Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932159AbcDSWjj (ORCPT ); Tue, 19 Apr 2016 18:39:39 -0400 Received: from mga04.intel.com ([192.55.52.120]:52627 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753322AbcDSWjf (ORCPT ); Tue, 19 Apr 2016 18:39:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,507,1455004800"; d="scan'208";a="88266099" From: Octavian Purdila To: "Rafael J. Wysocki" , Len Brown , Matt Fleming , Mark Brown , Wolfram Sang Cc: Joel Becker , 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, irina.tirdea@intel.com, Octavian Purdila Subject: [RFC PATCH v2 01/10] kernel: add TAINT_OVERLAY_ACPI_TABLE Date: Wed, 20 Apr 2016 01:38:59 +0300 Message-Id: <1461105548-20618-2-git-send-email-octavian.purdila@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1461105548-20618-1-git-send-email-octavian.purdila@intel.com> References: <1461105548-20618-1-git-send-email-octavian.purdila@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5320 Lines: 143 Add a new tain flag that indicates wheather the user has loaded ACPI SSDT overlays. This will provide a clean indication in bug reports that the user has added new information to the ACPI tables. Signed-off-by: Octavian Purdila --- Documentation/acpi/ssdt-overlays.txt | 64 ++++++++++++++++++++++++++++++++++++ Documentation/oops-tracing.txt | 2 ++ Documentation/sysctl/kernel.txt | 1 + include/linux/kernel.h | 1 + kernel/panic.c | 2 ++ 5 files changed, 70 insertions(+) create mode 100644 Documentation/acpi/ssdt-overlays.txt diff --git a/Documentation/acpi/ssdt-overlays.txt b/Documentation/acpi/ssdt-overlays.txt new file mode 100644 index 0000000..54ee74a --- /dev/null +++ b/Documentation/acpi/ssdt-overlays.txt @@ -0,0 +1,64 @@ + +In order to support ACPI open-ended hardware configurations (e.g. development +boards) we need a way to augment the ACPI configuration provided by the firmware +image. A common example is connecting sensors on I2C / SPI buses on development +boards. + +Although this can be accomplished by creating a kernel platform driver or +recompiling the firmware image with updated ACPI tables, neither is practical: +the former proliferates board specific kernel code while the latter requires +access to firmware tools which are often not publicly available. + +Because ACPI supports external references in AML code a more practical +way to augment firmware ACPI configuration is by dynamically loading +user defined SSDT tables that contain the board specific information. + +For example, to enumerate a Bosch BMA222E accelerometer on the I2C bus of the +Minnowboard MAX development board exposed via the LSE connector [1], the +following ASL code can be used: + +DefinitionBlock ("minnowmax.aml", "SSDT", 1, "Vendor", "Accel", 0x00000003) +{ + External (\_SB.I2C6, DeviceObj) + + Scope (\_SB.I2C6) + { + Device (STAC) + { + Name (_ADR, Zero) + Name (_HID, "BMA222E") + + Method (_CRS, 0, Serialized) + { + Name (RBUF, ResourceTemplate () + { + I2cSerialBus (0x0018, ControllerInitiated, 0x00061A80, + AddressingMode7Bit, "\\_SB.I2C6", 0x00, + ResourceConsumer, ,) + GpioInt (Edge, ActiveHigh, Exclusive, PullDown, 0x0000, + "\\_SB.GPO2", 0x00, ResourceConsumer, , ) + { // Pin list + 0 + } + }) + Return (RBUF) + } + } + } +} + +which can then be compiled to AML binary format: + +$ iasl minnowmax.asl + +Intel ACPI Component Architecture +ASL Optimizing Compiler version 20140214-64 [Mar 29 2014] +Copyright (c) 2000 - 2014 Intel Corporation + +ASL Input: minnomax.asl - 30 lines, 614 bytes, 7 keywords +AML Output: minnowmax.aml - 165 bytes, 6 named objects, 1 executable opcodes + +[1] http://wiki.minnowboard.org/MinnowBoard_MAX#Low_Speed_Expansion_Connector_.28Top.29 + +The resulting AML code can then be loaded by the kernel using one of the methods +below. diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt index f3ac05c..40e1117 100644 --- a/Documentation/oops-tracing.txt +++ b/Documentation/oops-tracing.txt @@ -272,6 +272,8 @@ characters, each representing a particular tainted value. 16: 'K' if the kernel has been live patched. + 17: 'N' if ACPI SSDT overlays have been loaded. + The primary reason for the 'Tainted: ' string is to tell kernel debuggers if this is a clean kernel or if anything unusual has occurred. Tainting is permanent: even if an offending module is diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 57653a4..e68d4168 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -917,6 +917,7 @@ can be ORed together: signature. 16384 - A soft lockup has previously occurred on the system. 32768 - The kernel has been live patched. +65536 - ACPI SSDT overlays have been loaded. ============================================================== diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2f7775e..8c90125 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -502,6 +502,7 @@ extern enum system_states { #define TAINT_UNSIGNED_MODULE 13 #define TAINT_SOFTLOCKUP 14 #define TAINT_LIVEPATCH 15 +#define TAINT_OVERLAY_ACPI_TABLE 16 extern const char hex_asc[]; #define hex_asc_lo(x) hex_asc[((x) & 0x0f)] diff --git a/kernel/panic.c b/kernel/panic.c index 535c965..1ff0819 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -284,6 +284,7 @@ static const struct tnt tnts[] = { { TAINT_UNSIGNED_MODULE, 'E', ' ' }, { TAINT_SOFTLOCKUP, 'L', ' ' }, { TAINT_LIVEPATCH, 'K', ' ' }, + { TAINT_OVERLAY_ACPI_TABLE, 'N', ' ' }, }; /** @@ -305,6 +306,7 @@ static const struct tnt tnts[] = { * 'E' - Unsigned module has been loaded. * 'L' - A soft lockup has previously occurred. * 'K' - Kernel has been live patched. + * 'N' - ACPI SSDT overlays have been loaded. * * The string is overwritten by the next call to print_tainted(). */ -- 1.9.1