czw., 5 gru 2019 o 18:02 Andy Shevchenko <andy.shevchenko@xxxxxxxxx> napisał(a): > > On Thu, Dec 5, 2019 at 3:47 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote: > > czw., 5 gru 2019 o 11:27 Andy Shevchenko <andy.shevchenko@xxxxxxxxx> napisał(a): > > > On Thu, Dec 5, 2019 at 11:42 AM Bartosz Golaszewski > > > <bgolaszewski@xxxxxxxxxxxx> wrote: > > > > śr., 4 gru 2019 o 23:34 Andy Shevchenko <andy.shevchenko@xxxxxxxxx> napisał(a): > > > > > On Wed, Dec 4, 2019 at 6:03 PM Bartosz Golaszewski <brgl@xxxxxxxx> wrote: > > > > So, the test cases, I can imagine of, should include (k - kernel, u - user): > > > - 64k-64u: LE and BE > > > - 64k-32u: LE and BE > > > - 32k-32u: LE and BE > > > > I usually use qemu VMs built with yocto for testing but I don't see > > any way of creating a 32-bit user-space with 64-bit kernel. Any ideas > > on how to prepare a testing environment? > > In my case it's very easy. I do > - compile kernel as 64-bit separately; > - compile initramfs of Buildroot distro with external kernel build provided. > Any specific config options are needed on x86-64 kernel to use 32-bit user-space? I'm not well versed in x86 architectures, that's why I'm asking. I built a 32-bit userspace qemu image with yocto and then manually built a 64-bit kernel. I tried running it but I'm getting a kernel panic when the rootfs is being mounted. On a different note: why would endianness be an issue here? 32-bit variables with 64-bit alignment should still be in the same place in memory, right? Any reason not to use __packed for this structure and not deal with this whole compat mess? I also noticed that my change will only allow user-space to read one event at a time which seems to be a regression with regard to the current implementation. I probably need to address this too. Bart > That's setup in which I observed the issue. > > -- > With Best Regards, > Andy Shevchenko