Add support to retrieve mpidr value via qom-get.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 scripts/arm_processor_error.py | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/scripts/arm_processor_error.py b/scripts/arm_processor_error.py
index 62e0c5662232..0a16d4f0d8b1 100644
--- a/scripts/arm_processor_error.py
+++ b/scripts/arm_processor_error.py
@@ -5,12 +5,10 @@
 #
 # Copyright (C) 2024 Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
 
-# TODO: current implementation has dummy defaults.
-#
-# For a better implementation, a QMP addition/call is needed to
-# retrieve some data for ARM Processor Error injection:
-#
-#   - ARM registers: power_state, mpidr.
+# Note: currently it lacks a method to fill the ARM Processor Error CPER
+# psci field from emulation. On a real hardware, this is filled only
+# when a CPU is not running. Implementing support for it to simulate a
+# real hardware is not trivial.
 
 import argparse
 import re
@@ -174,11 +172,24 @@ def send_cper(self, args):
         else:
             cper["running-state"] = 0
 
+        if args.mpidr:
+            cper["mpidr-el1"] = arg["mpidr"]
+        elif cpus:
+            cmd_arg = {
+                'path': cpus[0],
+                'property': "x-mpidr"
+            }
+            ret = qmp_cmd.send_cmd("qom-get", cmd_arg, may_open=True)
+            if isinstance(ret, int):
+                cper["mpidr-el1"] = ret
+            else:
+                cper["mpidr-el1"] = 0
+
         if arm_valid_init:
             if args.affinity:
                 cper["valid"] |= self.arm_valid_bits["affinity"]
 
-            if args.mpidr:
+            if "mpidr-el1" in cper:
                 cper["valid"] |= self.arm_valid_bits["mpidr"]
 
             if "running-state" in cper:
@@ -362,7 +373,7 @@ def send_cper(self, args):
                 if isinstance(ret, int):
                     arg["midr-el1"] = ret
 
-        util.data_add(data, arg.get("mpidr-el1", 0), 8)
+        util.data_add(data, cper["mpidr-el1"], 8)
         util.data_add(data, arg.get("midr-el1", 0), 8)
         util.data_add(data, cper["running-state"], 4)
         util.data_add(data, arg.get("psci-state", 0), 4)
-- 
2.46.0