Squashed commit of the following:
commit 02c0365e512a0205375034c9ca4bcbf10b41caa5
Author: huoyujia081 huoyujia081@126.com
Date:   Tue Jan 20 21:26:12 2026 +0800
Add (arch): Support RISC-V-64GC architecture with P550 platform integration

RISC-V Core Infrastructure:
- Implement RISC-V-64GC boot sequence (boot.S, exception.S, root_pt.S)
- Add RISC-V-specific memory management with root page table initialization
- Implement architecture-specific fences for RISC-V (acquire, release semantics)
- Add P550 UART controller driver with platform-specific configuration

Board Support (P550):
- Create riscv-board hierarchy with Kconfig system integration
- Add P550 platform descriptor (riscv_board_info.c) with CPU topology and PSCI configuration
- Add P550 VM configuration template (riscv_board_vm_config.c)
- Generate board_config.h from Kconfig for P550 board

Architecture Refactoring:
- Refactor fences.h to be architecture-agnostic (public interface)
- Move architecture-specific fences to armv8a-aarch64/arch_fences.h
- Remove deprecated spinlock.h (consolidated into architecture implementations)
- Separate ARMv8-A and RISC-V implementations with architecture-specific subdirectories

Build System Enhancements:
- Update Makefile with RISC-V compilation flags (-mcmodel=medany, -mno-relax)
- Add RISC-V linker flags (--no-relax) for proper relocation handling
- Reorganize Objects.mk hierarchy for multi-architecture builds
- Refactor menuconfig target for better .config management

Standardization:
- Rename uart_board.h → uart_zcu104.h for platform clarity
- Update console.h with architecture-aware log handling
- Add BOOT_DEBUG_MARKERS.md documentation for boot sequence tracing
- Add bao-hypervisor-LICENSE.txt for license attribution

Compatibility:
- Ensure ARMv8-A builds remain unchanged and stable
- Maintain softvisor layer consistency across architectures
- Support multi-platform concurrent builds (ARMv8-A + RISC-V)

---

添加 (架构): 支持RISC-V-64GC架构及P550平台集成

RISC-V核心基础设施：
- 实现RISC-V-64GC启动序列（boot.S、exception.S、root_pt.S）
- 添加RISC-V特定的内存管理，含根页表初始化
- 实现RISC-V架构特定的栅栏原语（获取/释放语义）
- 添加P550 UART控制器驱动，包含平台特定配置

板级支持（P550）：
- 创建riscv-board层级，集成Kconfig系统
- 添加P550平台描述符（riscv_board_info.c），包含CPU拓扑和PSCI配置
- 添加P550 VM配置模板（riscv_board_vm_config.c）
- 从Kconfig为P550生成board_config.h

架构重构：
- 重构fences.h为架构无关的公共接口
- 将架构特定的栅栏实现移至armv8a-aarch64/arch_fences.h
- 删除已弃用的spinlock.h（合并至架构实现）
- 分离ARMv8-A和RISC-V实现至架构特定子目录

构建系统增强：
- 更新Makefile，添加RISC-V编译标志（-mcmodel=medany、-mno-relax）
- 添加RISC-V链接标志（--no-relax）用于正确的重定位处理
- 重组Objects.mk层级以支持多架构构建
- 优化menuconfig目标的.config管理

标准化改进：
- 重命名uart_board.h → uart_zcu104.h以提高平台清晰度
- 更新console.h，支持架构感知的日志处理
- 添加BOOT_DEBUG_MARKERS.md文档用于启动序列追踪
- 添加bao-hypervisor-LICENSE.txt用于许可证说明

兼容性保证：
- 确保ARMv8-A构建保持不变且稳定
- 保持softvisor层跨架构一致性
- 支持多平台并发构建（ARMv8-A + RISC-V）