diff options
| -rw-r--r-- | riscv/encoding.h | 12 | ||||
| -rw-r--r-- | riscv/entropy_source.h | 57 | ||||
| -rw-r--r-- | riscv/processor.cc | 25 |
3 files changed, 27 insertions, 67 deletions
diff --git a/riscv/encoding.h b/riscv/encoding.h index fa30993..2c331a6 100644 --- a/riscv/encoding.h +++ b/riscv/encoding.h @@ -1035,10 +1035,6 @@ #define MASK_FCVT_H_L 0xfff0007f #define MATCH_FCVT_H_LU 0xd4300053 #define MASK_FCVT_H_LU 0xfff0007f -#define MATCH_POLLENTROPY 0xf1500073 -#define MASK_POLLENTROPY 0xfffff07f -#define MATCH_GETNOISE 0x7a900073 -#define MASK_GETNOISE 0xfffff07f #define MATCH_SM4ED 0x30000033 #define MASK_SM4ED 0x3e00707f #define MATCH_SM4KS 0x34000033 @@ -3013,8 +3009,7 @@ #define CSR_MARCHID 0xf12 #define CSR_MIMPID 0xf13 #define CSR_MHARTID 0xf14 -#define CSR_MENTROPY 0xf15 -#define CSR_MNOISE 0x7a9 +#define CSR_SENTROPY 0x546 #define CSR_HTIMEDELTAH 0x615 #define CSR_CYCLEH 0xc80 #define CSR_TIMEH 0xc81 @@ -3477,8 +3472,6 @@ DECLARE_INSN(fcvt_l_h, MATCH_FCVT_L_H, MASK_FCVT_L_H) DECLARE_INSN(fcvt_lu_h, MATCH_FCVT_LU_H, MASK_FCVT_LU_H) DECLARE_INSN(fcvt_h_l, MATCH_FCVT_H_L, MASK_FCVT_H_L) DECLARE_INSN(fcvt_h_lu, MATCH_FCVT_H_LU, MASK_FCVT_H_LU) -DECLARE_INSN(pollentropy, MATCH_POLLENTROPY, MASK_POLLENTROPY) -DECLARE_INSN(getnoise, MATCH_GETNOISE, MASK_GETNOISE) DECLARE_INSN(sm4ed, MATCH_SM4ED, MASK_SM4ED) DECLARE_INSN(sm4ks, MATCH_SM4KS, MASK_SM4KS) DECLARE_INSN(sm3p0, MATCH_SM3P0, MASK_SM3P0) @@ -4573,8 +4566,7 @@ DECLARE_CSR(mvendorid, CSR_MVENDORID) DECLARE_CSR(marchid, CSR_MARCHID) DECLARE_CSR(mimpid, CSR_MIMPID) DECLARE_CSR(mhartid, CSR_MHARTID) -DECLARE_CSR(mentropy, CSR_MENTROPY) -DECLARE_CSR(mnoise, CSR_MNOISE) +DECLARE_CSR(sentropy, CSR_SENTROPY) DECLARE_CSR(htimedeltah, CSR_HTIMEDELTAH) DECLARE_CSR(cycleh, CSR_CYCLEH) DECLARE_CSR(timeh, CSR_TIMEH) diff --git a/riscv/entropy_source.h b/riscv/entropy_source.h index 7b4635f..8ae3ddd 100644 --- a/riscv/entropy_source.h +++ b/riscv/entropy_source.h @@ -11,10 +11,10 @@ class entropy_source { public: - // Valid return codes for OPST bits [31:30] when reading mentropy. + // Valid return codes for OPST bits [31:30] when reading sentropy. static const uint32_t OPST_BIST = 0x0 << 30; - static const uint32_t OPST_ES16 = 0x1 << 30; - static const uint32_t OPST_WAIT = 0x2 << 30; + static const uint32_t OPST_WAIT = 0x1 << 30; + static const uint32_t OPST_ES16 = 0x2 << 30; static const uint32_t OPST_DEAD = 0x3 << 30; // @@ -27,27 +27,28 @@ public: } // - // mentropy register + // sentropy register // ------------------------------------------------------------ - void set_mentropy(reg_t val) { - // Always ignore writes to mentropy. - // This CSR *must never* accept write values, it is strictly read only. + void set_sentropy(reg_t val) { + // Always ignore writes to sentropy. + // This CSR is strictly read only. It occupies a RW CSR address + // to handle the side-effect of the changing seed value on a read. } // - // The format of mentropy is described in Table 3 / Section 4.1 of + // The format of sentropy is described in Section 4.1 of // the scalar cryptography specification. - reg_t get_mentropy() { + reg_t get_sentropy() { uint32_t result = 0; - // Currently, always return ES16 (i.e. good randomness) unless in - // noise capture mode. In the future, we can more realistically model - // things like WAIT states, BIST warm up and maybe scriptable entry - // into the DEAD state, but until then, this is the bare minimum. - uint32_t return_status = noise_capture_mode ? OPST_BIST : OPST_ES16; + // Currently, always return ES16 (i.e. good randomness) In the future, we + // can more realistically model things like WAIT states, BIST warm up and + // maybe scriptable entry into the DEAD state, but until then, this is + // the bare minimum. + uint32_t return_status = OPST_ES16; if(return_status == OPST_ES16) { @@ -83,37 +84,9 @@ public: } // - // mnoise register - // ------------------------------------------------------------ - - - void set_mnoise(reg_t val) { - // Almost all of the behaviour for mnoise is vendor specific, - // except for bit 31. - int new_noisemode = (val >> 31) & 0x1; - noise_capture_mode = new_noisemode == 1; - } - - - reg_t get_mnoise() { - reg_t to_return = 0; - - if(this -> noise_capture_mode) { - // Set bit 31 indicating we are in noise capture mode. - to_return |= 0x1 << 31; - } - - return to_return; - } - - // // Utility / support variables and functions. // ------------------------------------------------------------ - // The ES is in noise capture mode? - // If so, then get_mentropy must always return OPST_BIST. - bool noise_capture_mode = false; - // The file to read entropy from. std::string randomness_source = "/dev/urandom"; diff --git a/riscv/processor.cc b/riscv/processor.cc index 655dd18..309f4da 100644 --- a/riscv/processor.cc +++ b/riscv/processor.cc @@ -905,11 +905,8 @@ void processor_t::set_csr(int which, reg_t val) switch (which) { - case CSR_MENTROPY: - es.set_mentropy(val); - break; - case CSR_MNOISE: - es.set_mnoise(val); + case CSR_SENTROPY: + es.set_sentropy(val); break; case CSR_FFLAGS: dirty_fp_state; @@ -1396,8 +1393,7 @@ void processor_t::set_csr(int which, reg_t val) case CSR_DPC: case CSR_DSCRATCH0: case CSR_DSCRATCH1: - case CSR_MENTROPY: - case CSR_MNOISE: + case CSR_SENTROPY: LOG_CSR(which); break; } @@ -1462,14 +1458,13 @@ reg_t processor_t::get_csr(int which, insn_t insn, bool write, bool peek) switch (which) { - case CSR_MENTROPY: - if(!supports_extension('K')) - break; - ret(es.get_mentropy()); - case CSR_MNOISE: - if(!supports_extension('K')) - break; - ret(es.get_mnoise()); + case CSR_SENTROPY: + if (!supports_extension('K')) + break; + /* Read-only access disallowed due to wipe-on-read side effect */ + if (!write) + break; + ret(es.get_sentropy()); case CSR_FFLAGS: require_fp; if (!supports_extension('F')) |