; > + > + if (!efi_enabled(EFI_BOOT)) > + return 0; > + > + mstart = (boot_params.efi_info.efi_systab | > + ((u64)boot_params.efi_info.efi_systab_hi<<32)); > + > + if (efi_enabled(EFI_64BIT)) > + mend = mstart + sizeof(efi_system_table_64_t); > + else > + mend = mstart + sizeof(efi_system_table_32_t); > + > + if (mstart) > + return kernel_ident_mapping_init(info, > + level4p, mstart, mend); Flip that logic: if (!mstart) return 0; return kernel_ident_mapping_init(info, level4p, mstart, mend); and let the function stick out. > + > + return 0; > +} > +#else > +static inline int init_efi_systab_pgtable(struct x86_mapping_info *info, > + pgd_t *level4p) > +{ > + return 0; > +} > +#endif > + > static void free_transition_pgtable(struct kimage *image) > { > free_page((unsigned long)image->arch.p4d); > @@ -159,6 +233,18 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable) > return result; > } > > + /** Two stars '**' are kernel-doc style comments above function names but not here. > + * Prepare EFI systab and ACPI table mapping for kexec kernel, > + * since they are not covered by pfn_mapped. > + */ > + result = init_efi_systab_pgtable(&info, level4p); > + if (result) > + return result; > + > + result = init_acpi_pgtable(&info, level4p); > + if (result) > + return result; > + > return init_transition_pgtable(image, level4p); > } > > -- > 2.17.2 > -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.