[PATCH 0/4] Fix kselftest build with sub-directory

[PATCH 0/4] Fix kselftest build with sub-directory

[Guillaume Tucker]

Earlier attempts to get "make O=build kselftest-all" to work were
not successful as they made undesirable changes to some functions
in the top-level Makefile.  This series takes a different
approach by removing the root cause of the problem within
kselftest, which is when the sub-Makefile tries to install kernel
headers "backwards" by calling make with the top-level Makefile.
The actual issue comes from the fact that $(srctree) is ".." when
building in a sub-directory with "O=build" which then obviously
makes "-C $(top_srcdir)" point outside of the real source tree.

With this series, the generic kselftest targets work as expected
from the top level with or without a build directory e.g.:

  $ make kselftest-all

  $ make O=build kselftest-all

Then in order to build using the sub-Makefile explicitly, the
headers have to be installed first.  This is arguably a valid
requirement to have when building a tool from a sub-Makefile.
For example, "make -C tools/testing/nvdimm/" fails in a similar
way until <asm/rwonce.h> has been generated by a kernel build.

Guillaume Tucker (4):
  selftests: drop khdr make target
  selftests: stop using KSFT_KHDR_INSTALL
  selftests: drop KSFT_KHDR_INSTALL make target
  Makefile: add headers_install to kselftest targets

 Makefile                                      |  4 +-
 tools/testing/selftests/Makefile              | 28 +-------------
 tools/testing/selftests/arm64/mte/Makefile    |  1 -
 tools/testing/selftests/arm64/signal/Makefile |  1 -
 .../selftests/arm64/signal/test_signals.h     |  4 +-
 .../selftests/drivers/s390x/uvdevice/Makefile |  1 -
 .../selftests/futex/functional/Makefile       |  1 -
 tools/testing/selftests/kvm/Makefile          |  1 -
 tools/testing/selftests/landlock/Makefile     |  1 -
 tools/testing/selftests/lib.mk                | 38 -------------------
 tools/testing/selftests/net/Makefile          |  1 -
 tools/testing/selftests/net/mptcp/Makefile    |  1 -
 tools/testing/selftests/tc-testing/Makefile   |  1 -
 tools/testing/selftests/vm/Makefile           |  1 -
 14 files changed, 5 insertions(+), 79 deletions(-)

--
2.30.2

[PATCH 1/4] selftests: drop khdr make target

[Guillaume Tucker]

Drop the "khdr" make target as it fails when the build directory is a
sub-directory of the source tree.  Rely on the "headers_install"
target to have been run first instead.

For example, here's a typical error this patch is addressing:

  $ make O=build -j32 kselftest-gen_tar
  make[1]: Entering directory '/home/kernelci/linux/build'
  make --no-builtin-rules INSTALL_HDR_PATH=/home/kernelci/linux/build/usr \
          ARCH=x86 -C ../../.. headers_install
  make[3]: Entering directory '/home/kernelci/linux'
  Makefile:1022: ../scripts/Makefile.extrawarn: No such file or directory

The source directory is determined in the top-level Makefile as ".."
relatively to the "build" directory, but then the kselftest Makefile
switches to "-C ../../.." so "../scripts" then points one level higher
than the source tree e.g. "linux/../scripts" - which fails obviously.
There is no other use-case in the kernel tree where a sub-directory
Makefile tries to call a top-level make target, and it appears this
isn't really a valid thing to do.

Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
---
 tools/testing/selftests/Makefile | 27 ++-------------------------
 1 file changed, 2 insertions(+), 25 deletions(-)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index de11992dc577..619451e82863 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -151,30 +151,7 @@ export KHDR_INCLUDES
 # all isn't the first target in the file.
 .DEFAULT_GOAL := all
 
-# Install headers here once for all tests. KSFT_KHDR_INSTALL_DONE
-# is used to avoid running headers_install from lib.mk.
-# Invoke headers install with --no-builtin-rules to avoid circular
-# dependency in "make kselftest" case. In this case, second level
-# make inherits builtin-rules which will use the rule generate
-# Makefile.o and runs into
-# "Circular Makefile.o <- prepare dependency dropped."
-# and headers_install fails and test compile fails.
-#
-# O= KBUILD_OUTPUT cases don't run into this error, since main Makefile
-# invokes them as sub-makes and --no-builtin-rules is not necessary,
-# but doesn't cause any failures. Keep it simple and use the same
-# flags in both cases.
-# Local build cases: "make kselftest", "make -C" - headers are installed
-# in the default INSTALL_HDR_PATH usr/include.
-khdr:
-ifeq (1,$(DEFAULT_INSTALL_HDR_PATH))
-	$(MAKE) --no-builtin-rules ARCH=$(ARCH) -C $(top_srcdir) headers_install
-else
-	$(MAKE) --no-builtin-rules INSTALL_HDR_PATH=$(abs_objtree)/usr \
-		ARCH=$(ARCH) -C $(top_srcdir) headers_install
-endif
-
-all: khdr
+all:
 	@ret=1;							\
 	for TARGET in $(TARGETS); do				\
 		BUILD_TARGET=$$BUILD/$$TARGET;			\
@@ -274,4 +251,4 @@ clean:
 		$(MAKE) OUTPUT=$$BUILD_TARGET -C $$TARGET clean;\
 	done;
 
-.PHONY: khdr all run_tests hotplug run_hotplug clean_hotplug run_pstore_crash install clean gen_tar
+.PHONY: all run_tests hotplug run_hotplug clean_hotplug run_pstore_crash install clean gen_tar
-- 
2.30.2

[PATCH 2/4] selftests: stop using KSFT_KHDR_INSTALL

[Guillaume Tucker]

Stop using the KSFT_KHDR_INSTALL flag as installing the kernel headers
from the kselftest Makefile is causing some issues.  Instead, rely on
the headers to be installed directly by the top-level Makefile
"headers_install" make target prior to building kselftest.

Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
---
 tools/testing/selftests/arm64/mte/Makefile              | 1 -
 tools/testing/selftests/arm64/signal/Makefile           | 1 -
 tools/testing/selftests/arm64/signal/test_signals.h     | 4 +---
 tools/testing/selftests/drivers/s390x/uvdevice/Makefile | 1 -
 tools/testing/selftests/futex/functional/Makefile       | 1 -
 tools/testing/selftests/kvm/Makefile                    | 1 -
 tools/testing/selftests/landlock/Makefile               | 1 -
 tools/testing/selftests/net/Makefile                    | 1 -
 tools/testing/selftests/net/mptcp/Makefile              | 1 -
 tools/testing/selftests/tc-testing/Makefile             | 1 -
 tools/testing/selftests/vm/Makefile                     | 1 -
 11 files changed, 1 insertion(+), 13 deletions(-)

diff --git a/tools/testing/selftests/arm64/mte/Makefile b/tools/testing/selftests/arm64/mte/Makefile
index 409e3e53d00a..a5a0744423d8 100644
--- a/tools/testing/selftests/arm64/mte/Makefile
+++ b/tools/testing/selftests/arm64/mte/Makefile
@@ -22,7 +22,6 @@ ifeq ($(mte_cc_support),1)
 TEST_GEN_PROGS := $(PROGS)
 
 # Get Kernel headers installed and use them.
-KSFT_KHDR_INSTALL := 1
 else
     $(warning compiler "$(CC)" does not support the ARMv8.5 MTE extension.)
     $(warning test program "mte" will not be created.)
diff --git a/tools/testing/selftests/arm64/signal/Makefile b/tools/testing/selftests/arm64/signal/Makefile
index ac4ad0005715..be7520a863b0 100644
--- a/tools/testing/selftests/arm64/signal/Makefile
+++ b/tools/testing/selftests/arm64/signal/Makefile
@@ -11,7 +11,6 @@ PROGS := $(patsubst %.c,%,$(SRCS))
 TEST_GEN_PROGS := $(notdir $(PROGS))
 
 # Get Kernel headers installed and use them.
-KSFT_KHDR_INSTALL := 1
 
 # Including KSFT lib.mk here will also mangle the TEST_GEN_PROGS list
 # to account for any OUTPUT target-dirs optionally provided by
diff --git a/tools/testing/selftests/arm64/signal/test_signals.h b/tools/testing/selftests/arm64/signal/test_signals.h
index c70fdec7d7c4..0c645834ddc3 100644
--- a/tools/testing/selftests/arm64/signal/test_signals.h
+++ b/tools/testing/selftests/arm64/signal/test_signals.h
@@ -9,9 +9,7 @@
 #include <ucontext.h>
 
 /*
- * Using ARCH specific and sanitized Kernel headers installed by KSFT
- * framework since we asked for it by setting flag KSFT_KHDR_INSTALL
- * in our Makefile.
+ * Using ARCH specific and sanitized Kernel headers from the tree.
  */
 #include <asm/ptrace.h>
 #include <asm/hwcap.h>
diff --git a/tools/testing/selftests/drivers/s390x/uvdevice/Makefile b/tools/testing/selftests/drivers/s390x/uvdevice/Makefile
index 5e701d2708d4..891215a7dc8a 100644
--- a/tools/testing/selftests/drivers/s390x/uvdevice/Makefile
+++ b/tools/testing/selftests/drivers/s390x/uvdevice/Makefile
@@ -11,7 +11,6 @@ else
 TEST_GEN_PROGS := test_uvdevice
 
 top_srcdir ?= ../../../../../..
-KSFT_KHDR_INSTALL := 1
 khdr_dir = $(top_srcdir)/usr/include
 LINUX_TOOL_ARCH_INCLUDE = $(top_srcdir)/tools/arch/$(ARCH)/include
 
diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile
index b8152c573e8a..732149011692 100644
--- a/tools/testing/selftests/futex/functional/Makefile
+++ b/tools/testing/selftests/futex/functional/Makefile
@@ -22,7 +22,6 @@ TEST_GEN_FILES := \
 TEST_PROGS := run.sh
 
 top_srcdir = ../../../../..
-KSFT_KHDR_INSTALL := 1
 DEFAULT_INSTALL_HDR_PATH := 1
 include ../../lib.mk
 
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 81470a99ed1c..e15bb9693922 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -4,7 +4,6 @@ include ../../../build/Build.include
 all:
 
 top_srcdir = ../../../..
-KSFT_KHDR_INSTALL := 1
 
 # For cross-builds to work, UNAME_M has to map to ARCH and arch specific
 # directories and targets in this Makefile. "uname -m" doesn't map to
diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile
index 0b0049e133bb..1313e44e8fb9 100644
--- a/tools/testing/selftests/landlock/Makefile
+++ b/tools/testing/selftests/landlock/Makefile
@@ -8,7 +8,6 @@ TEST_GEN_PROGS := $(src_test:.c=)
 
 TEST_GEN_PROGS_EXTENDED := true
 
-KSFT_KHDR_INSTALL := 1
 OVERRIDE_TARGETS := 1
 include ../lib.mk
 
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 464df13831f2..eaf3bb457576 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -63,7 +63,6 @@ TEST_GEN_FILES += bind_bhash_test
 
 TEST_FILES := settings
 
-KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
 include bpf/Makefile
diff --git a/tools/testing/selftests/net/mptcp/Makefile b/tools/testing/selftests/net/mptcp/Makefile
index f905d5358e68..1af2f66fb59a 100644
--- a/tools/testing/selftests/net/mptcp/Makefile
+++ b/tools/testing/selftests/net/mptcp/Makefile
@@ -1,7 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
 top_srcdir = ../../../../..
-KSFT_KHDR_INSTALL := 1
 
 CFLAGS =  -Wall -Wl,--no-as-needed -O2 -g -I$(top_srcdir)/usr/include $(KHDR_INCLUDES)
 
diff --git a/tools/testing/selftests/tc-testing/Makefile b/tools/testing/selftests/tc-testing/Makefile
index 4d639279f41e..cb553eac9f41 100644
--- a/tools/testing/selftests/tc-testing/Makefile
+++ b/tools/testing/selftests/tc-testing/Makefile
@@ -5,7 +5,6 @@ top_srcdir = $(abspath ../../../..)
 APIDIR := $(top_scrdir)/include/uapi
 TEST_GEN_FILES = action.o
 
-KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
 PROBE := $(shell $(LLC) -march=bpf -mcpu=probe -filetype=null /dev/null 2>&1)
diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
index 44f25acfbeca..108587cb327a 100644
--- a/tools/testing/selftests/vm/Makefile
+++ b/tools/testing/selftests/vm/Makefile
@@ -94,7 +94,6 @@ TEST_PROGS := run_vmtests.sh
 TEST_FILES := test_vmalloc.sh
 TEST_FILES += test_hmm.sh
 
-KSFT_KHDR_INSTALL := 1
 include ../lib.mk
 
 $(OUTPUT)/madv_populate: vm_util.c
-- 
2.30.2

[PATCH 3/4] selftests: drop KSFT_KHDR_INSTALL make target

[Guillaume Tucker]

Drop the KSFT_KHDR_INSTALL make target now that all use-cases have
been removed from the other kselftest Makefiles.

Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
---
 tools/testing/selftests/Makefile |  1 -
 tools/testing/selftests/lib.mk   | 38 --------------------------------
 2 files changed, 39 deletions(-)

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 619451e82863..e060777239a4 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -143,7 +143,6 @@ endif
 # Prepare for headers install
 include $(top_srcdir)/scripts/subarch.include
 ARCH           ?= $(SUBARCH)
-export KSFT_KHDR_INSTALL_DONE := 1
 export BUILD
 export KHDR_INCLUDES
 
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 2a2d240cdc1b..df5f853951f2 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -30,45 +30,7 @@ TEST_GEN_PROGS := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS))
 TEST_GEN_PROGS_EXTENDED := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_PROGS_EXTENDED))
 TEST_GEN_FILES := $(patsubst %,$(OUTPUT)/%,$(TEST_GEN_FILES))
 
-ifdef KSFT_KHDR_INSTALL
-top_srcdir ?= ../../../..
-include $(top_srcdir)/scripts/subarch.include
-ARCH		?= $(SUBARCH)
-
-# set default goal to all, so make without a target runs all, even when
-# all isn't the first target in the file.
-.DEFAULT_GOAL := all
-
-# Invoke headers install with --no-builtin-rules to avoid circular
-# dependency in "make kselftest" case. In this case, second level
-# make inherits builtin-rules which will use the rule generate
-# Makefile.o and runs into
-# "Circular Makefile.o <- prepare dependency dropped."
-# and headers_install fails and test compile fails.
-# O= KBUILD_OUTPUT cases don't run into this error, since main Makefile
-# invokes them as sub-makes and --no-builtin-rules is not necessary,
-# but doesn't cause any failures. Keep it simple and use the same
-# flags in both cases.
-# Note that the support to install headers from lib.mk is necessary
-# when test Makefile is run directly with "make -C".
-# When local build is done, headers are installed in the default
-# INSTALL_HDR_PATH usr/include.
-.PHONY: khdr
-.NOTPARALLEL:
-khdr:
-ifndef KSFT_KHDR_INSTALL_DONE
-ifeq (1,$(DEFAULT_INSTALL_HDR_PATH))
-	$(MAKE) --no-builtin-rules ARCH=$(ARCH) -C $(top_srcdir) headers_install
-else
-	$(MAKE) --no-builtin-rules INSTALL_HDR_PATH=$$OUTPUT/usr \
-		ARCH=$(ARCH) -C $(top_srcdir) headers_install
-endif
-endif
-
-all: khdr $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
-else
 all: $(TEST_GEN_PROGS) $(TEST_GEN_PROGS_EXTENDED) $(TEST_GEN_FILES)
-endif
 
 define RUN_TESTS
 	BASE_DIR="$(selfdir)";			\
-- 
2.30.2

[PATCH 4/4] Makefile: add headers_install to kselftest targets

[Guillaume Tucker]

Add headers_install as a dependency to kselftest targets so that they
can be run directly from the top of the tree.  The kselftest Makefile
used to try to call headers_install "backwards" but failed due to the
relative path not being consistent.

Now we can either run this directly:

  $ make O=build kselftest-all

or this:

  $ make O=build headers_install
  $ make O=build -C tools/testing/selftest all

The same commands work as well when building directly in the source
tree (no O=) or any arbitrary path (relative or absolute).

Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
---
 Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 1a6678d817bd..afc9d739ba44 100644
--- a/Makefile
+++ b/Makefile
@@ -1347,10 +1347,10 @@ tools/%: FORCE
 # Kernel selftest
 
 PHONY += kselftest
-kselftest:
+kselftest: headers_install
 	$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests
 
-kselftest-%: FORCE
+kselftest-%: headers_install FORCE
 	$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $*
 
 PHONY += kselftest-merge
-- 
2.30.2

Re: [PATCH 4/4] Makefile: add headers_install to kselftest targets

[Masahiro Yamada]

On Sat, Jul 9, 2022 at 1:23 AM Guillaume Tucker
<guillaume.tucker@collabora.com> wrote:
>
> Add headers_install as a dependency to kselftest targets so that they
> can be run directly from the top of the tree.  The kselftest Makefile
> used to try to call headers_install "backwards" but failed due to the
> relative path not being consistent.
>
> Now we can either run this directly:
>
>   $ make O=build kselftest-all
>
> or this:
>
>   $ make O=build headers_install
>   $ make O=build -C tools/testing/selftest all
>
> The same commands work as well when building directly in the source
> tree (no O=) or any arbitrary path (relative or absolute).
>
> Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
> ---
>  Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index 1a6678d817bd..afc9d739ba44 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1347,10 +1347,10 @@ tools/%: FORCE
>  # Kernel selftest
>
>  PHONY += kselftest
> -kselftest:
> +kselftest: headers_install
>         $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests

Nit.
Please use 'headers' for in-kernel use of exportedI headers.

kselftest: headers


>
> -kselftest-%: FORCE
> +kselftest-%: headers_install FORCE
>         $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $*

Ditto.

kselftest-%: headers FORCE


>
>  PHONY += kselftest-merge
> --
> 2.30.2
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH 4/4] Makefile: add headers_install to kselftest targets

[Guillaume Tucker]

On 12/07/2022 02:35, Masahiro Yamada wrote:
> On Sat, Jul 9, 2022 at 1:23 AM Guillaume Tucker
> <guillaume.tucker@collabora.com> wrote:
>>
>> Add headers_install as a dependency to kselftest targets so that they
>> can be run directly from the top of the tree.  The kselftest Makefile
>> used to try to call headers_install "backwards" but failed due to the
>> relative path not being consistent.
>>
>> Now we can either run this directly:
>>
>>   $ make O=build kselftest-all
>>
>> or this:
>>
>>   $ make O=build headers_install
>>   $ make O=build -C tools/testing/selftest all
>>
>> The same commands work as well when building directly in the source
>> tree (no O=) or any arbitrary path (relative or absolute).
>>
>> Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
>> ---
>>  Makefile | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/Makefile b/Makefile
>> index 1a6678d817bd..afc9d739ba44 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -1347,10 +1347,10 @@ tools/%: FORCE
>>  # Kernel selftest
>>
>>  PHONY += kselftest
>> -kselftest:
>> +kselftest: headers_install
>>         $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests
> 
> Nit.
> Please use 'headers' for in-kernel use of exportedI headers.
> 
> kselftest: headers
> 
> 
>>
>> -kselftest-%: FORCE
>> +kselftest-%: headers_install FORCE
>>         $(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $*
> 
> Ditto.
> 
> kselftest-%: headers FORCE

Thank you all for the reviews.

I've sent a v2 with this tweak and double-checked that the
kselftest build produced exactly the same result.

Best wishes,
Guillaume

Re: [PATCH 4/4] Makefile: add headers_install to kselftest targets

[Guillaume Tucker]

On 08/07/2022 18:23, Guillaume Tucker wrote:
> 
>   $ make O=build headers_install
>   $ make O=build -C tools/testing/selftest all

Typo, it should be selftests:

    $ make O=build -C tools/testing/selftests all

Thanks,
Guillaume

Re: [PATCH 0/4] Fix kselftest build with sub-directory

[Shuah Khan]

On 7/8/22 10:23 AM, Guillaume Tucker wrote:
> Earlier attempts to get "make O=build kselftest-all" to work were
> not successful as they made undesirable changes to some functions
> in the top-level Makefile.  This series takes a different
> approach by removing the root cause of the problem within
> kselftest, which is when the sub-Makefile tries to install kernel
> headers "backwards" by calling make with the top-level Makefile.
> The actual issue comes from the fact that $(srctree) is ".." when
> building in a sub-directory with "O=build" which then obviously
> makes "-C $(top_srcdir)" point outside of the real source tree.
> 
> With this series, the generic kselftest targets work as expected
> from the top level with or without a build directory e.g.:
> 
>    $ make kselftest-all
> 
>    $ make O=build kselftest-all
> 
> Then in order to build using the sub-Makefile explicitly, the
> headers have to be installed first.  This is arguably a valid
> requirement to have when building a tool from a sub-Makefile.
> For example, "make -C tools/testing/nvdimm/" fails in a similar
> way until <asm/rwonce.h> has been generated by a kernel build.
> 
> Guillaume Tucker (4):
>    selftests: drop khdr make target
>    selftests: stop using KSFT_KHDR_INSTALL
>    selftests: drop KSFT_KHDR_INSTALL make target
>    Makefile: add headers_install to kselftest targets
> 

This takes us to back to the state before b2d35fa5fc80 added
khdr support. I reluctantly agreed to the change and it has
proven to be a problematic change. I would rather have had the
dependency stated that headers should be installed prior to
building tests - test build depends on kernel build anyway and
having dependency on headers having build isn't a huge deal.

So I am in favor of getting rid of khdr support. However, this
khdr support was a change originated from Linaro test ring. Undoing
this might have implication on their workflow.

I will pull them into the discussion so they are aware of it and
be prepared for this change.

thanks,
-- Shuah

RE: [PATCH 0/4] Fix kselftest build with sub-directory

[Bird, Tim]

> -----Original Message-----
> From: Shuah Khan <skhan@linuxfoundation.org>
> 
> On 7/8/22 10:23 AM, Guillaume Tucker wrote:
> > Earlier attempts to get "make O=build kselftest-all" to work were
> > not successful as they made undesirable changes to some functions
> > in the top-level Makefile.  This series takes a different
> > approach by removing the root cause of the problem within
> > kselftest, which is when the sub-Makefile tries to install kernel
> > headers "backwards" by calling make with the top-level Makefile.
> > The actual issue comes from the fact that $(srctree) is ".." when
> > building in a sub-directory with "O=build" which then obviously
> > makes "-C $(top_srcdir)" point outside of the real source tree.
> >
> > With this series, the generic kselftest targets work as expected
> > from the top level with or without a build directory e.g.:
> >
> >    $ make kselftest-all
> >
> >    $ make O=build kselftest-all
> >
> > Then in order to build using the sub-Makefile explicitly, the
> > headers have to be installed first.  This is arguably a valid
> > requirement to have when building a tool from a sub-Makefile.
> > For example, "make -C tools/testing/nvdimm/" fails in a similar
> > way until <asm/rwonce.h> has been generated by a kernel build.
> >
> > Guillaume Tucker (4):
> >    selftests: drop khdr make target
> >    selftests: stop using KSFT_KHDR_INSTALL
> >    selftests: drop KSFT_KHDR_INSTALL make target
> >    Makefile: add headers_install to kselftest targets
> >
> 
> This takes us to back to the state before b2d35fa5fc80 added
> khdr support. I reluctantly agreed to the change and it has
> proven to be a problematic change. I would rather have had the
> dependency stated that headers should be installed prior to
> building tests - test build depends on kernel build anyway and
> having dependency on headers having build isn't a huge deal.
> 
> So I am in favor of getting rid of khdr support. However, this
> khdr support was a change originated from Linaro test ring. Undoing
> this might have implication on their workflow.
> 
> I will pull them into the discussion so they are aware of it and
> be prepared for this change.

I ran into this bug quite a while ago.  I reported it here:
https://lore.kernel.org/all/ECADFF3FD767C149AD96A924E7EA6EAF977BD214@USCULXMSG01.am.sony.com/
it was fixed here:
https://lore.kernel.org/all/20191015014505.14259-1-skhan@linuxfoundation.org/
but apparently reverting it was discussed, based on this:
https://lore.kernel.org/all/8d34a9b9-f8f3-0e37-00bf-c342cf3d4074@arm.com/

I'm not sure what happened after that.

I was able to work around it by avoiding
putting the build directory inside the source tree.

I strongly support getting rid of the khdr stuff, as it's quite hard
to follow.  I think my workflow would not be affected (but I should
run off and test it.)

Thanks for working on this Guillaume!
 -- Tim

Re: [PATCH 0/4] Fix kselftest build with sub-directory

[Anders Roxell]

On Fri, 8 Jul 2022 at 19:14, Shuah Khan <skhan@linuxfoundation.org> wrote:
>
> On 7/8/22 10:23 AM, Guillaume Tucker wrote:
> > Earlier attempts to get "make O=build kselftest-all" to work were
> > not successful as they made undesirable changes to some functions
> > in the top-level Makefile.  This series takes a different
> > approach by removing the root cause of the problem within
> > kselftest, which is when the sub-Makefile tries to install kernel
> > headers "backwards" by calling make with the top-level Makefile.
> > The actual issue comes from the fact that $(srctree) is ".." when
> > building in a sub-directory with "O=build" which then obviously
> > makes "-C $(top_srcdir)" point outside of the real source tree.
> >
> > With this series, the generic kselftest targets work as expected
> > from the top level with or without a build directory e.g.:
> >
> >    $ make kselftest-all
> >
> >    $ make O=build kselftest-all
> >
> > Then in order to build using the sub-Makefile explicitly, the
> > headers have to be installed first.  This is arguably a valid
> > requirement to have when building a tool from a sub-Makefile.
> > For example, "make -C tools/testing/nvdimm/" fails in a similar
> > way until <asm/rwonce.h> has been generated by a kernel build.
> >
> > Guillaume Tucker (4):
> >    selftests: drop khdr make target
> >    selftests: stop using KSFT_KHDR_INSTALL
> >    selftests: drop KSFT_KHDR_INSTALL make target
> >    Makefile: add headers_install to kselftest targets
> >
>
> This takes us to back to the state before b2d35fa5fc80 added
> khdr support. I reluctantly agreed to the change and it has
> proven to be a problematic change. I would rather have had the
> dependency stated that headers should be installed prior to
> building tests - test build depends on kernel build anyway and
> having dependency on headers having build isn't a huge deal.

I agree that it's not a huge deal.

>
> So I am in favor of getting rid of khdr support. However, this
> khdr support was a change originated from Linaro test ring. Undoing
> this might have implication on their workflow.

It shouldn't be a problem.
I've been running these patches through a smoke test and it looks
good.

Tested-by: Anders Roxell <anders.roxell@linaro.org>


Cheers,
Anders

>
> I will pull them into the discussion so they are aware of it and
> be prepared for this change.
>
> thanks,
> -- Shuah
>
>

Re: [PATCH 0/4] Fix kselftest build with sub-directory

[Shuah Khan]

On 7/11/22 6:13 AM, Anders Roxell wrote:
> On Fri, 8 Jul 2022 at 19:14, Shuah Khan <skhan@linuxfoundation.org> wrote:
>>
>> On 7/8/22 10:23 AM, Guillaume Tucker wrote:
>>> Earlier attempts to get "make O=build kselftest-all" to work were
>>> not successful as they made undesirable changes to some functions
>>> in the top-level Makefile.  This series takes a different
>>> approach by removing the root cause of the problem within
>>> kselftest, which is when the sub-Makefile tries to install kernel
>>> headers "backwards" by calling make with the top-level Makefile.
>>> The actual issue comes from the fact that $(srctree) is ".." when
>>> building in a sub-directory with "O=build" which then obviously
>>> makes "-C $(top_srcdir)" point outside of the real source tree.
>>>
>>> With this series, the generic kselftest targets work as expected
>>> from the top level with or without a build directory e.g.:
>>>
>>>     $ make kselftest-all
>>>
>>>     $ make O=build kselftest-all
>>>
>>> Then in order to build using the sub-Makefile explicitly, the
>>> headers have to be installed first.  This is arguably a valid
>>> requirement to have when building a tool from a sub-Makefile.
>>> For example, "make -C tools/testing/nvdimm/" fails in a similar
>>> way until <asm/rwonce.h> has been generated by a kernel build.
>>>
>>> Guillaume Tucker (4):
>>>     selftests: drop khdr make target
>>>     selftests: stop using KSFT_KHDR_INSTALL
>>>     selftests: drop KSFT_KHDR_INSTALL make target
>>>     Makefile: add headers_install to kselftest targets
>>>
>>
>> This takes us to back to the state before b2d35fa5fc80 added
>> khdr support. I reluctantly agreed to the change and it has
>> proven to be a problematic change. I would rather have had the
>> dependency stated that headers should be installed prior to
>> building tests - test build depends on kernel build anyway and
>> having dependency on headers having build isn't a huge deal.
> 
> I agree that it's not a huge deal.
> 
>>
>> So I am in favor of getting rid of khdr support. However, this
>> khdr support was a change originated from Linaro test ring. Undoing
>> this might have implication on their workflow.
> 
> It shouldn't be a problem.
> I've been running these patches through a smoke test and it looks
> good.
> 
> Tested-by: Anders Roxell <anders.roxell@linaro.org>
> 
> 

Thank you Anders for confirming this isn't a problem for Linaro workflow
and testing.

Than you Guillaume for fixing the problem. I will apply these for 5.20-rc1.

thanks,
-- Shuah