Re: [PATCH] x86-64: adjust ia32entry.S

[Jan Beulich]

>>> Andi Kleen <ak@xxxxxxx> 11.11.05 16:34:44 >>>
>On Wednesday 09 November 2005 17:10, Jan Beulich wrote:
>> IA32 compatibility entry points needlessly played with extended
>> registers. Additionally, frame unwind information was still
incorrect
>> for ia32_ptregs_common (sorry, my fault).
>
>What do you mean with needlessly played? That it didn't initialize 
>all on the stack frame? That was more a feature than a bug.
>Did it cause you problems?

It saved and restored R12-R15, even though these registers have no
meaning (and are architecturally undefined) when coming from/going to
32-bit mode. Problems? No, except that without the extra loads (stores
don't matter that much I believe) performance is better...

>In general I'm weary of making the asm macros more complex
>(adding more arguments etc.) Please keep it simple.

Then ignore this, perhaps with the exception of the unwind info
adjustment.

Jan
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/