Quoting Guenter Roeck (2024-09-28 14:32:35) > On 9/28/24 12:27, Shuah Khan wrote: > > On 9/28/24 11:54, Shuah Khan wrote: > >> On 9/28/24 11:31, Guenter Roeck wrote: > >>> On 9/27/24 17:08, Guenter Roeck wrote: > >>>> On 9/27/24 13:45, Shuah Khan wrote: > >>>>> On 9/27/24 10:19, Guenter Roeck wrote: > >>>>>> Copying devicetree maintainers. > >>>>>> > >>>>>> On Thu, Sep 26, 2024 at 09:39:38PM -0700, Guenter Roeck wrote: > >>>>>>> On Thu, Sep 26, 2024 at 09:14:11PM -0700, Guenter Roeck wrote: > >>>>>>>> Hi Stephen, > >>>>>>>> > >>>>>>>> On Thu, Jul 18, 2024 at 02:05:07PM -0700, Stephen Boyd wrote: > >>>>>>>>> Test that clks registered with 'struct clk_parent_data' work as > >>>>>>>>> intended and can find their parents. > >>>>>>>>> > >>>>>>>> > >>>>>>>> When testing this on arm64, I see the error below. The error is only > >>>>>>>> seen if I boot through efi, i.e., with "-bios QEMU_EFI-aarch64.fd" > >>>>>>>> qemu parameter. > >>>>>>>> > >>>>>>>> Any idea what might cause the problem ? > >>>>>>>> > >>>>>>> I noticed that the new overlay tests fail as well, also with "path '/' not > >>>>>>> found". > >>>>>>> > >>>>>>> [Maybe] answering my own question: I think the problem may be that there > >>>>>>> is no devicetree file and thus no devicetree root when booting through > >>>>>>> efi (in other words, of_root is NULL). Would it make sense to skip the > >>>>>>> tests in that case ? > >>>>>>> > >>>>>> > >>>>>> The problem is that of_root is not initialized in arm64 boots if ACPI > >>>>>> is enabled. > >>>>>> > >>>>>> From arch/arm64/kernel/setup.c:setup_arch(): > >>>>>> > >>>>>> if (acpi_disabled) > >>>>>> unflatten_device_tree(); // initializes of_root Oof I forgot that Rob didn't apply the patch that let an empty root live on ARM64 ACPI systems. See this thread[1] for all the details. > >>>>>> > >>>>>> ACPI is enabled if the system boots from EFI. This also affects > >>>>>> CONFIG_OF_KUNIT_TEST, which explicitly checks if of_root exists and > >>>>>> fails the test if it doesn't. > >>>>>> > >>>>>> I think those tests need to add a check for this condition, or affected > >>>>>> machines won't be able to run those unit tests. The obvious solution would > >>>>>> be to check if of_root is set, but then the associated test case in > >>>>>> CONFIG_OF_KUNIT_TEST would not make sense. > >>>>>> > >>>>>> Any suggestions ? > >>>>>> I think that's the best we can do for now. Basically add a check like if (IS_ENABLED(CONFIG_ARM64) && acpi_disabled) kunit_skip(test, "ARM64 + ACPI rejects DT overlays"); to the overlay application function and the DT test. > >>>>> > >>>>> Would it work if these tests check if acpi_disabled and skip if it isn't > >>>>> disabled? It might be low overhead condition to check from these tests. > >>>>> > >>>>> acpi_disabled is exported: > >>>>> > >>>>> arch/arm64/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled); > >>>>> arch/loongarch/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled); > >>>>> arch/riscv/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled); > >>>>> arch/x86/kernel/acpi/boot.c:EXPORT_SYMBOL(acpi_disabled); > >>>>> > >>>> > >>>> I don't think that would work. Looking through the use of acpi_init, > >>>> I don't think that of_root is always NULL when acpi_init is false; that > >>>> just happens to be the case on arm64 when booting through efi. > >>>> However, even arm64 has the following code. > >>>> > >>>> if (acpi_disabled) > >>>> psci_dt_init(); > >>>> else > >>>> psci_acpi_init(); > >>>> > >>>> While psci_dt_init() doesn't set of_root, it does try to do a devicetree > >>>> match. So there must be some other condition where acpi_disabled is set > >>>> but of_root is set anyway. I just have not found that code path. > >>>> > >>> > >>> I ended up disabling all affected unit tests for arm64. I'll do the same > >>> for other architectures if I encounter the problem there as well. > >>> > >>> Unfortunately that includes all clock unit tests because the tests requiring > >>> devicetree support can not be enabled/disabled separately, but that can't be > >>> helped and is still better than "mandatory" failures. > >>> > >> > > > > of_root is set in drivers/of/pdt.c when it creates the root node. > > This could be a definitive test for kunit tests that depend on > > devicetree support. > > > > That is not always the case, including arm64. It is primarily set in > unflatten_devicetree(), which is not called on arm64 unless acpi_is disabled > (see above). > > > It is an exported symbol. drivers/of/base.c exports it. > > > > Yes, checking if of_root is NULL and skipping the test in that case might help, > but then there is the of_dtb_root_node_populates_of_root unit test which > explicitly fails if of_root is NULL. The comment describing the test is > > /* > * Test that the 'of_root' global variable is always populated when DT code is > * enabled. Remove this test once of_root is removed from global access. > */ > > The devicetree unit test code explicitly assumes that of_root is set if > CONFIG_OF_EARLY_FLATTREE is enabled, but that is not always the case > (again, of_root is NULL on arm64 unless acpi is disabled). > That DT test has been there for a few releases. Is this the first time those tests have been run on arm64+acpi? I didn't try after sending the patches and forgot that the patch was dropped. How are you running kunit tests? I installed the qemu-efi-aarch64 debian package to get QEMU_EFI.fd but passing that to the kunit.py run command with --qemu_args="-bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd" didn't get me beyond the point that the EFI stub boots linux. I think the serial console must not be working and thus the kunit wrapper waits for something to show up but nothing ever does. I haven't dug any further though, so maybe you have a working command. Here's my command that isn't working: ./tools/testing/kunit/kunit.py run --arch=arm64 --kunitconfig=drivers/of --qemu_args="-bios /usr/share/qemu-efi-aarch64/QEMU_EFI.fd" [1] https://lore.kernel.org/all/20240217010557.2381548-6-sboyd@xxxxxxxxxx/
