ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 25 insertions, 0 deletions

diff --git a/include/crypto/twofish.h b/include/crypto/twofish.h
new file mode 100644
index 000000000..f6b307a58
--- /dev/null
+++ b/include/crypto/twofish.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _CRYPTO_TWOFISH_H
+#define _CRYPTO_TWOFISH_H
+
+#include <linux/types.h>
+
+#define TF_MIN_KEY_SIZE 16
+#define TF_MAX_KEY_SIZE 32
+#define TF_BLOCK_SIZE 16
+
+struct crypto_tfm;
+
+/* Structure for an expanded Twofish key.  s contains the key-dependent
+ * S-boxes composed with the MDS matrix; w contains the eight "whitening"
+ * subkeys, K[0] through K[7].	k holds the remaining, "round" subkeys.  Note
+ * that k[i] corresponds to what the Twofish paper calls K[i+8]. */
+struct twofish_ctx {
+	u32 s[4][256], w[8], k[32];
+};
+
+int __twofish_setkey(struct twofish_ctx *ctx, const u8 *key,
+		     unsigned int key_len);
+int twofish_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int key_len);
+
+#endif