Introduce csrr and csrw helpers, for read-only and write-only insns. Note that we do not properly implement this in riscv_csrrw, in that we cannot distinguish true read-only (rs1 == 0) from any other zero write_mask another source register -- this should still raise an exception for read-only registers.
Only issue gen_io_start for CF_USE_ICOUNT. Use ctx->zero for csrrc. Use get_gpr and dest_gpr. Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- target/riscv/helper.h | 6 +- target/riscv/op_helper.c | 18 +-- target/riscv/insn_trans/trans_rvi.c.inc | 172 +++++++++++++++++------- 3 files changed, 131 insertions(+), 65 deletions(-) diff --git a/target/riscv/helper.h b/target/riscv/helper.h index 415e37bc37..460eee9988 100644 --- a/target/riscv/helper.h +++ b/target/riscv/helper.h @@ -65,9 +65,9 @@ DEF_HELPER_FLAGS_2(gorc, TCG_CALL_NO_RWG_SE, tl, tl, tl) DEF_HELPER_FLAGS_2(gorcw, TCG_CALL_NO_RWG_SE, tl, tl, tl) /* Special functions */ -DEF_HELPER_3(csrrw, tl, env, tl, tl) -DEF_HELPER_4(csrrs, tl, env, tl, tl, tl) -DEF_HELPER_4(csrrc, tl, env, tl, tl, tl) +DEF_HELPER_2(csrr, tl, env, int) +DEF_HELPER_3(csrw, void, env, int, tl) +DEF_HELPER_4(csrrw, tl, env, int, tl, tl) #ifndef CONFIG_USER_ONLY DEF_HELPER_2(sret, tl, env, tl) DEF_HELPER_2(mret, tl, env, tl) diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c index 3c48e739ac..ee7c24efe7 100644 --- a/target/riscv/op_helper.c +++ b/target/riscv/op_helper.c @@ -37,11 +37,10 @@ void helper_raise_exception(CPURISCVState *env, uint32_t exception) riscv_raise_exception(env, exception, 0); } -target_ulong helper_csrrw(CPURISCVState *env, target_ulong src, - target_ulong csr) +target_ulong helper_csrr(CPURISCVState *env, int csr) { target_ulong val = 0; - RISCVException ret = riscv_csrrw(env, csr, &val, src, -1); + RISCVException ret = riscv_csrrw(env, csr, &val, 0, 0); if (ret != RISCV_EXCP_NONE) { riscv_raise_exception(env, ret, GETPC()); @@ -49,23 +48,20 @@ target_ulong helper_csrrw(CPURISCVState *env, target_ulong src, return val; } -target_ulong helper_csrrs(CPURISCVState *env, target_ulong src, - target_ulong csr, target_ulong rs1_pass) +void helper_csrw(CPURISCVState *env, int csr, target_ulong src) { - target_ulong val = 0; - RISCVException ret = riscv_csrrw(env, csr, &val, -1, rs1_pass ? src : 0); + RISCVException ret = riscv_csrrw(env, csr, NULL, src, -1); if (ret != RISCV_EXCP_NONE) { riscv_raise_exception(env, ret, GETPC()); } - return val; } -target_ulong helper_csrrc(CPURISCVState *env, target_ulong src, - target_ulong csr, target_ulong rs1_pass) +target_ulong helper_csrrw(CPURISCVState *env, int csr, + target_ulong src, target_ulong write_mask) { target_ulong val = 0; - RISCVException ret = riscv_csrrw(env, csr, &val, 0, rs1_pass ? src : 0); + RISCVException ret = riscv_csrrw(env, csr, &val, src, write_mask); if (ret != RISCV_EXCP_NONE) { riscv_raise_exception(env, ret, GETPC()); diff --git a/target/riscv/insn_trans/trans_rvi.c.inc b/target/riscv/insn_trans/trans_rvi.c.inc index f616a26c82..688cb6a6ad 100644 --- a/target/riscv/insn_trans/trans_rvi.c.inc +++ b/target/riscv/insn_trans/trans_rvi.c.inc @@ -416,80 +416,150 @@ static bool trans_fence_i(DisasContext *ctx, arg_fence_i *a) return true; } -#define RISCV_OP_CSR_PRE do {\ - source1 = tcg_temp_new(); \ - csr_store = tcg_temp_new(); \ - dest = tcg_temp_new(); \ - rs1_pass = tcg_temp_new(); \ - gen_get_gpr(ctx, source1, a->rs1); \ - tcg_gen_movi_tl(cpu_pc, ctx->base.pc_next); \ - tcg_gen_movi_tl(rs1_pass, a->rs1); \ - tcg_gen_movi_tl(csr_store, a->csr); \ - gen_io_start();\ -} while (0) +static bool do_csr_post(DisasContext *ctx) +{ + /* We may have changed important cpu state -- exit to main loop. */ + tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn); + exit_tb(ctx); + ctx->base.is_jmp = DISAS_NORETURN; + return true; +} -#define RISCV_OP_CSR_POST do {\ - gen_set_gpr(ctx, a->rd, dest); \ - tcg_gen_movi_tl(cpu_pc, ctx->pc_succ_insn); \ - exit_tb(ctx); \ - ctx->base.is_jmp = DISAS_NORETURN; \ - tcg_temp_free(source1); \ - tcg_temp_free(csr_store); \ - tcg_temp_free(dest); \ - tcg_temp_free(rs1_pass); \ -} while (0) +static bool do_csrr(DisasContext *ctx, int rd, int rc) +{ + TCGv dest = dest_gpr(ctx, rd); + TCGv_i32 csr = tcg_constant_i32(rc); + if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) { + gen_io_start(); + } + gen_helper_csrr(dest, cpu_env, csr); + gen_set_gpr(ctx, rd, dest); + return do_csr_post(ctx); +} + +static bool do_csrw(DisasContext *ctx, int rc, TCGv src) +{ + TCGv_i32 csr = tcg_constant_i32(rc); + + if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) { + gen_io_start(); + } + gen_helper_csrw(cpu_env, csr, src); + return do_csr_post(ctx); +} + +static bool do_csrrw(DisasContext *ctx, int rd, int rc, TCGv src, TCGv mask) +{ + TCGv dest = dest_gpr(ctx, rd); + TCGv_i32 csr = tcg_constant_i32(rc); + + if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) { + gen_io_start(); + } + gen_helper_csrrw(dest, cpu_env, csr, src, mask); + gen_set_gpr(ctx, rd, dest); + return do_csr_post(ctx); +} static bool trans_csrrw(DisasContext *ctx, arg_csrrw *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrw(dest, cpu_env, source1, csr_store); - RISCV_OP_CSR_POST; - return true; + TCGv src = get_gpr(ctx, a->rs1, EXT_NONE); + + /* + * If rd == 0, the insn shall not read the csr, nor cause any of the + * side effects that might occur on a csr read. + */ + if (a->rd == 0) { + return do_csrw(ctx, a->csr, src); + } + + TCGv mask = tcg_constant_tl(-1); + return do_csrrw(ctx, a->rd, a->csr, src, mask); } static bool trans_csrrs(DisasContext *ctx, arg_csrrs *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrs(dest, cpu_env, source1, csr_store, rs1_pass); - RISCV_OP_CSR_POST; - return true; + /* + * If rs1 == 0, the insn shall not write to the csr at all, nor + * cause any of the side effects that might occur on a csr write. + * Note that if rs1 specifies a register other than x0, holding + * a zero value, the instruction will still attempt to write the + * unmodified value back to the csr and will cause side effects. + */ + if (a->rs1 == 0) { + return do_csrr(ctx, a->rd, a->csr); + } + + TCGv ones = tcg_constant_tl(-1); + TCGv mask = get_gpr(ctx, a->rs1, EXT_ZERO); + return do_csrrw(ctx, a->rd, a->csr, ones, mask); } static bool trans_csrrc(DisasContext *ctx, arg_csrrc *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrc(dest, cpu_env, source1, csr_store, rs1_pass); - RISCV_OP_CSR_POST; - return true; + /* + * If rs1 == 0, the insn shall not write to the csr at all, nor + * cause any of the side effects that might occur on a csr write. + * Note that if rs1 specifies a register other than x0, holding + * a zero value, the instruction will still attempt to write the + * unmodified value back to the csr and will cause side effects. + */ + if (a->rs1 == 0) { + return do_csrr(ctx, a->rd, a->csr); + } + + TCGv mask = get_gpr(ctx, a->rs1, EXT_ZERO); + return do_csrrw(ctx, a->rd, a->csr, ctx->zero, mask); } static bool trans_csrrwi(DisasContext *ctx, arg_csrrwi *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrw(dest, cpu_env, rs1_pass, csr_store); - RISCV_OP_CSR_POST; - return true; + TCGv src = tcg_constant_tl(a->rs1); + + /* + * If rd == 0, the insn shall not read the csr, nor cause any of the + * side effects that might occur on a csr read. + */ + if (a->rd == 0) { + return do_csrw(ctx, a->csr, src); + } + + TCGv mask = tcg_constant_tl(-1); + return do_csrrw(ctx, a->rd, a->csr, src, mask); } static bool trans_csrrsi(DisasContext *ctx, arg_csrrsi *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrs(dest, cpu_env, rs1_pass, csr_store, rs1_pass); - RISCV_OP_CSR_POST; - return true; + /* + * If rs1 == 0, the insn shall not write to the csr at all, nor + * cause any of the side effects that might occur on a csr write. + * Note that if rs1 specifies a register other than x0, holding + * a zero value, the instruction will still attempt to write the + * unmodified value back to the csr and will cause side effects. + */ + if (a->rs1 == 0) { + return do_csrr(ctx, a->rd, a->csr); + } + + TCGv ones = tcg_constant_tl(-1); + TCGv mask = tcg_constant_tl(a->rs1); + return do_csrrw(ctx, a->rd, a->csr, ones, mask); } static bool trans_csrrci(DisasContext *ctx, arg_csrrci *a) { - TCGv source1, csr_store, dest, rs1_pass; - RISCV_OP_CSR_PRE; - gen_helper_csrrc(dest, cpu_env, rs1_pass, csr_store, rs1_pass); - RISCV_OP_CSR_POST; - return true; + /* + * If rs1 == 0, the insn shall not write to the csr at all, nor + * cause any of the side effects that might occur on a csr write. + * Note that if rs1 specifies a register other than x0, holding + * a zero value, the instruction will still attempt to write the + * unmodified value back to the csr and will cause side effects. + */ + if (a->rs1 == 0) { + return do_csrr(ctx, a->rd, a->csr); + } + + TCGv mask = tcg_constant_tl(a->rs1); + return do_csrrw(ctx, a->rd, a->csr, ctx->zero, mask); } -- 2.25.1