3 files changed, 27 insertions, 1 deletions
diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 35253481f4..3c84f72928 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -79,6 +79,27 @@ static void cp_reg_reset(gpointer key, gpointer value, gpointer opaque)
     }
 }
 
+static void cp_reg_check_reset(gpointer key, gpointer value,  gpointer opaque)
+{
+    /* Purely an assertion check: we've already done reset once,
+     * so now check that running the reset for the cpreg doesn't
+     * change its value. This traps bugs where two different cpregs
+     * both try to reset the same state field but to different values.
+     */
+    ARMCPRegInfo *ri = value;
+    ARMCPU *cpu = opaque;
+    uint64_t oldvalue, newvalue;
+
+    if (ri->type & (ARM_CP_SPECIAL | ARM_CP_ALIAS | ARM_CP_NO_RAW)) {
+        return;
+    }
+
+    oldvalue = read_raw_cp_reg(&cpu->env, ri);
+    cp_reg_reset(key, value, opaque);
+    newvalue = read_raw_cp_reg(&cpu->env, ri);
+    assert(oldvalue == newvalue);
+}
+
 /* CPUClass::reset() */
 static void arm_cpu_reset(CPUState *s)
 {
@@ -90,6 +111,8 @@ static void arm_cpu_reset(CPUState *s)
 
     memset(env, 0, offsetof(CPUARMState, features));
     g_hash_table_foreach(cpu->cp_regs, cp_reg_reset, cpu);
+    g_hash_table_foreach(cpu->cp_regs, cp_reg_check_reset, cpu);
+
     env->vfp.xregs[ARM_VFP_FPSID] = cpu->reset_fpsid;
     env->vfp.xregs[ARM_VFP_MVFR0] = cpu->mvfr0;
     env->vfp.xregs[ARM_VFP_MVFR1] = cpu->mvfr1;
diff --git a/target-arm/cpu.h b/target-arm/cpu.h
index 7346c5f9d6..ebca342e42 100644
--- a/target-arm/cpu.h
+++ b/target-arm/cpu.h
@@ -1448,6 +1448,9 @@ static inline bool cp_access_ok(int current_el,
     return (ri->access >> ((current_el * 2) + isread)) & 1;
 }
 
+/* Raw read of a coprocessor register (as needed for migration, etc) */
+uint64_t read_raw_cp_reg(CPUARMState *env, const ARMCPRegInfo *ri);
+
 /**
  * write_list_to_cpustate
  * @cpu: ARMCPU
diff --git a/target-arm/helper.c b/target-arm/helper.c
index 4a7dd24bb2..49ce612ab1 100644
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -144,7 +144,7 @@ static void *raw_ptr(CPUARMState *env, const ARMCPRegInfo *ri)
     return (char *)env + ri->fieldoffset;
 }
 
-static uint64_t read_raw_cp_reg(CPUARMState *env, const ARMCPRegInfo *ri)
+uint64_t read_raw_cp_reg(CPUARMState *env, const ARMCPRegInfo *ri)
 {
     /* Raw read of a coprocessor register (as needed for migration, etc). */
     if (ri->type & ARM_CP_CONST) {