[PATCH][MIPS] Add linker emulation for N64 ABI with forced 32-bit symbols

Paul_Koning@Dell.com Paul_Koning@Dell.com
Thu Nov 15 22:23:00 GMT 2012


On Nov 15, 2012, at 5:08 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:
> 
>    http://sourceware.org/ml/binutils/2008-06/msg00285.html
> 
> 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.
> 
> 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 :-)

Isn't this an OS question more than an OS-independent tools question?

Also, I disagree with your description as "lecturing".  The interesting case isn't the one where a correctly working program that happens to misuse 32 bit addresses is turned into a broken one by the current start address rule.

The interesting case is where a program executes without immediately crashing, but because it uses 32-bit addresses it does some wrong things -- writing wrong data into a database, or things like that.  So this isn't a case of lecturing, it's a security improvement.

	paul




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