From: Mayuresh Chitale <mchitale@ventanamicro.com>
To: qemu-devel@nongnu.org,
	qemu-riscv@nongnu.org
Cc: Mayuresh Chitale <mchitale@ventanamicro.com>,
	alistair.francis@wdc.com
Subject: [RFC PATCH v5 3/4] target/riscv: smstateen check for fcsr
Date: Fri,  3 Jun 2022 21:34:24 +0530
Message-Id: <20220603160425.3667456-4-mchitale@ventanamicro.com>
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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 ae91ae1f7e..8bbbed38ff 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -77,6 +77,10 @@ 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;
 }
@@ -1700,6 +1704,10 @@ 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;
@@ -1724,6 +1732,10 @@ static RISCVException write_mstateenh(CPURISCVState *env, int csrno,
     reg = &env->mstateen[csrno - CSR_MSTATEEN0H];
     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;
@@ -1745,6 +1757,10 @@ 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);
@@ -1769,6 +1785,10 @@ 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;
@@ -1794,6 +1814,10 @@ 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];
-- 
2.25.1