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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: alistair.francis@wdc.com, qemu-riscv@nongnu.org, zhiwei_liu@c-sky.com
Subject: [PATCH v6 15/15] target/riscv: Compute mstatus.sd on demand
Date: Tue, 19 Oct 2021 20:17:09 -0700	[thread overview]
Message-ID: <20211020031709.359469-16-richard.henderson@linaro.org> (raw)
In-Reply-To: <20211020031709.359469-1-richard.henderson@linaro.org>

The position of this read-only field is dependent on the current xlen.
Rather than having to compute that difference in many places, compute
it only on read.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/riscv/cpu_helper.c |  3 +--
 target/riscv/csr.c        | 37 ++++++++++++++++++++++---------------
 target/riscv/translate.c  |  5 ++---
 3 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 429afd1f48..0d1132f39d 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -185,10 +185,9 @@ bool riscv_cpu_fp_enabled(CPURISCVState *env)
 
 void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
 {
-    uint64_t sd = riscv_cpu_mxl(env) == MXL_RV32 ? MSTATUS32_SD : MSTATUS64_SD;
     uint64_t mstatus_mask = MSTATUS_MXR | MSTATUS_SUM | MSTATUS_FS |
                             MSTATUS_SPP | MSTATUS_SPIE | MSTATUS_SIE |
-                            MSTATUS64_UXL | sd;
+                            MSTATUS64_UXL;
     bool current_virt = riscv_cpu_virt_enabled(env);
 
     g_assert(riscv_has_ext(env, RVH));
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index c4a479ddd2..69e4d65fcd 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -477,10 +477,28 @@ static RISCVException read_mhartid(CPURISCVState *env, int csrno,
 }
 
 /* Machine Trap Setup */
+
+/* We do not store SD explicitly, only compute it on demand. */
+static uint64_t add_status_sd(RISCVMXL xl, uint64_t status)
+{
+    if ((status & MSTATUS_FS) == MSTATUS_FS ||
+        (status & MSTATUS_XS) == MSTATUS_XS) {
+        switch (xl) {
+        case MXL_RV32:
+            return status | MSTATUS32_SD;
+        case MXL_RV64:
+            return status | MSTATUS64_SD;
+        default:
+            g_assert_not_reached();
+        }
+    }
+    return status;
+}
+
 static RISCVException read_mstatus(CPURISCVState *env, int csrno,
                                    target_ulong *val)
 {
-    *val = env->mstatus;
+    *val = add_status_sd(riscv_cpu_mxl(env), env->mstatus);
     return RISCV_EXCP_NONE;
 }
 
@@ -498,7 +516,6 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno,
 {
     uint64_t mstatus = env->mstatus;
     uint64_t mask = 0;
-    int dirty;
 
     /* flush tlb on mstatus fields that affect VM */
     if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV |
@@ -520,12 +537,7 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno,
 
     mstatus = (mstatus & ~mask) | (val & mask);
 
-    dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
-            ((mstatus & MSTATUS_XS) == MSTATUS_XS);
-    if (riscv_cpu_mxl(env) == MXL_RV32) {
-        mstatus = set_field(mstatus, MSTATUS32_SD, dirty);
-    } else {
-        mstatus = set_field(mstatus, MSTATUS64_SD, dirty);
+    if (riscv_cpu_mxl(env) == MXL_RV64) {
         /* SXL and UXL fields are for now read only */
         mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64);
         mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64);
@@ -798,13 +810,8 @@ static RISCVException read_sstatus(CPURISCVState *env, int csrno,
 {
     target_ulong mask = (sstatus_v1_10_mask);
 
-    if (riscv_cpu_mxl(env) == MXL_RV32) {
-        mask |= SSTATUS32_SD;
-    } else {
-        mask |= SSTATUS64_SD;
-    }
-
-    *val = env->mstatus & mask;
+    /* TODO: Use SXL not MXL. */
+    *val = add_status_sd(riscv_cpu_mxl(env), env->mstatus & mask);
     return RISCV_EXCP_NONE;
 }
 
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 0b3da060fd..1d6bf01a48 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -305,7 +305,6 @@ static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)
 static void mark_fs_dirty(DisasContext *ctx)
 {
     TCGv tmp;
-    target_ulong sd = get_xl(ctx) == MXL_RV32 ? MSTATUS32_SD : MSTATUS64_SD;
 
     if (ctx->mstatus_fs != MSTATUS_FS) {
         /* Remember the state change for the rest of the TB. */
@@ -313,7 +312,7 @@ static void mark_fs_dirty(DisasContext *ctx)
 
         tmp = tcg_temp_new();
         tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
-        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
+        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
         tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
         tcg_temp_free(tmp);
     }
@@ -324,7 +323,7 @@ static void mark_fs_dirty(DisasContext *ctx)
 
         tmp = tcg_temp_new();
         tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus_hs));
-        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | sd);
+        tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
         tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus_hs));
         tcg_temp_free(tmp);
     }
-- 
2.25.1



  parent reply	other threads:[~2021-10-20  3:37 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-20  3:16 [PATCH v6 00/15] target/riscv: Rationalize XLEN and operand length Richard Henderson
2021-10-20  3:16 ` [PATCH v6 01/15] target/riscv: Move cpu_get_tb_cpu_state out of line Richard Henderson
2021-10-20  3:16 ` [PATCH v6 02/15] target/riscv: Create RISCVMXL enumeration Richard Henderson
2021-10-20  3:16 ` [PATCH v6 03/15] target/riscv: Split misa.mxl and misa.ext Richard Henderson
2021-10-20  3:16 ` [PATCH v6 04/15] target/riscv: Replace riscv_cpu_is_32bit with riscv_cpu_mxl Richard Henderson
2021-10-20  3:16 ` [PATCH v6 05/15] target/riscv: Add MXL/SXL/UXL to TB_FLAGS Richard Henderson
2021-10-20  3:17 ` [PATCH v6 06/15] target/riscv: Use REQUIRE_64BIT in amo_check64 Richard Henderson
2021-10-20  3:17 ` [PATCH v6 07/15] target/riscv: Properly check SEW in amo_op Richard Henderson
2021-10-20  3:17 ` [PATCH v6 08/15] target/riscv: Replace is_32bit with get_xl/get_xlen Richard Henderson
2021-10-20  3:17 ` [PATCH v6 09/15] target/riscv: Replace DisasContext.w with DisasContext.ol Richard Henderson
2021-10-20  3:17 ` [PATCH v6 10/15] target/riscv: Use gen_arith_per_ol for RVM Richard Henderson
2021-10-20  3:17 ` [PATCH v6 11/15] target/riscv: Adjust trans_rev8_32 for riscv64 Richard Henderson
2021-10-20  3:17 ` [PATCH v6 12/15] target/riscv: Use gen_unary_per_ol for RVB Richard Henderson
2021-10-20  3:17 ` [PATCH v6 13/15] target/riscv: Use gen_shift*_per_ol for RVB, RVI Richard Henderson
2021-10-20  3:17 ` [PATCH v6 14/15] target/riscv: Use riscv_csrrw_debug for cpu_dump Richard Henderson
2021-10-20  3:17 ` Richard Henderson [this message]
2021-10-20 11:02 ` [PATCH v6 00/15] target/riscv: Rationalize XLEN and operand length Alistair Francis
2021-10-22  8:26 ` LIU Zhiwei
2021-10-22 15:50   ` Richard Henderson
2021-10-25  9:24     ` LIU Zhiwei
2021-10-25 14:58       ` Richard Henderson

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