On 03/09/2014 12:47 AM, Stefani Seibold wrote: > > But let me ask an other question: Is the compat mode still needed > anymore? > > Since Lguest, XEN, OPLC and the reservetop kernel parameter will change > the __FIXADDR_TOP, there is no fix place for the VDSO page. Also in the > 32 bit emulation layer the address is not fix. > > So all applications can fail when try directly access the VDSO page with > a hard coded address 0xffffe000. > > IMHO this is broken. So an other solution is to remove the whole VDSO > compat code. >
Lguest, Xen, OLPC and reservetop are corner cases. My understanding is that at least one widely used distro actually cared about this, and Linus especially is adamant that "we don't break userspace." The dual vdso approach might be the best bet, for the cases where compatibility is even possible. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/