Am Mittwoch, den 12.12.2012, 15:34 -0800 schrieb H. Peter Anvin: > On 12/12/2012 12:19 PM, [email protected] wrote: > > diff --git a/arch/x86/vdso/vdso32/vclock_gettime.c > > b/arch/x86/vdso/vdso32/vclock_gettime.c > > new file mode 100644 > > index 0000000..c9a1909 > > --- /dev/null > > +++ b/arch/x86/vdso/vdso32/vclock_gettime.c > > @@ -0,0 +1,7 @@ > > +/* > > + * since vgtod layout differs between X86_64 and x86_32, it is not > > possible to > > + * provide a 32 bit vclock with a 64 bit kernel > > + */ > > +#ifdef CONFIG_X86_32 > > +#include "../vclock_gettime.c" > > +#endif > > This is where this goes fail. Sorry, it is not acceptable to introduce > an ABI on x86-32 without providing it also on x86-64 in compatibility mode. > > I also don't believe it is not possible... it might require some more > cleverness; perhaps we need to do the 32-bit vgtod in such a way that it > *is* compatible with 64 bits. >
The comment is ambiguous: Since vgtod layout differs between X86_64 and x86_32 AND the vgtod is not inside the accessible address space of a 32 bit program, it is CURRENTLY not possible to provide a 32 bit vclock with a 64 bit kernel As i understand VDSO it is an alternativ way, so if there is no support for it, there must be a fall back to the system call interface in the program or lib, which tries to use it. So there is no drawback for 32 bit programs running on a 64 bit kernel. I think this feature is not so important and can implemented in a subsequent patch, because a 64 bit kernel system mostly runs 64 bit programs. Let us fix this things step by step. - Stefani -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
