Messages in this thread | | | Subject | Re: [PATCH] arch/x86: reset MXCSR to default in kernel_fpu_begin() | From | Shuah Khan <> | Date | Tue, 2 Jun 2020 11:27:08 -0600 |
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On 6/2/20 11:03 AM, Andy Lutomirski wrote: > On Tue, Jun 2, 2020 at 3:56 AM Borislav Petkov <bp@alien8.de> wrote: >> >> Hi, >> >> On Tue, Jun 02, 2020 at 01:29:51PM +0300, Petteri Aimonen wrote: >>> The kernel module is not actually x86-specific, even though it is >>> currently only enabled for x86. amdgpu driver already does kernel mode >>> floating point operations on PPC64 also, and the same module could be >>> used to test the same thing there. >> >> Then make it generic please and put the user portion in, say, >> tools/testing/selftests/fpu/ and we can ask ppc people to test it too. >> People might wanna add more stuff to it in the future, which would be >> good. >> >>> To deterministically trigger the bug, the syscall has to come from the >>> same thread that has modified MXCSR. Going through /usr/sbin/modprobe >>> won't work, and manually doing the necessary syscalls for module loading >>> seems too complicated. >> >> Ok, fair enough. But put that file in debugfs pls. > > I think I agree. While it would be delightful to have general > selftest tooling for kernel modules, we don't have that right now, and > having the test just work with an appropriately configured kernel > would be nice. >
Let's extend it to do what we want it to do. I will happy to take patches. If you have some concrete ideas on what we can add, please do a short summary of what is missing. I will find a way to get this done.
> How about putting the file you frob in > /sys/kernel/debug/selftest_helpers/something_or_other. The idea would > be that /sys/kernel/debug/selftest_helpers would be a general place > for kernel helpers needed to make selftests work. >
Is this a workaround for the lack of selftest tooling for kernel modules? In which case, let's us focus on fix selftest tooling.
thanks, -- Shuah
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