target/riscv: Add support for the 32-bit MSTATUSH CSR

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

6 files changed, 62 insertions, 0 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 44ad768a84..b27066f6a7 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -237,6 +237,9 @@ static void riscv_cpu_dump_state(CPUState *cs, FILE *f, int flags)
 #ifndef CONFIG_USER_ONLY
     qemu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mhartid ", env->mhartid);
     qemu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mstatus ", env->mstatus);
+#ifdef TARGET_RISCV32
+    qemu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mstatush ", env->mstatush);
+#endif
     if (riscv_has_ext(env, RVH)) {
         qemu_fprintf(f, " %s " TARGET_FMT_lx "\n", "hstatus ", env->hstatus);
         qemu_fprintf(f, " %s " TARGET_FMT_lx "\n", "vsstatus ", env->vsstatus);
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index a8534fdf2b..6f9c29322a 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -127,6 +127,10 @@ struct CPURISCVState {
 
     target_ulong mip;
 
+#ifdef TARGET_RISCV32
+    target_ulong mstatush;
+#endif
+
     uint32_t miclaim;
 
     target_ulong mie;
@@ -164,6 +168,9 @@ struct CPURISCVState {
     target_ulong vscause;
     target_ulong vstval;
     target_ulong vsatp;
+#ifdef TARGET_RISCV32
+    target_ulong vsstatush;
+#endif
 
     target_ulong mtval2;
     target_ulong mtinst;
@@ -176,6 +183,9 @@ struct CPURISCVState {
     target_ulong stval_hs;
     target_ulong satp_hs;
     target_ulong mstatus_hs;
+#ifdef TARGET_RISCV32
+    target_ulong mstatush_hs;
+#endif
 
     target_ulong scounteren;
     target_ulong mcounteren;
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index a24654d137..049032f2ae 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -135,6 +135,9 @@
 #define CSR_MTVEC           0x305
 #define CSR_MCOUNTEREN      0x306
 
+/* 32-bit only */
+#define CSR_MSTATUSH        0x310
+
 /* Legacy Counter Setup (priv v1.9.1) */
 /* Update to #define CSR_MCOUNTINHIBIT 0x320 for 1.11.0 */
 #define CSR_MUCOUNTEREN     0x320
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index d3b764e694..10f246ddf8 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -126,6 +126,11 @@ void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
         env->mstatus &= ~mstatus_mask;
         env->mstatus |= env->mstatus_hs;
 
+#if defined(TARGET_RISCV32)
+        env->vsstatush = env->mstatush;
+        env->mstatush |= env->mstatush_hs;
+#endif
+
         env->vstvec = env->stvec;
         env->stvec = env->stvec_hs;
 
@@ -149,6 +154,11 @@ void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env)
         env->mstatus &= ~mstatus_mask;
         env->mstatus |= env->vsstatus;
 
+#if defined(TARGET_RISCV32)
+        env->mstatush_hs = env->mstatush;
+        env->mstatush |= env->vsstatush;
+#endif
+
         env->stvec_hs = env->stvec;
         env->stvec = env->vstvec;
 
@@ -939,10 +949,17 @@ void riscv_cpu_do_interrupt(CPUState *cs)
             if (riscv_cpu_virt_enabled(env)) {
                 riscv_cpu_swap_hypervisor_regs(env);
             }
+#ifdef TARGET_RISCV32
+            env->mstatush = set_field(env->mstatush, MSTATUS_MPV,
+                                       riscv_cpu_virt_enabled(env));
+            env->mstatush = set_field(env->mstatush, MSTATUS_MTL,
+                                       riscv_cpu_force_hs_excep_enabled(env));
+#else
             env->mstatus = set_field(env->mstatus, MSTATUS_MPV,
                                       riscv_cpu_virt_enabled(env));
             env->mstatus = set_field(env->mstatus, MSTATUS_MTL,
                                       riscv_cpu_force_hs_excep_enabled(env));
+#endif
 
             mtval2 = env->guest_phys_fault_addr;
 
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 2e6700bbeb..572a478e8c 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -371,6 +371,27 @@ static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
     return 0;
 }
 
+#ifdef TARGET_RISCV32
+static int read_mstatush(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->mstatush;
+    return 0;
+}
+
+static int write_mstatush(CPURISCVState *env, int csrno, target_ulong val)
+{
+    if ((val ^ env->mstatush) & (MSTATUS_MPV)) {
+        tlb_flush(env_cpu(env));
+    }
+
+    val &= MSTATUS_MPV | MSTATUS_MTL;
+
+    env->mstatush = val;
+
+    return 0;
+}
+#endif
+
 static int read_misa(CPURISCVState *env, int csrno, target_ulong *val)
 {
     *val = env->misa;
@@ -1214,6 +1235,10 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MTVEC] =               { any,  read_mtvec,       write_mtvec       },
     [CSR_MCOUNTEREN] =          { any,  read_mcounteren,  write_mcounteren  },
 
+#if defined(TARGET_RISCV32)
+    [CSR_MSTATUSH] =            { any,  read_mstatush,    write_mstatush    },
+#endif
+
     /* Legacy Counter Setup (priv v1.9.1) */
     [CSR_MUCOUNTEREN] =         { any,  read_mucounteren, write_mucounteren },
     [CSR_MSCOUNTEREN] =         { any,  read_mscounteren, write_mscounteren },
diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
index 804936e9d5..dca68fa96e 100644
--- a/target/riscv/op_helper.c
+++ b/target/riscv/op_helper.c
@@ -153,7 +153,11 @@ target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
         get_field(mstatus, MSTATUS_MPIE));
     mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
+#ifdef TARGET_RISCV32
+    env->mstatush = set_field(env->mstatush, MSTATUS_MPV, 0);
+#else
     mstatus = set_field(mstatus, MSTATUS_MPV, 0);
+#endif
     env->mstatus = mstatus;
     riscv_cpu_set_mode(env, prev_priv);