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Re: [PATCH][MIPS] Add linker emulation for N64 ABI with forced 32-bit symbols
On Nov 15, 2012, at 2:08 PM, Richard Sandiford wrote:
> Huh. I'm very much against the original change to the n64 TEXT_START_ADDR.
> See this previous discussion on the topic:
> The justification for changing TEXT_START_ADDR from a 32-bit value to a
> larger value was that it would show users if their code was non-portable,
> because anything that assumed 32-bit addresses would now fault. But that
> seems to me like the tools lecturing to the user. As I said in that thread,
> I think users who want to smoke out such portability problems (by making
> sure that the lower 4GB aren't mapped) should be the ones who need to do
> something special.
Gee, should we go back and stop making sure VA 0 is unmapped too? Sure it helps find NULL pointer dereferences but isn't that the tools lecturing to the user as well? Having the TEXT_START_ADDR at 5GB doesn't hurt anyone and will errant catch 32-bit deferences instead of allowing possible silent corruption. Why is that a bad thing?
> I think we should simply revert to a 32-bit TEXT_START_ADDR for all
> n64 emulations. This time I'm even in a position to approve it :-)
I strongly disagree. Just because you can approve it doesn't mean you are right. If you do make the change, NetBSD will still use the 5GB start address.