diff options
Diffstat (limited to 'crypto/bn/bn_exp.c')
-rw-r--r-- | crypto/bn/bn_exp.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/crypto/bn/bn_exp.c b/crypto/bn/bn_exp.c index 1254415a43..4f6445434b 100644 --- a/crypto/bn/bn_exp.c +++ b/crypto/bn/bn_exp.c @@ -1390,3 +1390,85 @@ int BN_mod_exp_simple(BIGNUM *r, const BIGNUM *a, const BIGNUM *p, bn_check_top(r); return ret; } + +/* + * This is a variant of modular exponentiation optimization that does + * parallel 2-primes exponentiation using 256-bit (AVX512VL) AVX512_IFMA ISA + * in 52-bit binary redundant representation. + * If such instructions are not available, or input data size is not supported, + * it falls back to two BN_mod_exp_mont_consttime() calls. + */ +int BN_mod_exp_mont_consttime_x2(BIGNUM *rr1, const BIGNUM *a1, const BIGNUM *p1, + const BIGNUM *m1, BN_MONT_CTX *in_mont1, + BIGNUM *rr2, const BIGNUM *a2, const BIGNUM *p2, + const BIGNUM *m2, BN_MONT_CTX *in_mont2, + BN_CTX *ctx) +{ + int ret = 0; + +#ifdef RSAZ_ENABLED + BN_MONT_CTX *mont1 = NULL; + BN_MONT_CTX *mont2 = NULL; + + if (rsaz_avx512ifma_eligible() && + ((a1->top == 16) && (p1->top == 16) && (BN_num_bits(m1) == 1024) && + (a2->top == 16) && (p2->top == 16) && (BN_num_bits(m2) == 1024))) { + + if (bn_wexpand(rr1, 16) == NULL) + goto err; + if (bn_wexpand(rr2, 16) == NULL) + goto err; + + /* Ensure that montgomery contexts are initialized */ + if (in_mont1 != NULL) { + mont1 = in_mont1; + } else { + if ((mont1 = BN_MONT_CTX_new()) == NULL) + goto err; + if (!BN_MONT_CTX_set(mont1, m1, ctx)) + goto err; + } + if (in_mont2 != NULL) { + mont2 = in_mont2; + } else { + if ((mont2 = BN_MONT_CTX_new()) == NULL) + goto err; + if (!BN_MONT_CTX_set(mont2, m2, ctx)) + goto err; + } + + ret = RSAZ_mod_exp_avx512_x2(rr1->d, a1->d, p1->d, m1->d, mont1->RR.d, + mont1->n0[0], + rr2->d, a2->d, p2->d, m2->d, mont2->RR.d, + mont2->n0[0], + 1024 /* factor bit size */); + + rr1->top = 16; + rr1->neg = 0; + bn_correct_top(rr1); + bn_check_top(rr1); + + rr2->top = 16; + rr2->neg = 0; + bn_correct_top(rr2); + bn_check_top(rr2); + + goto err; + } +#endif + + /* rr1 = a1^p1 mod m1 */ + ret = BN_mod_exp_mont_consttime(rr1, a1, p1, m1, ctx, in_mont1); + /* rr2 = a2^p2 mod m2 */ + ret &= BN_mod_exp_mont_consttime(rr2, a2, p2, m2, ctx, in_mont2); + +#ifdef RSAZ_ENABLED +err: + if (in_mont2 == NULL) + BN_MONT_CTX_free(mont2); + if (in_mont1 == NULL) + BN_MONT_CTX_free(mont1); +#endif + + return ret; +} |