[Qemu-riscv] [RFC v1 10/23] target/riscv: Add background CSRs accesses

[Alistair Francis]

Signed-off-by: Alistair Francis <address@hidden>
---
 target/riscv/cpu_bits.h |  11 ++++
 target/riscv/csr.c      | 119 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index c898bb1102..9c27727e6f 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -169,6 +169,17 @@
 #define CSR_SPTBR           0x180
 #define CSR_SATP            0x180
 
+/* Background CSRs */
+#define CSR_BSSTATUS        0x200
+#define CSR_BSIE            0x204
+#define CSR_BSTVEC          0x205
+#define CSR_BSSCRATCH       0x240
+#define CSR_BSEPC           0x241
+#define CSR_BSCAUSE         0x242
+#define CSR_BSTVAL          0x243
+#define CSR_BSIP            0x244
+#define CSR_BSATP           0x280
+
 /* Physical Memory Protection */
 #define CSR_PMPCFG0         0x3a0
 #define CSR_PMPCFG1         0x3a1
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index c52fde6e7f..908e166426 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -790,6 +790,115 @@ static int write_hgatp(CPURISCVState *env, int csrno, 
target_ulong val)
     return 0;
 }
 
+/* Background CSR Registers */
+static int read_bsstatus(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bsstatus;
+    return 0;
+}
+
+static int write_bsstatus(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bsstatus = val;
+    return 0;
+}
+
+static int read_bsie(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bsie;
+    return 0;
+}
+
+static int write_bsie(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bsie = val;
+    return 0;
+}
+
+static int read_bstvec(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bstvec;
+    return 0;
+}
+
+static int write_bstvec(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bstvec = val;
+    return 0;
+}
+
+static int read_bsscratch(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bsscratch;
+    return 0;
+}
+
+static int write_bsscratch(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bsscratch = val;
+    return 0;
+}
+
+static int read_bsepc(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bsepc;
+    return 0;
+}
+
+static int write_bsepc(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bsepc = val;
+    return 0;
+}
+
+static int read_bscause(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bscause;
+    return 0;
+}
+
+static int write_bscause(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bscause = val;
+    return 0;
+}
+
+static int read_bstval(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bstval;
+    return 0;
+}
+
+static int write_bstval(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bstval = val;
+    return 0;
+}
+
+static int read_bsip(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = (target_ulong)atomic_read(&env->bsip);
+    return 0;
+}
+
+static int write_bsip(CPURISCVState *env, int csrno, target_ulong val)
+{
+    atomic_set(&env->bsip, val);
+    return 0;
+}
+
+static int read_bsatp(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->bsatp;
+    return 0;
+}
+
+static int write_bsatp(CPURISCVState *env, int csrno, target_ulong val)
+{
+    env->bsatp = val;
+    return 0;
+}
+
 /* Physical Memory Protection */
 static int read_pmpcfg(CPURISCVState *env, int csrno, target_ulong *val)
 {
@@ -978,6 +1087,16 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_HIDELEG] =             { hmode,   read_hideleg,     write_hideleg    
},
     [CSR_HGATP] =               { hmode,   read_hgatp,       write_hgatp      
},
 
+    [CSR_BSSTATUS] =            { hmode,   read_bsstatus,    write_bsstatus   
},
+    [CSR_BSIE] =                { hmode,   read_bsie,        write_bsie       
},
+    [CSR_BSTVEC] =              { hmode,   read_bstvec,      write_bstvec     
},
+    [CSR_BSSCRATCH] =           { hmode,   read_bsscratch,   write_bsscratch  
},
+    [CSR_BSEPC] =               { hmode,   read_bsepc,       write_bsepc      
},
+    [CSR_BSCAUSE] =             { hmode,   read_bscause,     write_bscause    
},
+    [CSR_BSTVAL] =              { hmode,   read_bstval,      write_bstval     
},
+    [CSR_BSIP] =                { hmode,   read_bsip,        write_bsip       
},
+    [CSR_BSATP] =               { hmode,   read_bsatp,       write_bsatp      
},
+
     /* Physical Memory Protection */
     [CSR_PMPCFG0  ... CSR_PMPADDR9] =  { pmp,   read_pmpcfg,  write_pmpcfg   },
     [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  },
-- 
2.21.0