block: sed-opal: Add support to read/write opal tables generically

This feature gives the user RW access to any opal table with admin1
authority. The flags described in the new structure determines if the user
wants to read/write the data. Flags are checked for valid values in
order to allow future features to be added to the ioctl.

The user can provide the desired table's UID. Also, the ioctl provides a
size and offset field and internally will loop data accesses to return
the full data block. Read overrun is prevented by the initiator's
sec_send_recv() backend. The ioctl provides a private field with the
intention to accommodate any future expansions to the ioctl.

Reviewed-by: Scott Bauer <[e-mail]>
Reviewed-by: Jon Derrick <[e-mail]>
Signed-off-by: Revanth Rajashekar <[e-mail]>
Signed-off-by: Jens Axboe <[e-mail]>

block/opal_proto.h

···
  * Derived from: TCG_Storage_Architecture_Core_Spec_v2.01_r1.00
  * Section: 6.3 Assigned UIDs
  */
-#define OPAL_UID_LENGTH 8
 #define OPAL_METHOD_LENGTH 8
 #define OPAL_MSID_KEYLEN 15
 #define OPAL_UID_LENGTH_HALF 4

block/sed-opal.c

···
 	return 0;
 }
 
+static int write_table_data(struct opal_dev *dev, void *data)
+{
+	struct opal_read_write_table *write_tbl = data;
+
+	return generic_table_write_data(dev, write_tbl->data, write_tbl->offset,
+					write_tbl->size, write_tbl->table_uid);
+}
+
+static int read_table_data_cont(struct opal_dev *dev)
+{
+	int err;
+	const char *data_read;
+
+	err = parse_and_check_status(dev);
+	if (err)
+		return err;
+
+	dev->prev_d_len = response_get_string(&dev->parsed, 1, &data_read);
+	dev->prev_data = (void *)data_read;
+	if (!dev->prev_data) {
+		pr_debug("%s: Couldn't read data from the table.\n", __func__);
+		return OPAL_INVAL_PARAM;
+	}
+
+	return 0;
+}
+
+/*
+ * IO_BUFFER_LENGTH = 2048
+ * sizeof(header) = 56
+ * No. of Token Bytes in the Response = 11
+ * MAX size of data that can be carried in response buffer
+ * at a time is : 2048 - (56 + 11) = 1981 = 0x7BD.
+ */
+#define OPAL_MAX_READ_TABLE (0x7BD)
+
+static int read_table_data(struct opal_dev *dev, void *data)
+{
+	struct opal_read_write_table *read_tbl = data;
+	int err;
+	size_t off = 0, max_read_size = OPAL_MAX_READ_TABLE;
+	u64 table_len, len;
+	u64 offset = read_tbl->offset, read_size = read_tbl->size - 1;
+	u8 __user *dst;
+
+	err = generic_get_table_info(dev, read_tbl->table_uid, OPAL_TABLE_ROWS);
+	if (err) {
+		pr_debug("Couldn't get the table size\n");
+		return err;
+	}
+
+	table_len = response_get_u64(&dev->parsed, 4);
+
+	/* Check if the user is trying to read from the table limits */
+	if (read_size > table_len || offset > table_len - read_size) {
+		pr_debug("Read size exceeds the Table size limits (%llu vs. %llu)\n",
+			  offset + read_size, table_len);
+		return -EINVAL;
+	}
+
+	while (off < read_size) {
+		err = cmd_start(dev, read_tbl->table_uid, opalmethod[OPAL_GET]);
+
+		add_token_u8(&err, dev, OPAL_STARTLIST);
+		add_token_u8(&err, dev, OPAL_STARTNAME);
+		add_token_u8(&err, dev, OPAL_STARTROW);
+		add_token_u64(&err, dev, offset + off); /* start row value */
+		add_token_u8(&err, dev, OPAL_ENDNAME);
+
+		add_token_u8(&err, dev, OPAL_STARTNAME);
+		add_token_u8(&err, dev, OPAL_ENDROW);
+
+		len = min(max_read_size, (size_t)(read_size - off));
+		add_token_u64(&err, dev, offset + off + len); /* end row value
+							       */
+		add_token_u8(&err, dev, OPAL_ENDNAME);
+		add_token_u8(&err, dev, OPAL_ENDLIST);
+
+		if (err) {
+			pr_debug("Error building read table data command.\n");
+			break;
+		}
+
+		err = finalize_and_send(dev, read_table_data_cont);
+		if (err)
+			break;
+
+		/* len+1: This includes the NULL terminator at the end*/
+		if (dev->prev_d_len > len + 1) {
+			err = -EOVERFLOW;
+			break;
+		}
+
+		dst = (u8 __user *)(uintptr_t)read_tbl->data;
+		if (copy_to_user(dst + off, dev->prev_data, dev->prev_d_len)) {
+			pr_debug("Error copying data to userspace\n");
+			err = -EFAULT;
+			break;
+		}
+		dev->prev_data = NULL;
+
+		off += len;
+	}
+
+	return err;
+}
+
 static int end_opal_session(struct opal_dev *dev, void *data)
 {
 	int err = 0;
···
 }
 EXPORT_SYMBOL(opal_unlock_from_suspend);
 
+static int opal_read_table(struct opal_dev *dev,
+			   struct opal_read_write_table *rw_tbl)
+{
+	const struct opal_step read_table_steps[] = {
+		{ start_admin1LSP_opal_session, &rw_tbl->key },
+		{ read_table_data, rw_tbl },
+		{ end_opal_session, }
+	};
+	int ret = 0;
+
+	if (!rw_tbl->size)
+		return ret;
+
+	return execute_steps(dev, read_table_steps,
+			     ARRAY_SIZE(read_table_steps));
+}
+
+static int opal_write_table(struct opal_dev *dev,
+			    struct opal_read_write_table *rw_tbl)
+{
+	const struct opal_step write_table_steps[] = {
+		{ start_admin1LSP_opal_session, &rw_tbl->key },
+		{ write_table_data, rw_tbl },
+		{ end_opal_session, }
+	};
+	int ret = 0;
+
+	if (!rw_tbl->size)
+		return ret;
+
+	return execute_steps(dev, write_table_steps,
+			     ARRAY_SIZE(write_table_steps));
+}
+
+static int opal_generic_read_write_table(struct opal_dev *dev,
+					 struct opal_read_write_table *rw_tbl)
+{
+	int ret, bit_set;
+
+	mutex_lock(&dev->dev_lock);
+	setup_opal_dev(dev);
+
+	bit_set = fls64(rw_tbl->flags) - 1;
+	switch (bit_set) {
+	case OPAL_READ_TABLE:
+		ret = opal_read_table(dev, rw_tbl);
+		break;
+	case OPAL_WRITE_TABLE:
+		ret = opal_write_table(dev, rw_tbl);
+		break;
+	default:
+		pr_debug("Invalid bit set in the flag (%016llx).\n",
+			 rw_tbl->flags);
+		ret = -EINVAL;
+		break;
+	}
+
+	mutex_unlock(&dev->dev_lock);
+
+	return ret;
+}
+
 int sed_ioctl(struct opal_dev *dev, unsigned int cmd, void __user *arg)
 {
 	void *p;
···
 		break;
 	case IOC_OPAL_PSID_REVERT_TPR:
 		ret = opal_reverttper(dev, p, true);
+		break;
+	case IOC_OPAL_GENERIC_TABLE_RW:
+		ret = opal_generic_read_write_table(dev, p);
 		break;
 	default:
 		break;

include/linux/sed-opal.h

···
 	case IOC_OPAL_PSID_REVERT_TPR:
 	case IOC_OPAL_MBR_DONE:
 	case IOC_OPAL_WRITE_SHADOW_MBR:
+	case IOC_OPAL_GENERIC_TABLE_RW:
 		return true;
 	}
 	return false;

include/uapi/linux/sed-opal.h

···
 	__u64 size;
 };
 
+/* Opal table operations */
+enum opal_table_ops {
+	OPAL_READ_TABLE,
+	OPAL_WRITE_TABLE,
+};
+
+#define OPAL_UID_LENGTH 8
+struct opal_read_write_table {
+	struct opal_key key;
+	const __u64 data;
+	const __u8 table_uid[OPAL_UID_LENGTH];
+	__u64 offset;
+	__u64 size;
+#define OPAL_TABLE_READ (1 << OPAL_READ_TABLE)
+#define OPAL_TABLE_WRITE (1 << OPAL_WRITE_TABLE)
+	__u64 flags;
+	__u64 priv;
+};
+
 #define IOC_OPAL_SAVE		    _IOW('p', 220, struct opal_lock_unlock)
 #define IOC_OPAL_LOCK_UNLOCK	    _IOW('p', 221, struct opal_lock_unlock)
 #define IOC_OPAL_TAKE_OWNERSHIP	    _IOW('p', 222, struct opal_key)
···
 #define IOC_OPAL_PSID_REVERT_TPR    _IOW('p', 232, struct opal_key)
 #define IOC_OPAL_MBR_DONE           _IOW('p', 233, struct opal_mbr_done)
 #define IOC_OPAL_WRITE_SHADOW_MBR   _IOW('p', 234, struct opal_shadow_mbr)
+#define IOC_OPAL_GENERIC_TABLE_RW   _IOW('p', 235, struct opal_read_write_table)
 
 #endif /* _UAPI_SED_OPAL_H */