----- Gavin Shan gshan@redhat.com 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?
Thanks,
Mathieu
Thanks, Gavin