blob: 18645f4e83cdd2f22d526276b320dac631be8940 [file] [log] [blame]
/*
* APEI Error Record Serialization Table support
*
* ERST is a way provided by APEI to save and retrieve hardware error
* infomation to and from a persistent store.
*
* For more information about ERST, please refer to ACPI Specification
* version 4.0, section 17.4.
*
* Copyright 2010 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/delay.h>
#include <linux/io.h>
#include <linux/acpi.h>
#include <linux/uaccess.h>
#include <linux/cper.h>
#include <linux/nmi.h>
#include <linux/hardirq.h>
#include <acpi/apei.h>
#include "apei-internal.h"
#define ERST_PFX "ERST: "
/* ERST command status */
#define ERST_STATUS_SUCCESS 0x0
#define ERST_STATUS_NOT_ENOUGH_SPACE 0x1
#define ERST_STATUS_HARDWARE_NOT_AVAILABLE 0x2
#define ERST_STATUS_FAILED 0x3
#define ERST_STATUS_RECORD_STORE_EMPTY 0x4
#define ERST_STATUS_RECORD_NOT_FOUND 0x5
#define ERST_TAB_ENTRY(tab) \
((struct acpi_whea_header *)((char *)(tab) + \
sizeof(struct acpi_table_erst)))
#define SPIN_UNIT 100 /* 100ns */
/* Firmware should respond within 1 miliseconds */
#define FIRMWARE_TIMEOUT (1 * NSEC_PER_MSEC)
#define FIRMWARE_MAX_STALL 50 /* 50us */
int erst_disable;
EXPORT_SYMBOL_GPL(erst_disable);
static struct acpi_table_erst *erst_tab;
/* ERST Error Log Address Range atrributes */
#define ERST_RANGE_RESERVED 0x0001
#define ERST_RANGE_NVRAM 0x0002
#define ERST_RANGE_SLOW 0x0004
/*
* ERST Error Log Address Range, used as buffer for reading/writing
* error records.
*/
static struct erst_erange {
u64 base;
u64 size;
void __iomem *vaddr;
u32 attr;
} erst_erange;
/*
* Prevent ERST interpreter to run simultaneously, because the
* corresponding firmware implementation may not work properly when
* invoked simultaneously.
*
* It is used to provide exclusive accessing for ERST Error Log
* Address Range too.
*/
static DEFINE_SPINLOCK(erst_lock);
static inline int erst_errno(int command_status)
{
switch (command_status) {
case ERST_STATUS_SUCCESS:
return 0;
case ERST_STATUS_HARDWARE_NOT_AVAILABLE:
return -ENODEV;
case ERST_STATUS_NOT_ENOUGH_SPACE:
return -ENOSPC;
case ERST_STATUS_RECORD_STORE_EMPTY:
case ERST_STATUS_RECORD_NOT_FOUND:
return -ENOENT;
default:
return -EINVAL;
}
}
static int erst_timedout(u64 *t, u64 spin_unit)
{
if ((s64)*t < spin_unit) {
pr_warning(FW_WARN ERST_PFX
"Firmware does not respond in time\n");
return 1;
}
*t -= spin_unit;
ndelay(spin_unit);
touch_nmi_watchdog();
return 0;
}
static int erst_exec_load_var1(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
return __apei_exec_read_register(entry, &ctx->var1);
}
static int erst_exec_load_var2(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
return __apei_exec_read_register(entry, &ctx->var2);
}
static int erst_exec_store_var1(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
return __apei_exec_write_register(entry, ctx->var1);
}
static int erst_exec_add(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
ctx->var1 += ctx->var2;
return 0;
}
static int erst_exec_subtract(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
ctx->var1 -= ctx->var2;
return 0;
}
static int erst_exec_add_value(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
int rc;
u64 val;
rc = __apei_exec_read_register(entry, &val);
if (rc)
return rc;
val += ctx->value;
rc = __apei_exec_write_register(entry, val);
return rc;
}
static int erst_exec_subtract_value(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
int rc;
u64 val;
rc = __apei_exec_read_register(entry, &val);
if (rc)
return rc;
val -= ctx->value;
rc = __apei_exec_write_register(entry, val);
return rc;
}
static int erst_exec_stall(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
u64 stall_time;
if (ctx->value > FIRMWARE_MAX_STALL) {
if (!in_nmi())
pr_warning(FW_WARN ERST_PFX
"Too long stall time for stall instruction: %llx.\n",
ctx->value);
stall_time = FIRMWARE_MAX_STALL;
} else
stall_time = ctx->value;
udelay(stall_time);
return 0;
}
static int erst_exec_stall_while_true(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
int rc;
u64 val;
u64 timeout = FIRMWARE_TIMEOUT;
u64 stall_time;
if (ctx->var1 > FIRMWARE_MAX_STALL) {
if (!in_nmi())
pr_warning(FW_WARN ERST_PFX
"Too long stall time for stall while true instruction: %llx.\n",
ctx->var1);
stall_time = FIRMWARE_MAX_STALL;
} else
stall_time = ctx->var1;
for (;;) {
rc = __apei_exec_read_register(entry, &val);
if (rc)
return rc;
if (val != ctx->value)
break;
if (erst_timedout(&timeout, stall_time * NSEC_PER_USEC))
return -EIO;
}
return 0;
}
static int erst_exec_skip_next_instruction_if_true(
struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
int rc;
u64 val;
rc = __apei_exec_read_register(entry, &val);
if (rc)
return rc;
if (val == ctx->value) {
ctx->ip += 2;
return APEI_EXEC_SET_IP;
}
return 0;
}
static int erst_exec_goto(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
ctx->ip = ctx->value;
return APEI_EXEC_SET_IP;
}
static int erst_exec_set_src_address_base(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
return __apei_exec_read_register(entry, &ctx->src_base);
}
static int erst_exec_set_dst_address_base(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
return __apei_exec_read_register(entry, &ctx->dst_base);
}
static int erst_exec_move_data(struct apei_exec_context *ctx,
struct acpi_whea_header *entry)
{
int rc;
u64 offset;
rc = __apei_exec_read_register(entry, &offset);
if (rc)
return rc;
memmove((void *)ctx->dst_base + offset,
(void *)ctx->src_base + offset,
ctx->var2);
return 0;
}
static struct apei_exec_ins_type erst_ins_type[] = {
[ACPI_ERST_READ_REGISTER] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = apei_exec_read_register,
},
[ACPI_ERST_READ_REGISTER_VALUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = apei_exec_read_register_value,
},
[ACPI_ERST_WRITE_REGISTER] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = apei_exec_write_register,
},
[ACPI_ERST_WRITE_REGISTER_VALUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = apei_exec_write_register_value,
},
[ACPI_ERST_NOOP] = {
.flags = 0,
.run = apei_exec_noop,
},
[ACPI_ERST_LOAD_VAR1] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_load_var1,
},
[ACPI_ERST_LOAD_VAR2] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_load_var2,
},
[ACPI_ERST_STORE_VAR1] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_store_var1,
},
[ACPI_ERST_ADD] = {
.flags = 0,
.run = erst_exec_add,
},
[ACPI_ERST_SUBTRACT] = {
.flags = 0,
.run = erst_exec_subtract,
},
[ACPI_ERST_ADD_VALUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_add_value,
},
[ACPI_ERST_SUBTRACT_VALUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_subtract_value,
},
[ACPI_ERST_STALL] = {
.flags = 0,
.run = erst_exec_stall,
},
[ACPI_ERST_STALL_WHILE_TRUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_stall_while_true,
},
[ACPI_ERST_SKIP_NEXT_IF_TRUE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_skip_next_instruction_if_true,
},
[ACPI_ERST_GOTO] = {
.flags = 0,
.run = erst_exec_goto,
},
[ACPI_ERST_SET_SRC_ADDRESS_BASE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_set_src_address_base,
},
[ACPI_ERST_SET_DST_ADDRESS_BASE] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_set_dst_address_base,
},
[ACPI_ERST_MOVE_DATA] = {
.flags = APEI_EXEC_INS_ACCESS_REGISTER,
.run = erst_exec_move_data,
},
};
static inline void erst_exec_ctx_init(struct apei_exec_context *ctx)
{
apei_exec_ctx_init(ctx, erst_ins_type, ARRAY_SIZE(erst_ins_type),
ERST_TAB_ENTRY(erst_tab), erst_tab->entries);
}
static int erst_get_erange(struct erst_erange *range)
{
struct apei_exec_context ctx;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_RANGE);
if (rc)
return rc;
range->base = apei_exec_ctx_get_output(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_LENGTH);
if (rc)
return rc;
range->size = apei_exec_ctx_get_output(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_GET_ERROR_ATTRIBUTES);
if (rc)
return rc;
range->attr = apei_exec_ctx_get_output(&ctx);
return 0;
}
static ssize_t __erst_get_record_count(void)
{
struct apei_exec_context ctx;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_COUNT);
if (rc)
return rc;
return apei_exec_ctx_get_output(&ctx);
}
ssize_t erst_get_record_count(void)
{
ssize_t count;
unsigned long flags;
if (erst_disable)
return -ENODEV;
spin_lock_irqsave(&erst_lock, flags);
count = __erst_get_record_count();
spin_unlock_irqrestore(&erst_lock, flags);
return count;
}
EXPORT_SYMBOL_GPL(erst_get_record_count);
static int __erst_get_next_record_id(u64 *record_id)
{
struct apei_exec_context ctx;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_GET_RECORD_ID);
if (rc)
return rc;
*record_id = apei_exec_ctx_get_output(&ctx);
return 0;
}
/*
* Get the record ID of an existing error record on the persistent
* storage. If there is no error record on the persistent storage, the
* returned record_id is APEI_ERST_INVALID_RECORD_ID.
*/
int erst_get_next_record_id(u64 *record_id)
{
int rc;
unsigned long flags;
if (erst_disable)
return -ENODEV;
spin_lock_irqsave(&erst_lock, flags);
rc = __erst_get_next_record_id(record_id);
spin_unlock_irqrestore(&erst_lock, flags);
return rc;
}
EXPORT_SYMBOL_GPL(erst_get_next_record_id);
static int __erst_write_to_storage(u64 offset)
{
struct apei_exec_context ctx;
u64 timeout = FIRMWARE_TIMEOUT;
u64 val;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_BEGIN_WRITE);
if (rc)
return rc;
apei_exec_ctx_set_input(&ctx, offset);
rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
if (rc)
return rc;
rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
if (rc)
return rc;
for (;;) {
rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
if (!val)
break;
if (erst_timedout(&timeout, SPIN_UNIT))
return -EIO;
}
rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_END);
if (rc)
return rc;
return erst_errno(val);
}
static int __erst_read_from_storage(u64 record_id, u64 offset)
{
struct apei_exec_context ctx;
u64 timeout = FIRMWARE_TIMEOUT;
u64 val;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_BEGIN_READ);
if (rc)
return rc;
apei_exec_ctx_set_input(&ctx, offset);
rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_OFFSET);
if (rc)
return rc;
apei_exec_ctx_set_input(&ctx, record_id);
rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
if (rc)
return rc;
rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
if (rc)
return rc;
for (;;) {
rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
if (!val)
break;
if (erst_timedout(&timeout, SPIN_UNIT))
return -EIO;
};
rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_END);
if (rc)
return rc;
return erst_errno(val);
}
static int __erst_clear_from_storage(u64 record_id)
{
struct apei_exec_context ctx;
u64 timeout = FIRMWARE_TIMEOUT;
u64 val;
int rc;
erst_exec_ctx_init(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_BEGIN_CLEAR);
if (rc)
return rc;
apei_exec_ctx_set_input(&ctx, record_id);
rc = apei_exec_run(&ctx, ACPI_ERST_SET_RECORD_ID);
if (rc)
return rc;
rc = apei_exec_run(&ctx, ACPI_ERST_EXECUTE_OPERATION);
if (rc)
return rc;
for (;;) {
rc = apei_exec_run(&ctx, ACPI_ERST_CHECK_BUSY_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
if (!val)
break;
if (erst_timedout(&timeout, SPIN_UNIT))
return -EIO;
}
rc = apei_exec_run(&ctx, ACPI_ERST_GET_COMMAND_STATUS);
if (rc)
return rc;
val = apei_exec_ctx_get_output(&ctx);
rc = apei_exec_run(&ctx, ACPI_ERST_END);
if (rc)
return rc;
return erst_errno(val);
}
/* NVRAM ERST Error Log Address Range is not supported yet */
static void pr_unimpl_nvram(void)
{
if (printk_ratelimit())
pr_warning(ERST_PFX
"NVRAM ERST Log Address Range is not implemented yet\n");
}
static int __erst_write_to_nvram(const struct cper_record_header *record)
{
/* do not print message, because printk is not safe for NMI */
return -ENOSYS;
}
static int __erst_read_to_erange_from_nvram(u64 record_id, u64 *offset)
{
pr_unimpl_nvram();
return -ENOSYS;
}
static int __erst_clear_from_nvram(u64 record_id)
{
pr_unimpl_nvram();
return -ENOSYS;
}
int erst_write(const struct cper_record_header *record)
{
int rc;
unsigned long flags;
struct cper_record_header *rcd_erange;
if (erst_disable)
return -ENODEV;
if (memcmp(record->signature, CPER_SIG_RECORD, CPER_SIG_SIZE))
return -EINVAL;
if (erst_erange.attr & ERST_RANGE_NVRAM) {
if (!spin_trylock_irqsave(&erst_lock, flags))
return -EBUSY;
rc = __erst_write_to_nvram(record);
spin_unlock_irqrestore(&erst_lock, flags);
return rc;
}
if (record->record_length > erst_erange.size)
return -EINVAL;
if (!spin_trylock_irqsave(&erst_lock, flags))
return -EBUSY;
memcpy(erst_erange.vaddr, record, record->record_length);
rcd_erange = erst_erange.vaddr;
/* signature for serialization system */
memcpy(&rcd_erange->persistence_information, "ER", 2);
rc = __erst_write_to_storage(0);
spin_unlock_irqrestore(&erst_lock, flags);
return rc;
}
EXPORT_SYMBOL_GPL(erst_write);
static int __erst_read_to_erange(u64 record_id, u64 *offset)
{
int rc;
if (erst_erange.attr & ERST_RANGE_NVRAM)
return __erst_read_to_erange_from_nvram(
record_id, offset);
rc = __erst_read_from_storage(record_id, 0);
if (rc)
return rc;
*offset = 0;
return 0;
}
static ssize_t __erst_read(u64 record_id, struct cper_record_header *record,
size_t buflen)
{
int rc;
u64 offset, len = 0;
struct cper_record_header *rcd_tmp;
rc = __erst_read_to_erange(record_id, &offset);
if (rc)
return rc;
rcd_tmp = erst_erange.vaddr + offset;
len = rcd_tmp->record_length;
if (len <= buflen)
memcpy(record, rcd_tmp, len);
return len;
}
/*
* If return value > buflen, the buffer size is not big enough,
* else if return value < 0, something goes wrong,
* else everything is OK, and return value is record length
*/
ssize_t erst_read(u64 record_id, struct cper_record_header *record,
size_t buflen)
{
ssize_t len;
unsigned long flags;
if (erst_disable)
return -ENODEV;
spin_lock_irqsave(&erst_lock, flags);
len = __erst_read(record_id, record, buflen);
spin_unlock_irqrestore(&erst_lock, flags);
return len;
}
EXPORT_SYMBOL_GPL(erst_read);
/*
* If return value > buflen, the buffer size is not big enough,
* else if return value = 0, there is no more record to read,
* else if return value < 0, something goes wrong,
* else everything is OK, and return value is record length
*/
ssize_t erst_read_next(struct cper_record_header *record, size_t buflen)
{
int rc;
ssize_t len;
unsigned long flags;
u64 record_id;
if (erst_disable)
return -ENODEV;
spin_lock_irqsave(&erst_lock, flags);
rc = __erst_get_next_record_id(&record_id);
if (rc) {
spin_unlock_irqrestore(&erst_lock, flags);
return rc;
}
/* no more record */
if (record_id == APEI_ERST_INVALID_RECORD_ID) {
spin_unlock_irqrestore(&erst_lock, flags);
return 0;
}
len = __erst_read(record_id, record, buflen);
spin_unlock_irqrestore(&erst_lock, flags);
return len;
}
EXPORT_SYMBOL_GPL(erst_read_next);
int erst_clear(u64 record_id)
{
int rc;
unsigned long flags;
if (erst_disable)
return -ENODEV;
spin_lock_irqsave(&erst_lock, flags);
if (erst_erange.attr & ERST_RANGE_NVRAM)
rc = __erst_clear_from_nvram(record_id);
else
rc = __erst_clear_from_storage(record_id);
spin_unlock_irqrestore(&erst_lock, flags);
return rc;
}
EXPORT_SYMBOL_GPL(erst_clear);
static int __init setup_erst_disable(char *str)
{
erst_disable = 1;
return 0;
}
__setup("erst_disable", setup_erst_disable);
static int erst_check_table(struct acpi_table_erst *erst_tab)
{
if (erst_tab->header_length != sizeof(struct acpi_table_erst))
return -EINVAL;
if (erst_tab->header.length < sizeof(struct acpi_table_erst))
return -EINVAL;
if (erst_tab->entries !=
(erst_tab->header.length - sizeof(struct acpi_table_erst)) /
sizeof(struct acpi_erst_entry))
return -EINVAL;
return 0;
}
static int __init erst_init(void)
{
int rc = 0;
acpi_status status;
struct apei_exec_context ctx;
struct apei_resources erst_resources;
struct resource *r;
if (acpi_disabled)
goto err;
if (erst_disable) {
pr_info(ERST_PFX
"Error Record Serialization Table (ERST) support is disabled.\n");
goto err;
}
status = acpi_get_table(ACPI_SIG_ERST, 0,
(struct acpi_table_header **)&erst_tab);
if (status == AE_NOT_FOUND) {
pr_info(ERST_PFX "Table is not found!\n");
goto err;
} else if (ACPI_FAILURE(status)) {
const char *msg = acpi_format_exception(status);
pr_err(ERST_PFX "Failed to get table, %s\n", msg);
rc = -EINVAL;
goto err;
}
rc = erst_check_table(erst_tab);
if (rc) {
pr_err(FW_BUG ERST_PFX "ERST table is invalid\n");
goto err;
}
apei_resources_init(&erst_resources);
erst_exec_ctx_init(&ctx);
rc = apei_exec_collect_resources(&ctx, &erst_resources);
if (rc)
goto err_fini;
rc = apei_resources_request(&erst_resources, "APEI ERST");
if (rc)
goto err_fini;
rc = apei_exec_pre_map_gars(&ctx);
if (rc)
goto err_release;
rc = erst_get_erange(&erst_erange);
if (rc) {
if (rc == -ENODEV)
pr_info(ERST_PFX
"The corresponding hardware device or firmware implementation "
"is not available.\n");
else
pr_err(ERST_PFX
"Failed to get Error Log Address Range.\n");
goto err_unmap_reg;
}
r = request_mem_region(erst_erange.base, erst_erange.size, "APEI ERST");
if (!r) {
pr_err(ERST_PFX
"Can not request iomem region <0x%16llx-0x%16llx> for ERST.\n",
(unsigned long long)erst_erange.base,
(unsigned long long)erst_erange.base + erst_erange.size);
rc = -EIO;
goto err_unmap_reg;
}
rc = -ENOMEM;
erst_erange.vaddr = ioremap_cache(erst_erange.base,
erst_erange.size);
if (!erst_erange.vaddr)
goto err_release_erange;
pr_info(ERST_PFX
"Error Record Serialization Table (ERST) support is initialized.\n");
return 0;
err_release_erange:
release_mem_region(erst_erange.base, erst_erange.size);
err_unmap_reg:
apei_exec_post_unmap_gars(&ctx);
err_release:
apei_resources_release(&erst_resources);
err_fini:
apei_resources_fini(&erst_resources);
err:
erst_disable = 1;
return rc;
}
device_initcall(erst_init);