37 static void subtract_modulus(const struct rsa_public_key *key, uint32_t num[])  in subtract_modulus()  argument
42 	for (i = 0; i < key->len; i++) {  in subtract_modulus()
43 		acc += (uint64_t)num[i] - key->modulus[i];  in subtract_modulus()
56 static int greater_equal_modulus(const struct rsa_public_key *key,  in greater_equal_modulus()  argument
61 	for (i = (int)key->len - 1; i >= 0; i--) {  in greater_equal_modulus()
62 		if (num[i] < key->modulus[i])  in greater_equal_modulus()
64 		if (num[i] > key->modulus[i])  in greater_equal_modulus()
81 static void montgomery_mul_add_step(const struct rsa_public_key *key,  in montgomery_mul_add_step()  argument
89 	d0 = (uint32_t)acc_a * key->n0inv;  in montgomery_mul_add_step()
90 	acc_b = (uint64_t)d0 * key->modulus[0] + (uint32_t)acc_a;  in montgomery_mul_add_step()
91 	for (i = 1; i < key->len; i++) {  in montgomery_mul_add_step()
93 		acc_b = (acc_b >> 32) + (uint64_t)d0 * key->modulus[i] +  in montgomery_mul_add_step()
103 		subtract_modulus(key, result);  in montgomery_mul_add_step()
116 static void montgomery_mul(const struct rsa_public_key *key,  in montgomery_mul()  argument
121 	for (i = 0; i < key->len; ++i)  in montgomery_mul()
123 	for (i = 0; i < key->len; ++i)  in montgomery_mul()
124 		montgomery_mul_add_step(key, result, a[i], b);  in montgomery_mul()
133 static int num_public_exponent_bits(const struct rsa_public_key *key,  in num_public_exponent_bits()  argument
140 	exponent = key->exponent;  in num_public_exponent_bits()
163 static int is_public_exponent_bit_set(const struct rsa_public_key *key,  in is_public_exponent_bit_set()  argument
166 	return key->exponent & (1ULL << pos);  in is_public_exponent_bit_set()
175 static int pow_mod(const struct rsa_public_key *key, uint32_t *inout)  in pow_mod()  argument
182 	if (key->len > RSA_MAX_KEY_BITS / 32) {  in pow_mod()
183 		debug("RSA key words %u exceeds maximum %d\n", key->len,  in pow_mod()
188 	uint32_t val[key->len], acc[key->len], tmp[key->len];  in pow_mod()
189 	uint32_t a_scaled[key->len];  in pow_mod()
193 	for (i = 0, ptr = inout + key->len - 1; i < key->len; i++, ptr--)  in pow_mod()
196 	if (0 != num_public_exponent_bits(key, &k))  in pow_mod()
205 	if (!is_public_exponent_bit_set(key, 0)) {  in pow_mod()
211 	montgomery_mul(key, acc, val, key->rr); /* acc = a * RR / R mod n */  in pow_mod()
213 	memcpy(a_scaled, acc, key->len * sizeof(a_scaled[0]));  in pow_mod()
216 		montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */  in pow_mod()
218 		if (is_public_exponent_bit_set(key, j)) {  in pow_mod()
220 			montgomery_mul(key, acc, tmp, a_scaled);  in pow_mod()
223 			memcpy(acc, tmp, key->len * sizeof(acc[0]));  in pow_mod()
228 	montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod n */  in pow_mod()
229 	montgomery_mul(key, acc, tmp, val); /* acc = tmp * a / R mod M */  in pow_mod()
230 	memcpy(result, acc, key->len * sizeof(result[0]));  in pow_mod()
233 	if (greater_equal_modulus(key, result))  in pow_mod()
234 		subtract_modulus(key, result);  in pow_mod()
237 	for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++)  in pow_mod()
258 	struct rsa_public_key key;  in rsa_mod_exp_sw()  local
265 	key.n0inv = prop->n0inv;  in rsa_mod_exp_sw()
266 	key.len = prop->num_bits;  in rsa_mod_exp_sw()
269 		key.exponent = RSA_DEFAULT_PUBEXP;  in rsa_mod_exp_sw()
279 		key.exponent = fdt64_to_cpu(tmp);  in rsa_mod_exp_sw()
282 	if (!key.len || !prop->modulus || !prop->rr) {  in rsa_mod_exp_sw()
288 	if (key.len > RSA_MAX_KEY_BITS || key.len < RSA_MIN_KEY_BITS) {  in rsa_mod_exp_sw()
290 		      key.len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);  in rsa_mod_exp_sw()
293 	key.len /= sizeof(uint32_t) * 8;  in rsa_mod_exp_sw()
294 	uint32_t key1[key.len], key2[key.len];  in rsa_mod_exp_sw()
296 	key.modulus = key1;  in rsa_mod_exp_sw()
297 	key.rr = key2;  in rsa_mod_exp_sw()
298 	rsa_convert_big_endian(key.modulus, (uint32_t *)prop->modulus, key.len);  in rsa_mod_exp_sw()
299 	rsa_convert_big_endian(key.rr, (uint32_t *)prop->rr, key.len);  in rsa_mod_exp_sw()
300 	if (!key.modulus || !key.rr) {  in rsa_mod_exp_sw()
309 	ret = pow_mod(&key, buf);  in rsa_mod_exp_sw()