arch: arm: BusFault, NMI, and HardFault in Secure state when in test

This commit enables the option to route the BusFault,
HardFault, and NMI exceptions in Secure state, when
building for Cortex-M CPUs with ARM_SECURE_FIRMWARE=y.
This allows the various test to utilize BusFault,
HardFault and NMI exceptions during testing.

Signed-off-by: Ioannis Glaropoulos <Ioannis.Glaropoulos@nordicsemi.no>

arch/arm/core/Kconfig

@@ -105,6 +105,13 @@ comment "Secure firmware"
 comment "Non-secure firmware"
 	depends on !ARM_SECURE_FIRMWARE
 
+config ARM_SECURE_BUSFAULT_HARDFAULT_NMI
+	bool "BusFault, HardFault, and NMI target Secure state"
+	depends on ARM_SECURE_FIRMWARE
+	help
+	  Force NMI, HardFault, and BusFault (in Mainline ARMv8-M)
+	  exceptions as Secure exceptions.
+
 config ARM_FIRMWARE_HAS_SECURE_ENTRY_FUNCS
 	bool "Secure Firmware has Secure Entry functions"
 	depends on ARM_SECURE_FIRMWARE

arch/arm/include/cortex_m/exc.h

@@ -112,7 +112,8 @@ static ALWAYS_INLINE void z_ExcSetup(void)
 #endif /* CONFIG_ARM_SECURE_FIRMWARE */
 #endif /* CONFIG_CPU_CORTEX_M_HAS_PROGRAMMABLE_FAULT_PRIOS */
 
-#if defined(CONFIG_ARM_SECURE_FIRMWARE)
+#if defined(CONFIG_ARM_SECURE_FIRMWARE) && \
+	!defined(CONFIG_ARM_SECURE_BUSFAULT_HARDFAULT_NMI)
 	/* Set NMI, Hard, and Bus Faults as Non-Secure.
 	 * NMI and Bus Faults targeting the Secure state will
 	 * escalate to a SecureFault or SecureHardFault.
@@ -126,7 +127,7 @@ static ALWAYS_INLINE void z_ExcSetup(void)
 	 * in a PE with the Main Extension instead generate a
 	 * SecureHardFault in a PE without the Main Extension.
 	 */
-#endif /* CONFIG_ARM_SECURE_FIRMWARE */
+#endif /* ARM_SECURE_FIRMWARE && !ARM_SECURE_BUSFAULT_HARDFAULT_NMI */
 }
 
 /**

subsys/testsuite/Kconfig

@@ -111,4 +111,19 @@ config TEST_FLASH_DRIVERS
 	  This option will help test the flash drivers. This should be enabled
 	  only when using qemu_x86.
 
+config TEST_ARM_CORTEX_M
+	bool
+	depends on CPU_CORTEX_M
+	default y
+	select ARM_SECURE_BUSFAULT_HARDFAULT_NMI if ARM_SECURE_FIRMWARE
+	help
+	  ARM Cortex-M configuration required when testing.
+
+	  Currently, this option is only utilized, to force routing
+	  BusFault, HardFault, and NMI exceptions to Secure State,
+	  when building a Secure ARMv8-M firmware. This will allow
+	  the testing suite to utilize these exceptions, in tests.
+	  Note that by default, when building with ARM_SECURE_FIRMWARE
+	  set, these exceptions are set to target the Non-Secure state.
+
 endmenu