Messages in this thread | | | From | Bartosz Golaszewski <> | Date | Fri, 6 Dec 2019 22:20:42 +0100 | Subject | Re: [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info |
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czw., 5 gru 2019 o 18:02 Andy Shevchenko <andy.shevchenko@gmail.com> napisał(a): > > On Thu, Dec 5, 2019 at 3:47 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote: > > czw., 5 gru 2019 o 11:27 Andy Shevchenko <andy.shevchenko@gmail.com> napisał(a): > > > On Thu, Dec 5, 2019 at 11:42 AM Bartosz Golaszewski > > > <bgolaszewski@baylibre.com> wrote: > > > > śr., 4 gru 2019 o 23:34 Andy Shevchenko <andy.shevchenko@gmail.com> napisał(a): > > > > > On Wed, Dec 4, 2019 at 6:03 PM Bartosz Golaszewski <brgl@bgdev.pl> 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
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