crypto: arch - conditionalize crypto api in arch glue for lib code

For glue code that's used by Zinc, the actual Crypto API functions might
not necessarily exist, and don't need to exist either. Before this
patch, there are valid build configurations that lead to a unbuildable
kernel. This fixes it to conditionalize those symbols on the existence
of the proper config entry.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 25 insertions, 15 deletions

diff --git a/arch/arm/crypto/chacha-glue.c b/arch/arm/crypto/chacha-glue.c
index 3f0c057aa050..6ebbb2b241d2 100644
--- a/arch/arm/crypto/chacha-glue.c
+++ b/arch/arm/crypto/chacha-glue.c
@@ -286,11 +286,13 @@ static struct skcipher_alg neon_algs[] = {
 
 static int __init chacha_simd_mod_init(void)
 {
-	int err;
+	int err = 0;
 
-	err = crypto_register_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
-	if (err)
-		return err;
+	if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
+		err = crypto_register_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
+		if (err)
+			return err;
+	}
 
 	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
 		int i;
@@ -310,18 +312,22 @@ static int __init chacha_simd_mod_init(void)
 			static_branch_enable(&use_neon);
 		}
 
-		err = crypto_register_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
-		if (err)
-			crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
+		if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
+			err = crypto_register_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
+			if (err)
+				crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
+		}
 	}
 	return err;
 }
 
 static void __exit chacha_simd_mod_fini(void)
 {
-	crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
-	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON))
-		crypto_unregister_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
+	if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
+		crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
+		if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON))
+			crypto_unregister_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
+	}
 }
 
 module_init(chacha_simd_mod_init);
diff --git a/arch/arm/crypto/curve25519-glue.c b/arch/arm/crypto/curve25519-glue.c
index 2e9e12d2f642..f3f42cf3b893 100644
--- a/arch/arm/crypto/curve25519-glue.c
+++ b/arch/arm/crypto/curve25519-glue.c
@@ -108,14 +108,15 @@ static int __init mod_init(void)
 {
 	if (elf_hwcap & HWCAP_NEON) {
 		static_branch_enable(&have_neon);
-		return crypto_register_kpp(&curve25519_alg);
+		return IS_REACHABLE(CONFIG_CRYPTO_KPP) ?
+			crypto_register_kpp(&curve25519_alg) : 0;
 	}
 	return 0;
 }
 
 static void __exit mod_exit(void)
 {
-	if (elf_hwcap & HWCAP_NEON)
+	if (IS_REACHABLE(CONFIG_CRYPTO_KPP) && elf_hwcap & HWCAP_NEON)
 		crypto_unregister_kpp(&curve25519_alg);
 }
 
diff --git a/arch/arm/crypto/poly1305-glue.c b/arch/arm/crypto/poly1305-glue.c
index 74a725ac89c9..abe3f2d587dc 100644
--- a/arch/arm/crypto/poly1305-glue.c
+++ b/arch/arm/crypto/poly1305-glue.c
@@ -249,16 +249,19 @@ static int __init arm_poly1305_mod_init(void)
 	if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
 	    (elf_hwcap & HWCAP_NEON))
 		static_branch_enable(&have_neon);
-	else
+	else if (IS_REACHABLE(CONFIG_CRYPTO_HASH))
 		/* register only the first entry */
 		return crypto_register_shash(&arm_poly1305_algs[0]);
 
-	return crypto_register_shashes(arm_poly1305_algs,
-				       ARRAY_SIZE(arm_poly1305_algs));
+	return IS_REACHABLE(CONFIG_CRYPTO_HASH) ?
+		crypto_register_shashes(arm_poly1305_algs,
+					ARRAY_SIZE(arm_poly1305_algs)) : 0;
 }
 
 static void __exit arm_poly1305_mod_exit(void)
 {
+	if (!IS_REACHABLE(CONFIG_CRYPTO_HASH))
+		return;
 	if (!static_branch_likely(&have_neon)) {
 		crypto_unregister_shash(&arm_poly1305_algs[0]);
 		return;