--- a/drivers/acpi/apei/Kconfig
+++ b/drivers/acpi/apei/Kconfig
@@ -7,3 +7,10 @@ config ACPI_APEI
 	  especially. In addition it supports error serialization and
 	  error injection.
 
+config ACPI_APEI_EINJ
+	tristate "APEI Error INJection (EINJ)"
+	depends on ACPI_APEI && DEBUG_FS
+	help
+	  EINJ provides a hardware error injection mechanism, it is
+	  mainly used for debugging and testing the other parts of
+	  APEI and some other RAS features.
--- a/drivers/acpi/apei/Makefile
+++ b/drivers/acpi/apei/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_ACPI_APEI)		+= apei.o
+obj-$(CONFIG_ACPI_APEI_EINJ)	+= einj.o
 
 apei-y := apei-base.o hest.o
--- /dev/null
+++ b/drivers/acpi/apei/einj.c
@@ -0,0 +1,486 @@
+/*
+ * APEI Error INJection support
+ *
+ * EINJ provides a hardware error injection mechanism, this is useful
+ * for debugging and testing of other APEI and RAS features.
+ *
+ * For more information about EINJ, please refer to ACPI Specification
+ * version 4.0, section 17.5.
+ *
+ * Copyright 2009 Intel Corp.
+ *   Author: Huang Ying <ying.huang@intel.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/nmi.h>
+#include <linux/delay.h>
+#include <acpi/acpi.h>
+
+#include "apei-internal.h"
+
+#define EINJ_PFX "EINJ: "
+
+#define SPIN_UNIT		100			/* 100ns */
+/* Firmware should respond within 1 miliseconds */
+#define FIRMWARE_TIMEOUT	(1 * NSEC_PER_MSEC)
+
+#define EINJ_OP_BUSY			0x1
+#define EINJ_STATUS_SUCCESS		0x0
+#define EINJ_STATUS_FAIL		0x1
+#define EINJ_STATUS_INVAL		0x2
+
+#define EINJ_TAB_ENTRY(tab)						\
+	((struct acpi_whea_header *)((char *)(tab) +			\
+				    sizeof(struct acpi_table_einj)))
+
+static struct acpi_table_einj *einj_tab;
+
+static struct apei_resources einj_resources;
+
+static struct apei_exec_ins_type einj_ins_type[] = {
+	[ACPI_EINJ_READ_REGISTER] = {
+		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
+		.run   = apei_exec_read_register,
+	},
+	[ACPI_EINJ_READ_REGISTER_VALUE] = {
+		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
+		.run   = apei_exec_read_register_value,
+	},
+	[ACPI_EINJ_WRITE_REGISTER] = {
+		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
+		.run   = apei_exec_write_register,
+	},
+	[ACPI_EINJ_WRITE_REGISTER_VALUE] = {
+		.flags = APEI_EXEC_INS_ACCESS_REGISTER,
+		.run   = apei_exec_write_register_value,
+	},
+	[ACPI_EINJ_NOOP] = {
+		.flags = 0,
+		.run   = apei_exec_noop,
+	},
+};
+
+/*
+ * Prevent EINJ interpreter to run simultaneously, because the
+ * corresponding firmware implementation may not work properly when
+ * invoked simultaneously.
+ */
+static DEFINE_MUTEX(einj_mutex);
+
+static void einj_exec_ctx_init(struct apei_exec_context *ctx)
+{
+	apei_exec_ctx_init(ctx, einj_ins_type, ARRAY_SIZE(einj_ins_type),
+			   EINJ_TAB_ENTRY(einj_tab), einj_tab->entries);
+}
+
+static int __einj_get_available_error_type(u32 *type)
+{
+	struct apei_exec_context ctx;
+	int rc;
+
+	einj_exec_ctx_init(&ctx);
+	rc = apei_exec_run(&ctx, ACPI_EINJ_GET_ERROR_TYPE);
+	if (rc)
+		return rc;
+	*type = apei_exec_ctx_get_output(&ctx);
+
+	return 0;
+}
+
+/* Get error injection capabilities of the platform */
+static int einj_get_available_error_type(u32 *type)
+{
+	int rc;
+
+	mutex_lock(&einj_mutex);
+	rc = __einj_get_available_error_type(type);
+	mutex_unlock(&einj_mutex);
+
+	return rc;
+}
+
+static int einj_timedout(u64 *t)
+{
+	if ((s64)*t < SPIN_UNIT) {
+		pr_warning(FW_WARN EINJ_PFX
+			   "Firmware does not respond in time\n");
+		return 1;
+	}
+	*t -= SPIN_UNIT;
+	ndelay(SPIN_UNIT);
+	touch_nmi_watchdog();
+	return 0;
+}
+
+/* do sanity check to trigger table */
+static int einj_check_trigger_header(struct acpi_einj_trigger *trigger_tab)
+{
+	if (trigger_tab->header_size != sizeof(struct acpi_einj_trigger))
+		return -EINVAL;
+	if (trigger_tab->table_size > PAGE_SIZE ||
+	    trigger_tab->table_size <= trigger_tab->header_size)
+		return -EINVAL;
+	if (trigger_tab->entry_count !=
+	    (trigger_tab->table_size - trigger_tab->header_size) /
+	    sizeof(struct acpi_einj_entry))
+		return -EINVAL;
+
+	return 0;
+}
+
+/* Execute instructions in trigger error action table */
+static int __einj_error_trigger(u64 trigger_paddr)
+{
+	struct acpi_einj_trigger *trigger_tab = NULL;
+	struct apei_exec_context trigger_ctx;
+	struct apei_resources trigger_resources;
+	struct acpi_whea_header *trigger_entry;
+	struct resource *r;
+	u32 table_size;
+	int rc = -EIO;
+
+	r = request_mem_region(trigger_paddr, sizeof(*trigger_tab),
+			       "APEI EINJ Trigger Table");
+	if (!r) {
+		pr_err(EINJ_PFX
+	"Can not request iomem region <%016llx-%016llx> for Trigger table.\n",
+		       (unsigned long long)trigger_paddr,
+		       (unsigned long long)trigger_paddr+sizeof(*trigger_tab));
+		goto out;
+	}
+	trigger_tab = ioremap_cache(trigger_paddr, sizeof(*trigger_tab));
+	if (!trigger_tab) {
+		pr_err(EINJ_PFX "Failed to map trigger table!\n");
+		goto out_rel_header;
+	}
+	rc = einj_check_trigger_header(trigger_tab);
+	if (rc) {
+		pr_warning(FW_BUG EINJ_PFX
+			   "The trigger error action table is invalid\n");
+		goto out_rel_header;
+	}
+	rc = -EIO;
+	table_size = trigger_tab->table_size;
+	r = request_mem_region(trigger_paddr + sizeof(*trigger_tab),
+			       table_size - sizeof(*trigger_tab),
+			       "APEI EINJ Trigger Table");
+	if (!r) {
+		pr_err(EINJ_PFX
+"Can not request iomem region <%016llx-%016llx> for Trigger Table Entry.\n",
+		       (unsigned long long)trigger_paddr+sizeof(*trigger_tab),
+		       (unsigned long long)trigger_paddr + table_size);
+		goto out_rel_header;
+	}
+	iounmap(trigger_tab);
+	trigger_tab = ioremap_cache(trigger_paddr, table_size);
+	if (!trigger_tab) {
+		pr_err(EINJ_PFX "Failed to map trigger table!\n");
+		goto out_rel_entry;
+	}
+	trigger_entry = (struct acpi_whea_header *)
+		((char *)trigger_tab + sizeof(struct acpi_einj_trigger));
+	apei_resources_init(&trigger_resources);
+	apei_exec_ctx_init(&trigger_ctx, einj_ins_type,
+			   ARRAY_SIZE(einj_ins_type),
+			   trigger_entry, trigger_tab->entry_count);
+	rc = apei_exec_collect_resources(&trigger_ctx, &trigger_resources);
+	if (rc)
+		goto out_fini;
+	rc = apei_resources_sub(&trigger_resources, &einj_resources);
+	if (rc)
+		goto out_fini;
+	rc = apei_resources_request(&trigger_resources, "APEI EINJ Trigger");
+	if (rc)
+		goto out_fini;
+	rc = apei_exec_pre_map_gars(&trigger_ctx);
+	if (rc)
+		goto out_release;
+
+	rc = apei_exec_run(&trigger_ctx, ACPI_EINJ_TRIGGER_ERROR);
+
+	apei_exec_post_unmap_gars(&trigger_ctx);
+out_release:
+	apei_resources_release(&trigger_resources);
+out_fini:
+	apei_resources_fini(&trigger_resources);
+out_rel_entry:
+	release_mem_region(trigger_paddr + sizeof(*trigger_tab),
+			   table_size - sizeof(*trigger_tab));
+out_rel_header:
+	release_mem_region(trigger_paddr, sizeof(*trigger_tab));
+out:
+	if (trigger_tab)
+		iounmap(trigger_tab);
+
+	return rc;
+}
+
+static int __einj_error_inject(u32 type)
+{
+	struct apei_exec_context ctx;
+	u64 val, trigger_paddr, timeout = FIRMWARE_TIMEOUT;
+	int rc;
+
+	einj_exec_ctx_init(&ctx);
+
+	rc = apei_exec_run(&ctx, ACPI_EINJ_BEGIN_OPERATION);
+	if (rc)
+		return rc;
+	apei_exec_ctx_set_input(&ctx, type);
+	rc = apei_exec_run(&ctx, ACPI_EINJ_SET_ERROR_TYPE);
+	if (rc)
+		return rc;
+	rc = apei_exec_run(&ctx, ACPI_EINJ_EXECUTE_OPERATION);
+	if (rc)
+		return rc;
+	for (;;) {
+		rc = apei_exec_run(&ctx, ACPI_EINJ_CHECK_BUSY_STATUS);
+		if (rc)
+			return rc;
+		val = apei_exec_ctx_get_output(&ctx);
+		if (!(val & EINJ_OP_BUSY))
+			break;
+		if (einj_timedout(&timeout))
+			return -EIO;
+	}
+	rc = apei_exec_run(&ctx, ACPI_EINJ_GET_COMMAND_STATUS);
+	if (rc)
+		return rc;
+	val = apei_exec_ctx_get_output(&ctx);
+	if (val != EINJ_STATUS_SUCCESS)
+		return -EBUSY;
+
+	rc = apei_exec_run(&ctx, ACPI_EINJ_GET_TRIGGER_TABLE);
+	if (rc)
+		return rc;
+	trigger_paddr = apei_exec_ctx_get_output(&ctx);
+	rc = __einj_error_trigger(trigger_paddr);
+	if (rc)
+		return rc;
+	rc = apei_exec_run(&ctx, ACPI_EINJ_END_OPERATION);
+
+	return rc;
+}
+
+/* Inject the specified hardware error */
+static int einj_error_inject(u32 type)
+{
+	int rc;
+
+	mutex_lock(&einj_mutex);
+	rc = __einj_error_inject(type);
+	mutex_unlock(&einj_mutex);
+
+	return rc;
+}
+
+static u32 error_type;
+static struct dentry *einj_debug_dir;
+
+static int available_error_type_show(struct seq_file *m, void *v)
+{
+	int rc;
+	u32 available_error_type = 0;
+
+	rc = einj_get_available_error_type(&available_error_type);
+	if (rc)
+		return rc;
+	if (available_error_type & 0x0001)
+		seq_printf(m, "0x00000001\tProcessor Correctable\n");
+	if (available_error_type & 0x0002)
+		seq_printf(m, "0x00000002\tProcessor Uncorrectable non-fatal\n");
+	if (available_error_type & 0x0004)
+		seq_printf(m, "0x00000004\tProcessor Uncorrectable fatal\n");
+	if (available_error_type & 0x0008)
+		seq_printf(m, "0x00000008\tMemory Correctable\n");
+	if (available_error_type & 0x0010)
+		seq_printf(m, "0x00000010\tMemory Uncorrectable non-fatal\n");
+	if (available_error_type & 0x0020)
+		seq_printf(m, "0x00000020\tMemory Uncorrectable fatal\n");
+	if (available_error_type & 0x0040)
+		seq_printf(m, "0x00000040\tPCI Express Correctable\n");
+	if (available_error_type & 0x0080)
+		seq_printf(m, "0x00000080\tPCI Express Uncorrectable non-fatal\n");
+	if (available_error_type & 0x0100)
+		seq_printf(m, "0x00000100\tPCI Express Uncorrectable fatal\n");
+	if (available_error_type & 0x0200)
+		seq_printf(m, "0x00000200\tPlatform Correctable\n");
+	if (available_error_type & 0x0400)
+		seq_printf(m, "0x00000400\tPlatform Uncorrectable non-fatal\n");
+	if (available_error_type & 0x0800)
+		seq_printf(m, "0x00000800\tPlatform Uncorrectable fatal\n");
+
+	return 0;
+}
+
+static int available_error_type_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, available_error_type_show, NULL);
+}
+
+static const struct file_operations available_error_type_fops = {
+	.open		= available_error_type_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int error_type_get(void *data, u64 *val)
+{
+	*val = error_type;
+
+	return 0;
+}
+
+static int error_type_set(void *data, u64 val)
+{
+	int rc;
+	u32 available_error_type = 0;
+
+	/* Only one error type can be specified */
+	if (val & (val - 1))
+		return -EINVAL;
+	rc = einj_get_available_error_type(&available_error_type);
+	if (rc)
+		return rc;
+	if (!(val & available_error_type))
+		return -EINVAL;
+	error_type = val;
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(error_type_fops, error_type_get,
+			error_type_set, "0x%llx\n");
+
+static int error_inject_set(void *data, u64 val)
+{
+	if (!error_type)
+		return -EINVAL;
+
+	return einj_error_inject(error_type);
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(error_inject_fops, NULL,
+			error_inject_set, "%llu\n");
+
+static int einj_check_table(struct acpi_table_einj *einj_tab)
+{
+	if (einj_tab->header_length != sizeof(struct acpi_table_einj))
+		return -EINVAL;
+	if (einj_tab->header.length < sizeof(struct acpi_table_einj))
+		return -EINVAL;
+	if (einj_tab->entries !=
+	    (einj_tab->header.length - sizeof(struct acpi_table_einj)) /
+	    sizeof(struct acpi_einj_entry))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int __init einj_init(void)
+{
+	int rc;
+	acpi_status status;
+	struct dentry *fentry;
+	struct apei_exec_context ctx;
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	status = acpi_get_table(ACPI_SIG_EINJ, 0,
+				(struct acpi_table_header **)&einj_tab);
+	if (status == AE_NOT_FOUND) {
+		pr_info(EINJ_PFX "Table is not found!\n");
+		return -ENODEV;
+	} else if (ACPI_FAILURE(status)) {
+		const char *msg = acpi_format_exception(status);
+		pr_err(EINJ_PFX "Failed to get table, %s\n", msg);
+		return -EINVAL;
+	}
+
+	rc = einj_check_table(einj_tab);
+	if (rc) {
+		pr_warning(FW_BUG EINJ_PFX "EINJ table is invalid\n");
+		return -EINVAL;
+	}
+
+	rc = -ENOMEM;
+	einj_debug_dir = debugfs_create_dir("einj", apei_get_debugfs_dir());
+	if (!einj_debug_dir)
+		goto err_cleanup;
+	fentry = debugfs_create_file("available_error_type", S_IRUSR,
+				     einj_debug_dir, NULL,
+				     &available_error_type_fops);
+	if (!fentry)
+		goto err_cleanup;
+	fentry = debugfs_create_file("error_type", S_IRUSR | S_IWUSR,
+				     einj_debug_dir, NULL, &error_type_fops);
+	if (!fentry)
+		goto err_cleanup;
+	fentry = debugfs_create_file("error_inject", S_IWUSR,
+				     einj_debug_dir, NULL, &error_inject_fops);
+	if (!fentry)
+		goto err_cleanup;
+
+	apei_resources_init(&einj_resources);
+	einj_exec_ctx_init(&ctx);
+	rc = apei_exec_collect_resources(&ctx, &einj_resources);
+	if (rc)
+		goto err_fini;
+	rc = apei_resources_request(&einj_resources, "APEI EINJ");
+	if (rc)
+		goto err_fini;
+	rc = apei_exec_pre_map_gars(&ctx);
+	if (rc)
+		goto err_release;
+
+	pr_info(EINJ_PFX "Error INJection is initialized.\n");
+
+	return 0;
+
+err_release:
+	apei_resources_release(&einj_resources);
+err_fini:
+	apei_resources_fini(&einj_resources);
+err_cleanup:
+	debugfs_remove_recursive(einj_debug_dir);
+
+	return rc;
+}
+
+static void __exit einj_exit(void)
+{
+	struct apei_exec_context ctx;
+
+	einj_exec_ctx_init(&ctx);
+	apei_exec_post_unmap_gars(&ctx);
+	apei_resources_release(&einj_resources);
+	apei_resources_fini(&einj_resources);
+	debugfs_remove_recursive(einj_debug_dir);
+}
+
+module_init(einj_init);
+module_exit(einj_exit);
+
+MODULE_AUTHOR("Huang Ying");
+MODULE_DESCRIPTION("APEI Error INJection support");
+MODULE_LICENSE("GPL");
