Partially Revert "Remove curve448 architecture specific files"

This reverts commit 7e492f3372ed83af074a63d5920f13de7e3455b6.

This brings back the 64-bit reference implementation for curve448.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14784)

3 files changed, 388 insertions, 0 deletions

diff --git a/crypto/ec/curve448/arch_ref64/arch_intrinsics.h b/crypto/ec/curve448/arch_ref64/arch_intrinsics.h
new file mode 100644
index 0000000000..650b63897d
--- /dev/null
+++ b/crypto/ec/curve448/arch_ref64/arch_intrinsics.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2016 Cryptography Research, Inc.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ *
+ * Originally written by Mike Hamburg
+ */
+
+#ifndef __ARCH_REF64_ARCH_INTRINSICS_H__
+# define __ARCH_REF64_ARCH_INTRINSICS_H__
+
+# define ARCH_WORD_BITS 64
+
+static __inline__ __attribute((always_inline, unused))
+uint64_t word_is_zero(uint64_t a)
+{
+    /* let's hope the compiler isn't clever enough to optimize this. */
+    return (((__uint128_t) a) - 1) >> 64;
+}
+
+static __inline__ __attribute((always_inline, unused))
+__uint128_t widemul(uint64_t a, uint64_t b)
+{
+    return ((__uint128_t) a) * b;
+}
+
+#endif                          /* ARCH_REF64_ARCH_INTRINSICS_H__ */
diff --git a/crypto/ec/curve448/arch_ref64/f_impl.c b/crypto/ec/curve448/arch_ref64/f_impl.c
new file mode 100644
index 0000000000..7cb5749cda
--- /dev/null
+++ b/crypto/ec/curve448/arch_ref64/f_impl.c
@@ -0,0 +1,308 @@
+/*
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2014 Cryptography Research, Inc.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ *
+ * Originally written by Mike Hamburg
+ */
+#include "field.h"
+
+void gf_mul(gf_s * __restrict__ cs, const gf as, const gf bs)
+{
+    const uint64_t *a = as->limb, *b = bs->limb;
+    uint64_t *c = cs->limb;
+    __uint128_t accum0 = 0, accum1 = 0, accum2;
+    uint64_t mask = (1ull << 56) - 1;
+    uint64_t aa[4], bb[4], bbb[4];
+    unsigned int i;
+
+    for (i = 0; i < 4; i++) {
+        aa[i] = a[i] + a[i + 4];
+        bb[i] = b[i] + b[i + 4];
+        bbb[i] = bb[i] + b[i + 4];
+    }
+
+    int I_HATE_UNROLLED_LOOPS = 0;
+
+    if (I_HATE_UNROLLED_LOOPS) {
+        /*
+         * The compiler probably won't unroll this, so it's like 80% slower.
+         */
+        for (i = 0; i < 4; i++) {
+            accum2 = 0;
+
+            unsigned int j;
+            for (j = 0; j <= i; j++) {
+                accum2 += widemul(a[j], b[i - j]);
+                accum1 += widemul(aa[j], bb[i - j]);
+                accum0 += widemul(a[j + 4], b[i - j + 4]);
+            }
+            for (; j < 4; j++) {
+                accum2 += widemul(a[j], b[i - j + 8]);
+                accum1 += widemul(aa[j], bbb[i - j + 4]);
+                accum0 += widemul(a[j + 4], bb[i - j + 4]);
+            }
+
+            accum1 -= accum2;
+            accum0 += accum2;
+
+            c[i] = ((uint64_t)(accum0)) & mask;
+            c[i + 4] = ((uint64_t)(accum1)) & mask;
+
+            accum0 >>= 56;
+            accum1 >>= 56;
+        }
+    } else {
+        accum2 = widemul(a[0], b[0]);
+        accum1 += widemul(aa[0], bb[0]);
+        accum0 += widemul(a[4], b[4]);
+
+        accum2 += widemul(a[1], b[7]);
+        accum1 += widemul(aa[1], bbb[3]);
+        accum0 += widemul(a[5], bb[3]);
+
+        accum2 += widemul(a[2], b[6]);
+        accum1 += widemul(aa[2], bbb[2]);
+        accum0 += widemul(a[6], bb[2]);
+
+        accum2 += widemul(a[3], b[5]);
+        accum1 += widemul(aa[3], bbb[1]);
+        accum0 += widemul(a[7], bb[1]);
+
+        accum1 -= accum2;
+        accum0 += accum2;
+
+        c[0] = ((uint64_t)(accum0)) & mask;
+        c[4] = ((uint64_t)(accum1)) & mask;
+
+        accum0 >>= 56;
+        accum1 >>= 56;
+
+        accum2 = widemul(a[0], b[1]);
+        accum1 += widemul(aa[0], bb[1]);
+        accum0 += widemul(a[4], b[5]);
+
+        accum2 += widemul(a[1], b[0]);
+        accum1 += widemul(aa[1], bb[0]);
+        accum0 += widemul(a[5], b[4]);
+
+        accum2 += widemul(a[2], b[7]);
+        accum1 += widemul(aa[2], bbb[3]);
+        accum0 += widemul(a[6], bb[3]);
+
+        accum2 += widemul(a[3], b[6]);
+        accum1 += widemul(aa[3], bbb[2]);
+        accum0 += widemul(a[7], bb[2]);
+
+        accum1 -= accum2;
+        accum0 += accum2;
+
+        c[1] = ((uint64_t)(accum0)) & mask;
+        c[5] = ((uint64_t)(accum1)) & mask;
+
+        accum0 >>= 56;
+        accum1 >>= 56;
+
+        accum2 = widemul(a[0], b[2]);
+        accum1 += widemul(aa[0], bb[2]);
+        accum0 += widemul(a[4], b[6]);
+
+        accum2 += widemul(a[1], b[1]);
+        accum1 += widemul(aa[1], bb[1]);
+        accum0 += widemul(a[5], b[5]);
+
+        accum2 += widemul(a[2], b[0]);
+        accum1 += widemul(aa[2], bb[0]);
+        accum0 += widemul(a[6], b[4]);
+
+        accum2 += widemul(a[3], b[7]);
+        accum1 += widemul(aa[3], bbb[3]);
+        accum0 += widemul(a[7], bb[3]);
+
+        accum1 -= accum2;
+        accum0 += accum2;
+
+        c[2] = ((uint64_t)(accum0)) & mask;
+        c[6] = ((uint64_t)(accum1)) & mask;
+
+        accum0 >>= 56;
+        accum1 >>= 56;
+
+        accum2 = widemul(a[0], b[3]);
+        accum1 += widemul(aa[0], bb[3]);
+        accum0 += widemul(a[4], b[7]);
+
+        accum2 += widemul(a[1], b[2]);
+        accum1 += widemul(aa[1], bb[2]);
+        accum0 += widemul(a[5], b[6]);
+
+        accum2 += widemul(a[2], b[1]);
+        accum1 += widemul(aa[2], bb[1]);
+        accum0 += widemul(a[6], b[5]);
+
+        accum2 += widemul(a[3], b[0]);
+        accum1 += widemul(aa[3], bb[0]);
+        accum0 += widemul(a[7], b[4]);
+
+        accum1 -= accum2;
+        accum0 += accum2;
+
+        c[3] = ((uint64_t)(accum0)) & mask;
+        c[7] = ((uint64_t)(accum1)) & mask;
+
+        accum0 >>= 56;
+        accum1 >>= 56;
+    }                           /* !I_HATE_UNROLLED_LOOPS */
+
+    accum0 += accum1;
+    accum0 += c[4];
+    accum1 += c[0];
+    c[4] = ((uint64_t)(accum0)) & mask;
+    c[0] = ((uint64_t)(accum1)) & mask;
+
+    accum0 >>= 56;
+    accum1 >>= 56;
+
+    c[5] += ((uint64_t)(accum0));
+    c[1] += ((uint64_t)(accum1));
+}
+
+void gf_mulw_unsigned(gf_s * __restrict__ cs, const gf as, uint32_t b)
+{
+    const uint64_t *a = as->limb;
+    uint64_t *c = cs->limb;
+    __uint128_t accum0 = 0, accum4 = 0;
+    uint64_t mask = (1ull << 56) - 1;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        accum0 += widemul(b, a[i]);
+        accum4 += widemul(b, a[i + 4]);
+        c[i] = accum0 & mask;
+        accum0 >>= 56;
+        c[i + 4] = accum4 & mask;
+        accum4 >>= 56;
+    }
+
+    accum0 += accum4 + c[4];
+    c[4] = accum0 & mask;
+    c[5] += accum0 >> 56;
+
+    accum4 += c[0];
+    c[0] = accum4 & mask;
+    c[1] += accum4 >> 56;
+}
+
+void gf_sqr(gf_s * __restrict__ cs, const gf as)
+{
+    const uint64_t *a = as->limb;
+    uint64_t *c = cs->limb;
+    __uint128_t accum0 = 0, accum1 = 0, accum2;
+    uint64_t mask = (1ull << 56) - 1;
+    uint64_t aa[4];
+
+    /* For some reason clang doesn't vectorize this without prompting? */
+    unsigned int i;
+    for (i = 0; i < 4; i++) {
+        aa[i] = a[i] + a[i + 4];
+    }
+
+    accum2 = widemul(a[0], a[3]);
+    accum0 = widemul(aa[0], aa[3]);
+    accum1 = widemul(a[4], a[7]);
+
+    accum2 += widemul(a[1], a[2]);
+    accum0 += widemul(aa[1], aa[2]);
+    accum1 += widemul(a[5], a[6]);
+
+    accum0 -= accum2;
+    accum1 += accum2;
+
+    c[3] = ((uint64_t)(accum1)) << 1 & mask;
+    c[7] = ((uint64_t)(accum0)) << 1 & mask;
+
+    accum0 >>= 55;
+    accum1 >>= 55;
+
+    accum0 += widemul(2 * aa[1], aa[3]);
+    accum1 += widemul(2 * a[5], a[7]);
+    accum0 += widemul(aa[2], aa[2]);
+    accum1 += accum0;
+
+    accum0 -= widemul(2 * a[1], a[3]);
+    accum1 += widemul(a[6], a[6]);
+
+    accum2 = widemul(a[0], a[0]);
+    accum1 -= accum2;
+    accum0 += accum2;
+
+    accum0 -= widemul(a[2], a[2]);
+    accum1 += widemul(aa[0], aa[0]);
+    accum0 += widemul(a[4], a[4]);
+
+    c[0] = ((uint64_t)(accum0)) & mask;
+    c[4] = ((uint64_t)(accum1)) & mask;
+
+    accum0 >>= 56;
+    accum1 >>= 56;
+
+    accum2 = widemul(2 * aa[2], aa[3]);
+    accum0 -= widemul(2 * a[2], a[3]);
+    accum1 += widemul(2 * a[6], a[7]);
+
+    accum1 += accum2;
+    accum0 += accum2;
+
+    accum2 = widemul(2 * a[0], a[1]);
+    accum1 += widemul(2 * aa[0], aa[1]);
+    accum0 += widemul(2 * a[4], a[5]);
+
+    accum1 -= accum2;
+    accum0 += accum2;
+
+    c[1] = ((uint64_t)(accum0)) & mask;
+    c[5] = ((uint64_t)(accum1)) & mask;
+
+    accum0 >>= 56;
+    accum1 >>= 56;
+
+    accum2 = widemul(aa[3], aa[3]);
+    accum0 -= widemul(a[3], a[3]);
+    accum1 += widemul(a[7], a[7]);
+
+    accum1 += accum2;
+    accum0 += accum2;
+
+    accum2 = widemul(2 * a[0], a[2]);
+    accum1 += widemul(2 * aa[0], aa[2]);
+    accum0 += widemul(2 * a[4], a[6]);
+
+    accum2 += widemul(a[1], a[1]);
+    accum1 += widemul(aa[1], aa[1]);
+    accum0 += widemul(a[5], a[5]);
+
+    accum1 -= accum2;
+    accum0 += accum2;
+
+    c[2] = ((uint64_t)(accum0)) & mask;
+    c[6] = ((uint64_t)(accum1)) & mask;
+
+    accum0 >>= 56;
+    accum1 >>= 56;
+
+    accum0 += c[3];
+    accum1 += c[7];
+    c[3] = ((uint64_t)(accum0)) & mask;
+    c[7] = ((uint64_t)(accum1)) & mask;
+
+    /* we could almost stop here, but it wouldn't be stable, so... */
+
+    accum0 >>= 56;
+    accum1 >>= 56;
+    c[4] += ((uint64_t)(accum0)) + ((uint64_t)(accum1));
+    c[0] += ((uint64_t)(accum1));
+}
diff --git a/crypto/ec/curve448/arch_ref64/f_impl.h b/crypto/ec/curve448/arch_ref64/f_impl.h
new file mode 100644
index 0000000000..8751ceecd9
--- /dev/null
+++ b/crypto/ec/curve448/arch_ref64/f_impl.h
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2014-2016 Cryptography Research, Inc.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ *
+ * Originally written by Mike Hamburg
+ */
+
+#define GF_HEADROOM 9999        /* Everything is reduced anyway */
+#define FIELD_LITERAL(a,b,c,d,e,f,g,h) {{a,b,c,d,e,f,g,h}}
+
+#define LIMB_PLACE_VALUE(i) 56
+
+void gf_add_RAW(gf out, const gf a, const gf b)
+{
+    for (unsigned int i = 0; i < 8; i++)
+        out->limb[i] = a->limb[i] + b->limb[i];
+    gf_weak_reduce(out);
+}
+
+void gf_sub_RAW(gf out, const gf a, const gf b)
+{
+    uint64_t co1 = ((1ull << 56) - 1) * 2, co2 = co1 - 2;
+
+    for (unsigned int i = 0; i < 8; i++)
+        out->limb[i] = a->limb[i] - b->limb[i] + ((i == 4) ? co2 : co1);
+    gf_weak_reduce(out);
+}
+
+void gf_bias(gf a, int amt)
+{
+    (void)a;
+    (void)amt;
+}
+
+void gf_weak_reduce(gf a)
+{
+    uint64_t mask = (1ull << 56) - 1;
+    uint64_t tmp = a->limb[7] >> 56;
+
+    a->limb[4] += tmp;
+    for (unsigned int i = 7; i > 0; i--)
+        a->limb[i] = (a->limb[i] & mask) + (a->limb[i - 1] >> 56);
+    a->limb[0] = (a->limb[0] & mask) + tmp;
+}