util: use shutdown from trezor-core instead of system_halt

bootloader/bootloader.c

@@ -46,7 +46,7 @@ void layoutFirmwareHash(const uint8_t *hash)
 void show_halt(void)
 {
 	layoutDialog(&bmp_icon_error, NULL, NULL, NULL, "Unofficial firmware", "aborted.", NULL, "Unplug your TREZOR", "contact our support.", NULL);
-	system_halt();
+	shutdown();
 }
 
 void show_unofficial_warning(const uint8_t *hash)

firmware/storage.c

@@ -130,7 +130,7 @@ static char CONFIDENTIAL sessionPassphrase[51];
 void storage_show_error(void)
 {
 	layoutDialog(&bmp_icon_error, NULL, NULL, NULL, _("Storage failure"), _("detected."), NULL, _("Please unplug"), _("the device."), NULL);
-	system_halt();
+	shutdown();
 }
 
 void storage_check_flash_errors(void)

startup.s

@@ -36,4 +36,28 @@ reset_handler:
   // loop forever if the application code returns
   b .
 
+  .global shutdown
+  .type shutdown, STT_FUNC
+shutdown:
+  cpsid f
+  ldr r0, =0
+  mov r1, r0
+  mov r2, r0
+  mov r3, r0
+  mov r4, r0
+  mov r5, r0
+  mov r6, r0
+  mov r7, r0
+  mov r8, r0
+  mov r9, r0
+  mov r10, r0
+  mov r11, r0
+  mov r12, r0
+  ldr lr, =0xffffffff
+  ldr r0, =_ram_start
+  ldr r1, =_ram_end
+  // set to value in r2
+  bl memset_reg
+  b . // loop forever
+
   .end

util.c

@@ -66,8 +66,3 @@ uint32_t readprotobufint(uint8_t **ptr)
 	(*ptr)++;
 	return result;
 }
-
-void __attribute__((noreturn)) system_halt(void)
-{
-	for (;;) {} // loop forever
-}

util.h

@@ -43,15 +43,13 @@ void data2hex(const void *data, uint32_t len, char *str);
 // read protobuf integer and advance pointer
 uint32_t readprotobufint(uint8_t **ptr);
 
-// halt execution (or do an endless loop)
-void __attribute__((noreturn)) system_halt(void);
-
 #if !EMULATOR
 // defined in memory.ld
 extern uint8_t _ram_start[], _ram_end[];
 
 // defined in startup.s
 extern void memset_reg(void *start, void *stop, uint32_t val);
+extern void __attribute__((noreturn)) shutdown(void);
 
 #define FW_SIGNED       0x5A3CA5C3
 #define FW_UNTRUSTED    0x00000000