zephyr: make images loaded by MCUboot enable arch core HW regs init

Instruct Zephyr images that are loaded by MCUboot to
force the initialization of architecture core HW registers,
if the architecture supports the functionality.

Signed-off-by: Ioannis Glaropoulos <[email protected]>

Kconfig.zephyr

@@ -384,6 +384,7 @@ config BOOTLOADER_SRAM_SIZE
 config BOOTLOADER_MCUBOOT
 	bool "MCUboot bootloader support"
 	select USE_DT_CODE_PARTITION
+	imply INIT_ARCH_HW_AT_BOOT if ARCH_SUPPORTS_ARCH_HW_INIT
 	help
 	  This option signifies that the target uses MCUboot as a bootloader,
 	  or in other words that the image is to be chain-loaded by MCUboot.
@@ -397,6 +398,11 @@ config BOOTLOADER_MCUBOOT
 	      (or Armv8-M baseline) targets with no built-in vector relocation
 	      mechanisms
 
+	  By default, this option instructs Zephyr to initialize the core
+	  architecture HW registers during boot, when this is supported by
+	  the application. This removes the need by MCUboot to reset
+	  the core registers' state itself.
+
 if BOOTLOADER_MCUBOOT
 
 config MCUBOOT_SIGNATURE_KEY_FILE