s390/crypto: simplify return code handling

The CPACF instructions can complete with three different condition codes:
CC=0 for successful completion, CC=1 if the protected key verification
failed, and CC=3 for partial completion.

The inline functions will restart the CPACF instruction for partial
completion, this removes the CC=3 case. The CC=1 case is only relevant
for the protected key functions of the KM, KMC, KMAC and KMCTR
instructions. As the protected key functions are not used by the
current code, there is no need for any kind of return code handling.

Reviewed-by: Harald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 23 insertions, 72 deletions

diff --git a/arch/s390/crypto/prng.c b/arch/s390/crypto/prng.c
index 41527b113f5a..bbf2af74c549 100644
--- a/arch/s390/crypto/prng.c
+++ b/arch/s390/crypto/prng.c
@@ -135,12 +135,7 @@ static int generate_entropy(u8 *ebuf, size_t nbytes)
 		else
 			h = ebuf;
 		/* generate sha256 from this page */
-		if (cpacf_kimd(CPACF_KIMD_SHA_256, h,
-			       pg, PAGE_SIZE) != PAGE_SIZE) {
-			prng_errorflag = PRNG_GEN_ENTROPY_FAILED;
-			ret = -EIO;
-			goto out;
-		}
+		cpacf_kimd(CPACF_KIMD_SHA_256, h, pg, PAGE_SIZE);
 		if (n < sizeof(hash))
 			memcpy(ebuf, hash, n);
 		ret += n;
@@ -148,7 +143,6 @@ static int generate_entropy(u8 *ebuf, size_t nbytes)
 		nbytes -= n;
 	}
 
-out:
 	free_page((unsigned long)pg);
 	return ret;
 }
@@ -160,13 +154,11 @@ static void prng_tdes_add_entropy(void)
 {
 	__u64 entropy[4];
 	unsigned int i;
-	int ret;
 
 	for (i = 0; i < 16; i++) {
-		ret = cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
-				(char *)entropy, (char *)entropy,
-				sizeof(entropy));
-		BUG_ON(ret < 0 || ret != sizeof(entropy));
+		cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
+			  (char *) entropy, (char *) entropy,
+			  sizeof(entropy));
 		memcpy(prng_data->prngws.parm_block, entropy, sizeof(entropy));
 	}
 }
@@ -303,21 +295,14 @@ static int __init prng_sha512_selftest(void)
 		0x21, 0xe4, 0xb0, 0x86, 0x44, 0xf6, 0x72, 0x7c,
 		0x36, 0x8c, 0x5a, 0x9f, 0x7a, 0x4b, 0x3e, 0xe2 };
 
-	int ret = 0;
 	u8 buf[sizeof(random)];
 	struct ppno_ws_s ws;
 
 	memset(&ws, 0, sizeof(ws));
 
 	/* initial seed */
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED, &ws, NULL, 0,
-			 seed, sizeof(seed));
-	if (ret < 0) {
-		pr_err("The prng self test seed operation for the "
-		       "SHA-512 mode failed with rc=%d\n", ret);
-		prng_errorflag = PRNG_SELFTEST_FAILED;
-		return -EIO;
-	}
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
+		   &ws, NULL, 0, seed, sizeof(seed));
 
 	/* check working states V and C */
 	if (memcmp(ws.V, V0, sizeof(V0)) != 0
@@ -329,22 +314,10 @@ static int __init prng_sha512_selftest(void)
 	}
 
 	/* generate random bytes */
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
-			 &ws, buf, sizeof(buf), NULL, 0);
-	if (ret < 0) {
-		pr_err("The prng self test generate operation for "
-		       "the SHA-512 mode failed with rc=%d\n", ret);
-		prng_errorflag = PRNG_SELFTEST_FAILED;
-		return -EIO;
-	}
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
-			 &ws, buf, sizeof(buf), NULL, 0);
-	if (ret < 0) {
-		pr_err("The prng self test generate operation for "
-		       "the SHA-512 mode failed with rc=%d\n", ret);
-		prng_errorflag = PRNG_SELFTEST_FAILED;
-		return -EIO;
-	}
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
+		   &ws, buf, sizeof(buf), NULL, 0);
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
+		   &ws, buf, sizeof(buf), NULL, 0);
 
 	/* check against expected data */
 	if (memcmp(buf, random, sizeof(random)) != 0) {
@@ -392,26 +365,16 @@ static int __init prng_sha512_instantiate(void)
 	get_tod_clock_ext(seed + 48);
 
 	/* initial seed of the ppno drng */
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
-			 &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
-	if (ret < 0) {
-		prng_errorflag = PRNG_SEED_FAILED;
-		ret = -EIO;
-		goto outfree;
-	}
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
+		   &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
 
 	/* if fips mode is enabled, generate a first block of random
 	   bytes for the FIPS 140-2 Conditional Self Test */
 	if (fips_enabled) {
 		prng_data->prev = prng_data->buf + prng_chunk_size;
-		ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
-				 &prng_data->ppnows,
-				 prng_data->prev, prng_chunk_size, NULL, 0);
-		if (ret < 0 || ret != prng_chunk_size) {
-			prng_errorflag = PRNG_GEN_FAILED;
-			ret = -EIO;
-			goto outfree;
-		}
+		cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
+			   &prng_data->ppnows,
+			   prng_data->prev, prng_chunk_size, NULL, 0);
 	}
 
 	return 0;
@@ -440,12 +403,8 @@ static int prng_sha512_reseed(void)
 		return ret;
 
 	/* do a reseed of the ppno drng with this bytestring */
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
-			 &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
-	if (ret) {
-		prng_errorflag = PRNG_RESEED_FAILED;
-		return -EIO;
-	}
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_SEED,
+		   &prng_data->ppnows, NULL, 0, seed, sizeof(seed));
 
 	return 0;
 }
@@ -463,12 +422,8 @@ static int prng_sha512_generate(u8 *buf, size_t nbytes)
 	}
 
 	/* PPNO generate */
-	ret = cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
-			 &prng_data->ppnows, buf, nbytes, NULL, 0);
-	if (ret < 0 || ret != nbytes) {
-		prng_errorflag = PRNG_GEN_FAILED;
-		return -EIO;
-	}
+	cpacf_ppno(CPACF_PPNO_SHA512_DRNG_GEN,
+		   &prng_data->ppnows, buf, nbytes, NULL, 0);
 
 	/* FIPS 140-2 Conditional Self Test */
 	if (fips_enabled) {
@@ -494,7 +449,7 @@ static int prng_open(struct inode *inode, struct file *file)
 static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
 			      size_t nbytes, loff_t *ppos)
 {
-	int chunk, n, tmp, ret = 0;
+	int chunk, n, ret = 0;
 
 	/* lock prng_data struct */
 	if (mutex_lock_interruptible(&prng_data->mutex))
@@ -545,13 +500,9 @@ static ssize_t prng_tdes_read(struct file *file, char __user *ubuf,
 		 *
 		 * Note: you can still get strict X9.17 conformity by setting
 		 * prng_chunk_size to 8 bytes.
-		*/
-		tmp = cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
-				prng_data->buf, prng_data->buf, n);
-		if (tmp < 0 || tmp != n) {
-			ret = -EIO;
-			break;
-		}
+		 */
+		cpacf_kmc(CPACF_KMC_PRNG, prng_data->prngws.parm_block,
+			  prng_data->buf, prng_data->buf, n);
 
 		prng_data->prngws.byte_counter += n;
 		prng_data->prngws.reseed_counter += n;