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- Introduction
- ============
- The scm-mpu driver allows enabling xpu protection of arbitrary physical memory
- addresses as a debug mechanism.
- Software description
- ====================
- Several methods of controlling this feature are provided.
- * CONFIG_KERNEL_TEXT_MPU_PROT - Enables protection of the kernel code and
- read-only sections by default.
- * kernel command line
- scm_mpu.mpu_start=0x0
- scm_mpu.mpu_size=0x1000
- * /sys/module/scm_mpu/parameters
- echo 0x0 > mpu_start
- echo 0x1000 > mpu_size
- echo 0x11 > mpu_enable
- The sysfs interface may also be used to unlock previously defined regions.
- echo 0x0 > mpu_start
- echo 0x1000 > mpu_size
- echo 0x10 > mpu_enable
- Limitations
- ===========
- The number of distinct regions allowed is limited by available resources.
- No provisions are made for "carving out" or otherwise removing xpu protected
- regions from the linux memory map.
- XPU protection currently uses 4K alignment.
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