Merge branch 'acpi-tables'

* acpi-tables:
  ACPI: Rename configfs.c to acpi_configfs.c to prevent link error
  ACPI: add support for loading SSDTs via configfs
  ACPI: add support for configfs
  efi / ACPI: load SSTDs from EFI variables
  spi / ACPI: add support for ACPI reconfigure notifications
  i2c / ACPI: add support for ACPI reconfigure notifications
  ACPI: add support for ACPI reconfiguration notifiers
  ACPI / scan: fix enumeration (visited) flags for bus rescans
  ACPI / documentation: add SSDT overlays documentation
  ACPI: ARM64: support for ACPI_TABLE_UPGRADE
  ACPI / tables: introduce ARCH_HAS_ACPI_TABLE_UPGRADE
  ACPI / tables: move arch-specific symbol to asm/acpi.h
  ACPI / tables: table upgrade: refactor function definitions
  ACPI / tables: table upgrade: use cacheable map for tables

Conflicts:
	arch/arm64/include/asm/acpi.h

Documentation/ABI/testing/configfs-acpi

+What:		/config/acpi
+Date:		July 2016
+KernelVersion:	4.8
+Contact:	linux-acpi@vger.kernel.org
+Description:
+		This represents the ACPI subsystem entry point directory. It
+		contains sub-groups corresponding to ACPI configurable options.
+
+What:		/config/acpi/table
+Date:		July 2016
+KernelVersion:	4.8
+Description:
+
+		This group contains the configuration for user defined ACPI
+		tables. The attributes of a user define table are:
+
+		aml 		- a binary attribute that the user can use to
+				fill in the ACPI aml definitions. Once the aml
+				data is written to this file and the file is
+				closed the table will be loaded and ACPI devices
+				will be enumerated. To check if the operation is
+				successful the user must check the error code
+				for close(). If the operation is successful,
+				subsequent writes to this attribute will fail.
+
+		The rest of the attributes are read-only and are valid only
+		after the table has been loaded by filling the aml entry:
+
+		signature 	- ASCII table signature
+		length 		- length of table in bytes, including the header
+		revision 	- ACPI Specification minor version number
+		oem_id 		- ASCII OEM identification
+		oem_table_id 	- ASCII OEM table identification
+		oem_revision 	- OEM revision number
+		asl_compiler_id - ASCII ASL compiler vendor ID
+		asl_compiler_revision - ASL compiler version

Documentation/acpi/ssdt-overlays.txt

+
+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.
+
+== Loading ACPI SSDTs from initrd ==
+
+This option allows loading of user defined SSDTs from initrd and it is useful
+when the system does not support EFI or when there is not enough EFI storage.
+
+It works in a similar way with initrd based ACPI tables override/upgrade: SSDT
+aml code must be placed in the first, uncompressed, initrd under the
+"kernel/firmware/acpi" path. Multiple files can be used and this will translate
+in loading multiple tables. Only SSDT and OEM tables are allowed. See
+initrd_table_override.txt for more details.
+
+Here is an example:
+
+# Add the raw ACPI tables to an uncompressed cpio archive.
+# They must be put into a /kernel/firmware/acpi directory inside the
+# cpio archive.
+# The uncompressed cpio archive must be the first.
+# Other, typically compressed cpio archives, must be
+# concatenated on top of the uncompressed one.
+mkdir -p kernel/firmware/acpi
+cp ssdt.aml kernel/firmware/acpi
+
+# Create the uncompressed cpio archive and concatenate the original initrd
+# 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
+
+== Loading ACPI SSDTs from configfs ==
+
+This option allows loading of user defined SSDTs from userspace via the configfs
+interface. The CONFIG_ACPI_CONFIGFS option must be select and configfs must be
+mounted. In the following examples, we assume that configfs has been mounted in
+/config.
+
+New tables can be loading by creating new directories in /config/acpi/table/ and
+writing the SSDT aml code in the aml attribute:
+
+cd /config/acpi/table
+mkdir my_ssdt
+cat ~/ssdt.aml > my_ssdt/aml

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.
 

MAINTAINERS

@@ -288,6 +288,7 @@ F:	include/linux/acpi.h
 F:	include/acpi/
 F:	Documentation/acpi/
 F:	Documentation/ABI/testing/sysfs-bus-acpi
+F:	Documentation/ABI/testing/configfs-acpi
 F:	drivers/pci/*acpi*
 F:	drivers/pci/*/*acpi*
 F:	drivers/pci/*/*/*acpi*

arch/arm64/Kconfig

@@ -4,6 +4,7 @@ config ARM64
 	select ACPI_GENERIC_GSI if ACPI
 	select ACPI_REDUCED_HARDWARE_ONLY if ACPI
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
+	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_GCOV_PROFILE_ALL

arch/arm64/include/asm/acpi.h

@@ -121,4 +121,6 @@ static inline int arm64_acpi_numa_init(void) { return -ENOSYS; }
 static inline int acpi_numa_get_nid(unsigned int cpu, u64 hwid) { return NUMA_NO_NODE; }
 #endif /* CONFIG_ACPI_NUMA */
 
+#define ACPI_TABLE_UPGRADE_MAX_PHYS MEMBLOCK_ALLOC_ACCESSIBLE
+
 #endif /*_ASM_ACPI_H*/

arch/arm64/kernel/setup.c

@@ -260,11 +260,13 @@ void __init setup_arch(char **cmdline_p)
 	efi_init();
 	arm64_memblock_init();
 
+	paging_init();
+
+	acpi_table_upgrade();
+
 	/* Parse the ACPI tables for possible boot-time configuration */
 	acpi_boot_table_init();
 
-	paging_init();
-
 	if (acpi_disabled)
 		unflatten_device_tree();
 

arch/x86/Kconfig

@@ -22,6 +22,7 @@ config X86
 	select ANON_INODES
 	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_DISCARD_MEMBLOCK
+	select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
 	select ARCH_HAS_DEVMEM_IS_ALLOWED

arch/x86/include/asm/acpi.h

@@ -169,4 +169,6 @@ static inline pgprot_t arch_apei_get_mem_attribute(phys_addr_t addr)
 }
 #endif
 
+#define ACPI_TABLE_UPGRADE_MAX_PHYS (max_low_pfn_mapped << PAGE_SHIFT)
+
 #endif /* _ASM_X86_ACPI_H */

arch/x86/kernel/setup.c

@@ -399,10 +399,6 @@ static void __init reserve_initrd(void)
 	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
 }
 
-static void __init early_initrd_acpi_init(void)
-{
-	early_acpi_table_init((void *)initrd_start, initrd_end - initrd_start);
-}
 #else
 static void __init early_reserve_initrd(void)
 {
@@ -410,9 +406,6 @@ static void __init early_reserve_initrd(void)
 static void __init reserve_initrd(void)
 {
 }
-static void __init early_initrd_acpi_init(void)
-{
-}
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 static void __init parse_setup_data(void)
@@ -1146,7 +1139,7 @@ void __init setup_arch(char **cmdline_p)
 
 	reserve_initrd();
 
-	early_initrd_acpi_init();
+	acpi_table_upgrade();
 
 	vsmp_init();
 

drivers/acpi/Kconfig

@@ -311,9 +311,12 @@ config ACPI_CUSTOM_DSDT
 	bool
 	default ACPI_CUSTOM_DSDT_FILE != ""
 
+config ARCH_HAS_ACPI_TABLE_UPGRADE
+	def_bool n
+
 config ACPI_TABLE_UPGRADE
 	bool "Allow upgrading ACPI tables via initrd"
-	depends on BLK_DEV_INITRD && X86
+	depends on BLK_DEV_INITRD && ARCH_HAS_ACPI_TABLE_UPGRADE
 	default y
 	help
 	  This option provides functionality to upgrade arbitrary ACPI tables
@@ -521,4 +524,12 @@ config XPOWER_PMIC_OPREGION
 
 endif
 
+config ACPI_CONFIGFS
+	tristate "ACPI configfs support"
+	select CONFIGFS_FS
+	help
+	  Select this option to enable support for ACPI configuration from
+	  userspace. The configurable ACPI groups will be visible under
+	  /config/acpi, assuming configfs is mounted under /config.
+
 endif	# ACPI

drivers/acpi/Makefile

@@ -99,5 +99,6 @@ obj-$(CONFIG_ACPI_EXTLOG)	+= acpi_extlog.o
 obj-$(CONFIG_PMIC_OPREGION)	+= pmic/intel_pmic.o
 obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
 obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
+obj-$(CONFIG_ACPI_CONFIGFS)	+= acpi_configfs.o
 
 video-objs			+= acpi_video.o video_detect.o

drivers/acpi/acpi_configfs.c

+/*
+ * ACPI configfs support
+ *
+ * Copyright (c) 2016 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "ACPI configfs: " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/configfs.h>
+#include <linux/acpi.h>
+
+static struct config_group *acpi_table_group;
+
+struct acpi_table {
+	struct config_item cfg;
+	struct acpi_table_header *header;
+};
+
+static ssize_t acpi_table_aml_write(struct config_item *cfg,
+				    const void *data, size_t size)
+{
+	const struct acpi_table_header *header = data;
+	struct acpi_table *table;
+	int ret;
+
+	table = container_of(cfg, struct acpi_table, cfg);
+
+	if (table->header) {
+		pr_err("table already loaded\n");
+		return -EBUSY;
+	}
+
+	if (header->length != size) {
+		pr_err("invalid table length\n");
+		return -EINVAL;
+	}
+
+	if (memcmp(header->signature, ACPI_SIG_SSDT, 4)) {
+		pr_err("invalid table signature\n");
+		return -EINVAL;
+	}
+
+	table = container_of(cfg, struct acpi_table, cfg);
+
+	table->header = kmemdup(header, header->length, GFP_KERNEL);
+	if (!table->header)
+		return -ENOMEM;
+
+	ret = acpi_load_table(table->header);
+	if (ret) {
+		kfree(table->header);
+		table->header = NULL;
+	}
+
+	return ret;
+}
+
+static inline struct acpi_table_header *get_header(struct config_item *cfg)
+{
+	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
+
+	if (!table->header)
+		pr_err("table not loaded\n");
+
+	return table->header;
+}
+
+static ssize_t acpi_table_aml_read(struct config_item *cfg,
+				   void *data, size_t size)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	if (data)
+		memcpy(data, h, h->length);
+
+	return h->length;
+}
+
+#define MAX_ACPI_TABLE_SIZE (128 * 1024)
+
+CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
+
+struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
+	&acpi_table_attr_aml,
+	NULL,
+};
+
+ssize_t acpi_table_signature_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->signature);
+}
+
+ssize_t acpi_table_length_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%d\n", h->length);
+}
+
+ssize_t acpi_table_revision_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%d\n", h->revision);
+}
+
+ssize_t acpi_table_oem_id_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%.*s\n", ACPI_OEM_ID_SIZE, h->oem_id);
+}
+
+ssize_t acpi_table_oem_table_id_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%.*s\n", ACPI_OEM_TABLE_ID_SIZE, h->oem_table_id);
+}
+
+ssize_t acpi_table_oem_revision_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%d\n", h->oem_revision);
+}
+
+ssize_t acpi_table_asl_compiler_id_show(struct config_item *cfg, char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%.*s\n", ACPI_NAME_SIZE, h->asl_compiler_id);
+}
+
+ssize_t acpi_table_asl_compiler_revision_show(struct config_item *cfg,
+					      char *str)
+{
+	struct acpi_table_header *h = get_header(cfg);
+
+	if (!h)
+		return -EINVAL;
+
+	return sprintf(str, "%d\n", h->asl_compiler_revision);
+}
+
+CONFIGFS_ATTR_RO(acpi_table_, signature);
+CONFIGFS_ATTR_RO(acpi_table_, length);
+CONFIGFS_ATTR_RO(acpi_table_, revision);
+CONFIGFS_ATTR_RO(acpi_table_, oem_id);
+CONFIGFS_ATTR_RO(acpi_table_, oem_table_id);
+CONFIGFS_ATTR_RO(acpi_table_, oem_revision);
+CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_id);
+CONFIGFS_ATTR_RO(acpi_table_, asl_compiler_revision);
+
+struct configfs_attribute *acpi_table_attrs[] = {
+	&acpi_table_attr_signature,
+	&acpi_table_attr_length,
+	&acpi_table_attr_revision,
+	&acpi_table_attr_oem_id,
+	&acpi_table_attr_oem_table_id,
+	&acpi_table_attr_oem_revision,
+	&acpi_table_attr_asl_compiler_id,
+	&acpi_table_attr_asl_compiler_revision,
+	NULL,
+};
+
+static struct config_item_type acpi_table_type = {
+	.ct_owner = THIS_MODULE,
+	.ct_bin_attrs = acpi_table_bin_attrs,
+	.ct_attrs = acpi_table_attrs,
+};
+
+static struct config_item *acpi_table_make_item(struct config_group *group,
+						const char *name)
+{
+	struct acpi_table *table;
+
+	table = kzalloc(sizeof(*table), GFP_KERNEL);
+	if (!table)
+		return ERR_PTR(-ENOMEM);
+
+	config_item_init_type_name(&table->cfg, name, &acpi_table_type);
+	return &table->cfg;
+}
+
+struct configfs_group_operations acpi_table_group_ops = {
+	.make_item = acpi_table_make_item,
+};
+
+static struct config_item_type acpi_tables_type = {
+	.ct_owner = THIS_MODULE,
+	.ct_group_ops = &acpi_table_group_ops,
+};
+
+static struct config_item_type acpi_root_group_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem acpi_configfs = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "acpi",
+			.ci_type = &acpi_root_group_type,
+		},
+	},
+	.su_mutex = __MUTEX_INITIALIZER(acpi_configfs.su_mutex),
+};
+
+static int __init acpi_configfs_init(void)
+{
+	int ret;
+	struct config_group *root = &acpi_configfs.su_group;
+
+	config_group_init(root);
+
+	ret = configfs_register_subsystem(&acpi_configfs);
+	if (ret)
+		return ret;
+
+	acpi_table_group = configfs_register_default_group(root, "table",
+							   &acpi_tables_type);
+	return PTR_ERR_OR_ZERO(acpi_table_group);
+}
+module_init(acpi_configfs_init);
+
+static void __exit acpi_configfs_exit(void)
+{
+	configfs_unregister_default_group(acpi_table_group);
+	configfs_unregister_subsystem(&acpi_configfs);
+}
+module_exit(acpi_configfs_exit);
+
+MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>");
+MODULE_DESCRIPTION("ACPI configfs support");
+MODULE_LICENSE("GPL v2");

drivers/acpi/bus.c

@@ -990,6 +990,13 @@ void __init acpi_subsystem_init(void)
 	}
 }
 
+static acpi_status acpi_bus_table_handler(u32 event, void *table, void *context)
+{
+	acpi_scan_table_handler(event, table, context);
+
+	return acpi_sysfs_table_handler(event, table, context);
+}
+
 static int __init acpi_bus_init(void)
 {
 	int result;
@@ -1043,6 +1050,8 @@ static int __init acpi_bus_init(void)
 	 * _PDC control method may load dynamic SSDT tables,
 	 * and we need to install the table handler before that.
 	 */
+	status = acpi_install_table_handler(acpi_bus_table_handler, NULL);
+
 	acpi_sysfs_init();
 
 	acpi_early_processor_set_pdc();

drivers/acpi/internal.h

@@ -87,6 +87,9 @@ bool acpi_queue_hotplug_work(struct work_struct *work);
 void acpi_device_hotplug(struct acpi_device *adev, u32 src);
 bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
 
+acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context);
+void acpi_scan_table_handler(u32 event, void *table, void *context);
+
 /* --------------------------------------------------------------------------
                      Device Node Initialization / Removal
    -------------------------------------------------------------------------- */

drivers/acpi/scan.c

@@ -494,6 +494,8 @@ static void acpi_device_del(struct acpi_device *device)
 	device_del(&device->dev);
 }
 
+static BLOCKING_NOTIFIER_HEAD(acpi_reconfig_chain);
+
 static LIST_HEAD(acpi_device_del_list);
 static DEFINE_MUTEX(acpi_device_del_lock);
 
@@ -514,6 +516,9 @@ static void acpi_device_del_work_fn(struct work_struct *work_not_used)
 
 		mutex_unlock(&acpi_device_del_lock);
 
+		blocking_notifier_call_chain(&acpi_reconfig_chain,
+					     ACPI_RECONFIG_DEVICE_REMOVE, adev);
+
 		acpi_device_del(adev);
 		/*
 		 * Drop references to all power resources that might have been
@@ -1406,7 +1411,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
 	acpi_bus_get_flags(device);
 	device->flags.match_driver = false;
 	device->flags.initialized = true;
-	device->flags.visited = false;
+	acpi_device_clear_enumerated(device);
 	device_initialize(&device->dev);
 	dev_set_uevent_suppress(&device->dev, true);
 	acpi_init_coherency(device);
@@ -1676,15 +1681,20 @@ static void acpi_default_enumeration(struct acpi_device *device)
 	bool is_spi_i2c_slave = false;
 
 	/*
-	 * Do not enemerate SPI/I2C slaves as they will be enuerated by their
+	 * Do not enumerate SPI/I2C slaves as they will be enumerated by their
 	 * respective parents.
 	 */
 	INIT_LIST_HEAD(&resource_list);
 	acpi_dev_get_resources(device, &resource_list, acpi_check_spi_i2c_slave,
 			       &is_spi_i2c_slave);
 	acpi_dev_free_resource_list(&resource_list);
-	if (!is_spi_i2c_slave)
+	if (!is_spi_i2c_slave) {
 		acpi_create_platform_device(device);
+		acpi_device_set_enumerated(device);
+	} else {
+		blocking_notifier_call_chain(&acpi_reconfig_chain,
+					     ACPI_RECONFIG_DEVICE_ADD, device);
+	}
 }
 
 static const struct acpi_device_id generic_device_ids[] = {
@@ -1751,7 +1761,7 @@ static void acpi_bus_attach(struct acpi_device *device)
 	acpi_bus_get_status(device);
 	/* Skip devices that are not present. */
 	if (!acpi_device_is_present(device)) {
-		device->flags.visited = false;
+		acpi_device_clear_enumerated(device);
 		device->flags.power_manageable = 0;
 		return;
 	}
@@ -1766,7 +1776,7 @@ static void acpi_bus_attach(struct acpi_device *device)
 
 		device->flags.initialized = true;
 	}
-	device->flags.visited = false;
+
 	ret = acpi_scan_attach_handler(device);
 	if (ret < 0)
 		return;
@@ -1780,7 +1790,6 @@ static void acpi_bus_attach(struct acpi_device *device)
 		if (!ret && device->pnp.type.platform_id)
 			acpi_default_enumeration(device);
 	}
-	device->flags.visited = true;
 
  ok:
 	list_for_each_entry(child, &device->children, node)
@@ -1872,7 +1881,7 @@ void acpi_bus_trim(struct acpi_device *adev)
 	 */
 	acpi_device_set_power(adev, ACPI_STATE_D3_COLD);
 	adev->flags.initialized = false;
-	adev->flags.visited = false;
+	acpi_device_clear_enumerated(adev);
 }
 EXPORT_SYMBOL_GPL(acpi_bus_trim);
 
@@ -1916,6 +1925,8 @@ static int acpi_bus_scan_fixed(void)
 	return result < 0 ? result : 0;
 }
 
+static bool acpi_scan_initialized;
+
 int __init acpi_scan_init(void)
 {
 	int result;
@@ -1960,6 +1971,8 @@ int __init acpi_scan_init(void)
 
 	acpi_update_all_gpes();
 
+	acpi_scan_initialized = true;
+
  out:
 	mutex_unlock(&acpi_scan_lock);
 	return result;
@@ -2003,3 +2016,57 @@ int __init __acpi_probe_device_table(struct acpi_probe_entry *ap_head, int nr)
 
 	return count;
 }
+
+struct acpi_table_events_work {
+	struct work_struct work;
+	void *table;
+	u32 event;
+};
+
+static void acpi_table_events_fn(struct work_struct *work)
+{
+	struct acpi_table_events_work *tew;
+
+	tew = container_of(work, struct acpi_table_events_work, work);
+
+	if (tew->event == ACPI_TABLE_EVENT_LOAD) {
+		acpi_scan_lock_acquire();
+		acpi_bus_scan(ACPI_ROOT_OBJECT);
+		acpi_scan_lock_release();
+	}
+
+	kfree(tew);
+}
+
+void acpi_scan_table_handler(u32 event, void *table, void *context)
+{
+	struct acpi_table_events_work *tew;
+
+	if (!acpi_scan_initialized)
+		return;
+
+	if (event != ACPI_TABLE_EVENT_LOAD)
+		return;
+
+	tew = kmalloc(sizeof(*tew), GFP_KERNEL);
+	if (!tew)
+		return;
+
+	INIT_WORK(&tew->work, acpi_table_events_fn);
+	tew->table = table;
+	tew->event = event;
+
+	schedule_work(&tew->work);
+}
+
+int acpi_reconfig_notifier_register(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&acpi_reconfig_chain, nb);
+}
+EXPORT_SYMBOL(acpi_reconfig_notifier_register);
+
+int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&acpi_reconfig_chain, nb);
+}
+EXPORT_SYMBOL(acpi_reconfig_notifier_unregister);

drivers/acpi/sysfs.c

@@ -378,8 +378,7 @@ static void acpi_table_attr_init(struct acpi_table_attr *table_attr,
 	return;
 }
 
-static acpi_status
-acpi_sysfs_table_handler(u32 event, void *table, void *context)
+acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context)
 {
 	struct acpi_table_attr *table_attr;
 
@@ -452,9 +451,8 @@ static int acpi_tables_sysfs_init(void)
 
 	kobject_uevent(tables_kobj, KOBJ_ADD);
 	kobject_uevent(dynamic_tables_kobj, KOBJ_ADD);
-	status = acpi_install_table_handler(acpi_sysfs_table_handler, NULL);
 
-	return ACPI_FAILURE(status) ? -EINVAL : 0;
+	return 0;
 err_dynamic_tables:
 	kobject_put(tables_kobj);
 err:

drivers/acpi/tables.c

@@ -34,6 +34,8 @@
 #include <linux/bootmem.h>
 #include <linux/earlycpio.h>
 #include <linux/memblock.h>
+#include <linux/initrd.h>
+#include <linux/acpi.h>
 #include "internal.h"
 
 #ifdef CONFIG_ACPI_CUSTOM_DSDT
@@ -481,8 +483,10 @@ static DECLARE_BITMAP(acpi_initrd_installed, NR_ACPI_INITRD_TABLES);
 
 #define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
 
-static void __init acpi_table_initrd_init(void *data, size_t size)
+void __init acpi_table_upgrade(void)
 {
+	void *data = (void *)initrd_start;
+	size_t size = initrd_end - initrd_start;
 	int sig, no, table_nr = 0, total_offset = 0;
 	long offset = 0;
 	struct acpi_table_header *table;
@@ -540,7 +544,7 @@ static void __init acpi_table_initrd_init(void *data, size_t size)
 		return;
 
 	acpi_tables_addr =
-		memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
+		memblock_find_in_range(0, ACPI_TABLE_UPGRADE_MAX_PHYS,
 				       all_tables_size, PAGE_SIZE);
 	if (!acpi_tables_addr) {
 		WARN_ON(1);
@@ -578,10 +582,10 @@ static void __init acpi_table_initrd_init(void *data, size_t size)
 			clen = size;
 			if (clen > MAP_CHUNK_SIZE - slop)
 				clen = MAP_CHUNK_SIZE - slop;
-			dest_p = early_ioremap(dest_addr & PAGE_MASK,
-						 clen + slop);
+			dest_p = early_memremap(dest_addr & PAGE_MASK,
+						clen + slop);
 			memcpy(dest_p + slop, src_p, clen);
-			early_iounmap(dest_p, clen + slop);
+			early_memunmap(dest_p, clen + slop);
 			src_p += clen;
 			dest_addr += clen;
 			size -= clen;
@@ -696,10 +700,6 @@ static void __init acpi_table_initrd_scan(void)
 	}
 }
 #else
-static void __init acpi_table_initrd_init(void *data, size_t size)
-{
-}
-
 static acpi_status
 acpi_table_initrd_override(struct acpi_table_header *existing_table,
 			   acpi_physical_address *address,
@@ -742,11 +742,6 @@ acpi_os_table_override(struct acpi_table_header *existing_table,
 	return AE_OK;
 }
 
-void __init early_acpi_table_init(void *data, size_t size)
-{
-	acpi_table_initrd_init(data, size);
-}
-
 /*
  * acpi_table_init()
  *

drivers/firmware/efi/efi.c

@@ -24,6 +24,9 @@
 #include <linux/of_fdt.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/acpi.h>
+#include <linux/ucs2_string.h>
 
 #include <asm/early_ioremap.h>
 
@@ -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",

drivers/i2c/i2c-core.c

@@ -107,12 +107,11 @@ struct acpi_i2c_lookup {
 	acpi_handle device_handle;
 };
 
-static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
+static int acpi_i2c_fill_info(struct acpi_resource *ares, void *data)
 {
 	struct acpi_i2c_lookup *lookup = data;
 	struct i2c_board_info *info = lookup->info;
 	struct acpi_resource_i2c_serialbus *sb;
-	acpi_handle adapter_handle;
 	acpi_status status;
 
 	if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
@@ -122,80 +121,102 @@ static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
 	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
 		return 1;
 
-	/*
-	 * Extract the ResourceSource and make sure that the handle matches
-	 * with the I2C adapter handle.
-	 */
 	status = acpi_get_handle(lookup->device_handle,
 				 sb->resource_source.string_ptr,
-				 &adapter_handle);
-	if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
-		info->addr = sb->slave_address;
-		if (sb->access_mode == ACPI_I2C_10BIT_MODE)
-			info->flags |= I2C_CLIENT_TEN;
-	}
+				 &lookup->adapter_handle);
+	if (!ACPI_SUCCESS(status))
+		return 1;
+
+	info->addr = sb->slave_address;
+	if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+		info->flags |= I2C_CLIENT_TEN;
 
 	return 1;
 }
 
-static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
-				       void *data, void **return_value)
+static int acpi_i2c_get_info(struct acpi_device *adev,
+			     struct i2c_board_info *info,
+			     acpi_handle *adapter_handle)
 {
-	struct i2c_adapter *adapter = data;
 	struct list_head resource_list;
-	struct acpi_i2c_lookup lookup;
 	struct resource_entry *entry;
-	struct i2c_board_info info;
-	struct acpi_device *adev;
+	struct acpi_i2c_lookup lookup;
 	int ret;
 
-	if (acpi_bus_get_device(handle, &adev))
-		return AE_OK;
-	if (acpi_bus_get_status(adev) || !adev->status.present)
-		return AE_OK;
+	if (acpi_bus_get_status(adev) || !adev->status.present ||
+	    acpi_device_enumerated(adev))
+		return -EINVAL;
 
-	memset(&info, 0, sizeof(info));
-	info.fwnode = acpi_fwnode_handle(adev);
+	memset(info, 0, sizeof(*info));
+	info->fwnode = acpi_fwnode_handle(adev);
 
 	memset(&lookup, 0, sizeof(lookup));
-	lookup.adapter_handle = ACPI_HANDLE(&adapter->dev);
-	lookup.device_handle = handle;
-	lookup.info = &info;
+	lookup.device_handle = acpi_device_handle(adev);
+	lookup.info = info;
 
-	/*
-	 * Look up for I2cSerialBus resource with ResourceSource that
-	 * matches with this adapter.
-	 */
+	/* Look up for I2cSerialBus resource */
 	INIT_LIST_HEAD(&resource_list);
 	ret = acpi_dev_get_resources(adev, &resource_list,
-				     acpi_i2c_find_address, &lookup);
+				     acpi_i2c_fill_info, &lookup);
 	acpi_dev_free_resource_list(&resource_list);
 
-	if (ret < 0 || !info.addr)
-		return AE_OK;
+	if (ret < 0 || !info->addr)
+		return -EINVAL;
+
+	*adapter_handle = lookup.adapter_handle;
 
 	/* Then fill IRQ number if any */
 	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
 	if (ret < 0)
-		return AE_OK;
+		return -EINVAL;
 
 	resource_list_for_each_entry(entry, &resource_list) {
 		if (resource_type(entry->res) == IORESOURCE_IRQ) {
-			info.irq = entry->res->start;
+			info->irq = entry->res->start;
 			break;
 		}
 	}
 
 	acpi_dev_free_resource_list(&resource_list);
 
+	strlcpy(info->type, dev_name(&adev->dev), sizeof(info->type));
+
+	return 0;
+}
+
+static void acpi_i2c_register_device(struct i2c_adapter *adapter,
+				     struct acpi_device *adev,
+				     struct i2c_board_info *info)
+{
 	adev->power.flags.ignore_parent = true;
-	strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
-	if (!i2c_new_device(adapter, &info)) {
+	acpi_device_set_enumerated(adev);
+
+	if (!i2c_new_device(adapter, info)) {
 		adev->power.flags.ignore_parent = false;
 		dev_err(&adapter->dev,
 			"failed to add I2C device %s from ACPI\n",
 			dev_name(&adev->dev));
 	}
+}
+
+static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct i2c_adapter *adapter = data;
+	struct acpi_device *adev;
+	acpi_handle adapter_handle;
+	struct i2c_board_info info;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+
+	if (acpi_i2c_get_info(adev, &info, &adapter_handle))
+		return AE_OK;
+
+	if (adapter_handle != ACPI_HANDLE(&adapter->dev))
+		return AE_OK;
+
+	acpi_i2c_register_device(adapter, adev, &info);
 
 	return AE_OK;
 }
@@ -225,8 +246,80 @@ static void acpi_i2c_register_devices(struct i2c_adapter *adap)
 		dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 }
 
+static int acpi_i2c_match_adapter(struct device *dev, void *data)
+{
+	struct i2c_adapter *adapter = i2c_verify_adapter(dev);
+
+	if (!adapter)
+		return 0;
+
+	return ACPI_HANDLE(dev) == (acpi_handle)data;
+}
+
+static int acpi_i2c_match_device(struct device *dev, void *data)
+{
+	return ACPI_COMPANION(dev) == data;
+}
+
+static struct i2c_adapter *acpi_i2c_find_adapter_by_handle(acpi_handle handle)
+{
+	struct device *dev;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, handle,
+			      acpi_i2c_match_adapter);
+	return dev ? i2c_verify_adapter(dev) : NULL;
+}
+
+static struct i2c_client *acpi_i2c_find_client_by_adev(struct acpi_device *adev)
+{
+	struct device *dev;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, adev, acpi_i2c_match_device);
+	return dev ? i2c_verify_client(dev) : NULL;
+}
+
+static int acpi_i2c_notify(struct notifier_block *nb, unsigned long value,
+			   void *arg)
+{
+	struct acpi_device *adev = arg;
+	struct i2c_board_info info;
+	acpi_handle adapter_handle;
+	struct i2c_adapter *adapter;
+	struct i2c_client *client;
+
+	switch (value) {
+	case ACPI_RECONFIG_DEVICE_ADD:
+		if (acpi_i2c_get_info(adev, &info, &adapter_handle))
+			break;
+
+		adapter = acpi_i2c_find_adapter_by_handle(adapter_handle);
+		if (!adapter)
+			break;
+
+		acpi_i2c_register_device(adapter, adev, &info);
+		break;
+	case ACPI_RECONFIG_DEVICE_REMOVE:
+		if (!acpi_device_enumerated(adev))
+			break;
+
+		client = acpi_i2c_find_client_by_adev(adev);
+		if (!client)
+			break;
+
+		i2c_unregister_device(client);
+		put_device(&client->dev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block i2c_acpi_notifier = {
+	.notifier_call = acpi_i2c_notify,
+};
 #else /* CONFIG_ACPI */
 static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
+extern struct notifier_block i2c_acpi_notifier;
 #endif /* CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI_I2C_OPREGION
@@ -1089,6 +1182,8 @@ void i2c_unregister_device(struct i2c_client *client)
 {
 	if (client->dev.of_node)
 		of_node_clear_flag(client->dev.of_node, OF_POPULATED);
+	if (ACPI_COMPANION(&client->dev))
+		acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 	device_unregister(&client->dev);
 }
 EXPORT_SYMBOL_GPL(i2c_unregister_device);
@@ -2117,6 +2212,8 @@ static int __init i2c_init(void)
 
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
+	if (IS_ENABLED(CONFIG_ACPI))
+		WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
 
 	return 0;
 
@@ -2132,6 +2229,8 @@ static int __init i2c_init(void)
 
 static void __exit i2c_exit(void)
 {
+	if (IS_ENABLED(CONFIG_ACPI))
+		WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
 	i2c_del_driver(&dummy_driver);

drivers/spi/spi.c

@@ -622,6 +622,8 @@ void spi_unregister_device(struct spi_device *spi)
 
 	if (spi->dev.of_node)
 		of_node_clear_flag(spi->dev.of_node, OF_POPULATED);
+	if (ACPI_COMPANION(&spi->dev))
+		acpi_device_clear_enumerated(ACPI_COMPANION(&spi->dev));
 	device_unregister(&spi->dev);
 }
 EXPORT_SYMBOL_GPL(spi_unregister_device);
@@ -1646,18 +1648,15 @@ static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
 	return 1;
 }
 
-static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
-				       void *data, void **return_value)
+static acpi_status acpi_register_spi_device(struct spi_master *master,
+					    struct acpi_device *adev)
 {
-	struct spi_master *master = data;
 	struct list_head resource_list;
-	struct acpi_device *adev;
 	struct spi_device *spi;
 	int ret;
 
-	if (acpi_bus_get_device(handle, &adev))
-		return AE_OK;
-	if (acpi_bus_get_status(adev) || !adev->status.present)
+	if (acpi_bus_get_status(adev) || !adev->status.present ||
+	    acpi_device_enumerated(adev))
 		return AE_OK;
 
 	spi = spi_alloc_device(master);
@@ -1683,6 +1682,8 @@ static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
 	if (spi->irq < 0)
 		spi->irq = acpi_dev_gpio_irq_get(adev, 0);
 
+	acpi_device_set_enumerated(adev);
+
 	adev->power.flags.ignore_parent = true;
 	strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
 	if (spi_add_device(spi)) {
@@ -1695,6 +1696,18 @@ static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
 	return AE_OK;
 }
 
+static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
+				       void *data, void **return_value)
+{
+	struct spi_master *master = data;
+	struct acpi_device *adev;
+
+	if (acpi_bus_get_device(handle, &adev))
+		return AE_OK;
+
+	return acpi_register_spi_device(master, adev);
+}
+
 static void acpi_register_spi_devices(struct spi_master *master)
 {
 	acpi_status status;
@@ -3107,6 +3120,77 @@ static struct notifier_block spi_of_notifier = {
 extern struct notifier_block spi_of_notifier;
 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
 
+#if IS_ENABLED(CONFIG_ACPI)
+static int spi_acpi_master_match(struct device *dev, const void *data)
+{
+	return ACPI_COMPANION(dev->parent) == data;
+}
+
+static int spi_acpi_device_match(struct device *dev, void *data)
+{
+	return ACPI_COMPANION(dev) == data;
+}
+
+static struct spi_master *acpi_spi_find_master_by_adev(struct acpi_device *adev)
+{
+	struct device *dev;
+
+	dev = class_find_device(&spi_master_class, NULL, adev,
+				spi_acpi_master_match);
+	if (!dev)
+		return NULL;
+
+	return container_of(dev, struct spi_master, dev);
+}
+
+static struct spi_device *acpi_spi_find_device_by_adev(struct acpi_device *adev)
+{
+	struct device *dev;
+
+	dev = bus_find_device(&spi_bus_type, NULL, adev, spi_acpi_device_match);
+
+	return dev ? to_spi_device(dev) : NULL;
+}
+
+static int acpi_spi_notify(struct notifier_block *nb, unsigned long value,
+			   void *arg)
+{
+	struct acpi_device *adev = arg;
+	struct spi_master *master;
+	struct spi_device *spi;
+
+	switch (value) {
+	case ACPI_RECONFIG_DEVICE_ADD:
+		master = acpi_spi_find_master_by_adev(adev->parent);
+		if (!master)
+			break;
+
+		acpi_register_spi_device(master, adev);
+		put_device(&master->dev);
+		break;
+	case ACPI_RECONFIG_DEVICE_REMOVE:
+		if (!acpi_device_enumerated(adev))
+			break;
+
+		spi = acpi_spi_find_device_by_adev(adev);
+		if (!spi)
+			break;
+
+		spi_unregister_device(spi);
+		put_device(&spi->dev);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block spi_acpi_notifier = {
+	.notifier_call = acpi_spi_notify,
+};
+#else
+extern struct notifier_block spi_acpi_notifier;
+#endif
+
 static int __init spi_init(void)
 {
 	int	status;
@@ -3127,6 +3211,8 @@ static int __init spi_init(void)
 
 	if (IS_ENABLED(CONFIG_OF_DYNAMIC))
 		WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
+	if (IS_ENABLED(CONFIG_ACPI))
+		WARN_ON(acpi_reconfig_notifier_register(&spi_acpi_notifier));
 
 	return 0;
 

include/linux/acpi.h

@@ -208,7 +208,6 @@ void acpi_boot_table_init (void);
 int acpi_mps_check (void);
 int acpi_numa_init (void);
 
-void early_acpi_table_init(void *data, size_t size);
 int acpi_table_init (void);
 int acpi_table_parse(char *id, acpi_tbl_table_handler handler);
 int __init acpi_parse_entries(char *id, unsigned long table_size,
@@ -546,6 +545,24 @@ void acpi_walk_dep_device_list(acpi_handle handle);
 struct platform_device *acpi_create_platform_device(struct acpi_device *);
 #define ACPI_PTR(_ptr)	(_ptr)
 
+static inline void acpi_device_set_enumerated(struct acpi_device *adev)
+{
+	adev->flags.visited = true;
+}
+
+static inline void acpi_device_clear_enumerated(struct acpi_device *adev)
+{
+	adev->flags.visited = false;
+}
+
+enum acpi_reconfig_event  {
+	ACPI_RECONFIG_DEVICE_ADD = 0,
+	ACPI_RECONFIG_DEVICE_REMOVE,
+};
+
+int acpi_reconfig_notifier_register(struct notifier_block *nb);
+int acpi_reconfig_notifier_unregister(struct notifier_block *nb);
+
 #else	/* !CONFIG_ACPI */
 
 #define acpi_disabled 1
@@ -602,7 +619,6 @@ static inline const char *acpi_dev_name(struct acpi_device *adev)
 	return NULL;
 }
 
-static inline void early_acpi_table_init(void *data, size_t size) { }
 static inline void acpi_early_init(void) { }
 static inline void acpi_subsystem_init(void) { }
 
@@ -692,6 +708,24 @@ static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
 
 #define ACPI_PTR(_ptr)	(NULL)
 
+static inline void acpi_device_set_enumerated(struct acpi_device *adev)
+{
+}
+
+static inline void acpi_device_clear_enumerated(struct acpi_device *adev)
+{
+}
+
+static inline int acpi_reconfig_notifier_register(struct notifier_block *nb)
+{
+	return -EINVAL;
+}
+
+static inline int acpi_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+	return -EINVAL;
+}
+
 #endif	/* !CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI
@@ -1011,4 +1045,10 @@ static inline struct fwnode_handle *acpi_get_next_subnode(struct device *dev,
 #define acpi_probe_device_table(t)	({ int __r = 0; __r;})
 #endif
 
+#ifdef CONFIG_ACPI_TABLE_UPGRADE
+void acpi_table_upgrade(void);
+#else
+static inline void acpi_table_upgrade(void) { }
+#endif
+
 #endif	/*_LINUX_ACPI_H*/