Function mem_validate_range 

pub fn mem_validate_range(
    address: usize,
    size: usize,
    memory_type: MemoryType,
) -> Result<()>

Validates a memory range against the PSP’s memory map.

May return INVALID_MEM_ADDR (bad start address), INVALID_MEM_TYPE (type mismatch), or INVALID_MEM_RANGE (range too small for address + size).