target-arm: Override do_interrupt for ARMv7-M profile

Enable ARMCPUInfo to specify a custom class_init functions.
Introduce arm_v7m_class_init() and use it for "cortex-m3" model.

Instead of forwarding from arm_cpu_do_interrupt() to do_interrupt_v7m(),
override CPUClass::do_interrupt with arm_v7m_cpu_do_interrupt()
in arm_v7m_class_init().
Acked-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NAndreas Färber <afaerber@suse.de>

target-arm/cpu-qom.h

@@ -114,5 +114,6 @@ static inline ARMCPU *arm_env_get_cpu(CPUARMState *env)
 void register_cp_regs_for_features(ARMCPU *cpu);
 
 void arm_cpu_do_interrupt(CPUState *cpu);
+void arm_v7m_cpu_do_interrupt(CPUState *cpu);
 
 #endif

target-arm/cpu.c

@@ -412,6 +412,15 @@ static void cortex_m3_initfn(Object *obj)
     cpu->midr = 0x410fc231;
 }
 
+static void arm_v7m_class_init(ObjectClass *oc, void *data)
+{
+#ifndef CONFIG_USER_ONLY
+    CPUClass *cc = CPU_CLASS(oc);
+
+    cc->do_interrupt = arm_v7m_cpu_do_interrupt;
+#endif
+}
+
 static const ARMCPRegInfo cortexa8_cp_reginfo[] = {
     { .name = "L2LOCKDOWN", .cp = 15, .crn = 9, .crm = 0, .opc1 = 1, .opc2 = 0,
       .access = PL1_RW, .type = ARM_CP_CONST, .resetvalue = 0 },
@@ -752,6 +761,7 @@ static void arm_any_initfn(Object *obj)
 typedef struct ARMCPUInfo {
     const char *name;
     void (*initfn)(Object *obj);
+    void (*class_init)(ObjectClass *oc, void *data);
 } ARMCPUInfo;
 
 static const ARMCPUInfo arm_cpus[] = {
@@ -766,7 +776,8 @@ static const ARMCPUInfo arm_cpus[] = {
     { .name = "arm1136",     .initfn = arm1136_initfn },
     { .name = "arm1176",     .initfn = arm1176_initfn },
     { .name = "arm11mpcore", .initfn = arm11mpcore_initfn },
-    { .name = "cortex-m3",   .initfn = cortex_m3_initfn },
+    { .name = "cortex-m3",   .initfn = cortex_m3_initfn,
+                             .class_init = arm_v7m_class_init },
     { .name = "cortex-a8",   .initfn = cortex_a8_initfn },
     { .name = "cortex-a9",   .initfn = cortex_a9_initfn },
     { .name = "cortex-a15",  .initfn = cortex_a15_initfn },
@@ -812,6 +823,7 @@ static void cpu_register(const ARMCPUInfo *info)
         .instance_size = sizeof(ARMCPU),
         .instance_init = info->initfn,
         .class_size = sizeof(ARMCPUClass),
+        .class_init = info->class_init,
     };
 
     type_info.name = g_strdup_printf("%s-" TYPE_ARM_CPU, info->name);

target-arm/helper.c

@@ -1725,8 +1725,10 @@ static void do_v7m_exception_exit(CPUARMState *env)
        pointer.  */
 }
 
-static void do_interrupt_v7m(CPUARMState *env)
+void arm_v7m_cpu_do_interrupt(CPUState *cs)
 {
+    ARMCPU *cpu = ARM_CPU(cs);
+    CPUARMState *env = &cpu->env;
     uint32_t xpsr = xpsr_read(env);
     uint32_t lr;
     uint32_t addr;
@@ -1811,10 +1813,8 @@ void arm_cpu_do_interrupt(CPUState *cs)
     int new_mode;
     uint32_t offset;
 
-    if (IS_M(env)) {
-        do_interrupt_v7m(env);
-        return;
-    }
+    assert(!IS_M(env));
+
     /* TODO: Vectored interrupt controller.  */
     switch (env->exception_index) {
     case EXCP_UDEF: