# MPU故障：在地址0x20001000处非特权访问特权区域

- **ID:** `embedded/arm-mpu-fault-unprivileged-access`
- **领域:** embedded
- **类别:** system_error
- **错误码:** `0x00000020`
- **验证级别:** ai_generated
- **修复率:** 88%

## 根因

MPU区域配置不匹配：在非特权模式下运行的代码尝试读取或写入标记为仅特权访问的内存区域。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| ARM Cortex-M7 r1p0 | active | — | — |
| FreeRTOS 10.4.6 with MPU support | active | — | — |

## 解决方案

1. ```
   Set MPU region attribute to 'privileged read-write, unprivileged execute never' for sensitive areas. Example: MPU->RBAR = (0x20001000 & MPU_RBAR_ADDR_Msk) | MPU_RBAR_VALID_Msk | (0 << MPU_RBAR_REGION_Pos); MPU->RASR = (0x3 << MPU_RASR_AP_Pos) | MPU_RASR_XN_Msk;
   ```
2. ```
   Switch offending task to privileged mode by setting configUSE_TASK_FPU_SUPPORT to 1 and using vTaskPrioritySet to adjust.
   ```

## 无效尝试

- **** — Disabling MPU entirely removes protection but does not fix root cause; security or safety requirements may be violated. (85% 失败率)
- **** — Increasing stack size does not resolve MPU access violations; fault is due to privilege level, not stack depth. (95% 失败率)