----- 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. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
