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ACPI/ADXL: Add address translation interface using an ACPI DSM
Some new Intel servers provide an interface so that the OS can ask the BIOS to translate a system physical address to a memory address (socket, memory controller, channel, rank, dimm, etc.). This is useful for EDAC drivers that want to take the address of an error reported in a machine check bank and let the user know which DIMM may need to be replaced. Specification for this interface is available at: https://cdrdv2.intel.com/v1/dl/getContent/603354 [ Based on earlier code by Qiuxu Zhuo <qiuxu.zhuo@intel.com>. ] [ bp: Make the first pr_info() in adxl_init() pr_debug() so that it doesn't pollute every dmesg. ] Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> CC: Len Brown <lenb@kernel.org> CC: linux-acpi@vger.kernel.org CC: linux-edac@vger.kernel.org Link: http://lkml.kernel.org/r/20181015202620.23610-1-tony.luck@intel.com
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‎drivers/acpi/Kconfig

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@@ -498,6 +498,9 @@ config ACPI_EXTLOG
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driver adds support for that functionality with corresponding
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tracepoint which carries that information to userspace.
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config ACPI_ADXL
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bool
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menuconfig PMIC_OPREGION
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bool "PMIC (Power Management Integrated Circuit) operation region support"
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help

‎drivers/acpi/Makefile

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@@ -61,6 +61,9 @@ acpi-$(CONFIG_ACPI_LPIT) += acpi_lpit.o
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acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
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acpi-$(CONFIG_ACPI_WATCHDOG) += acpi_watchdog.o
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# Address translation
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acpi-$(CONFIG_ACPI_ADXL) += acpi_adxl.o
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# These are (potentially) separate modules
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# IPMI may be used by other drivers, so it has to initialise before them

‎drivers/acpi/acpi_adxl.c

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// SPDX-License-Identifier: GPL-2.0
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/*
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* Address translation interface via ACPI DSM.
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* Copyright (C) 2018 Intel Corporation
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*
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* Specification for this interface is available at:
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*
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* https://cdrdv2.intel.com/v1/dl/getContent/603354
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*/
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#include <linux/acpi.h>
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#include <linux/adxl.h>
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#define ADXL_REVISION 0x1
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#define ADXL_IDX_GET_ADDR_PARAMS 0x1
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#define ADXL_IDX_FORWARD_TRANSLATE 0x2
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#define ACPI_ADXL_PATH "\\_SB.ADXL"
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/*
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* The specification doesn't provide a limit on how many
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* components are in a memory address. But since we allocate
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* memory based on the number the BIOS tells us, we should
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* defend against insane values.
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*/
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#define ADXL_MAX_COMPONENTS 500
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#undef pr_fmt
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#define pr_fmt(fmt) "ADXL: " fmt
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static acpi_handle handle;
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static union acpi_object *params;
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static const guid_t adxl_guid =
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GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F,
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0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D);
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static int adxl_count;
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static char **adxl_component_names;
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static union acpi_object *adxl_dsm(int cmd, union acpi_object argv[])
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{
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union acpi_object *obj, *o;
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obj = acpi_evaluate_dsm_typed(handle, &adxl_guid, ADXL_REVISION,
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cmd, argv, ACPI_TYPE_PACKAGE);
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if (!obj) {
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pr_info("DSM call failed for cmd=%d\n", cmd);
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return NULL;
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}
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if (obj->package.count != 2) {
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pr_info("Bad pkg count %d\n", obj->package.count);
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goto err;
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}
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o = obj->package.elements;
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if (o->type != ACPI_TYPE_INTEGER) {
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pr_info("Bad 1st element type %d\n", o->type);
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goto err;
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}
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if (o->integer.value) {
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pr_info("Bad ret val %llu\n", o->integer.value);
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goto err;
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}
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o = obj->package.elements + 1;
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if (o->type != ACPI_TYPE_PACKAGE) {
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pr_info("Bad 2nd element type %d\n", o->type);
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goto err;
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}
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return obj;
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err:
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ACPI_FREE(obj);
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return NULL;
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}
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/**
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* adxl_get_component_names - get list of memory component names
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* Returns NULL terminated list of string names
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*
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* Give the caller a pointer to the list of memory component names
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* e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL }
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* Caller should count how many strings in order to allocate a buffer
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* for the return from adxl_decode().
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*/
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const char * const *adxl_get_component_names(void)
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{
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return (const char * const *)adxl_component_names;
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}
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EXPORT_SYMBOL_GPL(adxl_get_component_names);
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/**
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* adxl_decode - ask BIOS to decode a system address to memory address
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* @addr: the address to decode
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* @component_values: pointer to array of values for each component
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* Returns 0 on success, negative error code otherwise
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*
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* The index of each value returned in the array matches the index of
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* each component name returned by adxl_get_component_names().
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* Components that are not defined for this address translation (e.g.
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* mirror channel number for a non-mirrored address) are set to ~0ull.
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*/
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int adxl_decode(u64 addr, u64 component_values[])
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{
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union acpi_object argv4[2], *results, *r;
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int i, cnt;
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if (!adxl_component_names)
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return -EOPNOTSUPP;
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argv4[0].type = ACPI_TYPE_PACKAGE;
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argv4[0].package.count = 1;
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argv4[0].package.elements = &argv4[1];
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argv4[1].integer.type = ACPI_TYPE_INTEGER;
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argv4[1].integer.value = addr;
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results = adxl_dsm(ADXL_IDX_FORWARD_TRANSLATE, argv4);
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if (!results)
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return -EINVAL;
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r = results->package.elements + 1;
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cnt = r->package.count;
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if (cnt != adxl_count) {
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ACPI_FREE(results);
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return -EINVAL;
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}
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r = r->package.elements;
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for (i = 0; i < cnt; i++)
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component_values[i] = r[i].integer.value;
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ACPI_FREE(results);
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return 0;
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}
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EXPORT_SYMBOL_GPL(adxl_decode);
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static int __init adxl_init(void)
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{
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char *path = ACPI_ADXL_PATH;
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union acpi_object *p;
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acpi_status status;
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int i;
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status = acpi_get_handle(NULL, path, &handle);
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if (ACPI_FAILURE(status)) {
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pr_debug("No ACPI handle for path %s\n", path);
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return -ENODEV;
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}
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if (!acpi_has_method(handle, "_DSM")) {
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pr_info("No DSM method\n");
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return -ENODEV;
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}
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if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION,
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ADXL_IDX_GET_ADDR_PARAMS |
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ADXL_IDX_FORWARD_TRANSLATE)) {
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pr_info("DSM method does not support forward translate\n");
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return -ENODEV;
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}
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params = adxl_dsm(ADXL_IDX_GET_ADDR_PARAMS, NULL);
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if (!params) {
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pr_info("Failed to get component names\n");
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return -ENODEV;
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}
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p = params->package.elements + 1;
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adxl_count = p->package.count;
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if (adxl_count > ADXL_MAX_COMPONENTS) {
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pr_info("Insane number of address component names %d\n", adxl_count);
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ACPI_FREE(params);
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return -ENODEV;
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}
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p = p->package.elements;
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/*
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* Allocate one extra for NULL termination.
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*/
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adxl_component_names = kcalloc(adxl_count + 1, sizeof(char *), GFP_KERNEL);
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if (!adxl_component_names) {
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ACPI_FREE(params);
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return -ENOMEM;
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}
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for (i = 0; i < adxl_count; i++)
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adxl_component_names[i] = p[i].string.pointer;
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return 0;
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}
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subsys_initcall(adxl_init);

‎include/linux/adxl.h

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/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Address translation interface via ACPI DSM.
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* Copyright (C) 2018 Intel Corporation
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*/
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#ifndef _LINUX_ADXL_H
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#define _LINUX_ADXL_H
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const char * const *adxl_get_component_names(void);
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int adxl_decode(u64 addr, u64 component_values[]);
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#endif /* _LINUX_ADXL_H */

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