[PATCH 16/20] lib/crypto: riscv/aes: Pass key struct to assembly code

[Eric Biggers]

Make the assembly code take the AES key struct directly, rather than the
round keys pointer and key length separately.  Make the aes_begin macro
assume this convention, and remove support for the legacy
'struct crypto_aes_ctx' from it since that isn't used here.

This aligns with the convention that is being used (and will continue to
be used) for the AES modes, it makes the C glue code slightly simpler,
and it avoids the unnecessary shuffling around of arguments.

Signed-off-by: Eric Biggers <ebiggers at kernel.org>
---
 lib/crypto/riscv/aes-macros.S         | 25 ++++++++++---------------
 lib/crypto/riscv/aes-riscv64-zvkned.S | 13 ++++++-------
 lib/crypto/riscv/aes.h                | 12 ++++++++----
 3 files changed, 24 insertions(+), 26 deletions(-)

diff --git a/lib/crypto/riscv/aes-macros.S b/lib/crypto/riscv/aes-macros.S
index 1384164621a5..720ad69a41ac 100644
--- a/lib/crypto/riscv/aes-macros.S
+++ b/lib/crypto/riscv/aes-macros.S
@@ -44,17 +44,20 @@
 // - RISC-V Vector ('V') with VLEN >= 128
 // - RISC-V Vector AES block cipher extension ('Zvkned')
 
-// Loads the AES round keys from \keyp into vector registers and jumps to code
-// specific to the length of the key.  Specifically:
+// Offsets in struct aes_enckey
+#define OFFSETOF_KEYLEN		0
+#define OFFSETOF_RNDKEYS	16
+
+// Loads the AES round keys from the struct aes_enckey \keyp into vector
+// registers and jumps to code specific to the length of the key.  Specifically:
 //   - If AES-128, loads round keys into v1-v11 and jumps to \label128.
 //   - If AES-192, loads round keys into v1-v13 and jumps to \label192.
 //   - If AES-256, loads round keys into v1-v15 and continues onwards.
 //
-// Also sets vl=4 and vtype=e32,m1,ta,ma.  Clobbers t0 and t1.
-.macro	aes_begin	keyp, label128, label192, key_len
-.ifb \key_len
-	lwu		t0, 480(\keyp)	// t0 = key length in bytes
-.endif
+// Also sets vl=4 and vtype=e32,m1,ta,ma.  Clobbers keyp, t0, and t1.
+.macro	aes_begin	keyp, label128, label192
+	lwu		t0, OFFSETOF_KEYLEN(\keyp) // t0 = key length in bytes
+	addi		\keyp, \keyp, OFFSETOF_RNDKEYS
 	li		t1, 24		// t1 = key length for AES-192
 	vsetivli	zero, 4, e32, m1, ta, ma
 	vle32.v		v1, (\keyp)
@@ -78,20 +81,12 @@
 	vle32.v		v10, (\keyp)
 	addi		\keyp, \keyp, 16
 	vle32.v		v11, (\keyp)
-.ifb \key_len
 	blt		t0, t1, \label128	// If AES-128, goto label128.
-.else
-	blt		\key_len, t1, \label128	// If AES-128, goto label128.
-.endif
 	addi		\keyp, \keyp, 16
 	vle32.v		v12, (\keyp)
 	addi		\keyp, \keyp, 16
 	vle32.v		v13, (\keyp)
-.ifb \key_len
 	beq		t0, t1, \label192	// If AES-192, goto label192.
-.else
-	beq		\key_len, t1, \label192	// If AES-192, goto label192.
-.endif
 	// Else, it's AES-256.
 	addi		\keyp, \keyp, 16
 	vle32.v		v14, (\keyp)
diff --git a/lib/crypto/riscv/aes-riscv64-zvkned.S b/lib/crypto/riscv/aes-riscv64-zvkned.S
index 7a52ea6c669d..374fc4dba11b 100644
--- a/lib/crypto/riscv/aes-riscv64-zvkned.S
+++ b/lib/crypto/riscv/aes-riscv64-zvkned.S
@@ -50,10 +50,9 @@
 
 #include "aes-macros.S"
 
-#define RNDKEYS		a0
-#define KEY_LEN		a1
-#define OUTP		a2
-#define INP		a3
+#define KEYP		a0
+#define OUTP		a1
+#define INP		a2
 
 .macro	__aes_crypt_zvkned	enc, keybits
 	vle32.v		v16, (INP)
@@ -63,7 +62,7 @@
 .endm
 
 .macro	aes_crypt_zvkned	enc
-	aes_begin	RNDKEYS, 128f, 192f, KEY_LEN
+	aes_begin	KEYP, 128f, 192f
 	__aes_crypt_zvkned	\enc, 256
 128:
 	__aes_crypt_zvkned	\enc, 128
@@ -71,13 +70,13 @@
 	__aes_crypt_zvkned	\enc, 192
 .endm
 
-// void aes_encrypt_zvkned(const u32 rndkeys[], int key_len,
+// void aes_encrypt_zvkned(const struct aes_enckey *key,
 //			   u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
 SYM_FUNC_START(aes_encrypt_zvkned)
 	aes_crypt_zvkned	1
 SYM_FUNC_END(aes_encrypt_zvkned)
 
-// void aes_decrypt_zvkned(const u32 rndkeys[], int key_len,
+// void aes_decrypt_zvkned(const struct aes_key *key,
 //			   u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
 SYM_FUNC_START(aes_decrypt_zvkned)
 	aes_crypt_zvkned	0
diff --git a/lib/crypto/riscv/aes.h b/lib/crypto/riscv/aes.h
index 0b26f58faf2b..a288b4c5b493 100644
--- a/lib/crypto/riscv/aes.h
+++ b/lib/crypto/riscv/aes.h
@@ -10,9 +10,13 @@
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_zvkned);
 
-void aes_encrypt_zvkned(const u32 rndkeys[], int key_len,
+/* The assembly code assumes the following offsets. */
+static_assert(offsetof(struct aes_enckey, len) == 0);
+static_assert(offsetof(struct aes_enckey, k.rndkeys) == 16);
+
+void aes_encrypt_zvkned(const struct aes_enckey *key,
 			u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
-void aes_decrypt_zvkned(const u32 rndkeys[], int key_len,
+void aes_decrypt_zvkned(const struct aes_key *key,
 			u8 out[AES_BLOCK_SIZE], const u8 in[AES_BLOCK_SIZE]);
 
 static void aes_preparekey_arch(union aes_enckey_arch *k,
@@ -29,7 +33,7 @@ static void aes_encrypt_arch(const struct aes_enckey *key,
 {
 	if (static_branch_likely(&have_zvkned) && likely(may_use_simd())) {
 		kernel_vector_begin();
-		aes_encrypt_zvkned(key->k.rndkeys, key->len, out, in);
+		aes_encrypt_zvkned(key, out, in);
 		kernel_vector_end();
 	} else {
 		aes_encrypt_generic(key->k.rndkeys, key->nrounds, out, in);
@@ -46,7 +50,7 @@ static void aes_decrypt_arch(const struct aes_key *key,
 	 */
 	if (static_branch_likely(&have_zvkned) && likely(may_use_simd())) {
 		kernel_vector_begin();
-		aes_decrypt_zvkned(key->k.rndkeys, key->len, out, in);
+		aes_decrypt_zvkned(key, out, in);
 		kernel_vector_end();
 	} else {
 		aes_decrypt_generic(key->inv_k.inv_rndkeys, key->nrounds,
-- 
2.55.0