tests/subsys/llext: cleanup memory protection options

Most of the tests in the LLEXT subsystem test suite run with memory
protection hardware (MPU/MMU) disabled, to avoid including memory domain
issues while testing the core functionality. Only a few tests need to
run with MPU/MMU enabled.

This patch simplifies the testcase.yaml by setting the memory protection
as disabled in a shared config file that is included by most tests.

Signed-off-by: Luca Burelli <l.burelli@arduino.cc>

tests/subsys/llext/simple/no_mem_protection.conf

@@ -0,0 +1,8 @@
+# Disable MPU and MMU on all supported arches for the bulk of the tests.
+#
+# This uses the fact that setting an unknown symbol to 'n' has no effect,
+# so it is safe to group different arch-specific settings here.
+#
+CONFIG_ARM_MPU=n
+CONFIG_ARM_AARCH32_MMU=n
+CONFIG_RISCV_PMP=n

tests/subsys/llext/simple/prj.conf

@@ -7,3 +7,6 @@ CONFIG_LLEXT_EXPORT_DEVICES=y
 CONFIG_LLEXT_LOG_LEVEL_DBG=y
 
 CONFIG_APPLICATION_DEFINED_SYSCALL=y
+
+# The bulk of the tests run with MPU/MMU disabled by including additional
+# configuration entries from no_mem_protection.conf.

tests/subsys/llext/simple/testcase.yaml

@@ -20,6 +20,8 @@ common:
     - mps2/an521/cpu0         # ARM Cortex-M33 (ARMv8-M ISA)
   extra_configs:
     - arch:arm64:CONFIG_LLEXT_HEAP_SIZE=128
+  extra_conf_files:
+    - prj.conf
 
 tests:
   # While there is in practice no value in compiling subsys/llext/*.c
@@ -29,15 +31,15 @@ tests:
   llext.simple.loader_build:
     build_only: true
 
-  # Run the suite with all combinations of core Kconfig options for the llext
-  # subsystem (storage type, ELF type, MPU/MMU etc)
+  # Run the suite with all combinations of core Kconfig options for the LLEXT
+  # subsystem (storage type, ELF type, MPU/MMU etc). To focus on LLEXT issues,
+  # most tests include no_mem_protection.conf, which disables memory protection
+  # hardware completely.
   llext.simple.readonly:
     arch_allow: arm riscv # Xtensa needs writable storage
     filter: not CONFIG_MPU and not CONFIG_MMU
+    extra_conf_files: ['no_mem_protection.conf']
     extra_configs:
-      - arch:arm:CONFIG_ARM_MPU=n
-      - arch:arm:CONFIG_ARM_AARCH32_MMU=n
-      - arch:riscv:CONFIG_RISCV_PMP=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=n
   llext.simple.readonly_mpu:
     min_ram: 128
@@ -58,20 +60,16 @@ tests:
     integration_platforms:
       - qemu_xtensa/dc233c      # Xtensa ISA
     filter: not CONFIG_MPU and not CONFIG_MMU
+    extra_conf_files: ['no_mem_protection.conf']
     extra_configs:
-      - arch:arm:CONFIG_ARM_MPU=n
-      - arch:arm:CONFIG_ARM_AARCH32_MMU=n
-      - arch:riscv:CONFIG_RISCV_PMP=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=y
   llext.simple.writable_relocatable:
     arch_allow: arm xtensa riscv
     integration_platforms:
       - qemu_xtensa/dc233c      # Xtensa ISA
     filter: not CONFIG_MPU and not CONFIG_MMU
+    extra_conf_files: ['no_mem_protection.conf']
     extra_configs:
-      - arch:arm:CONFIG_ARM_MPU=n
-      - arch:arm:CONFIG_ARM_AARCH32_MMU=n
-      - arch:riscv:CONFIG_RISCV_PMP=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=y
       - CONFIG_LLEXT_TYPE_ELF_RELOCATABLE=y
 
@@ -82,10 +80,8 @@ tests:
     integration_platforms:
       - qemu_xtensa/dc233c      # Xtensa ISA
     filter: not CONFIG_MPU and not CONFIG_MMU
+    extra_conf_files: ['no_mem_protection.conf']
     extra_configs:
-      - arch:arm:CONFIG_ARM_MPU=n
-      - arch:arm:CONFIG_ARM_AARCH32_MMU=n
-      - arch:riscv:CONFIG_RISCV_PMP=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=y
       - CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID=y
   llext.simple.writable_relocatable_slid_linking:
@@ -93,10 +89,8 @@ tests:
     integration_platforms:
       - qemu_xtensa/dc233c      # Xtensa ISA
     filter: not CONFIG_MPU and not CONFIG_MMU
+    extra_conf_files: ['no_mem_protection.conf']
     extra_configs:
-      - arch:arm:CONFIG_ARM_MPU=n
-      - arch:arm:CONFIG_ARM_AARCH32_MMU=n
-      - arch:riscv:CONFIG_RISCV_PMP=n
       - CONFIG_LLEXT_STORAGE_WRITABLE=y
       - CONFIG_LLEXT_TYPE_ELF_RELOCATABLE=y
       - CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID=y