[RFC PATCH v2 3/4] target/riscv: smstateen check for fcsr

[Mayuresh Chitale]

If smstateen is implemented and sstateen0.fcsr is clear
then the floating point operations must return illegal
instruction exception.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
---
 target/riscv/csr.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 2388f0226f..5959adc9b3 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -75,6 +75,10 @@ static RISCVException fs(CPURISCVState *env, int csrno)
         !RISCV_CPU(env_cpu(env))->cfg.ext_zfinx) {
         return RISCV_EXCP_ILLEGAL_INST;
     }
+
+    if (!env->debugger && !riscv_cpu_fp_enabled(env)) {
+        return smstateen_acc_ok(env, PRV_U, SMSTATEEN0_FCSR);
+    }
 #endif
     return RISCV_EXCP_NONE;
 }
@@ -2006,6 +2010,10 @@ static RISCVException write_mstateen(CPURISCVState *env, 
int csrno,
                        (1UL << SMSTATEEN0_HSENVCFG);
 
     reg = &env->mstateen[csrno - CSR_MSTATEEN0];
+    if (riscv_has_ext(env, RVF)) {
+        wr_mask |= 1UL << SMSTATEEN0_FCSR;
+    }
+
     write_smstateen(env, reg, wr_mask, new_val);
 
     return RISCV_EXCP_NONE;
@@ -2030,6 +2038,10 @@ static RISCVException write_mstateenh(CPURISCVState 
*env, int csrno,
     reg = &env->mstateen[csrno - CSR_MSTATEEN0H - 0x10];
     val = (uint64_t)new_val << 32;
     val |= *reg & 0xFFFFFFFF;
+    if (riscv_has_ext(env, RVF)) {
+        wr_mask |= 1UL << SMSTATEEN0_FCSR;
+    }
+
     write_smstateen(env, reg, wr_mask, val);
 
     return RISCV_EXCP_NONE;
@@ -2051,6 +2063,10 @@ static RISCVException write_hstateen(CPURISCVState *env, 
int csrno,
                        (1UL << SMSTATEEN0_HSENVCFG);
     int index = csrno - CSR_HSTATEEN0;
 
+    if (riscv_has_ext(env, RVF)) {
+        wr_mask |= 1UL << SMSTATEEN0_FCSR;
+    }
+
     reg = &env->hstateen[index];
     wr_mask &= env->mstateen[index];
     write_smstateen(env, reg, wr_mask, new_val);
@@ -2075,6 +2091,10 @@ static RISCVException write_hstateenh(CPURISCVState 
*env, int csrno,
     uint64_t wr_mask = (1UL << SMSTATEEN_STATEN) |
                        (1UL << SMSTATEEN0_HSENVCFG);
 
+    if (riscv_has_ext(env, RVF)) {
+        wr_mask |= 1UL << SMSTATEEN0_FCSR;
+    }
+
     reg = &env->hstateen[index];
     val = (uint64_t)new_val << 32;
     val |= *reg & 0xFFFFFFFF;
@@ -2100,6 +2120,10 @@ static RISCVException write_sstateen(CPURISCVState *env, 
int csrno,
     int index = csrno - CSR_SSTATEEN0;
     bool virt = riscv_cpu_virt_enabled(env);
 
+    if (riscv_has_ext(env, RVF)) {
+        wr_mask |= 1UL << SMSTATEEN0_FCSR;
+    }
+
     reg = &env->sstateen[index];
     if (virt) {
         wr_mask &= env->mstateen[index];
-- 
2.17.1