From a9814e3e08d2aacbd9018c36c77c2fb652537848 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 4 Jun 2022 23:10:04 +0000 Subject: [PATCH] target/riscv: Minimize the calls to decode_save_opc The set of instructions that require decode_save_opc for unwinding is really fairly small -- only insns that can raise ILLEGAL_INSN at runtime. This includes CSR, anything that uses a *new* fp rounding mode, and many privileged insns. Since unwind info is stored as the difference from the previous insn, storing a 0 for most insns minimizes the size of the unwind info. Booting a debian kernel image to the missing rootfs panic yields - gen code size 22226819/1026886656 + gen code size 21601907/1026886656 on 41k TranslationBlocks, a savings of 610kB or a bit less than 3%. Signed-off-by: Richard Henderson Reviewed-by: Alistair Francis Message-Id: <20220604231004.49990-4-richard.henderson@linaro.org> Signed-off-by: Alistair Francis --- target/riscv/insn_trans/trans_privileged.c.inc | 4 ++++ target/riscv/insn_trans/trans_rvh.c.inc | 2 ++ target/riscv/insn_trans/trans_rvi.c.inc | 2 ++ target/riscv/translate.c | 18 +++++++++--------- 4 files changed, 17 insertions(+), 9 deletions(-) diff --git a/target/riscv/insn_trans/trans_privileged.c.inc b/target/riscv/insn_trans/trans_privileged.c.inc index 53613682e8..46f96ad74d 100644 --- a/target/riscv/insn_trans/trans_privileged.c.inc +++ b/target/riscv/insn_trans/trans_privileged.c.inc @@ -75,6 +75,7 @@ static bool trans_sret(DisasContext *ctx, arg_sret *a) { #ifndef CONFIG_USER_ONLY if (has_ext(ctx, RVS)) { + decode_save_opc(ctx); gen_helper_sret(cpu_pc, cpu_env); tcg_gen_exit_tb(NULL, 0); /* no chaining */ ctx->base.is_jmp = DISAS_NORETURN; @@ -90,6 +91,7 @@ static bool trans_sret(DisasContext *ctx, arg_sret *a) static bool trans_mret(DisasContext *ctx, arg_mret *a) { #ifndef CONFIG_USER_ONLY + decode_save_opc(ctx); gen_helper_mret(cpu_pc, cpu_env); tcg_gen_exit_tb(NULL, 0); /* no chaining */ ctx->base.is_jmp = DISAS_NORETURN; @@ -102,6 +104,7 @@ static bool trans_mret(DisasContext *ctx, arg_mret *a) static bool trans_wfi(DisasContext *ctx, arg_wfi *a) { #ifndef CONFIG_USER_ONLY + decode_save_opc(ctx); gen_set_pc_imm(ctx, ctx->pc_succ_insn); gen_helper_wfi(cpu_env); return true; @@ -113,6 +116,7 @@ static bool trans_wfi(DisasContext *ctx, arg_wfi *a) static bool trans_sfence_vma(DisasContext *ctx, arg_sfence_vma *a) { #ifndef CONFIG_USER_ONLY + decode_save_opc(ctx); gen_helper_tlb_flush(cpu_env); return true; #endif diff --git a/target/riscv/insn_trans/trans_rvh.c.inc b/target/riscv/insn_trans/trans_rvh.c.inc index cebcb3f8f6..4f8aecddc7 100644 --- a/target/riscv/insn_trans/trans_rvh.c.inc +++ b/target/riscv/insn_trans/trans_rvh.c.inc @@ -169,6 +169,7 @@ static bool trans_hfence_gvma(DisasContext *ctx, arg_sfence_vma *a) { REQUIRE_EXT(ctx, RVH); #ifndef CONFIG_USER_ONLY + decode_save_opc(ctx); gen_helper_hyp_gvma_tlb_flush(cpu_env); return true; #endif @@ -179,6 +180,7 @@ static bool trans_hfence_vvma(DisasContext *ctx, arg_sfence_vma *a) { REQUIRE_EXT(ctx, RVH); #ifndef CONFIG_USER_ONLY + decode_save_opc(ctx); gen_helper_hyp_tlb_flush(cpu_env); return true; #endif diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc index c190a59f22..ca8e3d1ea1 100644 --- a/target/riscv/insn_trans/trans_rvi.c.inc +++ b/target/riscv/insn_trans/trans_rvi.c.inc @@ -818,6 +818,8 @@ static bool trans_fence_i(DisasContext *ctx, arg_fence_i *a) static bool do_csr_post(DisasContext *ctx) { + /* The helper may raise ILLEGAL_INSN -- record binv for unwind. */ + decode_save_opc(ctx); /* We may have changed important cpu state -- exit to main loop. */ gen_set_pc_imm(ctx, ctx->pc_succ_insn); tcg_gen_exit_tb(NULL, 0); diff --git a/target/riscv/translate.c b/target/riscv/translate.c index 7205a29603..63b04e8a94 100644 --- a/target/riscv/translate.c +++ b/target/riscv/translate.c @@ -206,6 +206,13 @@ static void gen_check_nanbox_s(TCGv_i64 out, TCGv_i64 in) tcg_gen_movcond_i64(TCG_COND_GEU, out, in, t_max, in, t_nan); } +static void decode_save_opc(DisasContext *ctx) +{ + assert(ctx->insn_start != NULL); + tcg_set_insn_start_param(ctx->insn_start, 1, ctx->opcode); + ctx->insn_start = NULL; +} + static void gen_set_pc_imm(DisasContext *ctx, target_ulong dest) { if (get_xl(ctx) == MXL_RV32) { @@ -635,6 +642,8 @@ static void gen_set_rm(DisasContext *ctx, int rm) return; } + /* The helper may raise ILLEGAL_INSN -- record binv for unwind. */ + decode_save_opc(ctx); gen_helper_set_rounding_mode(cpu_env, tcg_constant_i32(rm)); } @@ -1013,13 +1022,6 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc) /* Include decoders for factored-out extensions */ #include "decode-XVentanaCondOps.c.inc" -static inline void decode_save_opc(DisasContext *ctx, target_ulong opc) -{ - assert(ctx->insn_start != NULL); - tcg_set_insn_start_param(ctx->insn_start, 1, opc); - ctx->insn_start = NULL; -} - static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode) { /* @@ -1036,7 +1038,6 @@ static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode) /* Check for compressed insn */ if (extract16(opcode, 0, 2) != 3) { - decode_save_opc(ctx, opcode); if (!has_ext(ctx, RVC)) { gen_exception_illegal(ctx); } else { @@ -1051,7 +1052,6 @@ static void decode_opc(CPURISCVState *env, DisasContext *ctx, uint16_t opcode) opcode32 = deposit32(opcode32, 16, 16, translator_lduw(env, &ctx->base, ctx->base.pc_next + 2)); - decode_save_opc(ctx, opcode32); ctx->opcode = opcode32; ctx->pc_succ_insn = ctx->base.pc_next + 4;