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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT 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 DAE18C43610 for ; Thu, 29 Nov 2018 08:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A817C2145D for ; Thu, 29 Nov 2018 08:17:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A817C2145D 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 S1727879AbeK2TVc (ORCPT ); Thu, 29 Nov 2018 14:21:32 -0500 Received: from mail.cn.fujitsu.com ([183.91.158.132]:27144 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727490AbeK2TVb (ORCPT ); Thu, 29 Nov 2018 14:21:31 -0500 X-IronPort-AV: E=Sophos;i="5.56,293,1539619200"; d="scan'208";a="48821857" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 29 Nov 2018 16:16:57 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id CA0A84B6ED56; Thu, 29 Nov 2018 16:16:56 +0800 (CST) Received: from localhost.local (10.167.225.56) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 29 Nov 2018 16:17:02 +0800 From: Chao Fan To: , , , , , , , , CC: , , Subject: [PATCH v12 3/5] x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory Date: Thu, 29 Nov 2018 16:16:29 +0800 Message-ID: <20181129081631.11139-4-fanc.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181129081631.11139-1-fanc.fnst@cn.fujitsu.com> References: <20181129081631.11139-1-fanc.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: CA0A84B6ED56.A8FAE 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 To fix the conflict between KASLR and memory-hotremove, memory information in SRAT table is necessary. So RSDP and SRAT table should be parsed. When booting form KEXEC/EFI/BIOS, the methods to compute RSDP pointer are different. When booting from BIOS, there is no variable who can point to RSDP directly, so scan memory for the RSDP and verify RSDP by signature and checksum. Signed-off-by: Chao Fan --- arch/x86/boot/compressed/acpitb.c | 85 +++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c index c43546648638..82d27c4b8978 100644 --- a/arch/x86/boot/compressed/acpitb.c +++ b/arch/x86/boot/compressed/acpitb.c @@ -110,3 +110,88 @@ static acpi_physical_address efi_get_rsdp_addr(void) return rsdp_addr; #endif } + +static u8 compute_checksum(u8 *buffer, u32 length) +{ + u8 *end = buffer + length; + u8 sum = 0; + + while (buffer < end) + sum += *(buffer++); + + return sum; +} + +/* Search a block of memory for the RSDP signature. */ +static u8 *scan_mem_for_rsdp(u8 *start, u32 length) +{ + struct acpi_table_rsdp *rsdp; + u8 *address; + u8 *end; + + end = start + length; + + /* Search from given start address for the requested length */ + for (address = start; address < end; address += ACPI_RSDP_SCAN_STEP) { + /* + * Both RSDP signature and checksum must be correct. + * Note: Sometimes there exists more than one RSDP in memory; + * the valid RSDP has a valid checksum, all others have an + * invalid checksum. + */ + rsdp = (struct acpi_table_rsdp *)address; + + /* BAD Signature */ + if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) + continue; + + /* Check the standard checksum */ + if (compute_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH)) + continue; + + /* Check extended checksum if table version >= 2 */ + if ((rsdp->revision >= 2) && + (compute_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH))) + continue; + + /* Signature and checksum valid, we have found a real RSDP */ + return address; + } + return NULL; +} + +/* Used to search RSDP physical address, based on acpi_find_root_pointer(). */ +static acpi_physical_address bios_get_rsdp_addr(void) +{ + u8 *table_ptr; + u32 address; + u8 *rsdp; + + /* Get the location of the Extended BIOS Data Area (EBDA) */ + table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION; + *(u32 *)(void *)&address = *(u16 *)(void *)table_ptr; + address <<= 4; + table_ptr = (u8 *)(long)address; + + /* + * Search EBDA paragraphs (EBDA is required to be a minimum of + * 1K length) + */ + if (address > 0x400) { + rsdp = scan_mem_for_rsdp(table_ptr, ACPI_EBDA_WINDOW_SIZE); + if (rsdp) { + address += (u32)ACPI_PTR_DIFF(rsdp, table_ptr); + return (acpi_physical_address)address; + } + } + + table_ptr = (u8 *)ACPI_HI_RSDP_WINDOW_BASE; + rsdp = scan_mem_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); + + /* Search upper memory: 16-byte boundaries in E0000h-FFFFFh */ + if (rsdp) { + address = (u32)(ACPI_HI_RSDP_WINDOW_BASE + + ACPI_PTR_DIFF(rsdp, table_ptr)); + return (acpi_physical_address)address; + } +} -- 2.19.1