Re: [PATCH][RFC] getting rid of stupid loop in BUG()

From: H. Peter Anvin
Date: Wed Jul 25 2007 - 01:14:18 EST


Keith Owens wrote:
> Trent Piepho (on Tue, 24 Jul 2007 19:31:36 -0700 (PDT)) wrote:
>> Adding __builtin_trap after the
>> asm might be an ok fix. It will emit a spurious int 6, but that won't even be
>> reached since the asm doesn't return, and it probably be less extra code than
>> the loop.
>
> int 6 is a two byte instruction, the loop generates jmp with an 8 bit
> offset, also two bytes. No change in code size.
>

INT 6 is #UD, so the __builtin_trap() replaces the ud2a as well as the loop.

How far back was __builtin_trap() supported?

-hpa
-
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/