Messages in this thread | | | From | Bernhard Rosenkraenzer <> | Subject | Re: 2.6.19-rc5-mm1 fails to compile with gcc 4.2 | Date | Sun, 12 Nov 2006 14:36:15 +0100 |
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On Sunday, 12. November 2006 10:24, Avi Kivity wrote: > >> Or better yet, preprocessed source and full gcc command line (as seen on > >> 'make V=1').
gcc -m32 -Wp,-MD,drivers/kvm/.kvm_main.o.d -nostdinc -isystem /usr/lib/gcc/i586-ark-linux/4.2.0/include -D__KERNEL__ -Iinclude -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mpreferred-stack-boundary=2 -march=i686 -mtune=pentium3 -maccumulate-outgoing-args -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1 -Iinclude/asm-i386/mach-default -fomit-frame-pointer -fno-stack-protector -Wdeclaration-after-statement -Wno-pointer-sign -DMODULE -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(kvm_main)" -D"KBUILD_MODNAME=KBUILD_STR(kvm)" -c -o drivers/kvm/.tmp_kvm_main.o drivers/kvm/kvm_main.c drivers/kvm/kvm_main.c: In function 'kvm_dev_ioctl_run': drivers/kvm/kvm_main.c:153: error: 'asm' operand has impossible constraints drivers/kvm/kvm_main.c:158: error: 'asm' operand has impossible constraints
> > It does look like a gcc bug -- -O0 makes it go away. > > Details at http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29808 > > That's a different bug, gcc generates code that the assembler can't > handle. Might be an assembler bug.
It's the same thing, the code is taken from kvm_main.c:
static void load_fs(u16 sel) { asm ("mov %0, %%fs" : : "g"(sel)); <--- line 153 }
static void load_gs(u16 sel) { asm ("mov %0, %%gs" : : "g"(sel)); <--- line 158 }
> Can you compile it with -S and post the generated assembly?
It can't generate assembly with asm() constructs it perceives as invalid -- -S produces the same error. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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