From 4696f0ab5c436ed53567ce6baec67c921d9b70ae Mon Sep 17 00:00:00 2001 From: Dao Lu Date: Sun, 24 Jul 2022 20:47:28 -0700 Subject: [PATCH] target/riscv: Add Zihintpause support Added support for RISC-V PAUSE instruction from Zihintpause extension, enabled by default. Tested-by: Heiko Stuebner Reviewed-by: Alistair Francis Signed-off-by: Dao Lu Message-Id: <20220725034728.2620750-2-daolu@rivosinc.com> Signed-off-by: Alistair Francis --- target/riscv/cpu.c | 2 ++ target/riscv/cpu.h | 1 + target/riscv/insn32.decode | 7 ++++++- target/riscv/insn_trans/trans_rvi.c.inc | 16 ++++++++++++++++ 4 files changed, 25 insertions(+), 1 deletion(-) diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c index 966e5f2dd7..d4635c7df4 100644 --- a/target/riscv/cpu.c +++ b/target/riscv/cpu.c @@ -73,6 +73,7 @@ static const struct isa_ext_data isa_edata_arr[] = { ISA_EXT_DATA_ENTRY(v, false, PRIV_VERSION_1_12_0, ext_v), ISA_EXT_DATA_ENTRY(zicsr, true, PRIV_VERSION_1_10_0, ext_icsr), ISA_EXT_DATA_ENTRY(zifencei, true, PRIV_VERSION_1_10_0, ext_ifencei), + ISA_EXT_DATA_ENTRY(zihintpause, true, PRIV_VERSION_1_10_0, ext_zihintpause), ISA_EXT_DATA_ENTRY(zfh, true, PRIV_VERSION_1_12_0, ext_zfh), ISA_EXT_DATA_ENTRY(zfhmin, true, PRIV_VERSION_1_12_0, ext_zfhmin), ISA_EXT_DATA_ENTRY(zfinx, true, PRIV_VERSION_1_12_0, ext_zfinx), @@ -987,6 +988,7 @@ static Property riscv_cpu_extensions[] = { DEFINE_PROP_UINT8("pmu-num", RISCVCPU, cfg.pmu_num, 16), DEFINE_PROP_BOOL("Zifencei", RISCVCPU, cfg.ext_ifencei, true), DEFINE_PROP_BOOL("Zicsr", RISCVCPU, cfg.ext_icsr, true), + DEFINE_PROP_BOOL("Zihintpause", RISCVCPU, cfg.ext_zihintpause, true), DEFINE_PROP_BOOL("Zfh", RISCVCPU, cfg.ext_zfh, false), DEFINE_PROP_BOOL("Zfhmin", RISCVCPU, cfg.ext_zfhmin, false), DEFINE_PROP_BOOL("Zve32f", RISCVCPU, cfg.ext_zve32f, false), diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 561d7fa92c..4be4b82a83 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -426,6 +426,7 @@ struct RISCVCPUConfig { bool ext_zkt; bool ext_ifencei; bool ext_icsr; + bool ext_zihintpause; bool ext_svinval; bool ext_svnapot; bool ext_svpbmt; diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode index 4033565393..595fdcdad8 100644 --- a/target/riscv/insn32.decode +++ b/target/riscv/insn32.decode @@ -149,7 +149,12 @@ srl 0000000 ..... ..... 101 ..... 0110011 @r sra 0100000 ..... ..... 101 ..... 0110011 @r or 0000000 ..... ..... 110 ..... 0110011 @r and 0000000 ..... ..... 111 ..... 0110011 @r -fence ---- pred:4 succ:4 ----- 000 ----- 0001111 + +{ + pause 0000 0001 0000 00000 000 00000 0001111 + fence ---- pred:4 succ:4 ----- 000 ----- 0001111 +} + fence_i ---- ---- ---- ----- 001 ----- 0001111 csrrw ............ ..... 001 ..... 1110011 @csr csrrs ............ ..... 010 ..... 1110011 @csr diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc index ca8e3d1ea1..c49dbec0eb 100644 --- a/target/riscv/insn_trans/trans_rvi.c.inc +++ b/target/riscv/insn_trans/trans_rvi.c.inc @@ -792,6 +792,22 @@ static bool trans_srad(DisasContext *ctx, arg_srad *a) return gen_shift(ctx, a, EXT_SIGN, tcg_gen_sar_tl, NULL); } +static bool trans_pause(DisasContext *ctx, arg_pause *a) +{ + if (!ctx->cfg_ptr->ext_zihintpause) { + return false; + } + + /* + * PAUSE is a no-op in QEMU, + * end the TB and return to main loop + */ + gen_set_pc_imm(ctx, ctx->pc_succ_insn); + tcg_gen_exit_tb(NULL, 0); + ctx->base.is_jmp = DISAS_NORETURN; + + return true; +} static bool trans_fence(DisasContext *ctx, arg_fence *a) {