diff --git a/tf-psa-crypto/drivers/builtin/src/sha256.c b/tf-psa-crypto/drivers/builtin/src/sha256.c
index aff626f..95bcf69 100644
--- a/tf-psa-crypto/drivers/builtin/src/sha256.c
+++ b/tf-psa-crypto/drivers/builtin/src/sha256.c
@@ -414,7 +414,7 @@
     return processed;
 }
 
-int mbedtls_internal_sha256_process_a64_crypto(mbedtls_sha256_context *ctx,
+static int mbedtls_internal_sha256_process_a64_crypto(mbedtls_sha256_context *ctx,
                                                const unsigned char data[SHA256_BLOCK_SIZE])
 {
     return (mbedtls_internal_sha256_process_many_a64_crypto(ctx, data,
@@ -467,7 +467,7 @@
         (d) += local.temp1; (h) = local.temp1 + local.temp2;        \
     } while (0)
 
-int mbedtls_internal_sha256_process_c(mbedtls_sha256_context *ctx,
+static int mbedtls_internal_sha256_process_c(mbedtls_sha256_context *ctx,
                                       const unsigned char data[SHA256_BLOCK_SIZE])
 {
     struct {
diff --git a/tf-psa-crypto/drivers/builtin/src/sha512.c b/tf-psa-crypto/drivers/builtin/src/sha512.c
index c1d5e59..27c7cf2 100644
--- a/tf-psa-crypto/drivers/builtin/src/sha512.c
+++ b/tf-psa-crypto/drivers/builtin/src/sha512.c
@@ -551,7 +551,7 @@
     return processed;
 }
 
-int mbedtls_internal_sha512_process_a64_crypto(mbedtls_sha512_context *ctx,
+static int mbedtls_internal_sha512_process_a64_crypto(mbedtls_sha512_context *ctx,
                                                const unsigned char data[SHA512_BLOCK_SIZE])
 {
     return (mbedtls_internal_sha512_process_many_a64_crypto(ctx, data,
@@ -579,7 +579,7 @@
 
 #if !defined(MBEDTLS_SHA512_USE_A64_CRYPTO_ONLY)
 
-int mbedtls_internal_sha512_process_c(mbedtls_sha512_context *ctx,
+static int mbedtls_internal_sha512_process_c(mbedtls_sha512_context *ctx,
                                       const unsigned char data[SHA512_BLOCK_SIZE])
 {
     int i;