ACPI, APEI, EINJ support

	  to the operating system. This improves NMI handling

	  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.

obj-$(CONFIG_ACPI_APEI)		+= apei.o

obj-$(CONFIG_ACPI_APEI_EINJ)	+= einj.o

apei-y := apei-base.o hest.o

/*

 * 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");