Commit 4cf841e3 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov

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:

 [ Based on earlier code by Qiuxu Zhuo <>. ]

 [ bp: Make the first pr_info() in adxl_init() pr_debug() so that it
   doesn't pollute every dmesg. ]
Signed-off-by: default avatarTony Luck <>
Signed-off-by: default avatarBorislav Petkov <>
Acked-by: default avatarRafael J. Wysocki <>
Tested-by: default avatarQiuxu Zhuo <>
CC: Len Brown <>
parent d8c27ba8
......@@ -498,6 +498,9 @@ config ACPI_EXTLOG
driver adds support for that functionality with corresponding
tracepoint which carries that information to userspace.
config ACPI_ADXL
menuconfig PMIC_OPREGION
bool "PMIC (Power Management Integrated Circuit) operation region support"
......@@ -61,6 +61,9 @@ acpi-$(CONFIG_ACPI_LPIT) += acpi_lpit.o
acpi-$(CONFIG_ACPI_GENERIC_GSI) += irq.o
acpi-$(CONFIG_ACPI_WATCHDOG) += acpi_watchdog.o
# Address translation
acpi-$(CONFIG_ACPI_ADXL) += acpi_adxl.o
# These are (potentially) separate modules
# IPMI may be used by other drivers, so it has to initialise before them
// SPDX-License-Identifier: GPL-2.0
* Address translation interface via ACPI DSM.
* Copyright (C) 2018 Intel Corporation
* Specification for this interface is available at:
#include <linux/acpi.h>
#include <linux/adxl.h>
#define ADXL_REVISION 0x1
* The specification doesn't provide a limit on how many
* components are in a memory address. But since we allocate
* memory based on the number the BIOS tells us, we should
* defend against insane values.
#undef pr_fmt
#define pr_fmt(fmt) "ADXL: " fmt
static acpi_handle handle;
static union acpi_object *params;
static const guid_t adxl_guid =
GUID_INIT(0xAA3C050A, 0x7EA4, 0x4C1F,
0xAF, 0xDA, 0x12, 0x67, 0xDF, 0xD3, 0xD4, 0x8D);
static int adxl_count;
static char **adxl_component_names;
static union acpi_object *adxl_dsm(int cmd, union acpi_object argv[])
union acpi_object *obj, *o;
obj = acpi_evaluate_dsm_typed(handle, &adxl_guid, ADXL_REVISION,
cmd, argv, ACPI_TYPE_PACKAGE);
if (!obj) {
pr_info("DSM call failed for cmd=%d\n", cmd);
return NULL;
if (obj->package.count != 2) {
pr_info("Bad pkg count %d\n", obj->package.count);
goto err;
o = obj->package.elements;
if (o->type != ACPI_TYPE_INTEGER) {
pr_info("Bad 1st element type %d\n", o->type);
goto err;
if (o->integer.value) {
pr_info("Bad ret val %llu\n", o->integer.value);
goto err;
o = obj->package.elements + 1;
if (o->type != ACPI_TYPE_PACKAGE) {
pr_info("Bad 2nd element type %d\n", o->type);
goto err;
return obj;
return NULL;
* adxl_get_component_names - get list of memory component names
* Returns NULL terminated list of string names
* Give the caller a pointer to the list of memory component names
* e.g. { "SystemAddress", "ProcessorSocketId", "ChannelId", ... NULL }
* Caller should count how many strings in order to allocate a buffer
* for the return from adxl_decode().
const char * const *adxl_get_component_names(void)
return (const char * const *)adxl_component_names;
* adxl_decode - ask BIOS to decode a system address to memory address
* @addr: the address to decode
* @component_values: pointer to array of values for each component
* Returns 0 on success, negative error code otherwise
* The index of each value returned in the array matches the index of
* each component name returned by adxl_get_component_names().
* Components that are not defined for this address translation (e.g.
* mirror channel number for a non-mirrored address) are set to ~0ull.
int adxl_decode(u64 addr, u64 component_values[])
union acpi_object argv4[2], *results, *r;
int i, cnt;
if (!adxl_component_names)
argv4[0].type = ACPI_TYPE_PACKAGE;
argv4[0].package.count = 1;
argv4[0].package.elements = &argv4[1];
argv4[1].integer.type = ACPI_TYPE_INTEGER;
argv4[1].integer.value = addr;
results = adxl_dsm(ADXL_IDX_FORWARD_TRANSLATE, argv4);
if (!results)
return -EINVAL;
r = results->package.elements + 1;
cnt = r->package.count;
if (cnt != adxl_count) {
return -EINVAL;
r = r->package.elements;
for (i = 0; i < cnt; i++)
component_values[i] = r[i].integer.value;
return 0;
static int __init adxl_init(void)
char *path = ACPI_ADXL_PATH;
union acpi_object *p;
acpi_status status;
int i;
status = acpi_get_handle(NULL, path, &handle);
if (ACPI_FAILURE(status)) {
pr_debug("No ACPI handle for path %s\n", path);
return -ENODEV;
if (!acpi_has_method(handle, "_DSM")) {
pr_info("No DSM method\n");
return -ENODEV;
if (!acpi_check_dsm(handle, &adxl_guid, ADXL_REVISION,
pr_info("DSM method does not support forward translate\n");
return -ENODEV;
params = adxl_dsm(ADXL_IDX_GET_ADDR_PARAMS, NULL);
if (!params) {
pr_info("Failed to get component names\n");
return -ENODEV;
p = params->package.elements + 1;
adxl_count = p->package.count;
if (adxl_count > ADXL_MAX_COMPONENTS) {
pr_info("Insane number of address component names %d\n", adxl_count);
return -ENODEV;
p = p->package.elements;
* Allocate one extra for NULL termination.
adxl_component_names = kcalloc(adxl_count + 1, sizeof(char *), GFP_KERNEL);
if (!adxl_component_names) {
return -ENOMEM;
for (i = 0; i < adxl_count; i++)
adxl_component_names[i] = p[i].string.pointer;
return 0;
/* SPDX-License-Identifier: GPL-2.0 */
* Address translation interface via ACPI DSM.
* Copyright (C) 2018 Intel Corporation
#ifndef _LINUX_ADXL_H
#define _LINUX_ADXL_H
const char * const *adxl_get_component_names(void);
int adxl_decode(u64 addr, u64 component_values[]);
#endif /* _LINUX_ADXL_H */
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