[Bug 31279] Age of Empires II SafeDisc v1.x driver crashes in IDT check (INT1/3 hooks)

[wine-bugs at winehq.org]

http://bugs.winehq.org/show_bug.cgi?id=31279

Charles Davis <cdavis at mymail.mines.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |UPSTREAM

--- Comment #11 from Charles Davis <cdavis at mymail.mines.edu> 2012-07-22 22:33:06 CDT ---
Well, it turns out SECDRV really wasn't caching the IDTR like I thought. Which
is even worse, because it means there's a race between SECDRV and Wine reading
the IDTR. If the scheduler changes the CPU NTOSKRNL is running on between the
time SECDRV reads the IDTR and the time Wine reads the IDTR, SECDRV and Wine
will end up reading different IDTR values.

I even tried to get Wine to remember all four IDTR values, and check each one.
But it's still subject to this same data race. This sucks.

So after trying to fix this problem in Wine multiple times, I'm convinced now
there are only two ways to make it work, and both of them require changing the
kernel:

1. The easy way: make the kernel use the same IDT for all cores. Probably not
realistic. I'm sure there's a good reason each core has its own IDT. (At the
very least, it seems to be used to distinguish one processor from another.)
2. The hard way: implement "strong" affinity (i.e. the kind that Windows and
Linux implement), as opposed to the "weak" kind Mac OS currently has. Then we
can force the NTOSKRNL thread onto a specific CPU and avoid the race.

I'll see about implementing 2 and getting my patch upstreamed for the next
version of Mac OS. For now, I'll just have to run a modified kernel.

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