commit 0c4e579aac30abd26818ebaec8e1b633eb9f3952
author Alvin Chang <alvinga@andestech.com> Tue Dec 19 20:32:44 2023 +0800
committer Alistair Francis <alistair.francis@wdc.com> Fri Feb 09 20:40:32 2024 +1000
tree c6bd791a8f63b2c5739179b15f21d20a7478a424
parent 10efbe01ce40845aa2324d2abecd6664c7d8bf1c

target/riscv: Implement optional CSR mcontext of debug Sdtrig extension

The debug Sdtrig extension defines an CSR "mcontext". This commit
implements its predicate and read/write operations into CSR table.
Its value is reset as 0 when the trigger module is reset.

Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20231219123244.290935-1-alvinga@andestech.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/csr.c

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 674ea07..d666620 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3906,6 +3906,31 @@
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException read_mcontext(CPURISCVState *env, int csrno,
+                                    target_ulong *val)
+{
+    *val = env->mcontext;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mcontext(CPURISCVState *env, int csrno,
+                                     target_ulong val)
+{
+    bool rv32 = riscv_cpu_mxl(env) == MXL_RV32 ? true : false;
+    int32_t mask;
+
+    if (riscv_has_ext(env, RVH)) {
+        /* Spec suggest 7-bit for RV32 and 14-bit for RV64 w/ H extension */
+        mask = rv32 ? MCONTEXT32_HCONTEXT : MCONTEXT64_HCONTEXT;
+    } else {
+        /* Spec suggest 6-bit for RV32 and 13-bit for RV64 w/o H extension */
+        mask = rv32 ? MCONTEXT32 : MCONTEXT64;
+    }
+
+    env->mcontext = val & mask;
+    return RISCV_EXCP_NONE;
+}
+
 /*
  * Functions to access Pointer Masking feature registers
  * We have to check if current priv lvl could modify
@@ -4800,11 +4825,12 @@
     [CSR_PMPADDR15] =  { "pmpaddr15", pmp, read_pmpaddr, write_pmpaddr },
 
     /* Debug CSRs */
-    [CSR_TSELECT]   =  { "tselect", debug, read_tselect, write_tselect },
-    [CSR_TDATA1]    =  { "tdata1",  debug, read_tdata,   write_tdata   },
-    [CSR_TDATA2]    =  { "tdata2",  debug, read_tdata,   write_tdata   },
-    [CSR_TDATA3]    =  { "tdata3",  debug, read_tdata,   write_tdata   },
-    [CSR_TINFO]     =  { "tinfo",   debug, read_tinfo,   write_ignore  },
+    [CSR_TSELECT]   =  { "tselect",  debug, read_tselect,  write_tselect  },
+    [CSR_TDATA1]    =  { "tdata1",   debug, read_tdata,    write_tdata    },
+    [CSR_TDATA2]    =  { "tdata2",   debug, read_tdata,    write_tdata    },
+    [CSR_TDATA3]    =  { "tdata3",   debug, read_tdata,    write_tdata    },
+    [CSR_TINFO]     =  { "tinfo",    debug, read_tinfo,    write_ignore   },
+    [CSR_MCONTEXT]  =  { "mcontext", debug, read_mcontext, write_mcontext },
 
     /* User Pointer Masking */
     [CSR_UMTE]    =    { "umte",    pointer_masking, read_umte,  write_umte },