Messages in this thread Patch in this message | | | Date | Tue, 14 Oct 2008 00:47:58 -0400 | From | Mathieu Desnoyers <> | Subject | Re: sparc64: Optimized immediate value implementation build error |
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* David Miller (davem@davemloft.net) wrote: > From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > Date: Mon, 13 Oct 2008 22:17:04 -0400 > > > * David Miller (davem@davemloft.net) wrote: > > > From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > > > Date: Mon, 13 Oct 2008 19:37:53 -0400 > > > > > > > * David Miller (davem@davemloft.net) wrote: > > > > > From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> > > > > > Date: Fri, 3 Oct 2008 16:10:07 -0400 > > > > > > > > > > > I ran a cross-compiler on the -lttng tree > > > > > > git://git.kernel.org/pub/scm/linux/kernel/git/compudj/linux-2.6-lttng.git > > > > > > > > > > > > to build the sparc64 arch, and ran across this build error : > > > > > > > > > > > > /home/compudj/git/morestable/linux-2.6-lttng/include/trace/sched.h: In function `do_fork': > > > > > > /home/compudj/git/morestable/linux-2.6-lttng/include/trace/sched.h:38: warning: asm operand 1 probably doesn't match constraints > > > > > > /home/compudj/git/morestable/linux-2.6-lttng/include/trace/sched.h:38: error: impossible constraint in `asm' > > > > > > /home/compudj/git/morestable/linux-2.6-lttng/include/trace/sched.h:38: warning: 'value' might be used uninitialized in this function > > > > > > make[2]: *** [kernel/fork.o] Error 1 > > > > > > > > > > > > I think it's caused by : > > > > > > http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=commit;h=c76bfa90a6eb02651368a152b3646aa672d9e625 > > > > > > > > > > It can't be "caused by" that commit because that's the initial > > > > > immediate value sparc64 support I wrote and the tree very much compiled > > > > > properly when I did test builds way back then. > > > > > > > > > > I don't have time to look further into this right now, sorry. > > > > > > > > Ok, I'll dig into this. I use gcc 3.4.5, that could be my problem; it's > > > > broken on x86_64. I'll do some testing in this direction. Also, I see > > > > that you have used .uaword and declared "int" in your sparc64 > > > > implementation to encode pointers. Am I missing something or should it > > > > be "long" and either .word or .xword (32 or 64 bits) ? > > > > > > long would be for ".uaxword", ".uaword" is 32-bit. It means > > > "UnAligned WORD" > > > > > > > Ok, it's fixed. > > How? :-) >
The int -> long uses commit http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=commitdiff;h=3940305f7248f269ae330982bcd6d51d5c55c2f4
Which adds a sparc asm.h to abstract the 32/64 bits "pointer" type at the assembler level. It's inspired from x86 32/64 :
diff --git a/arch/sparc/include/asm/asm.h b/arch/sparc/include/asm/asm.h new file mode 100644 (file) index 0000000..2be3d10 --- /dev/null +++ b/arch/sparc/include/asm/asm.h @@ -0,0 +1,19 @@ +#ifndef _ASM_SPARC_ASM_H +#define _ASM_SPARC_ASM_H + +#ifdef __ASSEMBLY__ +# define __ASM_FORM(x) x +#else +# define __ASM_FORM(x) " " #x " " +#endif + +#ifdef CONFIG_SPARC32 +# define __ASM_SEL(a,b) __ASM_FORM(a) +#else +# define __ASM_SEL(a,b) __ASM_FORM(b) +#endif + +#define _ASM_PTR __ASM_SEL(.word, .xword) +#define _ASM_UAPTR __ASM_SEL(.uaword, .uaxword) + +#endif /* _ASM_SPARC_ASM_H */ I also check for the compiler version to only enable immediate values if gcc is >= 4.0.0. I suspect that sparc64 gcc has similar issues x86_64 gcc 3.x has with base+offset addresses and "i" inline asm constraint.
This is done in commit : http://git.kernel.org/?p=linux/kernel/git/compudj/linux-2.6-lttng.git;a=commit;h=3c1106cf88f849a381c0bc01ccb185a3911e6a51
But my cross-compiler for sparc64 is only gcc 3.4.5 and I did not succeed to find the right versions of gcc/glibc and binutils working together to cross-build with a gcc >= 4.0.0 on x86_64. So some testing is welcome.
> > If someone has access to a sparc64 gcc >= 4.0.0 compiler (native or > > cross) and some spare cycles, if would be interesting to build test this > > with CONFIG_IMMEDIATE=y and with CONFIG_TRACEPOINTS=y and > > CONFIG_MARKERS=y : > > > > git://git.kernel.org/pub/scm/linux/kernel/git/compudj/linux-2.6-lttng.git > > branch : 2.6.27-lttng-0.40 > > I just checked out 0.39 and was building it to try and reproduce your failure. > I'll pull in 0.40 next.
I'm looking forward to hear about the results. Thanks !
Mathieu
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