From patchwork Fri Jul 8 16:13:12 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Octavian Purdila X-Patchwork-Id: 9221311 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 08D3460467 for ; Fri, 8 Jul 2016 16:14:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EE38322638 for ; Fri, 8 Jul 2016 16:14:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E2F2A22B1F; Fri, 8 Jul 2016 16:14:56 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable 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 5E04122638 for ; Fri, 8 Jul 2016 16:14:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932302AbcGHQOj (ORCPT ); Fri, 8 Jul 2016 12:14:39 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34180 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932651AbcGHQOI (ORCPT ); Fri, 8 Jul 2016 12:14:08 -0400 Received: by mail-wm0-f66.google.com with SMTP id w75so8967701wmd.1; Fri, 08 Jul 2016 09:14:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=0Xfe6af9V1WqTRY+6ClUXzuyGuXnPNY23EpPiI9i9UM=; b=bZbR/B9kVX1uaSy5U1yLFPGm/DDevc1jOxgiVrfRe1SpCRDVfz5SD55UiE+zbgtiH7 4iIA7hAWofXtbviGcMRnF6JNhvHPXQDXsdc2PYiyBylizsgiWXy9//+dXW08KMRmCq9P 2FRFVWJ4Bvmza2b0vKvaJTKnB7fMTAae5Ud9DD1dK8JxhxTyVoJ+cjYCGcAcE6X0e2mp 3StFuILXBi78iXmKPJWwBnv0JbQk4MVQNeu8inSJGSi+Vo/Cxvt2b/+1UgWh/+wgmPr3 IT93nWN+jpwnxB+pM7jzBIkf0ryvYf/22oxd693b6zw/6zIhFgU89lJQv0/XOclhyb4N LvIw== X-Gm-Message-State: ALyK8tIhA35qc3rBhe2tYrn2orewWjYEjbb0DraJ4qMiGOsQfnDvPMNL67RyGS68GTZnzQ== X-Received: by 10.28.136.21 with SMTP id k21mr4361045wmd.24.1467994445808; Fri, 08 Jul 2016 09:14:05 -0700 (PDT) Received: from localhost.localdomain ([109.98.36.115]) by smtp.gmail.com with ESMTPSA id t3sm3726508wmf.6.2016.07.08.09.14.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 08 Jul 2016 09:14:05 -0700 (PDT) From: Octavian Purdila To: "Rafael J . Wysocki" Cc: linux-acpi@vger.kernel.org, linux-efi@vger.kernel.org, linux-i2c@vger.kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, leonard.crestez@intel.com, Octavian Purdila Subject: [PATCH v7 6/8] efi: load SSTDs from EFI variables Date: Fri, 8 Jul 2016 19:13:12 +0300 Message-Id: <1467994394-23983-7-git-send-email-octavian.purdila@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1467994394-23983-1-git-send-email-octavian.purdila@intel.com> References: <1467994394-23983-1-git-send-email-octavian.purdila@intel.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch allows SSDTs to be loaded from EFI variables. It works by specifying the EFI variable name containing the SSDT to be loaded. All variables with the same name (regardless of the vendor GUID) will be loaded. Note that we can't use acpi_install_table and we must rely on the dynamic ACPI table loading and bus re-scanning mechanisms. That is because I2C/SPI controllers are initialized earlier then the EFI subsystems and all I2C/SPI ACPI devices are enumerated when the I2C/SPI controllers are initialized. Signed-off-by: Octavian Purdila Reviewed-by: Matt Fleming --- Documentation/acpi/ssdt-overlays.txt | 67 +++++++++++++++++++++++++ Documentation/kernel-parameters.txt | 7 +++ drivers/firmware/efi/efi.c | 96 ++++++++++++++++++++++++++++++++++++ 3 files changed, 170 insertions(+) diff --git a/Documentation/acpi/ssdt-overlays.txt b/Documentation/acpi/ssdt-overlays.txt index 8050259..c4b57ba 100644 --- a/Documentation/acpi/ssdt-overlays.txt +++ b/Documentation/acpi/ssdt-overlays.txt @@ -89,3 +89,70 @@ cp ssdt.aml kernel/firmware/acpi # on top: find kernel | cpio -H newc --create > /boot/instrumented_initrd cat /boot/initrd >>/boot/instrumented_initrd + +== Loading ACPI SSDTs from EFI variables == + +This is the preferred method, when EFI is supported on the platform, because it +allows a persistent, OS independent way of storing the user defined SSDTs. There +is also work underway to implement EFI support for loading user defined SSDTs +and using this method will make it easier to convert to the EFI loading +mechanism when that will arrive. + +In order to load SSDTs from an EFI variable the efivar_ssdt kernel command line +parameter can be used. The argument for the option is the variable name to +use. If there are multiple variables with the same name but with different +vendor GUIDs, all of them will be loaded. + +In order to store the AML code in an EFI variable the efivarfs filesystem can be +used. It is enabled and mounted by default in /sys/firmware/efi/efivars in all +recent distribution. + +Creating a new file in /sys/firmware/efi/efivars will automatically create a new +EFI variable. Updating a file in /sys/firmware/efi/efivars will update the EFI +variable. Please note that the file name needs to be specially formatted as +"Name-GUID" and that the first 4 bytes in the file (little-endian format) +represent the attributes of the EFI variable (see EFI_VARIABLE_MASK in +include/linux/efi.h). Writing to the file must also be done with one write +operation. + +For example, you can use the following bash script to create/update an EFI +variable with the content from a given file: + +#!/bin/sh -e + +while ! [ -z "$1" ]; do + case "$1" in + "-f") filename="$2"; shift;; + "-g") guid="$2"; shift;; + *) name="$1";; + esac + shift +done + +usage() +{ + echo "Syntax: ${0##*/} -f filename [ -g guid ] name" + exit 1 +} + +[ -n "$name" -a -f "$filename" ] || usage + +EFIVARFS="/sys/firmware/efi/efivars" + +[ -d "$EFIVARFS" ] || exit 2 + +if stat -tf $EFIVARFS | grep -q -v de5e81e4; then + mount -t efivarfs none $EFIVARFS +fi + +# try to pick up an existing GUID +[ -n "$guid" ] || guid=$(find "$EFIVARFS" -name "$name-*" | head -n1 | cut -f2- -d-) + +# use a randomly generated GUID +[ -n "$guid" ] || guid="$(cat /proc/sys/kernel/random/uuid)" + +# efivarfs expects all of the data in one write +tmp=$(mktemp) +/bin/echo -ne "\007\000\000\000" | cat - $filename > $tmp +dd if=$tmp of="$EFIVARFS/$name-$guid" bs=$(stat -c %s $tmp) +rm $tmp diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 82b42c9..bbfb56f 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1185,6 +1185,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Address Range Mirroring feature even if your box doesn't support it. + efivar_ssdt= [EFI; X86] Name of an EFI variable that contains an SSDT + that is to be dynamically loaded by Linux. If there are + multiple variables with the same name but with different + vendor GUIDs, all of them will be loaded. See + Documentation/acpi/ssdt-overlays.txt for details. + + eisa_irq_edge= [PARISC,HW] See header of drivers/parisc/eisa.c. diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 05509f3..8730fd4 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -24,6 +24,9 @@ #include #include #include +#include +#include +#include #include @@ -195,6 +198,96 @@ static void generic_ops_unregister(void) efivars_unregister(&generic_efivars); } +#if IS_ENABLED(CONFIG_ACPI) +#define EFIVAR_SSDT_NAME_MAX 16 +static char efivar_ssdt[EFIVAR_SSDT_NAME_MAX] __initdata; +static int __init efivar_ssdt_setup(char *str) +{ + if (strlen(str) < sizeof(efivar_ssdt)) + memcpy(efivar_ssdt, str, strlen(str)); + else + pr_warn("efivar_ssdt: name too long: %s\n", str); + return 0; +} +__setup("efivar_ssdt=", efivar_ssdt_setup); + +static __init int efivar_ssdt_iter(efi_char16_t *name, efi_guid_t vendor, + unsigned long name_size, void *data) +{ + struct efivar_entry *entry; + struct list_head *list = data; + char utf8_name[EFIVAR_SSDT_NAME_MAX]; + int limit = min_t(unsigned long, EFIVAR_SSDT_NAME_MAX, name_size); + + ucs2_as_utf8(utf8_name, name, limit - 1); + if (strncmp(utf8_name, efivar_ssdt, limit) != 0) + return 0; + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return 0; + + memcpy(entry->var.VariableName, name, name_size); + memcpy(&entry->var.VendorGuid, &vendor, sizeof(efi_guid_t)); + + efivar_entry_add(entry, list); + + return 0; +} + +static __init int efivar_ssdt_load(void) +{ + LIST_HEAD(entries); + struct efivar_entry *entry, *aux; + unsigned long size; + void *data; + int ret; + + ret = efivar_init(efivar_ssdt_iter, &entries, true, &entries); + + list_for_each_entry_safe(entry, aux, &entries, list) { + pr_info("loading SSDT from variable %s-%pUl\n", efivar_ssdt, + &entry->var.VendorGuid); + + list_del(&entry->list); + + ret = efivar_entry_size(entry, &size); + if (ret) { + pr_err("failed to get var size\n"); + goto free_entry; + } + + data = kmalloc(size, GFP_KERNEL); + if (!data) + goto free_entry; + + ret = efivar_entry_get(entry, NULL, &size, data); + if (ret) { + pr_err("failed to get var data\n"); + goto free_data; + } + + ret = acpi_load_table(data); + if (ret) { + pr_err("failed to load table: %d\n", ret); + goto free_data; + } + + goto free_entry; + +free_data: + kfree(data); + +free_entry: + kfree(entry); + } + + return ret; +} +#else +static inline int efivar_ssdt_load(void) { return 0; } +#endif + /* * We register the efi subsystem with the firmware subsystem and the * efivars subsystem with the efi subsystem, if the system was booted with @@ -218,6 +311,9 @@ static int __init efisubsys_init(void) if (error) goto err_put; + if (efi_enabled(EFI_RUNTIME_SERVICES)) + efivar_ssdt_load(); + error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group); if (error) { pr_err("efi: Sysfs attribute export failed with error %d.\n",