[S390] zcrypt: cope with cca restriction of cex3

The cca on the crypto adapter has a restriction in the size of the
exponent if a key with a modulus bigger than 2048 bit is used. Thus
in that case we have to avoid that the crypto device driver thinks
the adapter is defect and sets it offline. Therfore a new member for
the zcrypt_device struct called max_exp_bit_length is introduced. This
will be set the first time the cca returns the error code function
not implemented. If this is done with an adapter twice it will return
-EINVAL.

Signed-off-by: Felix Beck <felix.beck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 21 insertions, 1 deletions

diff --git a/drivers/s390/crypto/zcrypt_api.h b/drivers/s390/crypto/zcrypt_api.h
index 8e7ffbf2466c..88ebd114735b 100644
--- a/drivers/s390/crypto/zcrypt_api.h
+++ b/drivers/s390/crypto/zcrypt_api.h
@@ -109,6 +109,7 @@ struct zcrypt_device {
         int request_count;              /* # current requests. */
 
         struct ap_message reply;        /* Per-device reply structure. */
+        int max_exp_bit_length;
 };
 
 struct zcrypt_device *zcrypt_device_alloc(size_t);
diff --git a/drivers/s390/crypto/zcrypt_cex2a.c b/drivers/s390/crypto/zcrypt_cex2a.c
index def0901767de..2176d00b395e 100644
--- a/drivers/s390/crypto/zcrypt_cex2a.c
+++ b/drivers/s390/crypto/zcrypt_cex2a.c
@@ -441,6 +441,7 @@ static int zcrypt_cex2a_probe(struct ap_device *ap_dev)
                 zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
                 zdev->short_crt = 1;
                 zdev->speed_rating = CEX2A_SPEED_RATING;
+                zdev->max_exp_bit_length = CEX2A_MAX_MOD_SIZE;
                 break;
         case AP_DEVICE_TYPE_CEX3A:
                 zdev = zcrypt_device_alloc(CEX3A_MAX_RESPONSE_SIZE);
@@ -450,8 +451,11 @@ static int zcrypt_cex2a_probe(struct ap_device *ap_dev)
                 zdev->type_string = "CEX3A";
                 zdev->min_mod_size = CEX2A_MIN_MOD_SIZE;
                 zdev->max_mod_size = CEX2A_MAX_MOD_SIZE;
-                if (ap_4096_commands_available(ap_dev->qid))
+                zdev->max_exp_bit_length = CEX2A_MAX_MOD_SIZE;
+                if (ap_4096_commands_available(ap_dev->qid)) {
                         zdev->max_mod_size = CEX3A_MAX_MOD_SIZE;
+                        zdev->max_exp_bit_length = CEX3A_MAX_MOD_SIZE;
+                }
                 zdev->short_crt = 1;
                 zdev->speed_rating = CEX3A_SPEED_RATING;
                 break;
diff --git a/drivers/s390/crypto/zcrypt_pcica.c b/drivers/s390/crypto/zcrypt_pcica.c
index 09e934b295a0..1afb69c75fea 100644
--- a/drivers/s390/crypto/zcrypt_pcica.c
+++ b/drivers/s390/crypto/zcrypt_pcica.c
@@ -373,6 +373,7 @@ static int zcrypt_pcica_probe(struct ap_device *ap_dev)
         zdev->min_mod_size = PCICA_MIN_MOD_SIZE;
         zdev->max_mod_size = PCICA_MAX_MOD_SIZE;
         zdev->speed_rating = PCICA_SPEED_RATING;
+        zdev->max_exp_bit_length = PCICA_MAX_MOD_SIZE;
         ap_dev->reply = &zdev->reply;
         ap_dev->private = zdev;
         rc = zcrypt_device_register(zdev);
diff --git a/drivers/s390/crypto/zcrypt_pcicc.c b/drivers/s390/crypto/zcrypt_pcicc.c
index 9dec5c77cff4..aa4c050a5694 100644
--- a/drivers/s390/crypto/zcrypt_pcicc.c
+++ b/drivers/s390/crypto/zcrypt_pcicc.c
@@ -579,6 +579,7 @@ static int zcrypt_pcicc_probe(struct ap_device *ap_dev)
         zdev->min_mod_size = PCICC_MIN_MOD_SIZE;
         zdev->max_mod_size = PCICC_MAX_MOD_SIZE;
         zdev->speed_rating = PCICC_SPEED_RATING;
+        zdev->max_exp_bit_length = PCICC_MAX_MOD_SIZE;
         ap_dev->reply = &zdev->reply;
         ap_dev->private = zdev;
         rc = zcrypt_device_register(zdev);
diff --git a/drivers/s390/crypto/zcrypt_pcixcc.c b/drivers/s390/crypto/zcrypt_pcixcc.c
index fc8eb9dce841..4f85eb725f4f 100644
--- a/drivers/s390/crypto/zcrypt_pcixcc.c
+++ b/drivers/s390/crypto/zcrypt_pcixcc.c
@@ -567,6 +567,15 @@ static int convert_response_ica(struct zcrypt_device *zdev,
         case TYPE88_RSP_CODE:
                 return convert_error(zdev, reply);
         case TYPE86_RSP_CODE:
+                if (msg->cprbx.ccp_rtcode &&
+                   (msg->cprbx.ccp_rscode == 0x14f) &&
+                   (outputdatalength > 256)) {
+                        if (zdev->max_exp_bit_length <= 17) {
+                                zdev->max_exp_bit_length = 17;
+                                return -EAGAIN;
+                        } else
+                                return -EINVAL;
+                }
                 if (msg->hdr.reply_code)
                         return convert_error(zdev, reply);
                 if (msg->cprbx.cprb_ver_id == 0x02)
@@ -1052,11 +1061,13 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
                         zdev->speed_rating = PCIXCC_MCL2_SPEED_RATING;
                         zdev->min_mod_size = PCIXCC_MIN_MOD_SIZE_OLD;
                         zdev->max_mod_size = PCIXCC_MAX_MOD_SIZE;
+                        zdev->max_exp_bit_length = PCIXCC_MAX_MOD_SIZE;
                 } else {
                         zdev->type_string = "PCIXCC_MCL3";
                         zdev->speed_rating = PCIXCC_MCL3_SPEED_RATING;
                         zdev->min_mod_size = PCIXCC_MIN_MOD_SIZE;
                         zdev->max_mod_size = PCIXCC_MAX_MOD_SIZE;
+                        zdev->max_exp_bit_length = PCIXCC_MAX_MOD_SIZE;
                 }
                 break;
         case AP_DEVICE_TYPE_CEX2C:
@@ -1065,6 +1076,7 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
                 zdev->speed_rating = CEX2C_SPEED_RATING;
                 zdev->min_mod_size = PCIXCC_MIN_MOD_SIZE;
                 zdev->max_mod_size = PCIXCC_MAX_MOD_SIZE;
+                zdev->max_exp_bit_length = PCIXCC_MAX_MOD_SIZE;
                 break;
         case AP_DEVICE_TYPE_CEX3C:
                 zdev->user_space_type = ZCRYPT_CEX3C;
@@ -1072,6 +1084,7 @@ static int zcrypt_pcixcc_probe(struct ap_device *ap_dev)
                 zdev->speed_rating = CEX3C_SPEED_RATING;
                 zdev->min_mod_size = CEX3C_MIN_MOD_SIZE;
                 zdev->max_mod_size = CEX3C_MAX_MOD_SIZE;
+                zdev->max_exp_bit_length = CEX3C_MAX_MOD_SIZE;
                 break;
         default:
                 goto out_free;