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Message-ID: <bf910fa5-0c96-3707-cce4-5bcc656b6274@collabora.com>
Date:   Fri, 2 Jun 2023 21:25:15 +0500
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Cc:     Muhammad Usama Anjum <usama.anjum@collabora.com>,
        Peter Xu <peterx@redhat.com>, Shuah Khan <shuah@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>, linux-mm@kvack.org,
        linux-kselftest@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 11/12] selftests/mm: fix missing UFFDIO_CONTINUE_MODE_WP
 and similar build failures
Content-Language: en-US
To:     John Hubbard <jhubbard@nvidia.com>,
        David Hildenbrand <david@redhat.com>
References: <20230602013358.900637-1-jhubbard@nvidia.com>
 <20230602013358.900637-12-jhubbard@nvidia.com>
From:   Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <20230602013358.900637-12-jhubbard@nvidia.com>
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On 6/2/23 6:33 AM, John Hubbard wrote:
> UFFDIO_CONTINUE_MODE_WP, UFFD_FEATURE_WP_UNPOPULATED, USERFAULTFD_IOC,
> and USERFAULTFD_IOC_NEW are needed lately, but they are not in my host
> (Arch Linux) distro's userfaultfd.h yet. So put them in here.
Selftests are never supposed to build with native header files. Build the
headers in kernel source first. Then building the selftests picks up these
newly built headers by itself. The method to build header files has changed
to `make headers`. The following command builds the mm selftests
successfully every time for me.

make headers && make -C tools/testing/selftests/mm

Please let me know if this doesn't work for you. I'll try to reproduce and fix.

> 
> A better approach would be to include the uapi version of userfaultfd.h
> from the kernel tree, but that currently fails with rather difficult
> linker problems (__packed is defined multiple times, ugg), so defer that
> to another day and just fix the build for now.
> 
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
>  tools/testing/selftests/mm/uffd-common.h | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
> index a1cdb78c0762..98847e41ecf9 100644
> --- a/tools/testing/selftests/mm/uffd-common.h
> +++ b/tools/testing/selftests/mm/uffd-common.h
> @@ -36,6 +36,23 @@
>  
>  #define UFFD_FLAGS	(O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY)
>  
> +#ifndef UFFDIO_CONTINUE_MODE_WP
> +#define UFFDIO_CONTINUE_MODE_WP			((__u64)1<<1)
> +#endif
> +
> +#ifndef UFFD_FEATURE_WP_UNPOPULATED
> +#define UFFD_FEATURE_WP_UNPOPULATED		(1<<13)
> +#endif
> +
> +/* ioctls for /dev/userfaultfd */
> +#ifndef USERFAULTFD_IOC
> +#define USERFAULTFD_IOC 0xAA
> +#endif
> +
> +#ifndef USERFAULTFD_IOC_NEW
> +#define USERFAULTFD_IOC_NEW _IO(USERFAULTFD_IOC, 0x00)
> +#endif
> +
>  #define _err(fmt, ...)						\
>  	do {							\
>  		int ret = errno;				\

-- 
BR,
Muhammad Usama Anjum