Add Nuvoton NuMaker M2354 Cortex-M23 target with TrustZone

[dgarske]

Summary

Adds support for the Nuvoton NuMaker-M2354 (Cortex-M23), introducing wolfBoot's first ARMv8-M baseline architecture target (CORTEX_M23). Includes a bare-metal HAL without BSP dependencies, necessary shared boot_arm.c fixes for ARMv8-M baseline support, updated build configs, unit tests, and emulator integration.

Key Changes

• HAL & Target Support (hal/m2354.*, arch.mk, config/examples/m2354*): Added bare-metal driver for FMC ISP flash, clock tree, UART0 console (PA6/PA7), and SAU/SCU TrustZone setup. Includes linker scripts and build configurations for TZ/non-TZ mode.
• ARMv8-M Boot Fixes (src/boot_arm.c):
  • Fixed do_boot() logic so ARMv8-M baseline targets perform secure-to-non-secure handoff instead of falling through to ARMv6/v7.
  • Replaced wide Thumb-2 encoding (bic.w) with C masking for BLXNS compatibility.
  • Sized vector table for 116 external interrupts; set IMAGE_HEADER_SIZE to 1024 for proper VTOR alignment.
• Crypto Math (sp_armthumb.o): Configured CORTEX_M23 to use Thumb-1 SP assembly (NO_ASM=0), dropping boot time from 2619 ms to 623 ms.
• Tooling & Tests: Added NSCBA provisioning script (set-m2354-nscba.sh), host flash unit tests, and m33mu emulator backend updates.

Hardware & Test Status

• NuMaker-M2354 Hardware: Tested both Non-TZ and TZ configurations (pyOCD/CMSIS-DAP). Validated image signature verification, secure-to-non-secure handoff via BLXNS, gateway veneers, swap updates, and rollback logic.
• Regression Check: Verified M33 code generation unchanged; confirmed handoff on STM32U585 (TZEN=1).
• CI Integration: Full update scenarios (factory boot, UART update, swap, fallback) passing on m33mu CI emulator workflow. Host unit tests pass for FMC flash driver.

Technical & Design Notes

• Memory Constraints: Only SRAM bank 0 is enabled at reset. wolfBoot links entirely within bank 0 so stack is valid prior to hal_init() enabling additional banks.
• Flash Aliases: Secure base is standard; NS view is offset by +0x10000000. Images are flashed separately due to non-contiguous address space under TZEN=1.
• Flash Optimization: hal_flash_erase() skips pre-erased pages to optimize update speed; hal_flash_write() uses 16-byte multi-word ISP programming.
• TrustZone Hardware Guard: hal_init() verifies SCU->FNSADDR against expected build bounds and panics on mismatch.

Out of Scope / Deferred

• TRNG & WOLFCRYPT_TZ: Non-secure crypto service deferred; HAL currently omits TRNG.
• CRPT Hardware Accelerator: Belongs in wolfCrypt port (weak isr_crpt alias included for future hookup).
• Key Store Root of Trust: Blocked due to upstream hardware/driver issue with M2354 Key Store ECC signature generation.

[Copilot]

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Pull request overview

Adds a new Nuvoton NuMaker-M2354 (Cortex-M23 / ARMv8-M baseline) target, including a self-contained HAL plus TrustZone support and host-side unit tests for the flash ISP driver.

Changes:

• Introduces M2354 HAL (flash ISP, clocks, UART0, TrustZone attribution) and linker scripts/configs for TZ and non-TZ builds
• Updates shared ARM boot path to support ARMv8-M baseline (Cortex-M23) handoff semantics
• Adds unit tests + CI build configs + provisioning script for the TrustZone flash boundary (NSCBA)

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
tools/unit-tests/unit-flash-m2354.c	New host unit tests for M2354 flash write/erase behavior and alias masking
tools/unit-tests/Makefile	Adds the new M2354 unit test target to the unit-test build
tools/scripts/set-m2354-nscba.sh	Provisioning helper script to program NSCBA via pyOCD
tools/config.mk	Adds CORTEX_M23 config knob into the shared config variable list
test-app/app_m2354.c	Adds a simple UART test application for update/confirm flows (TZ + non-TZ)
test-app/Makefile	Adds build flags/linker scripts for M2354 test app, including TZ non-secure build handling
test-app/ARM-m2354.ld	Linker script for secure/non-TZ M2354 test application
test-app/ARM-m2354-ns.ld	Linker script for non-secure (TZ) M2354 test application
src/boot_arm.c	Extends ARMv8-M boot procedure to include Cortex-M23 + adds M2354 IRQ vector mapping
hal/m2354.ld	Secure/TZ linker script for wolfBoot on M2354 (includes NSC veneers region)
hal/m2354.h	New M2354 register/geometry definitions (including NS alias conventions)
hal/m2354.c	New M2354 HAL implementation (flash ISP, clocks, UART, TrustZone setup)
hal/m2354-ns.ld	Non-TZ linker script variant for wolfBoot on M2354
docs/Targets.md	Documents M2354 target build/flash/TZ provisioning details
config/examples/m2354.config	Example config for non-TZ M2354 build
config/examples/m2354-tz.config	Example config for TrustZone M2354 build
arch.mk	Adds M2354 target wiring + Cortex-M23 toolchain flags + SP math selection
Makefile	Adjusts main target outputs for M2354 in TZ mode (non-contiguous images)
.github/workflows/test-configs.yml	Adds CI build jobs for M2354 configs

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[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #884

Scan targets checked: wolfboot-src, wolfboot-bugs

Findings: 2
2 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Fixed