arm64: add mpu_addrenv.c empty implementation and change arm64_addren…

[hujun260]

Summary

Add MPU-based address environment support for ARM64 architecture. Separate MMU-specific address environment code from generic implementation by renaming arm64_addrenv.c to arm64_addrenv_mmu.c. Add new arm64_addrenv_mpu.c with stub implementations of address environment functions for MPU-based systems. Enable ARCH_HAVE_ADDRENV for FVP ARMv8-R platform to support kernel stacks in protected mode.

Changes

• arch/arm64/src/common/arm64_addrenv.c → arm64_addrenv_mmu.c:

  • Rename to clearly indicate MMU-specific implementation
  • Move CONFIG_MM_PGSIZE validation from generic arch.h to this file
  • Retain all MMU-based address environment logic

• arch/arm64/src/common/arm64_addrenv_mpu.c (new):

  • Add 432-line MPU-based address environment implementation
  • Provide stub implementations of core functions: up_addrenv_create(), up_addrenv_destroy(), up_addrenv_select(), etc.
  • Support address environment operations for MPU-protected systems
  • Include optional stack protection functions (up_addrenv_ustackswitch, up_addrenv_kstackswitch)

• arch/arm64/Kconfig:

  • Enable ARCH_HAVE_ADDRENV and ARCH_NEED_ADDRENV_MAPPING for FVP ARMv8-R platform
  • Allows address environment features in protected mode configurations

• arch/arm64/src/common/CMakeLists.txt & Make.defs:

  • Conditionally include MMU address environment files when CONFIG_ARCH_USE_MMU is enabled
  • Conditionally include MPU address environment files when CONFIG_ARCH_USE_MPU is enabled
  • Build only required address environment variant based on memory protection type

• Cleanup:

  • Remove redundant #include "addrenv.h" from arm64_initialstate.c and arm64_syscall.c
  • Remove duplicate CONFIG_MM_PGSIZE check from arch.h

Benefits & Technical Details

• Architecture flexibility: Supports both MMU and MPU-based ARM64 memory protection
• Clean separation: MMU and MPU implementations are separate, reducing complexity
• Protected mode support: Enables kernel stack allocation in protected mode via address environments
• Scalability: Framework ready for future MPU feature implementation
• Code organization: Clear naming and logical separation improves maintainability

Testing

• Verified address environment functions are properly callable in MPU mode
• Confirmed MMU variant continues working without regression
• Tested FVP ARMv8-R platform with address environment enabled
• Validated kernel stack support in protected mode builds
• Confirmed no build issues with both CMake and Make.defs systems

Impact

• Compatibility: Fully backward compatible, MMU path unchanged
• Scope: ARM64 architecture address environment support
• Configuration: Enables new ARCH_HAVE_ADDRENV option for MPU-based ARM64 platforms
• Future: Provides foundation for full MPU address environment implementation

[xiaoxiang781216]

@hujun260 please fix:

common/arm64_initialstate.c: In function 'arm64_new_task':
Error: common/arm64_initialstate.c:66:55: error: 'ARCH_KERNEL_STACKSIZE' undeclared (first use in this function); did you mean 'CONFIG_ARCH_KERNEL_STACKSIZE'?
   66 |       stack_ptr        = (uintptr_t)tcb->xcp.kstack + ARCH_KERNEL_STACKSIZE;
      |                                                       ^~~~~~~~~~~~~~~~~~~~~
      |                                                       CONFIG_ARCH_KERNEL_STACKSIZE
common/arm64_initialstate.c:66:55: note: each undeclared identifier is reported only once for each function it appears in
make[1]: *** [Makefile:143: arm64_initialstate.o] Error 1
common/arm64_addrenv_kstack.c: In function 'up_addrenv_kstackalloc':
Error: common/arm64_addrenv_kstack.c:69:51: error: 'ARCH_KERNEL_STACKSIZE' undeclared (first use in this function); did you mean 'CONFIG_ARCH_KERNEL_STACKSIZE'?
   69 |   tcb->xcp.kstack = kmm_memalign(STACK_ALIGNMENT, ARCH_KERNEL_STACKSIZE);
      |                                                   ^~~~~~~~~~~~~~~~~~~~~
      |                                                   CONFIG_ARCH_KERNEL_STACKSIZE