esp-idf/components/mbedtls/port/esp32c3/bignum.c
morris 16677b0d3c global: make periph enable/disable APIs private
peripheral enable/disable usually should be managed by driver itself,
so make it as espressif private APIs, not recommended for user to use it
in application code.
However, if user want to re-write the driver or ports to other platform,
this is still possible by including the header in this way:
"esp_private/peripheral_ctrl.h"
2021-11-08 10:37:47 +08:00

231 lines
6.7 KiB
C

/**
* \brief Multi-precision integer library, ESP32 C3 hardware accelerated parts
*
* based on mbedTLS implementation
*
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* Additions Copyright (C) 2016-2020, Espressif Systems (Shanghai) PTE Ltd
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <string.h>
#include <sys/param.h>
#include "soc/hwcrypto_periph.h"
#include "esp_private/periph_ctrl.h"
#include "mbedtls/bignum.h"
#include "bignum_impl.h"
#include "soc/system_reg.h"
#include "soc/periph_defs.h"
#include "esp_crypto_lock.h"
size_t esp_mpi_hardware_words(size_t words)
{
return words;
}
void esp_mpi_enable_hardware_hw_op( void )
{
esp_crypto_mpi_lock_acquire();
/* Enable RSA hardware */
periph_module_enable(PERIPH_RSA_MODULE);
REG_CLR_BIT(SYSTEM_RSA_PD_CTRL_REG, SYSTEM_RSA_MEM_PD);
while (REG_READ(RSA_QUERY_CLEAN_REG) != 1) {
}
// Note: from enabling RSA clock to here takes about 1.3us
}
void esp_mpi_disable_hardware_hw_op( void )
{
REG_SET_BIT(SYSTEM_RSA_PD_CTRL_REG, SYSTEM_RSA_MEM_PD);
/* Disable RSA hardware */
periph_module_disable(PERIPH_RSA_MODULE);
esp_crypto_mpi_lock_release();
}
/* Copy mbedTLS MPI bignum 'mpi' to hardware memory block at 'mem_base'.
If num_words is higher than the number of words in the bignum then
these additional words will be zeroed in the memory buffer.
*/
static inline void mpi_to_mem_block(uint32_t mem_base, const mbedtls_mpi *mpi, size_t num_words)
{
uint32_t *pbase = (uint32_t *)mem_base;
uint32_t copy_words = MIN(num_words, mpi->n);
/* Copy MPI data to memory block registers */
for (int i = 0; i < copy_words; i++) {
pbase[i] = mpi->p[i];
}
/* Zero any remaining memory block data */
for (int i = copy_words; i < num_words; i++) {
pbase[i] = 0;
}
}
/* Read mbedTLS MPI bignum back from hardware memory block.
Reads num_words words from block.
*/
static inline void mem_block_to_mpi(mbedtls_mpi *x, uint32_t mem_base, int num_words)
{
/* Copy data from memory block registers */
const size_t REG_WIDTH = sizeof(uint32_t);
for (size_t i = 0; i < num_words; i++) {
x->p[i] = REG_READ(mem_base + (i * REG_WIDTH));
}
/* Zero any remaining limbs in the bignum, if the buffer is bigger
than num_words */
for (size_t i = num_words; i < x->n; i++) {
x->p[i] = 0;
}
}
/* Begin an RSA operation. op_reg specifies which 'START' register
to write to.
*/
static inline void start_op(uint32_t op_reg)
{
/* Clear interrupt status */
REG_WRITE(RSA_CLEAR_INTERRUPT_REG, 1);
/* Note: above REG_WRITE includes a memw, so we know any writes
to the memory blocks are also complete. */
REG_WRITE(op_reg, 1);
}
/* Wait for an RSA operation to complete.
*/
static inline void wait_op_complete(void)
{
while (REG_READ(RSA_QUERY_INTERRUPT_REG) != 1)
{ }
/* clear the interrupt */
REG_WRITE(RSA_CLEAR_INTERRUPT_REG, 1);
}
/* Read result from last MPI operation */
void esp_mpi_read_result_hw_op(mbedtls_mpi *Z, size_t z_words)
{
wait_op_complete();
mem_block_to_mpi(Z, RSA_MEM_Z_BLOCK_BASE, z_words);
}
/* Z = (X * Y) mod M
Not an mbedTLS function
*/
void esp_mpi_mul_mpi_mod_hw_op(const mbedtls_mpi *X, const mbedtls_mpi *Y, const mbedtls_mpi *M, const mbedtls_mpi *Rinv, mbedtls_mpi_uint Mprime, size_t num_words)
{
REG_WRITE(RSA_LENGTH_REG, (num_words - 1));
/* Load M, X, Rinv, Mprime (Mprime is mod 2^32) */
mpi_to_mem_block(RSA_MEM_X_BLOCK_BASE, X, num_words);
mpi_to_mem_block(RSA_MEM_Y_BLOCK_BASE, Y, num_words);
mpi_to_mem_block(RSA_MEM_M_BLOCK_BASE, M, num_words);
mpi_to_mem_block(RSA_MEM_RB_BLOCK_BASE, Rinv, num_words);
REG_WRITE(RSA_M_DASH_REG, Mprime);
start_op(RSA_MOD_MULT_START_REG);
}
/* Z = (X ^ Y) mod M
*/
void esp_mpi_exp_mpi_mod_hw_op(const mbedtls_mpi *X, const mbedtls_mpi *Y, const mbedtls_mpi *M, const mbedtls_mpi *Rinv, mbedtls_mpi_uint Mprime, size_t num_words)
{
size_t y_bits = mbedtls_mpi_bitlen(Y);
REG_WRITE(RSA_LENGTH_REG, (num_words - 1));
/* Load M, X, Rinv, Mprime (Mprime is mod 2^32) */
mpi_to_mem_block(RSA_MEM_X_BLOCK_BASE, X, num_words);
mpi_to_mem_block(RSA_MEM_Y_BLOCK_BASE, Y, num_words);
mpi_to_mem_block(RSA_MEM_M_BLOCK_BASE, M, num_words);
mpi_to_mem_block(RSA_MEM_RB_BLOCK_BASE, Rinv, num_words);
REG_WRITE(RSA_M_DASH_REG, Mprime);
/* Enable acceleration options */
REG_WRITE(RSA_CONSTANT_TIME_REG, 0);
REG_WRITE(RSA_SEARCH_ENABLE_REG, 1);
REG_WRITE(RSA_SEARCH_POS_REG, y_bits - 1);
/* Execute first stage montgomery multiplication */
start_op(RSA_MODEXP_START_REG);
REG_WRITE(RSA_SEARCH_ENABLE_REG, 0);
}
/* Z = X * Y */
void esp_mpi_mul_mpi_hw_op(const mbedtls_mpi *X, const mbedtls_mpi *Y, size_t num_words)
{
/* Copy X (right-extended) & Y (left-extended) to memory block */
mpi_to_mem_block(RSA_MEM_X_BLOCK_BASE, X, num_words);
mpi_to_mem_block(RSA_MEM_Z_BLOCK_BASE + num_words * 4, Y, num_words);
/* NB: as Y is left-extended, we don't zero the bottom words_mult words of Y block.
This is OK for now because zeroing is done by hardware when we do esp_mpi_acquire_hardware().
*/
REG_WRITE(RSA_LENGTH_REG, (num_words * 2 - 1));
start_op(RSA_MULT_START_REG);
}
/**
* @brief Special-case of (X * Y), where we use hardware montgomery mod
multiplication to calculate result where either A or B are >2048 bits so
can't use the standard multiplication method.
*
*/
void esp_mpi_mult_mpi_failover_mod_mult_hw_op(const mbedtls_mpi *X, const mbedtls_mpi *Y, size_t num_words)
{
/* M = 2^num_words - 1, so block is entirely FF */
for (int i = 0; i < num_words; i++) {
REG_WRITE(RSA_MEM_M_BLOCK_BASE + i * 4, UINT32_MAX);
}
/* Mprime = 1 */
REG_WRITE(RSA_M_DASH_REG, 1);
REG_WRITE(RSA_LENGTH_REG, num_words - 1);
/* Load X & Y */
mpi_to_mem_block(RSA_MEM_X_BLOCK_BASE, X, num_words);
mpi_to_mem_block(RSA_MEM_Y_BLOCK_BASE, Y, num_words);
/* Rinv = 1, write first word */
REG_WRITE(RSA_MEM_RB_BLOCK_BASE, 1);
/* Zero out rest of the Rinv words */
for (int i = 1; i < num_words; i++) {
REG_WRITE(RSA_MEM_RB_BLOCK_BASE + i * 4, 0);
}
start_op(RSA_MOD_MULT_START_REG);
}