Re: More LTTng patches

Hello.

Mathieu Desnoyers wrote:

>>Source: MontaVista Software, Inc.
>>MR: 20036
>>Type: Defect Fix
>>Disposition: needs submitting to LTTng community
>>Signed-off-by: Mark A. Greer <[email protected]>
>>Description:
>>    Apparently, gcc 4.2 has tighter constrainst for the 'i' asm operands
>>    than previous gcc versions.  This patch changes a 'i' to a 'g' which
>>    is a more relaxed constraint.

>>Index: linux-2.6.18/include/asm-powerpc/marker.h
>>===================================================================
>>--- linux-2.6.18.orig/include/asm-powerpc/marker.h
>>+++ linux-2.6.18/include/asm-powerpc/marker.h
>>@@ -40,7 +40,7 @@ struct __mark_marker {
>> 					"0:\n\t" \
>> 					"li %0,0;\n\t" \
>> 				: "=r" (condition) \
>>-				: "i" (&__mark_c_##name)); \
>>+				: "g" (&__mark_c_##name)); \
>> 		__mark_check_format(format, ## args); \
>> 		if (unlikely(condition)) { \
>> 			preempt_disable(); \

> I will also change it for asm-generic and asm-i386. I hope to find some
> consistency in the way asm operands are treated across architectures.

    It looks like that issue got fixed in gcc 4.2:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27528

    The bad part is that when compiled with fixed gcc, the kernel receives 
SIGSEGV and dies on bootup... "i" works again now. :-/

WBR, Sergei