diff --git a/Makefile b/Makefile index a9abbc11f..70d5338eb 100644 --- a/Makefile +++ b/Makefile @@ -1079,6 +1079,7 @@ $(eval $(call assert_booleans,\ ENABLE_MPMM_FCONF \ SIMICS_BUILD \ FEATURE_DETECTION \ + TRNG_SUPPORT \ ))) $(eval $(call assert_numerics,\ diff --git a/changelog.yaml b/changelog.yaml index b1d52212d..cfb2bb5cc 100644 --- a/changelog.yaml +++ b/changelog.yaml @@ -650,6 +650,9 @@ subsections: - title: DRTM scope: drtm + - title: TRNG + scope: trng + - title: Libraries subsections: diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst index 59800506e..68ef4cefd 100644 --- a/docs/getting_started/build-options.rst +++ b/docs/getting_started/build-options.rst @@ -851,6 +851,9 @@ Common build options hardware will limit the effective VL to the maximum physically supported VL. +- ``TRNG_SUPPORT``: Setting this to ``1`` enables support for True + Random Number Generator Interface to BL31 image. This defaults to ``0``. + - ``TRUSTED_BOARD_BOOT``: Boolean flag to include support for the Trusted Board Boot feature. When set to '1', BL1 and BL2 images include support to load and verify the certificates and images in a FIP, and BL1 includes support diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst index 6996c17db..668af5714 100644 --- a/docs/getting_started/porting-guide.rst +++ b/docs/getting_started/porting-guide.rst @@ -2468,7 +2468,7 @@ value: uuid_t plat_trng_uuid [mandatory] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This value must be defined to the UUID of the TRNG backend that is specific to -the hardware after ``plat_trng_setup`` function is called. This value must +the hardware after ``plat_entropy_setup`` function is called. This value must conform to the SMCCC calling convention; The most significant 32 bits of the UUID must not equal ``0xffffffff`` or the signed integer ``-1`` as this value in w0 indicates failure to get a TRNG source. diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h index c90441c67..c7b7908b5 100644 --- a/include/plat/common/platform.h +++ b/include/plat/common/platform.h @@ -16,10 +16,10 @@ #if ENABLE_RME #include #endif +#include #if TRNG_SUPPORT #include "plat_trng.h" -#endif -#include +#endif /* TRNG_SUPPORT */ #if DRTM_SUPPORT #include "plat_drtm.h" #endif /* DRTM_SUPPORT */ diff --git a/include/services/trng_svc.h b/include/services/trng_svc.h index ed4d557ca..92417c22d 100644 --- a/include/services/trng_svc.h +++ b/include/services/trng_svc.h @@ -1,5 +1,5 @@ /* - * Copyright (c) 2021, ARM Limited. All rights reserved. + * Copyright (c) 2021-2022, ARM Limited. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ @@ -17,7 +17,7 @@ #define ARM_TRNG_FEATURES U(0x84000051) #define ARM_TRNG_GET_UUID U(0x84000052) #define ARM_TRNG_RND32 U(0x84000053) -#define ARM_TRNG_RND64 U(0xc4000053) +#define ARM_TRNG_RND64 U(0xC4000053) /* TRNG version numbers */ #define TRNG_VERSION_MAJOR (0x1) @@ -30,19 +30,17 @@ #define TRNG_E_NO_ENTROPY (-3) #define TRNG_E_NOT_IMPLEMENTED (-4) -#if TRNG_SUPPORT -void trng_setup(void); -bool is_trng_fid(uint32_t smc_fid); -#else -static inline void trng_setup(void) -{ -} +/* TRNG Entropy Bit Numbers */ +#define TRNG_RND32_ENTROPY_MAXBITS (96U) +#define TRNG_RND64_ENTROPY_MAXBITS (192U) -static inline bool is_trng_fid(uint32_t smc_fid) -{ - return false; -} -#endif +/* Public API to perform the initial TRNG entropy setup */ +void trng_setup(void); + +/* Public API to verify function id is part of TRNG */ +bool is_trng_fid(uint32_t smc_fid); + +/* Handler to be called to handle TRNG smc calls */ uintptr_t trng_smc_handler( uint32_t smc_fid, u_register_t x1, diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk index 65ceb7f20..772b28de0 100644 --- a/make_helpers/defaults.mk +++ b/make_helpers/defaults.mk @@ -270,7 +270,7 @@ SAVE_KEYS := 0 # Software Delegated Exception support SDEI_SUPPORT := 0 -# True Random Number firmware Interface +# True Random Number firmware Interface support TRNG_SUPPORT := 0 # SMCCC PCI support diff --git a/services/std_svc/std_svc_setup.c b/services/std_svc/std_svc_setup.c index 08d16e21a..2884a3b9e 100644 --- a/services/std_svc/std_svc_setup.c +++ b/services/std_svc/std_svc_setup.c @@ -74,7 +74,10 @@ static int32_t std_svc_setup(void) sdei_init(); #endif +#if TRNG_SUPPORT + /* TRNG initialisation */ trng_setup(); +#endif /* TRNG_SUPPORT */ #if DRTM_SUPPORT if (drtm_setup() != 0) { @@ -172,7 +175,8 @@ static uintptr_t std_svc_smc_handler(uint32_t smc_fid, return trng_smc_handler(smc_fid, x1, x2, x3, x4, cookie, handle, flags); } -#endif +#endif /* TRNG_SUPPORT */ + #if ENABLE_RME if (is_rmmd_el3_fid(smc_fid)) { diff --git a/services/std_svc/trng/trng_entropy_pool.c b/services/std_svc/trng/trng_entropy_pool.c index ac13b1d7a..30105b3a3 100644 --- a/services/std_svc/trng/trng_entropy_pool.c +++ b/services/std_svc/trng/trng_entropy_pool.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2021, ARM Limited. All rights reserved. + * Copyright (c) 2021-2022, ARM Limited. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ @@ -18,7 +18,7 @@ * 192 bits of entropy, we don't have to throw out the leftover 1-63 bits of * entropy. */ -#define WORDS_IN_POOL (4) +#define WORDS_IN_POOL (4) static uint64_t entropy[WORDS_IN_POOL]; /* index in bits of the first bit of usable entropy */ static uint32_t entropy_bit_index; @@ -27,14 +27,14 @@ static uint32_t entropy_bit_size; static spinlock_t trng_pool_lock; -#define BITS_PER_WORD (sizeof(entropy[0]) * 8) -#define BITS_IN_POOL (WORDS_IN_POOL * BITS_PER_WORD) -#define ENTROPY_MIN_WORD (entropy_bit_index / BITS_PER_WORD) -#define ENTROPY_FREE_BIT (entropy_bit_size + entropy_bit_index) -#define _ENTROPY_FREE_WORD (ENTROPY_FREE_BIT / BITS_PER_WORD) -#define ENTROPY_FREE_INDEX (_ENTROPY_FREE_WORD % WORDS_IN_POOL) +#define BITS_PER_WORD (sizeof(entropy[0]) * 8) +#define BITS_IN_POOL (WORDS_IN_POOL * BITS_PER_WORD) +#define ENTROPY_MIN_WORD (entropy_bit_index / BITS_PER_WORD) +#define ENTROPY_FREE_BIT (entropy_bit_size + entropy_bit_index) +#define _ENTROPY_FREE_WORD (ENTROPY_FREE_BIT / BITS_PER_WORD) +#define ENTROPY_FREE_INDEX (_ENTROPY_FREE_WORD % WORDS_IN_POOL) /* ENTROPY_WORD_INDEX(0) includes leftover bits in the lower bits */ -#define ENTROPY_WORD_INDEX(i) ((ENTROPY_MIN_WORD + i) % WORDS_IN_POOL) +#define ENTROPY_WORD_INDEX(i) ((ENTROPY_MIN_WORD + i) % WORDS_IN_POOL) /* * Fill the entropy pool until we have at least as many bits as requested. @@ -65,12 +65,12 @@ static bool trng_fill_entropy(uint32_t nbits) */ bool trng_pack_entropy(uint32_t nbits, uint64_t *out) { - bool success = true; + bool ret = true; spin_lock(&trng_pool_lock); if (!trng_fill_entropy(nbits)) { - success = false; + ret = false; goto out; } @@ -82,9 +82,8 @@ bool trng_pack_entropy(uint32_t nbits, uint64_t *out) for (word_i = 0; word_i < to_fill; word_i++) { /* * Repack the entropy from the pool into the passed in out - * buffer. This takes the lower bits from the valid upper bits - * of word_i and the upper bits from the lower bits of - * (word_i + 1). + * buffer. This takes lesser bits from the valid upper bits + * of word_i and more bits from the lower bits of (word_i + 1). * * I found the following diagram useful. note: `e` represents * valid entropy, ` ` represents invalid bits (not entropy) and @@ -136,7 +135,7 @@ bool trng_pack_entropy(uint32_t nbits, uint64_t *out) out: spin_unlock(&trng_pool_lock); - return success; + return ret; } void trng_entropy_pool_setup(void) diff --git a/services/std_svc/trng/trng_main.c b/services/std_svc/trng/trng_main.c index 38aa64997..90098a8f2 100644 --- a/services/std_svc/trng/trng_main.c +++ b/services/std_svc/trng/trng_main.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2021, ARM Limited and Contributors. All rights reserved. + * Copyright (c) 2021-2022, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ @@ -23,9 +23,9 @@ static const uuid_t uuid_null; static uintptr_t trng_rnd32(uint32_t nbits, void *handle) { uint32_t mask = ~0U; - uint64_t ent[2]; + uint64_t ent[2] = {0}; - if (nbits == 0U || nbits > 96U) { + if (nbits == 0U || nbits > TRNG_RND32_ENTROPY_MAXBITS) { SMC_RET1(handle, TRNG_E_INVALID_PARAMS); } @@ -59,9 +59,9 @@ static uintptr_t trng_rnd32(uint32_t nbits, void *handle) static uintptr_t trng_rnd64(uint32_t nbits, void *handle) { uint64_t mask = ~0ULL; - uint64_t ent[3]; + uint64_t ent[3] = {0}; - if (nbits == 0U || nbits > 192U) { + if (nbits == 0U || nbits > TRNG_RND64_ENTROPY_MAXBITS) { SMC_RET1(handle, TRNG_E_INVALID_PARAMS); } @@ -117,9 +117,9 @@ uintptr_t trng_smc_handler(uint32_t smc_fid, u_register_t x1, u_register_t x2, switch (smc_fid) { case ARM_TRNG_VERSION: SMC_RET1(handle, MAKE_SMCCC_VERSION( - TRNG_VERSION_MAJOR, TRNG_VERSION_MINOR - )); + 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); @@ -127,16 +127,19 @@ uintptr_t trng_smc_handler(uint32_t smc_fid, u_register_t x1, u_register_t x2, 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); + WARN("Unimplemented TRNG Service Call: 0x%x\n", smc_fid); SMC_RET1(handle, TRNG_E_NOT_IMPLEMENTED); break; /* unreachable */ }