--- /dev/null
+/*
+ * APEI Error Record Serialization Table debug support
+ *
+ * ERST is a way provided by APEI to save and retrieve hardware error
+ * infomation to and from a persistent store. This file provide the
+ * debugging/testing support for ERST kernel support and firmware
+ * implementation.
+ *
+ * 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/uaccess.h>
+#include <acpi/apei.h>
+#include <linux/miscdevice.h>
+
+#include "apei-internal.h"
+
+#define ERST_DBG_PFX "ERST DBG: "
+
+#define ERST_DBG_RECORD_LEN_MAX 4096
+
+static void *erst_dbg_buf;
+static unsigned int erst_dbg_buf_len;
+
+/* Prevent erst_dbg_read/write from being invoked concurrently */
+static DEFINE_MUTEX(erst_dbg_mutex);
+
+static int erst_dbg_open(struct inode *inode, struct file *file)
+{
+ if (erst_disable)
+ return -ENODEV;
+
+ return nonseekable_open(inode, file);
+}
+
+static long erst_dbg_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ int rc;
+ u64 record_id;
+ u32 record_count;
+
+ switch (cmd) {
+ case APEI_ERST_CLEAR_RECORD:
+ rc = copy_from_user(&record_id, (void __user *)arg,
+ sizeof(record_id));
+ if (rc)
+ return -EFAULT;
+ return erst_clear(record_id);
+ case APEI_ERST_GET_RECORD_COUNT:
+ rc = erst_get_record_count();
+ if (rc < 0)
+ return rc;
+ record_count = rc;
+ rc = put_user(record_count, (u32 __user *)arg);
+ if (rc)
+ return rc;
+ return 0;
+ default:
+ return -ENOTTY;
+ }
+}
+
+static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
+ size_t usize, loff_t *off)
+{
+ int rc;
+ ssize_t len = 0;
+ u64 id;
+
+ if (*off != 0)
+ return -EINVAL;
+
+ if (mutex_lock_interruptible(&erst_dbg_mutex) != 0)
+ return -EINTR;
+
+retry_next:
+ rc = erst_get_next_record_id(&id);
+ if (rc)
+ goto out;
+ /* no more record */
+ if (id == APEI_ERST_INVALID_RECORD_ID)
+ goto out;
+retry:
+ rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
+ /* The record may be cleared by others, try read next record */
+ if (rc == -ENOENT)
+ goto retry_next;
+ if (rc < 0)
+ goto out;
+ if (len > ERST_DBG_RECORD_LEN_MAX) {
+ pr_warning(ERST_DBG_PFX
+ "Record (ID: 0x%llx) length is too long: %zd\n",
+ id, len);
+ rc = -EIO;
+ goto out;
+ }
+ if (len > erst_dbg_buf_len) {
+ kfree(erst_dbg_buf);
+ rc = -ENOMEM;
+ erst_dbg_buf = kmalloc(len, GFP_KERNEL);
+ if (!erst_dbg_buf)
+ goto out;
+ erst_dbg_buf_len = len;
+ goto retry;
+ }
+
+ rc = -EINVAL;
+ if (len > usize)
+ goto out;
+
+ rc = -EFAULT;
+ if (copy_to_user(ubuf, erst_dbg_buf, len))
+ goto out;
+ rc = 0;
+out:
+ mutex_unlock(&erst_dbg_mutex);
+ return rc ? rc : len;
+}
+
+static ssize_t erst_dbg_write(struct file *filp, const char __user *ubuf,
+ size_t usize, loff_t *off)
+{
+ int rc;
+ struct cper_record_header *rcd;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (usize > ERST_DBG_RECORD_LEN_MAX) {
+ pr_err(ERST_DBG_PFX "Too long record to be written\n");
+ return -EINVAL;
+ }
+
+ if (mutex_lock_interruptible(&erst_dbg_mutex))
+ return -EINTR;
+ if (usize > erst_dbg_buf_len) {
+ kfree(erst_dbg_buf);
+ rc = -ENOMEM;
+ erst_dbg_buf = kmalloc(usize, GFP_KERNEL);
+ if (!erst_dbg_buf)
+ goto out;
+ erst_dbg_buf_len = usize;
+ }
+ rc = copy_from_user(erst_dbg_buf, ubuf, usize);
+ if (rc) {
+ rc = -EFAULT;
+ goto out;
+ }
+ rcd = erst_dbg_buf;
+ rc = -EINVAL;
+ if (rcd->record_length != usize)
+ goto out;
+
+ rc = erst_write(erst_dbg_buf);
+
+out:
+ mutex_unlock(&erst_dbg_mutex);
+ return rc < 0 ? rc : usize;
+}
+
+static const struct file_operations erst_dbg_ops = {
+ .owner = THIS_MODULE,
+ .open = erst_dbg_open,
+ .read = erst_dbg_read,
+ .write = erst_dbg_write,
+ .unlocked_ioctl = erst_dbg_ioctl,
+};
+
+static struct miscdevice erst_dbg_dev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "erst_dbg",
+ .fops = &erst_dbg_ops,
+};
+
+static __init int erst_dbg_init(void)
+{
+ return misc_register(&erst_dbg_dev);
+}
+
+static __exit void erst_dbg_exit(void)
+{
+ misc_deregister(&erst_dbg_dev);
+ kfree(erst_dbg_buf);
+}
+
+module_init(erst_dbg_init);
+module_exit(erst_dbg_exit);
+
+MODULE_AUTHOR("Huang Ying");
+MODULE_DESCRIPTION("APEI Error Record Serialization Table debug support");
+MODULE_LICENSE("GPL");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff