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, 85 insertions, 0 deletions

diff --git a/include/crypto/gcm.h b/include/crypto/gcm.h
new file mode 100644
index 000000000..1d5f39ff1
--- /dev/null
+++ b/include/crypto/gcm.h
@@ -0,0 +1,85 @@
+#ifndef _CRYPTO_GCM_H
+#define _CRYPTO_GCM_H
+
+#include <linux/errno.h>
+
+#include <crypto/aes.h>
+#include <crypto/gf128hash.h>
+
+#define GCM_AES_IV_SIZE 12
+#define GCM_RFC4106_IV_SIZE 8
+#define GCM_RFC4543_IV_SIZE 8
+
+/*
+ * validate authentication tag for GCM
+ */
+static inline int crypto_gcm_check_authsize(unsigned int authsize)
+{
+	switch (authsize) {
+	case 4:
+	case 8:
+	case 12:
+	case 13:
+	case 14:
+	case 15:
+	case 16:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * validate authentication tag for RFC4106
+ */
+static inline int crypto_rfc4106_check_authsize(unsigned int authsize)
+{
+	switch (authsize) {
+	case 8:
+	case 12:
+	case 16:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * validate assoclen for RFC4106/RFC4543
+ */
+static inline int crypto_ipsec_check_assoclen(unsigned int assoclen)
+{
+	switch (assoclen) {
+	case 16:
+	case 20:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+struct aesgcm_ctx {
+	struct ghash_key	ghash_key;
+	struct aes_enckey	aes_key;
+	unsigned int		authsize;
+};
+
+int aesgcm_expandkey(struct aesgcm_ctx *ctx, const u8 *key,
+		     unsigned int keysize, unsigned int authsize);
+
+void aesgcm_encrypt(const struct aesgcm_ctx *ctx, u8 *dst, const u8 *src,
+		    int crypt_len, const u8 *assoc, int assoc_len,
+		    const u8 iv[GCM_AES_IV_SIZE], u8 *authtag);
+
+bool __must_check aesgcm_decrypt(const struct aesgcm_ctx *ctx, u8 *dst,
+				 const u8 *src, int crypt_len, const u8 *assoc,
+				 int assoc_len, const u8 iv[GCM_AES_IV_SIZE],
+				 const u8 *authtag);
+
+#endif