From 9e69e760fdc34a9d13a8c434d6a9fada835a05ad Mon Sep 17 00:00:00 2001 From: Rajnesh Kanwal Date: Wed, 5 Feb 2025 11:18:49 +0000 Subject: [PATCH] target/riscv: Add CTR sctrclr instruction. CTR extension adds a new instruction sctrclr to quickly clear the recorded entries buffer. Signed-off-by: Rajnesh Kanwal Acked-by: Alistair Francis Message-ID: <20250205-b4-ctr_upstream_v6-v6-5-439d8e06c8ef@rivosinc.com> Signed-off-by: Alistair Francis --- target/riscv/cpu.h | 1 + target/riscv/cpu_helper.c | 7 +++++ target/riscv/helper.h | 1 + target/riscv/insn32.decode | 1 + .../riscv/insn_trans/trans_privileged.c.inc | 11 +++++++ target/riscv/op_helper.c | 29 +++++++++++++++++++ 6 files changed, 50 insertions(+) diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 9e92144b61..616c3bdc1c 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -619,6 +619,7 @@ void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv, bool virt_en); void riscv_ctr_add_entry(CPURISCVState *env, target_long src, target_long dst, enum CTRType type, target_ulong prev_priv, bool prev_virt); +void riscv_ctr_clear(CPURISCVState *env); void riscv_translate_init(void); void riscv_translate_code(CPUState *cs, TranslationBlock *tb, diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index 7dbdb34b17..356e84b9a2 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -887,6 +887,13 @@ static void riscv_ctr_freeze(CPURISCVState *env, uint64_t freeze_mask, } } +void riscv_ctr_clear(CPURISCVState *env) +{ + memset(env->ctr_src, 0x0, sizeof(env->ctr_src)); + memset(env->ctr_dst, 0x0, sizeof(env->ctr_dst)); + memset(env->ctr_data, 0x0, sizeof(env->ctr_data)); +} + static uint64_t riscv_ctr_priv_to_mask(target_ulong priv, bool virt) { switch (priv) { diff --git a/target/riscv/helper.h b/target/riscv/helper.h index 163121ade5..85d73e492d 100644 --- a/target/riscv/helper.h +++ b/target/riscv/helper.h @@ -132,6 +132,7 @@ DEF_HELPER_6(csrrw_i128, tl, env, int, tl, tl, tl, tl) DEF_HELPER_1(sret, tl, env) DEF_HELPER_1(mret, tl, env) DEF_HELPER_1(mnret, tl, env) +DEF_HELPER_1(ctr_clear, void, env) DEF_HELPER_1(wfi, void, env) DEF_HELPER_1(wrs_nto, void, env) DEF_HELPER_1(tlb_flush, void, env) diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode index a98dab0205..6d1a13c826 100644 --- a/target/riscv/insn32.decode +++ b/target/riscv/insn32.decode @@ -114,6 +114,7 @@ # *** Privileged Instructions *** ecall 000000000000 00000 000 00000 1110011 ebreak 000000000001 00000 000 00000 1110011 +sctrclr 000100000100 00000 000 00000 1110011 uret 0000000 00010 00000 000 00000 1110011 sret 0001000 00010 00000 000 00000 1110011 mret 0011000 00010 00000 000 00000 1110011 diff --git a/target/riscv/insn_trans/trans_privileged.c.inc b/target/riscv/insn_trans/trans_privileged.c.inc index ca52405d7d..8a62b4cfcd 100644 --- a/target/riscv/insn_trans/trans_privileged.c.inc +++ b/target/riscv/insn_trans/trans_privileged.c.inc @@ -75,6 +75,17 @@ static bool trans_ebreak(DisasContext *ctx, arg_ebreak *a) return true; } +static bool trans_sctrclr(DisasContext *ctx, arg_sctrclr *a) +{ +#ifndef CONFIG_USER_ONLY + if (ctx->cfg_ptr->ext_smctr || ctx->cfg_ptr->ext_ssctr) { + gen_helper_ctr_clear(tcg_env); + return true; + } +#endif + return false; +} + static bool trans_uret(DisasContext *ctx, arg_uret *a) { return false; diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c index 5a99c47b12..f156bfab12 100644 --- a/target/riscv/op_helper.c +++ b/target/riscv/op_helper.c @@ -485,6 +485,35 @@ void helper_ctr_add_entry(CPURISCVState *env, target_ulong src, env->priv, env->virt_enabled); } +void helper_ctr_clear(CPURISCVState *env) +{ + /* + * It's safe to call smstateen_acc_ok() for umode access regardless of the + * state of bit 54 (CTR bit in case of m/hstateen) of sstateen. If the bit + * is zero, smstateen_acc_ok() will return the correct exception code and + * if it's one, smstateen_acc_ok() will return RISCV_EXCP_NONE. In that + * scenario the U-mode check below will handle that case. + */ + RISCVException ret = smstateen_acc_ok(env, 0, SMSTATEEN0_CTR); + if (ret != RISCV_EXCP_NONE) { + riscv_raise_exception(env, ret, GETPC()); + } + + if (env->priv == PRV_U) { + /* + * One corner case is when sctrclr is executed from VU-mode and + * mstateen.CTR = 0, in which case we are supposed to raise + * RISCV_EXCP_ILLEGAL_INST. This case is already handled in + * smstateen_acc_ok(). + */ + uint32_t excep = env->virt_enabled ? RISCV_EXCP_VIRT_INSTRUCTION_FAULT : + RISCV_EXCP_ILLEGAL_INST; + riscv_raise_exception(env, excep, GETPC()); + } + + riscv_ctr_clear(env); +} + void helper_wfi(CPURISCVState *env) { CPUState *cs = env_cpu(env); -- 2.30.2