From: Jan Kiszka <jan.kiszka@siemens.com>
Date: Fri, 9 Jun 2017 20:36:31 +0200
Subject: ACPI: configfs: Unload SSDT on configfs entry removal
Patch-mainline: v4.13-rc1
Git-commit: 772bf1e2878ecfca0d1f332071c83e021dd9cf01
References: bsc#1117419

Call directly into acpica to load a table to obtain its index on return.
We choose the direct call of acpica internal functions to avoid having
to modify its API which is used outside of Linux as well.

Use that index to unload the table again when the corresponding
directory in configfs gets removed. This allows to change SSDTs without
rebooting the system. It also allows to destroy devices again that a
dynamically loaded SSDT created.

This is widely similar to the DT overlay behavior.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/acpi/acpi_configfs.c |   20 +++++++++++++++++++-
 drivers/acpi/acpica/tbdata.c |    4 ++++
 2 files changed, 23 insertions(+), 1 deletion(-)

--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -15,11 +15,15 @@
 #include <linux/configfs.h>
 #include <linux/acpi.h>
 
+#include "acpica/accommon.h"
+#include "acpica/actables.h"
+
 static struct config_group *acpi_table_group;
 
 struct acpi_table {
 	struct config_item cfg;
 	struct acpi_table_header *header;
+	u32 index;
 };
 
 static ssize_t acpi_table_aml_write(struct config_item *cfg,
@@ -52,7 +56,11 @@ static ssize_t acpi_table_aml_write(stru
 	if (!table->header)
 		return -ENOMEM;
 
-	ret = acpi_load_table(table->header);
+	ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
+	ret = acpi_tb_install_and_load_table(
+			ACPI_PTR_TO_PHYSADDR(table->header),
+			ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL, FALSE,
+			&table->index);
 	if (ret) {
 		kfree(table->header);
 		table->header = NULL;
@@ -215,8 +223,18 @@ static struct config_item *acpi_table_ma
 	return &table->cfg;
 }
 
+static void acpi_table_drop_item(struct config_group *group,
+				 struct config_item *cfg)
+{
+	struct acpi_table *table = container_of(cfg, struct acpi_table, cfg);
+
+	ACPI_INFO(("Host-directed Dynamic ACPI Table Unload"));
+	acpi_tb_unload_table(table->index);
+}
+
 struct configfs_group_operations acpi_table_group_ops = {
 	.make_item = acpi_table_make_item,
+	.drop_item = acpi_table_drop_item,
 };
 
 static struct config_item_type acpi_tables_type = {
--- a/drivers/acpi/acpica/tbdata.c
+++ b/drivers/acpi/acpica/tbdata.c
@@ -867,6 +867,8 @@ exit:
 	return_ACPI_STATUS(status);
 }
 
+ACPI_EXPORT_SYMBOL(acpi_tb_install_and_load_table)
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_tb_unload_table
@@ -914,3 +916,5 @@ acpi_status acpi_tb_unload_table(u32 tab
 	acpi_tb_set_table_loaded_flag(table_index, FALSE);
 	return_ACPI_STATUS(status);
 }
+
+ACPI_EXPORT_SYMBOL(acpi_tb_unload_table)