On Wed, Oct 7, 2020 at 10:56 AM Luka Perkov <luka.perkov@xxxxxxxxxx> wrote: > > Hello Andrii, > > On Fri, Oct 2, 2020 at 3:09 AM Andrii Nakryiko <andriin@xxxxxx> wrote: > > Patch set implements logic in libbpf to auto-adjust memory size (1-, 2-, 4-, > > 8-bytes) of load/store (LD/ST/STX) instructions which have BPF CO-RE field > > offset relocation associated with it. In practice this means transparent > > handling of 32-bit kernels, both pointer and unsigned integers. Signed > > integers are not relocatable with zero-extending loads/stores, so libbpf > > poisons them and generates a warning. If/when BPF gets support for sign-extending > > loads/stores, it would be possible to automatically relocate them as well. > > > > All the details are contained in patch #1 comments and commit message. > > Patch #2 is a simple change in libbpf to make advanced testing with custom BTF > > easier. Patch #3 validates correct uses of auto-resizable loads, as well as > > check that libbpf fails invalid uses. > > > > I'd really appreciate folks that use BPF on 32-bit architectures to test this > > out with their BPF programs and report if there are any problems with the > > approach. > > > > Cc: Luka Perkov <luka.perkov@xxxxxxxxxx> > > First, thank you for the support and sending this series. It took us a > bit longer to run the tests as our target hardware still did not fully > get complete mainline support and we had to rebase our patches. These > are not related to BPF. > > Related to this patch, we have tested various BPF programs with this > patch, and can confirm that it fixed previous issues with pointer > offsets that we had and reported at: > > https://lore.kernel.org/r/CA+XBgLU=8PFkP8S32e4gpst0=R4MFv8rZA5KaO+cEPYSnTRYYw@xxxxxxxxxxxxxx/. > > Most of our programs now work and we are currently debugging other > programs that still aren't working. We are still not sure if the > remaining issues are related to this or not, but will let you know > sometime this week after further and more detailed investigation. > Ok, great, thanks for the update. > Thanks, > Luka
