refactor(core): refactor coreapp emu startup, run coreapp as a task

diff --git a/core/SConscript.unix b/core/SConscript.unix
index e17d8cad6..6bcb389f5 100644
--- a/core/SConscript.unix
+++ b/core/SConscript.unix
@@ -24,6 +24,7 @@ if BENCHMARK and PYOPT != '0':
   exit(1)
 
 FEATURES_WANTED = [
+    "applet",
     "ble",
     "display",
     "dma2d",
@@ -263,6 +264,7 @@ if not PRODUCTION:
     SOURCE_MOD += ['embed/rtl/printf.c']
 
 CPPDEFINES_MOD += [
+    'KERNEL',
     'TRANSLATIONS',
     'FANCY_FATAL_ERROR',
     ]
@@ -417,6 +419,7 @@ SOURCE_UNIX = [
     'embed/projects/unix/main_main.c',
     'embed/projects/unix/main.c',
     'embed/projects/unix/profile.c',
+    'embed/projects/unix/rust_c_setup.c',
     'vendor/micropython/ports/unix/alloc.c',
     'vendor/micropython/ports/unix/gccollect.c',
     'vendor/micropython/ports/unix/input.c',
diff --git a/core/embed/projects/unix/main.c b/core/embed/projects/unix/main.c
index 9f33d13b3..1cc870225 100644
--- a/core/embed/projects/unix/main.c
+++ b/core/embed/projects/unix/main.c
@@ -26,50 +26,26 @@
 
 #include <trezor_rtl.h>
 
-#include <SDL.h>
+#include <sys/system.h>
+
+#ifdef USE_DBG_CONSOLE
+#include <sys/dbg_console.h>
+#endif
 
 #include <ctype.h>
 #include <errno.h>
 #include <signal.h>
 #include <stdarg.h>
+#include <stdlib.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
-#include <io/display.h>
-#include <io/rsod.h>
-#include <io/usb_config.h>
-#include <sec/secret.h>
-#include <sec/unit_properties.h>
-#include <sys/flash.h>
-#include <sys/flash_otp.h>
-#include <sys/system.h>
-#include <sys/systimer.h>
 #include "extmod/misc.h"
 #include "extmod/vfs_posix.h"
 #include "genhdr/mpversion.h"
 #include "input.h"
 
-#ifdef USE_BUTTON
-#include <io/button.h>
-#endif
-
-#ifdef USE_TOUCH
-#include <io/touch.h>
-#endif
-
-#ifdef USE_BLE
-#include <io/ble.h>
-#endif
-
-#ifdef USE_TROPIC
-#include <sec/tropic.h>
-#endif
-
-#ifdef USE_DBG_CONSOLE
-#include <sys/dbg_console.h>
-#endif
-
 #include "py/builtin.h"
 #include "py/compile.h"
 #include "py/gc.h"
@@ -432,19 +408,6 @@ STATIC void set_sys_argv(char *argv[], int argc, int start_arg) {
   }
 }
 
-// Inject SystemExit exception. This is primarily needed by `prof/__main__.py`
-// to run the flush the coverage data.
-static void __attribute__((noreturn)) main_clean_exit() {
-  const int status = 3;
-  fflush(stdout);
-  fflush(stderr);
-  // sys.exit is disabled, so raise a SystemExit exception directly
-  nlr_raise(mp_obj_new_exception_arg1(&mp_type_SystemExit,
-                                      MP_OBJ_NEW_SMALL_INT(status)));
-  // the above shouldn't return, but make sure we exit just in case
-  exit(status);
-}
-
 #ifdef _WIN32
 #define PATHLIST_SEP_CHAR ';'
 #else
@@ -491,61 +454,14 @@ reimport:
   return 0;
 }
 
-static int sdl_event_filter(void *userdata, SDL_Event *event) {
-  switch (event->type) {
-    case SDL_QUIT:
-      main_clean_exit();
-      return 0;
-    case SDL_KEYUP:
-      if (event->key.repeat) {
-        return 0;
-      }
-      switch (event->key.keysym.sym) {
-        case SDLK_ESCAPE:
-          main_clean_exit();
-          return 0;
-        case SDLK_s:
-          display_save("emu");
-          return 0;
-      }
-      break;
-  }
-  return 1;
-}
-
-void drivers_init(uint16_t tropic_model_port) {
-  flash_init();
-  flash_otp_init();
-
-  unit_properties_init();
-
-  display_init(DISPLAY_RESET_CONTENT);
-
-#if USE_TOUCH
-  touch_init();
-#endif
-
-#ifdef USE_BUTTON
-  button_init();
-#endif
-
-#ifdef USE_TROPIC
-  ensure(tropic_init(tropic_model_port) ? sectrue : secfalse,
-         "tropic initialization failed");
-#endif
-
-  usb_configure(NULL);
-
-#ifdef USE_BLE
-  ble_init();
-#endif
-}
-
-// Initialize the system and drivers for running tests in the Rust code.
-// The function is called from the Rust before the test main function is run.
-void rust_tests_c_setup(void) {
-  system_init(NULL);
-  drivers_init(28992);
+// Inject SystemExit exception. This is primarily needed by `prof/__main__.py`
+// to run the flush the coverage data.
+void __attribute__((noreturn)) coreapp_throw_exit_exception(int code) {
+  // sys.exit is disabled, so raise a SystemExit exception directly
+  nlr_raise(mp_obj_new_exception_arg1(&mp_type_SystemExit,
+                                      MP_OBJ_NEW_SMALL_INT(code)));
+  // the above shouldn't return, but make sure we exit just in case
+  exit(code);
 }
 
 MP_NOINLINE int main_(int argc, char **argv) {
@@ -567,32 +483,6 @@ MP_NOINLINE int main_(int argc, char **argv) {
 
   pre_process_options(argc, argv);
 
-#ifdef LOCKABLE_BOOTLOADER
-  secret_lock_bootloader();
-#endif
-
-  system_init(&rsod_panic_handler);
-
-  char *tropic_model_port_str = getenv("TROPIC_MODEL_PORT");
-  uint16_t tropic_model_port;
-  if (tropic_model_port_str == NULL) {
-    tropic_model_port = 28992;
-  } else {
-    char *endptr;
-    long port_long = strtol(tropic_model_port_str, &endptr, 10);
-
-    if (*endptr != '\0' || port_long < 0 || port_long > 65535) {
-      printf("FATAL: invalid TROPIC_MODEL_PORT\n");
-      exit(1);
-    }
-
-    tropic_model_port = (uint16_t)port_long;
-  }
-
-  drivers_init(tropic_model_port);
-
-  SDL_SetEventFilter(sdl_event_filter, NULL);
-
 #if MICROPY_ENABLE_GC
   char *heap = malloc(heap_size);
   gc_init(heap, heap + heap_size);
@@ -789,6 +679,19 @@ MP_NOINLINE int main_(int argc, char **argv) {
   return ret & 0xff;
 }
 
+int coreapp_emu(int argc, char **argv) {
+#if MICROPY_PY_THREAD
+  mp_thread_init();
+#endif
+  // We should capture stack top ASAP after start, and it should be
+  // captured guaranteedly before any other stack variables are allocated.
+  // For this, actual main (renamed main_) should not be inlined into
+  // this function. main_() itself may have other functions inlined (with
+  // their own stack variables), that's why we need this main/main_ split.
+  mp_stack_ctrl_init();
+  return main_(argc, argv);
+}
+
 #if !MICROPY_VFS
 
 #ifdef TREZOR_EMULATOR_FROZEN
diff --git a/core/embed/projects/unix/main_main.c b/core/embed/projects/unix/main_main.c
index 6a59764c1..85e7b9f98 100644
--- a/core/embed/projects/unix/main_main.c
+++ b/core/embed/projects/unix/main_main.c
@@ -1,27 +1,188 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
 #include <trezor_rtl.h>
 
-#include "py/mpthread.h"
-#include "py/runtime.h"
-#include "py/stackctrl.h"
+#include <io/display.h>
+#include <io/rsod.h>
+#include <io/usb_config.h>
+#include <sec/secret.h>
+#include <sec/unit_properties.h>
+#include <sys/applet.h>
+#include <sys/bootutils.h>
+#include <sys/coreapp.h>
+#include <sys/flash.h>
+#include <sys/flash_otp.h>
+#include <sys/system.h>
+#include <sys/systick.h>
+#include <sys/systimer.h>
+
+#ifdef USE_BUTTON
+#include <io/button.h>
+#endif
+
+#ifdef USE_BLE
+#include <io/ble.h>
+#endif
+
+#ifdef USE_TOUCH
+#include <io/touch.h>
+#endif
+
+#ifdef USE_TROPIC
+#include <sec/tropic.h>
+#endif
+
 #ifdef USE_SECP256K1_ZKP
 #include "zkp_context.h"
 #endif
 
-MP_NOINLINE int main_(int argc, char **argv);
+#include <SDL.h>
+
+#ifdef USE_TROPIC
+static uint16_t get_tropic_model_port(void) {
+  char *port_str = getenv("TROPIC_MODEL_PORT");
+  if (port_str != NULL) {
+    char *endptr;
+    long port_long = strtol(port_str, &endptr, 10);
+    if (*endptr != '\0' || port_long < 0 || port_long > 65535) {
+      printf("FATAL: invalid TROPIC_MODEL_PORT\n");
+      exit(1);
+    }
+    return (uint16_t)port_long;
+  }
+  return 28992;
+}
+#endif
+
+static void drivers_deinit(void) { flash_deinit(); }
+
+static void drivers_init(void) {
+  flash_init();
+  flash_otp_init();
+
+  unit_properties_init();
+
+  display_init(DISPLAY_RESET_CONTENT);
+
+#if USE_TOUCH
+  touch_init();
+#endif
+
+#ifdef USE_BUTTON
+  button_init();
+#endif
+
+#ifdef USE_TROPIC
+  tropic_init(get_tropic_model_port());
+#endif
+
+  usb_configure(NULL);
+
+#ifdef USE_BLE
+  ble_init();
+#endif
+}
+
+// Throws MicroPython SystemExit exception in the context of the given task
+static void throw_exit_exception(systask_t *task, int code) {
+  extern void coreapp_throw_exit_exception(int code);
+  // Push call to the task
+  systask_push_call(task, (void *)coreapp_throw_exit_exception, code, 0, 0);
+  // Yield to the task and throw the exception
+  systask_yield_to(task);
+  // We are back and the task should be terminated by now
+}
+
+static int sdl_event_filter(void *userdata, SDL_Event *event) {
+  applet_t *coreapp = (applet_t *)userdata;
+
+  switch (event->type) {
+    case SDL_QUIT:
+      throw_exit_exception(&coreapp->task, 0);
+      return 0;
+    case SDL_KEYUP:
+      if (event->key.repeat) {
+        return 0;
+      }
+      switch (event->key.keysym.sym) {
+        case SDLK_ESCAPE:
+          throw_exit_exception(&coreapp->task, 0);
+          return 0;
+        case SDLK_s:
+          display_save("emu");
+          return 0;
+      }
+      break;
+  }
+  return 1;
+}
+
+// Kernel task main loop
+//
+// Returns when the coreapp task is terminated
+static void kernel_loop(applet_t *coreapp) {
+  do {
+    sysevents_t awaited = {0};
+    sysevents_t signalled = {0};
+
+    sysevents_poll(&awaited, &signalled, ticks_timeout(100));
+
+  } while (applet_is_alive(coreapp));
+}
 
 int main(int argc, char **argv) {
+  system_init(&rsod_panic_handler);
+
+#ifdef LOCKABLE_BOOTLOADER
+  secret_lock_bootloader();
+#endif
+
 #ifdef USE_SECP256K1_ZKP
   ensure(sectrue * (zkp_context_init() == 0), NULL);
 #endif
 
-#if MICROPY_PY_THREAD
-  mp_thread_init();
-#endif
-  // We should capture stack top ASAP after start, and it should be
-  // captured guaranteedly before any other stack variables are allocated.
-  // For this, actual main (renamed main_) should not be inlined into
-  // this function. main_() itself may have other functions inlined (with
-  // their own stack variables), that's why we need this main/main_ split.
-  mp_stack_ctrl_init();
-  return main_(argc, argv);
+  drivers_init();
+
+  applet_t coreapp;
+
+  // Initialize coreapp task
+  if (!coreapp_init(&coreapp, argc, argv)) {
+    error_shutdown("Cannot start coreapp");
+  }
+
+  // Set SDL event filter to catch quit events
+  SDL_SetEventFilter(sdl_event_filter, &coreapp);
+
+  // Run the coreapp task
+  applet_run(&coreapp);
+
+  // Loop until the coreapp task is terminated
+  kernel_loop(&coreapp);
+
+  // Show RSOD if the coreapp task did not exit cleanly
+  if (coreapp.task.pminfo.reason != TASK_TERM_REASON_EXIT) {
+    rsod_gui(&coreapp.task.pminfo);
+    reboot_or_halt_after_rsod();
+  }
+
+  drivers_deinit();
+
+  return coreapp.task.pminfo.exit.code;
 }
diff --git a/core/embed/projects/unix/rust_c_setup.c b/core/embed/projects/unix/rust_c_setup.c
new file mode 100644
index 000000000..92a180e58
--- /dev/null
+++ b/core/embed/projects/unix/rust_c_setup.c
@@ -0,0 +1,66 @@
+/*
+ * This file is part of the Trezor project, https://trezor.io/
+ *
+ * Copyright (c) SatoshiLabs
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <trezor_rtl.h>
+
+#include <io/display.h>
+#include <io/usb_config.h>
+#include <sec/unit_properties.h>
+#include <sys/flash.h>
+#include <sys/flash_otp.h>
+#include <sys/system.h>
+
+#ifdef USE_BUTTON
+#include <io/button.h>
+#endif
+
+#ifdef USE_TOUCH
+#include <io/touch.h>
+#endif
+
+#ifdef USE_TROPIC
+#include <sec/tropic.h>
+#endif
+
+// Initialize the system and drivers for running tests in the Rust code.
+// The function is called from the Rust before the test main function is run.
+void rust_tests_c_setup(void) {
+  system_init(NULL);
+
+  flash_init();
+  flash_otp_init();
+
+  unit_properties_init();
+
+  display_init(DISPLAY_RESET_CONTENT);
+
+#if USE_TOUCH
+  touch_init();
+#endif
+
+#ifdef USE_BUTTON
+  button_init();
+#endif
+
+#ifdef USE_TROPIC
+  tropic_init(28992);
+#endif
+
+  usb_configure(NULL);
+}