[PATCH v2 1/6] target/microblaze: Add the opcode-0x0-illegal CPU property

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>

Add the opcode-0x0-illegal CPU property to control if the core
should trap opcode zero as illegal.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
---
 target/microblaze/cpu.c       | 6 +++++-
 target/microblaze/cpu.h       | 1 +
 target/microblaze/translate.c | 2 +-
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/target/microblaze/cpu.c b/target/microblaze/cpu.c
index a2c2f271df..1044120702 100644
--- a/target/microblaze/cpu.c
+++ b/target/microblaze/cpu.c
@@ -206,7 +206,9 @@ static void mb_cpu_realizefn(DeviceState *dev, Error **errp)
                         (cpu->cfg.dopb_bus_exception ?
                                                  PVR2_DOPB_BUS_EXC_MASK : 0) |
                         (cpu->cfg.iopb_bus_exception ?
-                                                 PVR2_IOPB_BUS_EXC_MASK : 0);
+                                                 PVR2_IOPB_BUS_EXC_MASK : 0) |
+                        (cpu->cfg.opcode_0_illegal ?
+                                                 PVR2_OPCODE_0x0_ILL_MASK : 0);
 
     env->pvr.regs[5] |= cpu->cfg.dcache_writeback ?
                                         PVR5_DCACHE_WRITEBACK_MASK : 0;
@@ -274,6 +276,8 @@ static Property mb_properties[] = {
     /* Enables bus exceptions on failed instruction fetches.  */
     DEFINE_PROP_BOOL("iopb-bus-exception", MicroBlazeCPU,
                      cfg.iopb_bus_exception, false),
+    DEFINE_PROP_BOOL("opcode-0x0-illegal", MicroBlazeCPU,
+                     cfg.opcode_0_illegal, false),
     DEFINE_PROP_STRING("version", MicroBlazeCPU, cfg.version),
     DEFINE_PROP_UINT8("pvr", MicroBlazeCPU, cfg.pvr, C_PVR_FULL),
     DEFINE_PROP_END_OF_LIST(),
diff --git a/target/microblaze/cpu.h b/target/microblaze/cpu.h
index 1a700a880c..d51587b342 100644
--- a/target/microblaze/cpu.h
+++ b/target/microblaze/cpu.h
@@ -303,6 +303,7 @@ struct MicroBlazeCPU {
         bool endi;
         bool dopb_bus_exception;
         bool iopb_bus_exception;
+        bool opcode_0_illegal;
         char *version;
         uint8_t pvr;
     } cfg;
diff --git a/target/microblaze/translate.c b/target/microblaze/translate.c
index 37a844db99..222632b670 100644
--- a/target/microblaze/translate.c
+++ b/target/microblaze/translate.c
@@ -1573,7 +1573,7 @@ static inline void decode(DisasContext *dc, uint32_t ir)
     LOG_DIS("%8.8x\t", dc->ir);
 
     if (ir == 0) {
-        trap_illegal(dc, dc->cpu->env.pvr.regs[2] & PVR2_OPCODE_0x0_ILL_MASK);
+        trap_illegal(dc, dc->cpu->cfg.opcode_0_illegal);
         /* Don't decode nop/zero instructions any further.  */
         return;
     }
-- 
2.20.1