Revert "selftests/mm: remove local __NR_* definitions"

This reverts commit a5c6bc590094a1a73cf6fa3f505e1945d2bf2461.

The general approach described in commit e076eaca5906 ("selftests: break
the dependency upon local header files") was taken one step too far here:
it should not have been extended to include the syscall numbers.  This is
because doing so would require per-arch support in tools/include/uapi, and
no such support exists.

This revert fixes two separate reports of test failures, from Dave
Hansen[1], and Li Wang[2].  An excerpt of Dave's report:

Before this commit (a5c6bc590094a1a73cf6fa3f505e1945d2bf2461) things are
fine.  But after, I get:

	running PKEY tests for unsupported CPU/OS

An excerpt of Li's report:

    I just found that mlock2_() return a wrong value in mlock2-test

[1] https://lore.kernel.org/dc585017-6740-4cab-a536-b12b37a7582d@intel.com
[2] https://lore.kernel.org/CAEemH2eW=UMu9+turT2jRie7+6ewUazXmA6kL+VBo3cGDGU6RA@mail.gmail.com

Link: https://lkml.kernel.org/r/20250214033850.235171-1-jhubbard@nvidia.com
Fixes: a5c6bc590094 ("selftests/mm: remove local __NR_* definitions")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Li Wang <liwang@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index 9ff71fa1f9bf..74c8bc02b506 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -5,11 +5,12 @@
  *  Copyright (C) 2015-2023  Red Hat, Inc.
  */
 
-#include <asm-generic/unistd.h>
 #include "uffd-common.h"
 
 #include "../../../../mm/gup_test.h"
 
+#ifdef __NR_userfaultfd
+
 /* The unit test doesn't need a large or random size, make it 32MB for now */
 #define  UFFD_TEST_MEM_SIZE               (32UL << 20)
 
@@ -1558,3 +1559,14 @@ int main(int argc, char *argv[])
 	return ksft_get_fail_cnt() ? KSFT_FAIL : KSFT_PASS;
 }
 
+#else /* __NR_userfaultfd */
+
+#warning "missing __NR_userfaultfd definition"
+
+int main(void)
+{
+	printf("Skipping %s (missing __NR_userfaultfd)\n", __file__);
+	return KSFT_SKIP;
+}
+
+#endif /* __NR_userfaultfd */