[PATCH 1/2] selftests: break the dependency upon local header files

[John Hubbard <jhubbard@nvidia.com>]

Use tools/include/uapi/ files instead. These are obtained by taking a
snapshot: run "make headers" at the top level, then copy the desired
header file into the appropriate subdir in tools/uapi/.

This was discussed and solved in [1].

However, even before copying any additional files there, there are
already quite a few in tools/include/uapi already. And these will
immediately fix a number of selftests/mm build failures.

So this patch:

a) Adds TOOLS_INCLUDES to selftests/lib.mk, so that all selftests can
immediately and easily include the snapshotted header files.

b) Uses $(TOOLS_INCLUDES) in the selftests/mm build. On today's Arch
Linux, this already fixes all build errors except for a few
userfaultfd.h (those will be addressed in a subsequent patch).

[1] https://lore.kernel.org/all/783a4178-1dec-4e30-989a-5174b8176b09@redhat.com/

Cc: David Hildenbrand <david@redhat.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/lib.mk      | 9 +++++++++
 tools/testing/selftests/mm/Makefile | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index da2cade3bab0..1dae4a02957f 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -48,6 +48,15 @@ ifeq ($(KHDR_INCLUDES),)
 KHDR_INCLUDES := -isystem $(top_srcdir)/usr/include
 endif
 
+# In order to use newer items that haven't yet been added to the user's system
+# header files, add $(TOOLS_INCLUDES) to the compiler invocation in each
+# each selftest.
+# You may need to add files to that location, or to refresh an existing file. In
+# order to do that, run "make headers" from $(top_srcdir), then copy the
+# header file that you want from $(top_srcdir)/usr/include/... , to the matching
+# subdir in $(TOOLS_INCLUDE).
+TOOLS_INCLUDES := -isystem $(top_srcdir)/tools/include/uapi
+
 # The following are built by lib.mk common compile rules.
 # TEST_CUSTOM_PROGS should be used by tests that require
 # custom build rule and prevent common build rule use.
diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile
index eb5f39a2668b..7ca9186a0639 100644
--- a/tools/testing/selftests/mm/Makefile
+++ b/tools/testing/selftests/mm/Makefile
@@ -32,7 +32,7 @@ endif
 # LDLIBS.
 MAKEFLAGS += --no-builtin-rules
 
-CFLAGS = -Wall -I $(top_srcdir) $(EXTRA_CFLAGS) $(KHDR_INCLUDES)
+CFLAGS = -Wall -I $(top_srcdir) $(EXTRA_CFLAGS) $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
 LDLIBS = -lrt -lpthread -lm
 
 TEST_GEN_FILES = cow
-- 
2.44.0