system_private

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Information needed by the operating system when booting

The system_private data structure is filled in by the startup library's init_system_private() function.

The entropy member

The system_private data structure includes the entropy member. It is an array of two 64-bit values that can be populated with random data provided by the startup process (e.g., from the TRNG provided by the SoC). The kernel can use this data to seed its PRNG. When the kernel has consumed the values, it sets them to zero. This behavior is useful for confirming that the kernel has used the data.

See also the SysSrandom() entry in the C Library Reference.

Other structure members

Other than populating entropy if needed, you should never need to do anything with this area of the system page. Nonetheless, below are descriptions of some other structure members that may be of interest:
user_cpupageptr
User address (R/O) for cpupage pointer
user_syspageptr
User address (R/O) for syspage pointer
kern_cpupageptr
Kernel address (R/W) for cpupage pointer
kern_syspageptr
Kernel address (R/W) for syspage pointer
pagesize
Granularity of the OS memory allocator (usually 4096 bytes).
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