1 files changed, 76 insertions, 0 deletions
diff --git a/arch/x86/crypto/ecb_cbc_helpers.h b/arch/x86/crypto/ecb_cbc_helpers.h
new file mode 100644
index 000000000000..eaa15c7b29d6
--- /dev/null
+++ b/arch/x86/crypto/ecb_cbc_helpers.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _CRYPTO_ECB_CBC_HELPER_H
+#define _CRYPTO_ECB_CBC_HELPER_H
+
+#include <crypto/internal/skcipher.h>
+#include <asm/fpu/api.h>
+
+/*
+ * Mode helpers to instantiate parameterized skcipher ECB/CBC modes without
+ * having to rely on indirect calls and retpolines.
+ */
+
+#define ECB_WALK_START(req, bsize, fpu_blocks) do {			\
+	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));	\
+	const int __bsize = (bsize);					\
+	struct skcipher_walk walk;					\
+	int err = skcipher_walk_virt(&walk, (req), false);		\
+	while (walk.nbytes > 0) {					\
+		unsigned int nbytes = walk.nbytes;			\
+		bool do_fpu = (fpu_blocks) != -1 &&			\
+			      nbytes >= (fpu_blocks) * __bsize;		\
+		const u8 *src = walk.src.virt.addr;			\
+		u8 *dst = walk.dst.virt.addr;				\
+		u8 __maybe_unused buf[(bsize)];				\
+		if (do_fpu) kernel_fpu_begin()
+
+#define CBC_WALK_START(req, bsize, fpu_blocks)				\
+	ECB_WALK_START(req, bsize, fpu_blocks)
+
+#define ECB_WALK_ADVANCE(blocks) do {					\
+	dst += (blocks) * __bsize;					\
+	src += (blocks) * __bsize;					\
+	nbytes -= (blocks) * __bsize;					\
+} while (0)
+
+#define ECB_BLOCK(blocks, func) do {					\
+	while (nbytes >= (blocks) * __bsize) {				\
+		(func)(ctx, dst, src);					\
+		ECB_WALK_ADVANCE(blocks);				\
+	}								\
+} while (0)
+
+#define CBC_ENC_BLOCK(func) do {					\
+	const u8 *__iv = walk.iv;					\
+	while (nbytes >= __bsize) {					\
+		crypto_xor_cpy(dst, src, __iv, __bsize);		\
+		(func)(ctx, dst, dst);					\
+		__iv = dst;						\
+		ECB_WALK_ADVANCE(1);					\
+	}								\
+	memcpy(walk.iv, __iv, __bsize);					\
+} while (0)
+
+#define CBC_DEC_BLOCK(blocks, func) do {				\
+	while (nbytes >= (blocks) * __bsize) {				\
+		const u8 *__iv = src + ((blocks) - 1) * __bsize;	\
+		if (dst == src)						\
+			__iv = memcpy(buf, __iv, __bsize);		\
+		(func)(ctx, dst, src);					\
+		crypto_xor(dst, walk.iv, __bsize);			\
+		memcpy(walk.iv, __iv, __bsize);				\
+		ECB_WALK_ADVANCE(blocks);				\
+	}								\
+} while (0)
+
+#define ECB_WALK_END()							\
+		if (do_fpu) kernel_fpu_end();				\
+		err = skcipher_walk_done(&walk, nbytes);		\
+	}								\
+	return err;							\
+} while (0)
+
+#define CBC_WALK_END() ECB_WALK_END()
+
+#endif