diff options
Diffstat (limited to 'services/std_svc/trng/trng_main.c')
| -rw-r--r-- | services/std_svc/trng/trng_main.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/services/std_svc/trng/trng_main.c b/services/std_svc/trng/trng_main.c new file mode 100644 index 0000000..90098a8 --- /dev/null +++ b/services/std_svc/trng/trng_main.c @@ -0,0 +1,146 @@ +/* + * Copyright (c) 2021-2022, 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] = {0}; + + if (nbits == 0U || nbits > TRNG_RND32_ENTROPY_MAXBITS) { + 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] = {0}; + + if (nbits == 0U || nbits > TRNG_RND64_ENTROPY_MAXBITS) { + 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 */ + } +} |