From patchwork Wed Oct 17 10:20:08 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Fan X-Patchwork-Id: 10645271 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 56F891057 for ; Wed, 17 Oct 2018 10:21:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 467802AC73 for ; Wed, 17 Oct 2018 10:21:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3AD9F2ACEE; Wed, 17 Oct 2018 10:21:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A94232AC73 for ; Wed, 17 Oct 2018 10:21:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727258AbeJQSQN (ORCPT ); Wed, 17 Oct 2018 14:16:13 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:62672 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727050AbeJQSQM (ORCPT ); Wed, 17 Oct 2018 14:16:12 -0400 X-IronPort-AV: E=Sophos;i="5.43,368,1503331200"; d="scan'208";a="46265550" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 17 Oct 2018 18:21:05 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id A82894B6ED8C; Wed, 17 Oct 2018 18:21:04 +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; Wed, 17 Oct 2018 18:21:10 +0800 From: Chao Fan To: , , , , , , , , , , CC: , , Subject: [PATCH v9 4/8] x86/boot: Add bios_get_rsdp_addr() to search RSDP in memory Date: Wed, 17 Oct 2018 18:20:08 +0800 Message-ID: <20181017102012.872-5-fanc.fnst@cn.fujitsu.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20181017102012.872-1-fanc.fnst@cn.fujitsu.com> References: <20181017102012.872-1-fanc.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: A82894B6ED8C.AF17E X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: fanc.fnst@cn.fujitsu.com Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Imitate acpi_find_root_pointer() and acpi_tb_scan_memory_for_rsdp() to search RSDP table pointer in memory. This function only works when RSDP not found in EFI table. Signed-off-by: Chao Fan --- arch/x86/boot/compressed/acpitb.c | 106 ++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) diff --git a/arch/x86/boot/compressed/acpitb.c b/arch/x86/boot/compressed/acpitb.c index 56b54b0e0889..50fa65cf824d 100644 --- a/arch/x86/boot/compressed/acpitb.c +++ b/arch/x86/boot/compressed/acpitb.c @@ -94,3 +94,109 @@ static void efi_get_rsdp_addr(acpi_physical_address *rsdp_addr) } #endif } + +static u8 compute_checksum(u8 *buffer, u32 length) +{ + u8 sum = 0; + u8 *end = buffer + length; + + while (buffer < end) + sum = (u8)(sum + *(buffer++)); + + return sum; +} + +/* + * Used to search a block of memory for the RSDP signature. + * Return Pointer to the RSDP if found, otherwise NULL. + * Based on acpi_tb_scan_memory_for_rsdp(). + */ +static u8 *scan_mem_for_rsdp(u8 *start, u32 length) +{ + struct acpi_table_rsdp *rsdp; + u8 *end; + u8 *rover; + + end = start + length; + + /* Search from given start address for the requested length */ + for (rover = start; rover < end; rover += ACPI_RSDP_SCAN_STEP) { + /* + * The RSDP signature and checksum must both 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 *)rover; + + /* Nope, 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; + + /* Sig and checksum valid, we have found a real RSDP */ + return rover; + } + return NULL; +} + +/* + * Used to search RSDP physical address. + * Based on acpi_find_root_pointer(). Since only use physical address + * in this period, so there is no need to do the memory map jobs. + */ +static void bios_get_rsdp_addr(acpi_physical_address *rsdp_addr) +{ + struct acpi_table_rsdp *rsdp; + u8 *table_ptr; + u8 *mem_rover; + u32 address; + + /* + * Get the location of the Extended BIOS Data Area (EBDA) + * Since we use physical address directely, so + * acpi_os_map_memory() and acpi_os_unmap_memory() are + * not needed here. + */ + table_ptr = (u8 *)ACPI_EBDA_PTR_LOCATION; + *(u32 *)(void *)&address = *(u16 *)(void *)table_ptr; + address <<= 4; + table_ptr = (u8 *)address; + + /* + * Search EBDA paragraphs (EBDA is required to be a minimum of + * 1K length) + */ + if (address > 0x400) { + mem_rover = scan_mem_for_rsdp(table_ptr, ACPI_EBDA_WINDOW_SIZE); + + if (mem_rover) { + address += (u32)ACPI_PTR_DIFF(mem_rover, table_ptr); + *rsdp_addr = (acpi_physical_address)address; + return; + } + } + + table_ptr = (u8 *)ACPI_HI_RSDP_WINDOW_BASE; + mem_rover = scan_mem_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); + + /* + * Search upper memory: 16-byte boundaries in E0000h-FFFFFh + * Since we use physical address directely, so + * acpi_os_map_memory() and acpi_os_unmap_memory() are + * not needed here. + */ + if (mem_rover) { + address = (u32)(ACPI_HI_RSDP_WINDOW_BASE + + ACPI_PTR_DIFF(mem_rover, table_ptr)); + *rsdp_addr = (acpi_physical_address)address; + } +}