On Tue, Aug 09, 2022, Mathieu Desnoyers wrote: > ----- On Aug 9, 2022, at 8:21 AM, Mathieu Desnoyers mathieu.desnoyers@xxxxxxxxxxxx wrote: > > > ----- Gavin Shan <gshan@xxxxxxxxxx> wrote: > >> Hi Florian, > >> > >> On 8/9/22 5:16 PM, Florian Weimer wrote: > >> >>> __builtin_thread_pointer doesn't work on all architectures/GCC > >> >>> versions. > >> >>> Is this a problem for selftests? > >> >>> > >> >> > >> >> It's a problem as the test case is running on all architectures. I think I > >> >> need introduce our own __builtin_thread_pointer() for where it's not > >> >> supported: (1) PowerPC (2) x86 without GCC 11 > >> >> > >> >> Please let me know if I still have missed cases where > >> >> __buitin_thread_pointer() isn't supported? > >> > > >> > As far as I know, these are the two outliers that also have rseq > >> > support. The list is a bit longer if we also consider non-rseq > >> > architectures (csky, hppa, ia64, m68k, microblaze, sparc, don't know > >> > about the Linux architectures without glibc support). > >> > > >> > >> For kvm/selftests, there are 3 architectures involved actually. So we > >> just need consider 4 cases: aarch64, x86, s390 and other. For other > >> case, we just use __builtin_thread_pointer() to maintain code's > >> integrity, but it's not called at all. > >> > >> I think kvm/selftest is always relying on glibc if I'm correct. > > > > All those are handled in the rseq selftests and in librseq. Why duplicate all > > that logic again? > > More to the point, considering that we have all the relevant rseq registration > code in tools/testing/selftests/rseq/rseq.c already, and the relevant thread > pointer getter code in tools/testing/selftests/rseq/rseq-*thread-pointer.h, > is there an easy way to get test applications in tools/testing/selftests/kvm > and in tools/testing/selftests/rseq to share that common code ? > > Keeping duplicated compatibility code is bad for long-term maintainability. Any reason not to simply add tools/lib/rseq.c and then expose a helper to get the registered rseq struct?
