How do the PROT flags within mmap(), translate to register values?

I am interested in tracing how the mmap system call translates to register values on an ARM cpu. More interested in the path taken and where and when do these "PROT" attributes actually translate to a page attribute within the kernel. I did trace the system call till the "mmap_region" call under mm/mmap.c. From here, I fai开发者_StackOverflow社区l to see where the "flags/PROT" values translate to a register value on the CPU.

Thanks

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MMU protection flags are set on arch/arm/mm/proc-xxx.S, on a function called xxx_set_pte_ext. Obviously, this is for processors with MMU.