hw/avr/atmega: Fix wrong initial value of stack pointer

The current implementation initializes the stack pointer of AVR devices
to 0. Although older AVR devices used to be like that, newer ones set
it to RAMEND.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1525
Signed-off-by: Gihun Nam <gihun.nam@outlook.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-ID: <PH0P222MB0010877445B594724D40C924DEBDA@PH0P222MB0010.NAMP222.PROD.OUTLOOK.COM>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
(cherry picked from commit 235948b)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

hw/avr/atmega.c

@@ -233,6 +233,10 @@ static void atmega_realize(DeviceState *dev, Error **errp)
 
     /* CPU */
     object_initialize_child(OBJECT(dev), "cpu", &s->cpu, mc->cpu_type);
+
+    object_property_set_uint(OBJECT(&s->cpu), "init-sp",
+                             mc->io_size + mc->sram_size - 1, &error_abort);
+
     qdev_realize(DEVICE(&s->cpu), NULL, &error_abort);
     cpudev = DEVICE(&s->cpu);
 

target/avr/cpu.c

@@ -25,6 +25,7 @@
 #include "cpu.h"
 #include "disas/dis-asm.h"
 #include "tcg/debug-assert.h"
+#include "hw/qdev-properties.h"
 
 static void avr_cpu_set_pc(CPUState *cs, vaddr value)
 {
@@ -95,7 +96,7 @@ static void avr_cpu_reset_hold(Object *obj)
     env->rampY = 0;
     env->rampZ = 0;
     env->eind = 0;
-    env->sp = 0;
+    env->sp = cpu->init_sp;
 
     env->skip = 0;
 
@@ -154,6 +155,11 @@ static void avr_cpu_initfn(Object *obj)
                       sizeof(cpu->env.intsrc) * 8);
 }
 
+static Property avr_cpu_properties[] = {
+    DEFINE_PROP_UINT32("init-sp", AVRCPU, init_sp, 0),
+    DEFINE_PROP_END_OF_LIST()
+};
+
 static ObjectClass *avr_cpu_class_by_name(const char *cpu_model)
 {
     ObjectClass *oc;
@@ -231,6 +237,8 @@ static void avr_cpu_class_init(ObjectClass *oc, void *data)
 
     device_class_set_parent_realize(dc, avr_cpu_realizefn, &mcc->parent_realize);
 
+    device_class_set_props(dc, avr_cpu_properties);
+
     resettable_class_set_parent_phases(rc, NULL, avr_cpu_reset_hold, NULL,
                                        &mcc->parent_phases);
 

target/avr/cpu.h

@@ -150,6 +150,9 @@ struct ArchCPU {
 
     CPUNegativeOffsetState neg;
     CPUAVRState env;
+
+    /* Initial value of stack pointer */
+    uint32_t init_sp;
 };
 
 extern const struct VMStateDescription vms_avr_cpu;