Re: [PATCH v2 0/3] selftests/hid: fix building for older kernels

[Nick Desaulniers <ndesaulniers@google.com>]

On Fri, Sep 08, 2023 at 10:22:37PM +0000, Justin Stitt wrote:
> Hi, I am sending this series on behalf of myself and Benjamin Tissoires. There
> existed an initial n=3 patch series which was later expanded to n=4 and
> is now back to n=3 with some fixes added in and rebased against
> mainline.
> 
> This patch series aims to ensure that the hid/bpf selftests can be built
> without errors.
> 
> Here's Benjamin's initial cover letter for context:
> |  These fixes have been triggered by [0]:
> |  basically, if you do not recompile the kernel first, and are
> |  running on an old kernel, vmlinux.h doesn't have the required
> |  symbols and the compilation fails.
> |
> |  The tests will fail if you run them on that very same machine,
> |  of course, but the binary should compile.
> |
> |  And while I was sorting out why it was failing, I realized I
> |  could do a couple of improvements on the Makefile.
> |
> |  [0] https://lore.kernel.org/linux-input/56ba8125-2c6f-a9c9-d498-0ca1c153dcb2@redhat.com/T/#t
> 
> Changes from v1 -> v2:
> - roll Justin's fix into patch 1/3
> - add __attribute__((preserve_access_index)) (thanks Eduard)
> - rebased onto mainline (2dde18cd1d8fac735875f2e4987f11817cc0bc2c)
> - Link to v1: https://lore.kernel.org/all/20230825-wip-selftests-v1-0-c862769020a8@kernel.org/
> 
> Link: https://github.com/ClangBuiltLinux/linux/issues/1698
> Link: https://github.com/ClangBuiltLinux/continuous-integration2/issues/61

Thanks to you and Benjamin for sorting all of this out! With this series
applied, I was able to build the hid selftests now without the previous
-Wvisibility diagnostics failing the build.

Tested-by: Nick Desaulniers <ndesaulniers@google.com> # Build

> ---
> Benjamin Tissoires (3):
>       selftests/hid: ensure we can compile the tests on kernels pre-6.3
>       selftests/hid: do not manually call headers_install
>       selftests/hid: force using our compiled libbpf headers
> 
>  tools/testing/selftests/hid/Makefile               | 10 ++---
>  tools/testing/selftests/hid/progs/hid.c            |  3 --
>  .../testing/selftests/hid/progs/hid_bpf_helpers.h  | 49 ++++++++++++++++++++++
>  3 files changed, 53 insertions(+), 9 deletions(-)
> ---
> base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c
> change-id: 20230908-kselftest-09-08-56d7f4a8d5c4
> 
> Best regards,
> --
> Justin Stitt <justinstitt@google.com>
>