s390/zcryt: Handle AP configuration changes

Detect external AP bus configuration changes and request
an AP device rescan.

Signed-off-by: Holger Dengler <hd@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 106 insertions, 8 deletions

diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index f1f026e0b18..31cfaa55607 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -38,7 +38,10 @@
 #include <linux/atomic.h>
 #include <asm/uaccess.h>
 #include <linux/hw_random.h>
+#include <linux/debugfs.h>
+#include <asm/debug.h>
 
+#include "zcrypt_debug.h"
 #include "zcrypt_api.h"
 
 /*
@@ -53,6 +56,10 @@ static DEFINE_SPINLOCK(zcrypt_device_lock);
 static LIST_HEAD(zcrypt_device_list);
 static int zcrypt_device_count = 0;
 static atomic_t zcrypt_open_count = ATOMIC_INIT(0);
+static atomic_t zcrypt_rescan_count = ATOMIC_INIT(0);
+
+atomic_t zcrypt_rescan_req = ATOMIC_INIT(0);
+EXPORT_SYMBOL(zcrypt_rescan_req);
 
 static int zcrypt_rng_device_add(void);
 static void zcrypt_rng_device_remove(void);
@@ -60,6 +67,10 @@ static void zcrypt_rng_device_remove(void);
 static DEFINE_SPINLOCK(zcrypt_ops_list_lock);
 static LIST_HEAD(zcrypt_ops_list);
 
+static debug_info_t *zcrypt_dbf_common;
+static debug_info_t *zcrypt_dbf_devices;
+static struct dentry *debugfs_root;
+
 /*
  * Device attributes common for all crypto devices.
  */
@@ -89,6 +100,8 @@ static ssize_t zcrypt_online_store(struct device *dev,
 	if (sscanf(buf, "%d\n", &online) != 1 || online < 0 || online > 1)
 		return -EINVAL;
 	zdev->online = online;
+	ZCRYPT_DBF_DEV(DBF_INFO, zdev, "dev%04xo%dman", zdev->ap_dev->qid,
+		       zdev->online);
 	if (!online)
 		ap_flush_queue(zdev->ap_dev);
 	return count;
@@ -107,6 +120,24 @@ static struct attribute_group zcrypt_device_attr_group = {
 };
 
 /**
+ * Process a rescan of the transport layer.
+ *
+ * Returns 1, if the rescan has been processed, otherwise 0.
+ */
+static inline int zcrypt_process_rescan(void)
+{
+	if (atomic_read(&zcrypt_rescan_req)) {
+		atomic_set(&zcrypt_rescan_req, 0);
+		atomic_inc(&zcrypt_rescan_count);
+		ap_bus_force_rescan();
+		ZCRYPT_DBF_COMMON(DBF_INFO, "rescan%07d",
+				  atomic_inc_return(&zcrypt_rescan_count));
+		return 1;
+	}
+	return 0;
+}
+
+/**
  * __zcrypt_increase_preference(): Increase preference of a crypto device.
  * @zdev: Pointer the crypto device
  *
@@ -194,6 +225,7 @@ struct zcrypt_device *zcrypt_device_alloc(size_t max_response_size)
 	zdev->reply.length = max_response_size;
 	spin_lock_init(&zdev->lock);
 	INIT_LIST_HEAD(&zdev->list);
+	zdev->dbf_area = zcrypt_dbf_devices;
 	return zdev;
 
 out_free:
@@ -229,6 +261,8 @@ int zcrypt_device_register(struct zcrypt_device *zdev)
 	kref_init(&zdev->refcount);
 	spin_lock_bh(&zcrypt_device_lock);
 	zdev->online = 1;	/* New devices are online by default. */
+	ZCRYPT_DBF_DEV(DBF_INFO, zdev, "dev%04xo%dreg", zdev->ap_dev->qid,
+		       zdev->online);
 	list_add_tail(&zdev->list, &zcrypt_device_list);
 	__zcrypt_increase_preference(zdev);
 	zcrypt_device_count++;
@@ -707,6 +741,11 @@ static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		do {
 			rc = zcrypt_rsa_modexpo(&mex);
 		} while (rc == -EAGAIN);
+		/* on failure: retry once again after a requested rescan */
+		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+			do {
+				rc = zcrypt_rsa_modexpo(&mex);
+			} while (rc == -EAGAIN);
 		if (rc)
 			return rc;
 		return put_user(mex.outputdatalength, &umex->outputdatalength);
@@ -719,6 +758,11 @@ static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		do {
 			rc = zcrypt_rsa_crt(&crt);
 		} while (rc == -EAGAIN);
+		/* on failure: retry once again after a requested rescan */
+		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+			do {
+				rc = zcrypt_rsa_crt(&crt);
+			} while (rc == -EAGAIN);
 		if (rc)
 			return rc;
 		return put_user(crt.outputdatalength, &ucrt->outputdatalength);
@@ -731,6 +775,11 @@ static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		do {
 			rc = zcrypt_send_cprb(&xcRB);
 		} while (rc == -EAGAIN);
+		/* on failure: retry once again after a requested rescan */
+		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+			do {
+				rc = zcrypt_send_cprb(&xcRB);
+			} while (rc == -EAGAIN);
 		if (copy_to_user(uxcRB, &xcRB, sizeof(xcRB)))
 			return -EFAULT;
 		return rc;
@@ -837,10 +886,15 @@ static long trans_modexpo32(struct file *filp, unsigned int cmd,
 	do {
 		rc = zcrypt_rsa_modexpo(&mex64);
 	} while (rc == -EAGAIN);
-	if (!rc)
-		rc = put_user(mex64.outputdatalength,
-			      &umex32->outputdatalength);
-	return rc;
+	/* on failure: retry once again after a requested rescan */
+	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+		do {
+			rc = zcrypt_rsa_modexpo(&mex64);
+		} while (rc == -EAGAIN);
+	if (rc)
+		return rc;
+	return put_user(mex64.outputdatalength,
+			&umex32->outputdatalength);
 }
 
 struct compat_ica_rsa_modexpo_crt {
@@ -877,10 +931,15 @@ static long trans_modexpo_crt32(struct file *filp, unsigned int cmd,
 	do {
 		rc = zcrypt_rsa_crt(&crt64);
 	} while (rc == -EAGAIN);
-	if (!rc)
-		rc = put_user(crt64.outputdatalength,
-			      &ucrt32->outputdatalength);
-	return rc;
+	/* on failure: retry once again after a requested rescan */
+	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+		do {
+			rc = zcrypt_rsa_crt(&crt64);
+		} while (rc == -EAGAIN);
+	if (rc)
+		return rc;
+	return put_user(crt64.outputdatalength,
+			&ucrt32->outputdatalength);
 }
 
 struct compat_ica_xcRB {
@@ -936,6 +995,11 @@ static long trans_xcRB32(struct file *filp, unsigned int cmd,
 	do {
 		rc = zcrypt_send_cprb(&xcRB64);
 	} while (rc == -EAGAIN);
+	/* on failure: retry once again after a requested rescan */
+	if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+		do {
+			rc = zcrypt_send_cprb(&xcRB64);
+		} while (rc == -EAGAIN);
 	xcRB32.reply_control_blk_length = xcRB64.reply_control_blk_length;
 	xcRB32.reply_data_length = xcRB64.reply_data_length;
 	xcRB32.status = xcRB64.status;
@@ -1193,6 +1257,9 @@ static int zcrypt_rng_data_read(struct hwrng *rng, u32 *data)
 	 */
 	if (zcrypt_rng_buffer_index == 0) {
 		rc = zcrypt_rng((char *) zcrypt_rng_buffer);
+		/* on failure: retry once again after a requested rescan */
+		if ((rc == -ENODEV) && (zcrypt_process_rescan()))
+			rc = zcrypt_rng((char *) zcrypt_rng_buffer);
 		if (rc < 0)
 			return -EIO;
 		zcrypt_rng_buffer_index = rc / sizeof *data;
@@ -1245,6 +1312,30 @@ static void zcrypt_rng_device_remove(void)
 	mutex_unlock(&zcrypt_rng_mutex);
 }
 
+int __init zcrypt_debug_init(void)
+{
+	debugfs_root = debugfs_create_dir("zcrypt", NULL);
+
+	zcrypt_dbf_common = debug_register("zcrypt_common", 1, 1, 16);
+	debug_register_view(zcrypt_dbf_common, &debug_hex_ascii_view);
+	debug_set_level(zcrypt_dbf_common, DBF_ERR);
+
+	zcrypt_dbf_devices = debug_register("zcrypt_devices", 1, 1, 16);
+	debug_register_view(zcrypt_dbf_devices, &debug_hex_ascii_view);
+	debug_set_level(zcrypt_dbf_devices, DBF_ERR);
+
+	return 0;
+}
+
+void zcrypt_debug_exit(void)
+{
+	debugfs_remove(debugfs_root);
+	if (zcrypt_dbf_common)
+		debug_unregister(zcrypt_dbf_common);
+	if (zcrypt_dbf_devices)
+		debug_unregister(zcrypt_dbf_devices);
+}
+
 /**
  * zcrypt_api_init(): Module initialization.
  *
@@ -1254,6 +1345,12 @@ int __init zcrypt_api_init(void)
 {
 	int rc;
 
+	rc = zcrypt_debug_init();
+	if (rc)
+		goto out;
+
+	atomic_set(&zcrypt_rescan_req, 0);
+
 	/* Register the request sprayer. */
 	rc = misc_register(&zcrypt_misc_device);
 	if (rc < 0)
@@ -1283,6 +1380,7 @@ void zcrypt_api_exit(void)
 {
 	remove_proc_entry("driver/z90crypt", NULL);
 	misc_deregister(&zcrypt_misc_device);
+	zcrypt_debug_exit();
 }
 
 module_init(zcrypt_api_init);