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=-8.5 required=3.0 tests=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 BB14BC43441 for ; Tue, 13 Nov 2018 01:58:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7974622507 for ; Tue, 13 Nov 2018 01:58:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7974622507 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=cn.fujitsu.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730643AbeKMLya (ORCPT ); Tue, 13 Nov 2018 06:54:30 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:45781 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725991AbeKMLya (ORCPT ); Tue, 13 Nov 2018 06:54:30 -0500 X-IronPort-AV: E=Sophos;i="5.43,368,1503331200"; d="scan'208";a="47979662" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 13 Nov 2018 09:58:37 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id 383024B6ED4F; Tue, 13 Nov 2018 09:58:37 +0800 (CST) Received: from localhost.localdomain (10.167.225.56) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 13 Nov 2018 09:58:41 +0800 Date: Tue, 13 Nov 2018 09:57:30 +0800 From: Chao Fan To: Borislav Petkov CC: , , , , , , , , , , , Subject: Re: [PATCH v11 1/5] x86/boot: Add efi_get_rsdp_addr() to dig out RSDP from EFI table Message-ID: <20181113015730.GB7453@localhost.localdomain> References: <20181112094645.4879-1-fanc.fnst@cn.fujitsu.com> <20181112094645.4879-2-fanc.fnst@cn.fujitsu.com> <20181112145433.GF8167@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20181112145433.GF8167@zn.tnic> User-Agent: Mutt/1.10.1 (2018-07-13) X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: 383024B6ED4F.AB123 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: fanc.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 12, 2018 at 03:54:33PM +0100, Borislav Petkov wrote: >On Mon, Nov 12, 2018 at 05:46:41PM +0800, Chao Fan wrote: >> In order to parse SRAT table and get memory information, RSDP pointer >> should be found. In kernel, there are three methods to get RSDP: >> EFI condition, BIOS condition and KEXEC condition. The first works >> for EFI condition. > >"condition"? > >Also, please explain shortly what all those abbreviations mean: think >of a person reading your commit message who doesn't have any clue from >ACPI. I will try to improve in next version. > >> Imitate ACPI code and EFI code to dig RSDP pointer from EFI tables. >> Process: boot_param->systab->efi_config_table->RSDP. >> Based on efi_init(), efi_config_init(), efi_config_parse_tables(). >> >> Signed-off-by: Chao Fan >> --- >> arch/x86/boot/compressed/acpitb.c | 96 +++++++++++++++++++++++++++++++ >> 1 file changed, 96 insertions(+) >> create mode 100644 arch/x86/boot/compressed/acpitb.c >> >> diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c >> new file mode 100644 >> index 000000000000..56b54b0e0889 >> --- /dev/null >> +++ b/arch/x86/boot/compressed/acpitb.c >> @@ -0,0 +1,96 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +#define BOOT_CTYPE_H >> +#include "misc.h" >> +#include "error.h" >> + >> +#include >> +#include >> +#include >> +#include >> + >> +/* Search EFI table for RSDP table. */ >> +static void efi_get_rsdp_addr(acpi_physical_address *rsdp_addr) > >This is just silly: the function returns void and has a single parameter >which is an *output* parameter?! > >Why isn't the signature > >static acpi_physical_address *efi_get_rsdp_addr(void) > >instead? I will change the function style. > >> +{ >> +#ifdef CONFIG_EFI >> + efi_system_table_t *systab; >> + bool efi_64 = false; > >You're setting it below already, why here too? I will drop. > >> + void *config_tables; >> + struct efi_info *e; >> + char *sig; >> + int size; >> + int i; >> + >> + e = &boot_params->efi_info; >> + sig = (char *)&e->efi_loader_signature; >> + >> + if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) >> + efi_64 = true; >> + else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) >> + efi_64 = false; >> + else { >> + debug_putstr("Wrong EFI loader signature.\n"); >> + return; >> + } >> + >> + /* Get systab from boot params. Based on efi_init(). */ >> +#ifdef CONFIG_X86_64 >> + systab = (efi_system_table_t *)( >> + e->efi_systab | ((__u64)e->efi_systab_hi<<32)); > >No ugly line breaks with open braces trailing like that, pls - just let >it stick out. Thanks for this suggestion. > >> +#else >> + if (e->efi_systab_hi || e->efi_memmap_hi) { >> + debug_putstr("Table located above 4GB. EFI should be disabled.\n"); > >You need to say here what really happens here: > > debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n"); > >The same below. I will change all the all the same message. > >> + return; >> + } >> + systab = (efi_system_table_t *)e->efi_systab; >> +#endif >> + >> + if (!systab) >> + return; >> + >> + /* >> + * Get EFI tables from systab. Based on efi_config_init() and >> + * efi_config_parse_tables(). Only dig out the config_table. >> + */ >> + size = efi_64 ? sizeof(efi_config_table_64_t) : >> + sizeof(efi_config_table_32_t); >> + >> + for (i = 0; i < systab->nr_tables; i++) { >> + efi_guid_t guid; >> + unsigned long table; > >Put the void *config_tables declaration here. OK. > >> + >> + config_tables = (void *)(systab->tables + size * i); >> + if (efi_64) { >> + efi_config_table_64_t *tmp_table; >> + >> + tmp_table = (efi_config_table_64_t *)config_tables; >> + guid = tmp_table->guid; >> + table = tmp_table->table; >> +#ifndef CONFIG_64BIT > >Above you have CONFIG_X86_64, here CONFIG_64BIT. Please use one only. > >Also, use IS_ENABLED() instead. OK. > >> + if (table >> 32) { >> + debug_putstr("Table located above 4G. EFI should be disabled.\n"); >> + return; >> + } >> +#endif >> + } else { >> + efi_config_table_32_t *tmp_table; >> + >> + tmp_table = (efi_config_table_32_t *)config_tables; >> + guid = tmp_table->guid; >> + table = tmp_table->table; >> + } >> + >> + /* >> + * Get RSDP from EFI tables. >> + * If ACPI20 table found, use it. >> + * If ACPI20 table not found, but ACPI table found, >> + * use the ACPI table. >> + */ > >That comment is the opposite of what the code does. Also, why is that >comment needed at all? If anything, it should say *why* ACPI_TABLE_GUID >is preferred and then the fallback to ACPI_20_TABLE_GUID is done - not >*what* it does. That's easily visible in the code. I will drop the comment. Thanks, Chao Fan > >Thx. > >-- >Regards/Gruss, > Boris. > >Good mailing practices for 400: avoid top-posting and trim the reply. > >