crypto: arm64/crct10dif - add non-SIMD generic fallback

The arm64 kernel will shortly disallow nested kernel mode NEON, so
add a fallback to scalar C code that can be invoked in that case.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 9 insertions, 4 deletions

diff --git a/arch/arm64/crypto/crct10dif-ce-glue.c b/arch/arm64/crypto/crct10dif-ce-glue.c
index 60cb590c2590..96f0cae4a022 100644
--- a/arch/arm64/crypto/crct10dif-ce-glue.c
+++ b/arch/arm64/crypto/crct10dif-ce-glue.c
@@ -1,7 +1,7 @@
 /*
  * Accelerated CRC-T10DIF using arm64 NEON and Crypto Extensions instructions
  *
- * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
+ * Copyright (C) 2016 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -18,6 +18,7 @@
 #include <crypto/internal/hash.h>
 
 #include <asm/neon.h>
+#include <asm/simd.h>
 
 #define CRC_T10DIF_PMULL_CHUNK_SIZE     16U
 
@@ -48,9 +49,13 @@ static int crct10dif_update(struct shash_desc *desc, const u8 *data,
         }
 
         if (length > 0) {
-                kernel_neon_begin_partial(14);
-                *crc = crc_t10dif_pmull(*crc, data, length);
-                kernel_neon_end();
+                if (may_use_simd()) {
+                        kernel_neon_begin();
+                        *crc = crc_t10dif_pmull(*crc, data, length);
+                        kernel_neon_end();
+                } else {
+                        *crc = crc_t10dif_generic(*crc, data, length);
+                }
         }
 
         return 0;