Nicholas Piggin <npig...@gmail.com> writes: > powerpc has a number of read-only sections and tables that are put > after RO_DATA(). Move the __end_rodata symbol to cover these as well. > > Setting memory to read-only at boot is done using __init_begin, > change that that to use __end_rodata.
Did you just do that because it seems logical? Because it does seem logical, but it leaves a RWX region in the gap between __end_rodata and __init_begin, which is bad. This is the current behaviour, on radix: ---[ Start of kernel VM ]--- 0xc000000000000000-0xc000000001ffffff 0x0000000000000000 32M r X pte valid present dirty accessed 0xc000000002000000-0xc00000007fffffff 0x0000000002000000 2016M r w pte valid present dirty accessed And with your change: ---[ Start of kernel VM ]--- 0xc000000000000000-0xc0000000013fffff 0x0000000000000000 20M r X pte valid present dirty accessed 0xc000000001400000-0xc000000001ffffff 0x0000000001400000 12M r w X pte valid present dirty accessed 0xc000000002000000-0xc00000007fffffff 0x0000000002000000 2016M r w pte valid present dirty accessed On radix the 16M alignment is larger than we need, but we need to chose a value at build time that works for radix and hash. We could make the code smarter on radix, to mark those pages in between __end_rodata and __init_begin as RW_ and use them for data. But that would be a more involved change. I think if we just drop the changes to the C files this patch is OK to go in. cheers