kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 609 insertions, 0 deletions

diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c
new file mode 100644
index 000000000..b21e7606c
--- /dev/null
+++ b/crypto/serpent_generic.c
@@ -0,0 +1,609 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Cryptographic API.
+ *
+ * Serpent Cipher Algorithm.
+ *
+ * Copyright (C) 2002 Dag Arne Osvik <osvik@ii.uib.no>
+ */
+
+#include <crypto/algapi.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/unaligned.h>
+#include <linux/types.h>
+#include <crypto/serpent.h>
+
+/* Key is padded to the maximum of 256 bits before round key generation.
+ * Any key length <= 256 bits (32 bytes) is allowed by the algorithm.
+ */
+
+#define PHI 0x9e3779b9UL
+
+#define keyiter(a, b, c, d, i, j) \
+	({ b ^= d; b ^= c; b ^= a; b ^= PHI ^ i; b = rol32(b, 11); k[j] = b; })
+
+#define loadkeys(x0, x1, x2, x3, i) \
+	({ x0 = k[i]; x1 = k[i+1]; x2 = k[i+2]; x3 = k[i+3]; })
+
+#define storekeys(x0, x1, x2, x3, i) \
+	({ k[i] = x0; k[i+1] = x1; k[i+2] = x2; k[i+3] = x3; })
+
+#define store_and_load_keys(x0, x1, x2, x3, s, l) \
+	({ storekeys(x0, x1, x2, x3, s); loadkeys(x0, x1, x2, x3, l); })
+
+#define K(x0, x1, x2, x3, i) ({				\
+	x3 ^= k[4*(i)+3];        x2 ^= k[4*(i)+2];	\
+	x1 ^= k[4*(i)+1];        x0 ^= k[4*(i)+0];	\
+	})
+
+#define LK(x0, x1, x2, x3, x4, i) ({					   \
+							x0 = rol32(x0, 13);\
+	x2 = rol32(x2, 3);	x1 ^= x0;		x4  = x0 << 3;	   \
+	x3 ^= x2;		x1 ^= x2;				   \
+	x1 = rol32(x1, 1);	x3 ^= x4;				   \
+	x3 = rol32(x3, 7);	x4  = x1;				   \
+	x0 ^= x1;		x4 <<= 7;		x2 ^= x3;	   \
+	x0 ^= x3;		x2 ^= x4;		x3 ^= k[4*i+3];	   \
+	x1 ^= k[4*i+1];		x0 = rol32(x0, 5);	x2 = rol32(x2, 22);\
+	x0 ^= k[4*i+0];		x2 ^= k[4*i+2];				   \
+	})
+
+#define KL(x0, x1, x2, x3, x4, i) ({					   \
+	x0 ^= k[4*i+0];		x1 ^= k[4*i+1];		x2 ^= k[4*i+2];	   \
+	x3 ^= k[4*i+3];		x0 = ror32(x0, 5);	x2 = ror32(x2, 22);\
+	x4 =  x1;		x2 ^= x3;		x0 ^= x3;	   \
+	x4 <<= 7;		x0 ^= x1;		x1 = ror32(x1, 1); \
+	x2 ^= x4;		x3 = ror32(x3, 7);	x4 = x0 << 3;	   \
+	x1 ^= x0;		x3 ^= x4;		x0 = ror32(x0, 13);\
+	x1 ^= x2;		x3 ^= x2;		x2 = ror32(x2, 3); \
+	})
+
+#define S0(x0, x1, x2, x3, x4) ({			\
+					x4  = x3;	\
+	x3 |= x0;	x0 ^= x4;	x4 ^= x2;	\
+	x4 = ~x4;	x3 ^= x1;	x1 &= x0;	\
+	x1 ^= x4;	x2 ^= x0;	x0 ^= x3;	\
+	x4 |= x0;	x0 ^= x2;	x2 &= x1;	\
+	x3 ^= x2;	x1 = ~x1;	x2 ^= x4;	\
+	x1 ^= x2;					\
+	})
+
+#define S1(x0, x1, x2, x3, x4) ({			\
+					x4  = x1;	\
+	x1 ^= x0;	x0 ^= x3;	x3 = ~x3;	\
+	x4 &= x1;	x0 |= x1;	x3 ^= x2;	\
+	x0 ^= x3;	x1 ^= x3;	x3 ^= x4;	\
+	x1 |= x4;	x4 ^= x2;	x2 &= x0;	\
+	x2 ^= x1;	x1 |= x0;	x0 = ~x0;	\
+	x0 ^= x2;	x4 ^= x1;			\
+	})
+
+#define S2(x0, x1, x2, x3, x4) ({			\
+					x3 = ~x3;	\
+	x1 ^= x0;	x4  = x0;	x0 &= x2;	\
+	x0 ^= x3;	x3 |= x4;	x2 ^= x1;	\
+	x3 ^= x1;	x1 &= x0;	x0 ^= x2;	\
+	x2 &= x3;	x3 |= x1;	x0 = ~x0;	\
+	x3 ^= x0;	x4 ^= x0;	x0 ^= x2;	\
+	x1 |= x2;					\
+	})
+
+#define S3(x0, x1, x2, x3, x4) ({			\
+					x4  = x1;	\
+	x1 ^= x3;	x3 |= x0;	x4 &= x0;	\
+	x0 ^= x2;	x2 ^= x1;	x1 &= x3;	\
+	x2 ^= x3;	x0 |= x4;	x4 ^= x3;	\
+	x1 ^= x0;	x0 &= x3;	x3 &= x4;	\
+	x3 ^= x2;	x4 |= x1;	x2 &= x1;	\
+	x4 ^= x3;	x0 ^= x3;	x3 ^= x2;	\
+	})
+
+#define S4(x0, x1, x2, x3, x4) ({			\
+					x4  = x3;	\
+	x3 &= x0;	x0 ^= x4;			\
+	x3 ^= x2;	x2 |= x4;	x0 ^= x1;	\
+	x4 ^= x3;	x2 |= x0;			\
+	x2 ^= x1;	x1 &= x0;			\
+	x1 ^= x4;	x4 &= x2;	x2 ^= x3;	\
+	x4 ^= x0;	x3 |= x1;	x1 = ~x1;	\
+	x3 ^= x0;					\
+	})
+
+#define S5(x0, x1, x2, x3, x4) ({			\
+	x4  = x1;	x1 |= x0;			\
+	x2 ^= x1;	x3 = ~x3;	x4 ^= x0;	\
+	x0 ^= x2;	x1 &= x4;	x4 |= x3;	\
+	x4 ^= x0;	x0 &= x3;	x1 ^= x3;	\
+	x3 ^= x2;	x0 ^= x1;	x2 &= x4;	\
+	x1 ^= x2;	x2 &= x0;			\
+	x3 ^= x2;					\
+	})
+
+#define S6(x0, x1, x2, x3, x4) ({			\
+					x4  = x1;	\
+	x3 ^= x0;	x1 ^= x2;	x2 ^= x0;	\
+	x0 &= x3;	x1 |= x3;	x4 = ~x4;	\
+	x0 ^= x1;	x1 ^= x2;			\
+	x3 ^= x4;	x4 ^= x0;	x2 &= x0;	\
+	x4 ^= x1;	x2 ^= x3;	x3 &= x1;	\
+	x3 ^= x0;	x1 ^= x2;			\
+	})
+
+#define S7(x0, x1, x2, x3, x4) ({			\
+					x1 = ~x1;	\
+	x4  = x1;	x0 = ~x0;	x1 &= x2;	\
+	x1 ^= x3;	x3 |= x4;	x4 ^= x2;	\
+	x2 ^= x3;	x3 ^= x0;	x0 |= x1;	\
+	x2 &= x0;	x0 ^= x4;	x4 ^= x3;	\
+	x3 &= x0;	x4 ^= x1;			\
+	x2 ^= x4;	x3 ^= x1;	x4 |= x0;	\
+	x4 ^= x1;					\
+	})
+
+#define SI0(x0, x1, x2, x3, x4) ({			\
+			x4  = x3;	x1 ^= x0;	\
+	x3 |= x1;	x4 ^= x1;	x0 = ~x0;	\
+	x2 ^= x3;	x3 ^= x0;	x0 &= x1;	\
+	x0 ^= x2;	x2 &= x3;	x3 ^= x4;	\
+	x2 ^= x3;	x1 ^= x3;	x3 &= x0;	\
+	x1 ^= x0;	x0 ^= x2;	x4 ^= x3;	\
+	})
+
+#define SI1(x0, x1, x2, x3, x4) ({			\
+	x1 ^= x3;	x4  = x0;			\
+	x0 ^= x2;	x2 = ~x2;	x4 |= x1;	\
+	x4 ^= x3;	x3 &= x1;	x1 ^= x2;	\
+	x2 &= x4;	x4 ^= x1;	x1 |= x3;	\
+	x3 ^= x0;	x2 ^= x0;	x0 |= x4;	\
+	x2 ^= x4;	x1 ^= x0;			\
+	x4 ^= x1;					\
+	})
+
+#define SI2(x0, x1, x2, x3, x4) ({			\
+	x2 ^= x1;	x4  = x3;	x3 = ~x3;	\
+	x3 |= x2;	x2 ^= x4;	x4 ^= x0;	\
+	x3 ^= x1;	x1 |= x2;	x2 ^= x0;	\
+	x1 ^= x4;	x4 |= x3;	x2 ^= x3;	\
+	x4 ^= x2;	x2 &= x1;			\
+	x2 ^= x3;	x3 ^= x4;	x4 ^= x0;	\
+	})
+
+#define SI3(x0, x1, x2, x3, x4) ({			\
+					x2 ^= x1;	\
+	x4  = x1;	x1 &= x2;			\
+	x1 ^= x0;	x0 |= x4;	x4 ^= x3;	\
+	x0 ^= x3;	x3 |= x1;	x1 ^= x2;	\
+	x1 ^= x3;	x0 ^= x2;	x2 ^= x3;	\
+	x3 &= x1;	x1 ^= x0;	x0 &= x2;	\
+	x4 ^= x3;	x3 ^= x0;	x0 ^= x1;	\
+	})
+
+#define SI4(x0, x1, x2, x3, x4) ({			\
+	x2 ^= x3;	x4  = x0;	x0 &= x1;	\
+	x0 ^= x2;	x2 |= x3;	x4 = ~x4;	\
+	x1 ^= x0;	x0 ^= x2;	x2 &= x4;	\
+	x2 ^= x0;	x0 |= x4;			\
+	x0 ^= x3;	x3 &= x2;			\
+	x4 ^= x3;	x3 ^= x1;	x1 &= x0;	\
+	x4 ^= x1;	x0 ^= x3;			\
+	})
+
+#define SI5(x0, x1, x2, x3, x4) ({			\
+			x4  = x1;	x1 |= x2;	\
+	x2 ^= x4;	x1 ^= x3;	x3 &= x4;	\
+	x2 ^= x3;	x3 |= x0;	x0 = ~x0;	\
+	x3 ^= x2;	x2 |= x0;	x4 ^= x1;	\
+	x2 ^= x4;	x4 &= x0;	x0 ^= x1;	\
+	x1 ^= x3;	x0 &= x2;	x2 ^= x3;	\
+	x0 ^= x2;	x2 ^= x4;	x4 ^= x3;	\
+	})
+
+#define SI6(x0, x1, x2, x3, x4) ({			\
+			x0 ^= x2;			\
+	x4  = x0;	x0 &= x3;	x2 ^= x3;	\
+	x0 ^= x2;	x3 ^= x1;	x2 |= x4;	\
+	x2 ^= x3;	x3 &= x0;	x0 = ~x0;	\
+	x3 ^= x1;	x1 &= x2;	x4 ^= x0;	\
+	x3 ^= x4;	x4 ^= x2;	x0 ^= x1;	\
+	x2 ^= x0;					\
+	})
+
+#define SI7(x0, x1, x2, x3, x4) ({			\
+	x4  = x3;	x3 &= x0;	x0 ^= x2;	\
+	x2 |= x4;	x4 ^= x1;	x0 = ~x0;	\
+	x1 |= x3;	x4 ^= x0;	x0 &= x2;	\
+	x0 ^= x1;	x1 &= x2;	x3 ^= x2;	\
+	x4 ^= x3;	x2 &= x3;	x3 |= x0;	\
+	x1 ^= x4;	x3 ^= x4;	x4 &= x0;	\
+	x4 ^= x2;					\
+	})
+
+/*
+ * both gcc and clang have misoptimized this function in the past,
+ * producing horrible object code from spilling temporary variables
+ * on the stack. Forcing this part out of line avoids that.
+ */
+static noinline void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2,
+					   u32 r3, u32 r4, u32 *k)
+{
+	k += 100;
+	S3(r3, r4, r0, r1, r2); store_and_load_keys(r1, r2, r4, r3, 28, 24);
+	S4(r1, r2, r4, r3, r0); store_and_load_keys(r2, r4, r3, r0, 24, 20);
+	S5(r2, r4, r3, r0, r1); store_and_load_keys(r1, r2, r4, r0, 20, 16);
+	S6(r1, r2, r4, r0, r3); store_and_load_keys(r4, r3, r2, r0, 16, 12);
+	S7(r4, r3, r2, r0, r1); store_and_load_keys(r1, r2, r0, r4, 12, 8);
+	S0(r1, r2, r0, r4, r3); store_and_load_keys(r0, r2, r4, r1, 8, 4);
+	S1(r0, r2, r4, r1, r3); store_and_load_keys(r3, r4, r1, r0, 4, 0);
+	S2(r3, r4, r1, r0, r2); store_and_load_keys(r2, r4, r3, r0, 0, -4);
+	S3(r2, r4, r3, r0, r1); store_and_load_keys(r0, r1, r4, r2, -4, -8);
+	S4(r0, r1, r4, r2, r3); store_and_load_keys(r1, r4, r2, r3, -8, -12);
+	S5(r1, r4, r2, r3, r0); store_and_load_keys(r0, r1, r4, r3, -12, -16);
+	S6(r0, r1, r4, r3, r2); store_and_load_keys(r4, r2, r1, r3, -16, -20);
+	S7(r4, r2, r1, r3, r0); store_and_load_keys(r0, r1, r3, r4, -20, -24);
+	S0(r0, r1, r3, r4, r2); store_and_load_keys(r3, r1, r4, r0, -24, -28);
+	k -= 50;
+	S1(r3, r1, r4, r0, r2); store_and_load_keys(r2, r4, r0, r3, 22, 18);
+	S2(r2, r4, r0, r3, r1); store_and_load_keys(r1, r4, r2, r3, 18, 14);
+	S3(r1, r4, r2, r3, r0); store_and_load_keys(r3, r0, r4, r1, 14, 10);
+	S4(r3, r0, r4, r1, r2); store_and_load_keys(r0, r4, r1, r2, 10, 6);
+	S5(r0, r4, r1, r2, r3); store_and_load_keys(r3, r0, r4, r2, 6, 2);
+	S6(r3, r0, r4, r2, r1); store_and_load_keys(r4, r1, r0, r2, 2, -2);
+	S7(r4, r1, r0, r2, r3); store_and_load_keys(r3, r0, r2, r4, -2, -6);
+	S0(r3, r0, r2, r4, r1); store_and_load_keys(r2, r0, r4, r3, -6, -10);
+	S1(r2, r0, r4, r3, r1); store_and_load_keys(r1, r4, r3, r2, -10, -14);
+	S2(r1, r4, r3, r2, r0); store_and_load_keys(r0, r4, r1, r2, -14, -18);
+	S3(r0, r4, r1, r2, r3); store_and_load_keys(r2, r3, r4, r0, -18, -22);
+	k -= 50;
+	S4(r2, r3, r4, r0, r1); store_and_load_keys(r3, r4, r0, r1, 28, 24);
+	S5(r3, r4, r0, r1, r2); store_and_load_keys(r2, r3, r4, r1, 24, 20);
+	S6(r2, r3, r4, r1, r0); store_and_load_keys(r4, r0, r3, r1, 20, 16);
+	S7(r4, r0, r3, r1, r2); store_and_load_keys(r2, r3, r1, r4, 16, 12);
+	S0(r2, r3, r1, r4, r0); store_and_load_keys(r1, r3, r4, r2, 12, 8);
+	S1(r1, r3, r4, r2, r0); store_and_load_keys(r0, r4, r2, r1, 8, 4);
+	S2(r0, r4, r2, r1, r3); store_and_load_keys(r3, r4, r0, r1, 4, 0);
+	S3(r3, r4, r0, r1, r2); storekeys(r1, r2, r4, r3, 0);
+}
+
+int __serpent_setkey(struct serpent_ctx *ctx, const u8 *key,
+		     unsigned int keylen)
+{
+	u32 *k = ctx->expkey;
+	u8  *k8 = (u8 *)k;
+	u32 r0, r1, r2, r3, r4;
+	__le32 *lk;
+	int i;
+
+	/* Copy key, add padding */
+
+	for (i = 0; i < keylen; ++i)
+		k8[i] = key[i];
+	if (i < SERPENT_MAX_KEY_SIZE)
+		k8[i++] = 1;
+	while (i < SERPENT_MAX_KEY_SIZE)
+		k8[i++] = 0;
+
+	lk = (__le32 *)k;
+	k[0] = le32_to_cpu(lk[0]);
+	k[1] = le32_to_cpu(lk[1]);
+	k[2] = le32_to_cpu(lk[2]);
+	k[3] = le32_to_cpu(lk[3]);
+	k[4] = le32_to_cpu(lk[4]);
+	k[5] = le32_to_cpu(lk[5]);
+	k[6] = le32_to_cpu(lk[6]);
+	k[7] = le32_to_cpu(lk[7]);
+
+	/* Expand key using polynomial */
+
+	r0 = k[3];
+	r1 = k[4];
+	r2 = k[5];
+	r3 = k[6];
+	r4 = k[7];
+
+	keyiter(k[0], r0, r4, r2, 0, 0);
+	keyiter(k[1], r1, r0, r3, 1, 1);
+	keyiter(k[2], r2, r1, r4, 2, 2);
+	keyiter(k[3], r3, r2, r0, 3, 3);
+	keyiter(k[4], r4, r3, r1, 4, 4);
+	keyiter(k[5], r0, r4, r2, 5, 5);
+	keyiter(k[6], r1, r0, r3, 6, 6);
+	keyiter(k[7], r2, r1, r4, 7, 7);
+
+	keyiter(k[0], r3, r2, r0, 8, 8);
+	keyiter(k[1], r4, r3, r1, 9, 9);
+	keyiter(k[2], r0, r4, r2, 10, 10);
+	keyiter(k[3], r1, r0, r3, 11, 11);
+	keyiter(k[4], r2, r1, r4, 12, 12);
+	keyiter(k[5], r3, r2, r0, 13, 13);
+	keyiter(k[6], r4, r3, r1, 14, 14);
+	keyiter(k[7], r0, r4, r2, 15, 15);
+	keyiter(k[8], r1, r0, r3, 16, 16);
+	keyiter(k[9], r2, r1, r4, 17, 17);
+	keyiter(k[10], r3, r2, r0, 18, 18);
+	keyiter(k[11], r4, r3, r1, 19, 19);
+	keyiter(k[12], r0, r4, r2, 20, 20);
+	keyiter(k[13], r1, r0, r3, 21, 21);
+	keyiter(k[14], r2, r1, r4, 22, 22);
+	keyiter(k[15], r3, r2, r0, 23, 23);
+	keyiter(k[16], r4, r3, r1, 24, 24);
+	keyiter(k[17], r0, r4, r2, 25, 25);
+	keyiter(k[18], r1, r0, r3, 26, 26);
+	keyiter(k[19], r2, r1, r4, 27, 27);
+	keyiter(k[20], r3, r2, r0, 28, 28);
+	keyiter(k[21], r4, r3, r1, 29, 29);
+	keyiter(k[22], r0, r4, r2, 30, 30);
+	keyiter(k[23], r1, r0, r3, 31, 31);
+
+	k += 50;
+
+	keyiter(k[-26], r2, r1, r4, 32, -18);
+	keyiter(k[-25], r3, r2, r0, 33, -17);
+	keyiter(k[-24], r4, r3, r1, 34, -16);
+	keyiter(k[-23], r0, r4, r2, 35, -15);
+	keyiter(k[-22], r1, r0, r3, 36, -14);
+	keyiter(k[-21], r2, r1, r4, 37, -13);
+	keyiter(k[-20], r3, r2, r0, 38, -12);
+	keyiter(k[-19], r4, r3, r1, 39, -11);
+	keyiter(k[-18], r0, r4, r2, 40, -10);
+	keyiter(k[-17], r1, r0, r3, 41, -9);
+	keyiter(k[-16], r2, r1, r4, 42, -8);
+	keyiter(k[-15], r3, r2, r0, 43, -7);
+	keyiter(k[-14], r4, r3, r1, 44, -6);
+	keyiter(k[-13], r0, r4, r2, 45, -5);
+	keyiter(k[-12], r1, r0, r3, 46, -4);
+	keyiter(k[-11], r2, r1, r4, 47, -3);
+	keyiter(k[-10], r3, r2, r0, 48, -2);
+	keyiter(k[-9], r4, r3, r1, 49, -1);
+	keyiter(k[-8], r0, r4, r2, 50, 0);
+	keyiter(k[-7], r1, r0, r3, 51, 1);
+	keyiter(k[-6], r2, r1, r4, 52, 2);
+	keyiter(k[-5], r3, r2, r0, 53, 3);
+	keyiter(k[-4], r4, r3, r1, 54, 4);
+	keyiter(k[-3], r0, r4, r2, 55, 5);
+	keyiter(k[-2], r1, r0, r3, 56, 6);
+	keyiter(k[-1], r2, r1, r4, 57, 7);
+	keyiter(k[0], r3, r2, r0, 58, 8);
+	keyiter(k[1], r4, r3, r1, 59, 9);
+	keyiter(k[2], r0, r4, r2, 60, 10);
+	keyiter(k[3], r1, r0, r3, 61, 11);
+	keyiter(k[4], r2, r1, r4, 62, 12);
+	keyiter(k[5], r3, r2, r0, 63, 13);
+	keyiter(k[6], r4, r3, r1, 64, 14);
+	keyiter(k[7], r0, r4, r2, 65, 15);
+	keyiter(k[8], r1, r0, r3, 66, 16);
+	keyiter(k[9], r2, r1, r4, 67, 17);
+	keyiter(k[10], r3, r2, r0, 68, 18);
+	keyiter(k[11], r4, r3, r1, 69, 19);
+	keyiter(k[12], r0, r4, r2, 70, 20);
+	keyiter(k[13], r1, r0, r3, 71, 21);
+	keyiter(k[14], r2, r1, r4, 72, 22);
+	keyiter(k[15], r3, r2, r0, 73, 23);
+	keyiter(k[16], r4, r3, r1, 74, 24);
+	keyiter(k[17], r0, r4, r2, 75, 25);
+	keyiter(k[18], r1, r0, r3, 76, 26);
+	keyiter(k[19], r2, r1, r4, 77, 27);
+	keyiter(k[20], r3, r2, r0, 78, 28);
+	keyiter(k[21], r4, r3, r1, 79, 29);
+	keyiter(k[22], r0, r4, r2, 80, 30);
+	keyiter(k[23], r1, r0, r3, 81, 31);
+
+	k += 50;
+
+	keyiter(k[-26], r2, r1, r4, 82, -18);
+	keyiter(k[-25], r3, r2, r0, 83, -17);
+	keyiter(k[-24], r4, r3, r1, 84, -16);
+	keyiter(k[-23], r0, r4, r2, 85, -15);
+	keyiter(k[-22], r1, r0, r3, 86, -14);
+	keyiter(k[-21], r2, r1, r4, 87, -13);
+	keyiter(k[-20], r3, r2, r0, 88, -12);
+	keyiter(k[-19], r4, r3, r1, 89, -11);
+	keyiter(k[-18], r0, r4, r2, 90, -10);
+	keyiter(k[-17], r1, r0, r3, 91, -9);
+	keyiter(k[-16], r2, r1, r4, 92, -8);
+	keyiter(k[-15], r3, r2, r0, 93, -7);
+	keyiter(k[-14], r4, r3, r1, 94, -6);
+	keyiter(k[-13], r0, r4, r2, 95, -5);
+	keyiter(k[-12], r1, r0, r3, 96, -4);
+	keyiter(k[-11], r2, r1, r4, 97, -3);
+	keyiter(k[-10], r3, r2, r0, 98, -2);
+	keyiter(k[-9], r4, r3, r1, 99, -1);
+	keyiter(k[-8], r0, r4, r2, 100, 0);
+	keyiter(k[-7], r1, r0, r3, 101, 1);
+	keyiter(k[-6], r2, r1, r4, 102, 2);
+	keyiter(k[-5], r3, r2, r0, 103, 3);
+	keyiter(k[-4], r4, r3, r1, 104, 4);
+	keyiter(k[-3], r0, r4, r2, 105, 5);
+	keyiter(k[-2], r1, r0, r3, 106, 6);
+	keyiter(k[-1], r2, r1, r4, 107, 7);
+	keyiter(k[0], r3, r2, r0, 108, 8);
+	keyiter(k[1], r4, r3, r1, 109, 9);
+	keyiter(k[2], r0, r4, r2, 110, 10);
+	keyiter(k[3], r1, r0, r3, 111, 11);
+	keyiter(k[4], r2, r1, r4, 112, 12);
+	keyiter(k[5], r3, r2, r0, 113, 13);
+	keyiter(k[6], r4, r3, r1, 114, 14);
+	keyiter(k[7], r0, r4, r2, 115, 15);
+	keyiter(k[8], r1, r0, r3, 116, 16);
+	keyiter(k[9], r2, r1, r4, 117, 17);
+	keyiter(k[10], r3, r2, r0, 118, 18);
+	keyiter(k[11], r4, r3, r1, 119, 19);
+	keyiter(k[12], r0, r4, r2, 120, 20);
+	keyiter(k[13], r1, r0, r3, 121, 21);
+	keyiter(k[14], r2, r1, r4, 122, 22);
+	keyiter(k[15], r3, r2, r0, 123, 23);
+	keyiter(k[16], r4, r3, r1, 124, 24);
+	keyiter(k[17], r0, r4, r2, 125, 25);
+	keyiter(k[18], r1, r0, r3, 126, 26);
+	keyiter(k[19], r2, r1, r4, 127, 27);
+	keyiter(k[20], r3, r2, r0, 128, 28);
+	keyiter(k[21], r4, r3, r1, 129, 29);
+	keyiter(k[22], r0, r4, r2, 130, 30);
+	keyiter(k[23], r1, r0, r3, 131, 31);
+
+	/* Apply S-boxes */
+	__serpent_setkey_sbox(r0, r1, r2, r3, r4, ctx->expkey);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__serpent_setkey);
+
+int serpent_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
+{
+	return __serpent_setkey(crypto_tfm_ctx(tfm), key, keylen);
+}
+EXPORT_SYMBOL_GPL(serpent_setkey);
+
+void __serpent_encrypt(const void *c, u8 *dst, const u8 *src)
+{
+	const struct serpent_ctx *ctx = c;
+	const u32 *k = ctx->expkey;
+	u32	r0, r1, r2, r3, r4;
+
+	r0 = get_unaligned_le32(src);
+	r1 = get_unaligned_le32(src + 4);
+	r2 = get_unaligned_le32(src + 8);
+	r3 = get_unaligned_le32(src + 12);
+
+					K(r0, r1, r2, r3, 0);
+	S0(r0, r1, r2, r3, r4);		LK(r2, r1, r3, r0, r4, 1);
+	S1(r2, r1, r3, r0, r4);		LK(r4, r3, r0, r2, r1, 2);
+	S2(r4, r3, r0, r2, r1);		LK(r1, r3, r4, r2, r0, 3);
+	S3(r1, r3, r4, r2, r0);		LK(r2, r0, r3, r1, r4, 4);
+	S4(r2, r0, r3, r1, r4);		LK(r0, r3, r1, r4, r2, 5);
+	S5(r0, r3, r1, r4, r2);		LK(r2, r0, r3, r4, r1, 6);
+	S6(r2, r0, r3, r4, r1);		LK(r3, r1, r0, r4, r2, 7);
+	S7(r3, r1, r0, r4, r2);		LK(r2, r0, r4, r3, r1, 8);
+	S0(r2, r0, r4, r3, r1);		LK(r4, r0, r3, r2, r1, 9);
+	S1(r4, r0, r3, r2, r1);		LK(r1, r3, r2, r4, r0, 10);
+	S2(r1, r3, r2, r4, r0);		LK(r0, r3, r1, r4, r2, 11);
+	S3(r0, r3, r1, r4, r2);		LK(r4, r2, r3, r0, r1, 12);
+	S4(r4, r2, r3, r0, r1);		LK(r2, r3, r0, r1, r4, 13);
+	S5(r2, r3, r0, r1, r4);		LK(r4, r2, r3, r1, r0, 14);
+	S6(r4, r2, r3, r1, r0);		LK(r3, r0, r2, r1, r4, 15);
+	S7(r3, r0, r2, r1, r4);		LK(r4, r2, r1, r3, r0, 16);
+	S0(r4, r2, r1, r3, r0);		LK(r1, r2, r3, r4, r0, 17);
+	S1(r1, r2, r3, r4, r0);		LK(r0, r3, r4, r1, r2, 18);
+	S2(r0, r3, r4, r1, r2);		LK(r2, r3, r0, r1, r4, 19);
+	S3(r2, r3, r0, r1, r4);		LK(r1, r4, r3, r2, r0, 20);
+	S4(r1, r4, r3, r2, r0);		LK(r4, r3, r2, r0, r1, 21);
+	S5(r4, r3, r2, r0, r1);		LK(r1, r4, r3, r0, r2, 22);
+	S6(r1, r4, r3, r0, r2);		LK(r3, r2, r4, r0, r1, 23);
+	S7(r3, r2, r4, r0, r1);		LK(r1, r4, r0, r3, r2, 24);
+	S0(r1, r4, r0, r3, r2);		LK(r0, r4, r3, r1, r2, 25);
+	S1(r0, r4, r3, r1, r2);		LK(r2, r3, r1, r0, r4, 26);
+	S2(r2, r3, r1, r0, r4);		LK(r4, r3, r2, r0, r1, 27);
+	S3(r4, r3, r2, r0, r1);		LK(r0, r1, r3, r4, r2, 28);
+	S4(r0, r1, r3, r4, r2);		LK(r1, r3, r4, r2, r0, 29);
+	S5(r1, r3, r4, r2, r0);		LK(r0, r1, r3, r2, r4, 30);
+	S6(r0, r1, r3, r2, r4);		LK(r3, r4, r1, r2, r0, 31);
+	S7(r3, r4, r1, r2, r0);		K(r0, r1, r2, r3, 32);
+
+	put_unaligned_le32(r0, dst);
+	put_unaligned_le32(r1, dst + 4);
+	put_unaligned_le32(r2, dst + 8);
+	put_unaligned_le32(r3, dst + 12);
+}
+EXPORT_SYMBOL_GPL(__serpent_encrypt);
+
+static void serpent_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
+{
+	struct serpent_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	__serpent_encrypt(ctx, dst, src);
+}
+
+void __serpent_decrypt(const void *c, u8 *dst, const u8 *src)
+{
+	const struct serpent_ctx *ctx = c;
+	const u32 *k = ctx->expkey;
+	u32	r0, r1, r2, r3, r4;
+
+	r0 = get_unaligned_le32(src);
+	r1 = get_unaligned_le32(src + 4);
+	r2 = get_unaligned_le32(src + 8);
+	r3 = get_unaligned_le32(src + 12);
+
+					K(r0, r1, r2, r3, 32);
+	SI7(r0, r1, r2, r3, r4);	KL(r1, r3, r0, r4, r2, 31);
+	SI6(r1, r3, r0, r4, r2);	KL(r0, r2, r4, r1, r3, 30);
+	SI5(r0, r2, r4, r1, r3);	KL(r2, r3, r0, r4, r1, 29);
+	SI4(r2, r3, r0, r4, r1);	KL(r2, r0, r1, r4, r3, 28);
+	SI3(r2, r0, r1, r4, r3);	KL(r1, r2, r3, r4, r0, 27);
+	SI2(r1, r2, r3, r4, r0);	KL(r2, r0, r4, r3, r1, 26);
+	SI1(r2, r0, r4, r3, r1);	KL(r1, r0, r4, r3, r2, 25);
+	SI0(r1, r0, r4, r3, r2);	KL(r4, r2, r0, r1, r3, 24);
+	SI7(r4, r2, r0, r1, r3);	KL(r2, r1, r4, r3, r0, 23);
+	SI6(r2, r1, r4, r3, r0);	KL(r4, r0, r3, r2, r1, 22);
+	SI5(r4, r0, r3, r2, r1);	KL(r0, r1, r4, r3, r2, 21);
+	SI4(r0, r1, r4, r3, r2);	KL(r0, r4, r2, r3, r1, 20);
+	SI3(r0, r4, r2, r3, r1);	KL(r2, r0, r1, r3, r4, 19);
+	SI2(r2, r0, r1, r3, r4);	KL(r0, r4, r3, r1, r2, 18);
+	SI1(r0, r4, r3, r1, r2);	KL(r2, r4, r3, r1, r0, 17);
+	SI0(r2, r4, r3, r1, r0);	KL(r3, r0, r4, r2, r1, 16);
+	SI7(r3, r0, r4, r2, r1);	KL(r0, r2, r3, r1, r4, 15);
+	SI6(r0, r2, r3, r1, r4);	KL(r3, r4, r1, r0, r2, 14);
+	SI5(r3, r4, r1, r0, r2);	KL(r4, r2, r3, r1, r0, 13);
+	SI4(r4, r2, r3, r1, r0);	KL(r4, r3, r0, r1, r2, 12);
+	SI3(r4, r3, r0, r1, r2);	KL(r0, r4, r2, r1, r3, 11);
+	SI2(r0, r4, r2, r1, r3);	KL(r4, r3, r1, r2, r0, 10);
+	SI1(r4, r3, r1, r2, r0);	KL(r0, r3, r1, r2, r4, 9);
+	SI0(r0, r3, r1, r2, r4);	KL(r1, r4, r3, r0, r2, 8);
+	SI7(r1, r4, r3, r0, r2);	KL(r4, r0, r1, r2, r3, 7);
+	SI6(r4, r0, r1, r2, r3);	KL(r1, r3, r2, r4, r0, 6);
+	SI5(r1, r3, r2, r4, r0);	KL(r3, r0, r1, r2, r4, 5);
+	SI4(r3, r0, r1, r2, r4);	KL(r3, r1, r4, r2, r0, 4);
+	SI3(r3, r1, r4, r2, r0);	KL(r4, r3, r0, r2, r1, 3);
+	SI2(r4, r3, r0, r2, r1);	KL(r3, r1, r2, r0, r4, 2);
+	SI1(r3, r1, r2, r0, r4);	KL(r4, r1, r2, r0, r3, 1);
+	SI0(r4, r1, r2, r0, r3);	K(r2, r3, r1, r4, 0);
+
+	put_unaligned_le32(r2, dst);
+	put_unaligned_le32(r3, dst + 4);
+	put_unaligned_le32(r1, dst + 8);
+	put_unaligned_le32(r4, dst + 12);
+}
+EXPORT_SYMBOL_GPL(__serpent_decrypt);
+
+static void serpent_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
+{
+	struct serpent_ctx *ctx = crypto_tfm_ctx(tfm);
+
+	__serpent_decrypt(ctx, dst, src);
+}
+
+static struct crypto_alg srp_alg = {
+	.cra_name		=	"serpent",
+	.cra_driver_name	=	"serpent-generic",
+	.cra_priority		=	100,
+	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
+	.cra_blocksize		=	SERPENT_BLOCK_SIZE,
+	.cra_ctxsize		=	sizeof(struct serpent_ctx),
+	.cra_module		=	THIS_MODULE,
+	.cra_u			=	{ .cipher = {
+	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,
+	.cia_max_keysize	=	SERPENT_MAX_KEY_SIZE,
+	.cia_setkey		=	serpent_setkey,
+	.cia_encrypt		=	serpent_encrypt,
+	.cia_decrypt		=	serpent_decrypt } }
+};
+
+static int __init serpent_mod_init(void)
+{
+	return crypto_register_alg(&srp_alg);
+}
+
+static void __exit serpent_mod_fini(void)
+{
+	crypto_unregister_alg(&srp_alg);
+}
+
+module_init(serpent_mod_init);
+module_exit(serpent_mod_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Serpent Cipher Algorithm");
+MODULE_AUTHOR("Dag Arne Osvik <osvik@ii.uib.no>");
+MODULE_ALIAS_CRYPTO("serpent");
+MODULE_ALIAS_CRYPTO("serpent-generic");