blob: 38aa6499733ad054d16d116b5dd453a54af37a68 [file] [log] [blame]
/*
* Copyright (c) 2021, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <arch_features.h>
#include <lib/smccc.h>
#include <services/trng_svc.h>
#include <smccc_helpers.h>
#include <plat/common/plat_trng.h>
#include "trng_entropy_pool.h"
static const uuid_t uuid_null;
/* handle the RND call in SMC 32 bit mode */
static uintptr_t trng_rnd32(uint32_t nbits, void *handle)
{
uint32_t mask = ~0U;
uint64_t ent[2];
if (nbits == 0U || nbits > 96U) {
SMC_RET1(handle, TRNG_E_INVALID_PARAMS);
}
if (!trng_pack_entropy(nbits, &ent[0])) {
SMC_RET1(handle, TRNG_E_NO_ENTROPY);
}
if ((nbits % 32U) != 0U) {
mask >>= 32U - (nbits % 32U);
}
switch ((nbits - 1U) / 32U) {
case 0:
SMC_RET4(handle, TRNG_E_SUCCESS, 0, 0, ent[0] & mask);
break; /* unreachable */
case 1:
SMC_RET4(handle, TRNG_E_SUCCESS, 0, (ent[0] >> 32) & mask,
ent[0] & 0xFFFFFFFF);
break; /* unreachable */
case 2:
SMC_RET4(handle, TRNG_E_SUCCESS, ent[1] & mask,
(ent[0] >> 32) & 0xFFFFFFFF, ent[0] & 0xFFFFFFFF);
break; /* unreachable */
default:
SMC_RET1(handle, TRNG_E_INVALID_PARAMS);
break; /* unreachable */
}
}
/* handle the RND call in SMC 64 bit mode */
static uintptr_t trng_rnd64(uint32_t nbits, void *handle)
{
uint64_t mask = ~0ULL;
uint64_t ent[3];
if (nbits == 0U || nbits > 192U) {
SMC_RET1(handle, TRNG_E_INVALID_PARAMS);
}
if (!trng_pack_entropy(nbits, &ent[0])) {
SMC_RET1(handle, TRNG_E_NO_ENTROPY);
}
/* Mask off higher bits if only part of register requested */
if ((nbits % 64U) != 0U) {
mask >>= 64U - (nbits % 64U);
}
switch ((nbits - 1U) / 64U) {
case 0:
SMC_RET4(handle, TRNG_E_SUCCESS, 0, 0, ent[0] & mask);
break; /* unreachable */
case 1:
SMC_RET4(handle, TRNG_E_SUCCESS, 0, ent[1] & mask, ent[0]);
break; /* unreachable */
case 2:
SMC_RET4(handle, TRNG_E_SUCCESS, ent[2] & mask, ent[1], ent[0]);
break; /* unreachable */
default:
SMC_RET1(handle, TRNG_E_INVALID_PARAMS);
break; /* unreachable */
}
}
void trng_setup(void)
{
trng_entropy_pool_setup();
plat_entropy_setup();
}
/* Predicate indicating that a function id is part of TRNG */
bool is_trng_fid(uint32_t smc_fid)
{
return ((smc_fid == ARM_TRNG_VERSION) ||
(smc_fid == ARM_TRNG_FEATURES) ||
(smc_fid == ARM_TRNG_GET_UUID) ||
(smc_fid == ARM_TRNG_RND32) ||
(smc_fid == ARM_TRNG_RND64));
}
uintptr_t trng_smc_handler(uint32_t smc_fid, u_register_t x1, u_register_t x2,
u_register_t x3, u_register_t x4, void *cookie,
void *handle, u_register_t flags)
{
if (!memcmp(&plat_trng_uuid, &uuid_null, sizeof(uuid_t))) {
SMC_RET1(handle, TRNG_E_NOT_IMPLEMENTED);
}
switch (smc_fid) {
case ARM_TRNG_VERSION:
SMC_RET1(handle, MAKE_SMCCC_VERSION(
TRNG_VERSION_MAJOR, TRNG_VERSION_MINOR
));
break; /* unreachable */
case ARM_TRNG_FEATURES:
if (is_trng_fid((uint32_t)x1)) {
SMC_RET1(handle, TRNG_E_SUCCESS);
} else {
SMC_RET1(handle, TRNG_E_NOT_SUPPORTED);
}
break; /* unreachable */
case ARM_TRNG_GET_UUID:
SMC_UUID_RET(handle, plat_trng_uuid);
break; /* unreachable */
case ARM_TRNG_RND32:
return trng_rnd32((uint32_t)x1, handle);
case ARM_TRNG_RND64:
return trng_rnd64((uint32_t)x1, handle);
default:
WARN("Unimplemented TRNG Service Call: 0x%x\n",
smc_fid);
SMC_RET1(handle, TRNG_E_NOT_IMPLEMENTED);
break; /* unreachable */
}
}