[PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Shuah Khan]

Fix seccomp relocatable builds. This is a simple fix to use the right
lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
header, and defining LDFLAGS for pthread lib.

Removes custom clean rule which is no longer necessary with the use of
TEST_GEN_PROGS. 

Uses $(OUTPUT) defined in lib.mk to handle build relocation.

The following use-cases work with this change:

In seccomp directory:
make all and make clean

From top level from main Makefile:
make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
 CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---

Changes since v2:
-- Using TEST_GEN_PROGS is sufficient to generate objects.
   Addresses review comments from Kees Cook.

 tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
index 1760b3e39730..a0388fd2c3f2 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -1,17 +1,15 @@
 # SPDX-License-Identifier: GPL-2.0
-all:
-
-include ../lib.mk
+CFLAGS += -Wl,-no-as-needed -Wall
+LDFLAGS += -lpthread
 
 .PHONY: all clean
 
-BINARIES := seccomp_bpf seccomp_benchmark
-CFLAGS += -Wl,-no-as-needed -Wall
+include ../lib.mk
+
+# OUTPUT set by lib.mk
+TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
 
-seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
-	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
+$(TEST_GEN_PROGS): ../kselftest_harness.h
 
-TEST_PROGS += $(BINARIES)
-EXTRA_CLEAN := $(BINARIES)
+all: $(TEST_GEN_PROGS)
 
-all: $(BINARIES)
-- 
2.20.1

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Kees Cook]

On Fri, Mar 13, 2020 at 03:24:04PM -0600, Shuah Khan wrote:
> Fix seccomp relocatable builds. This is a simple fix to use the right
> lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
> header, and defining LDFLAGS for pthread lib.
> 
> Removes custom clean rule which is no longer necessary with the use of
> TEST_GEN_PROGS. 
> 
> Uses $(OUTPUT) defined in lib.mk to handle build relocation.
> 
> The following use-cases work with this change:
> 
> In seccomp directory:
> make all and make clean
> 
> From top level from main Makefile:
> make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
>  CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
> 
> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
> ---
> 
> Changes since v2:
> -- Using TEST_GEN_PROGS is sufficient to generate objects.
>    Addresses review comments from Kees Cook.
> 
>  tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
> index 1760b3e39730..a0388fd2c3f2 100644
> --- a/tools/testing/selftests/seccomp/Makefile
> +++ b/tools/testing/selftests/seccomp/Makefile
> @@ -1,17 +1,15 @@
>  # SPDX-License-Identifier: GPL-2.0
> -all:
> -
> -include ../lib.mk
> +CFLAGS += -Wl,-no-as-needed -Wall
> +LDFLAGS += -lpthread
>  
>  .PHONY: all clean

Isn't this line redundant to ../lib.mk's?

>  
> -BINARIES := seccomp_bpf seccomp_benchmark
> -CFLAGS += -Wl,-no-as-needed -Wall
> +include ../lib.mk
> +
> +# OUTPUT set by lib.mk
> +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
>  
> -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
> -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
> +$(TEST_GEN_PROGS): ../kselftest_harness.h
>  
> -TEST_PROGS += $(BINARIES)
> -EXTRA_CLEAN := $(BINARIES)
> +all: $(TEST_GEN_PROGS)

And isn't this one too?

I think if those are removed it should all still work? Regardless:

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

>  
> -all: $(BINARIES)
> -- 
> 2.20.1
> 

-- 
Kees Cook

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Shuah Khan]

On 3/13/20 5:18 PM, Kees Cook wrote:
> On Fri, Mar 13, 2020 at 03:24:04PM -0600, Shuah Khan wrote:
>> Fix seccomp relocatable builds. This is a simple fix to use the right
>> lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
>> header, and defining LDFLAGS for pthread lib.
>>
>> Removes custom clean rule which is no longer necessary with the use of
>> TEST_GEN_PROGS.
>>
>> Uses $(OUTPUT) defined in lib.mk to handle build relocation.
>>
>> The following use-cases work with this change:
>>
>> In seccomp directory:
>> make all and make clean
>>
>>  From top level from main Makefile:
>> make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
>>   CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
>>
>> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
>> ---
>>
>> Changes since v2:
>> -- Using TEST_GEN_PROGS is sufficient to generate objects.
>>     Addresses review comments from Kees Cook.
>>
>>   tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
>>   1 file changed, 8 insertions(+), 10 deletions(-)
>>
>> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
>> index 1760b3e39730..a0388fd2c3f2 100644
>> --- a/tools/testing/selftests/seccomp/Makefile
>> +++ b/tools/testing/selftests/seccomp/Makefile
>> @@ -1,17 +1,15 @@
>>   # SPDX-License-Identifier: GPL-2.0
>> -all:
>> -
>> -include ../lib.mk
>> +CFLAGS += -Wl,-no-as-needed -Wall
>> +LDFLAGS += -lpthread
>>   
>>   .PHONY: all clean
> 
> Isn't this line redundant to ../lib.mk's?
>
>>   
>> -BINARIES := seccomp_bpf seccomp_benchmark
>> -CFLAGS += -Wl,-no-as-needed -Wall
>> +include ../lib.mk
>> +
>> +# OUTPUT set by lib.mk
>> +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
>>   
>> -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
>> -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
>> +$(TEST_GEN_PROGS): ../kselftest_harness.h
>>   
>> -TEST_PROGS += $(BINARIES)
>> -EXTRA_CLEAN := $(BINARIES)
>> +all: $(TEST_GEN_PROGS)
> 
> And isn't this one too?

make in seccomp directory won't work. lib.mk won't build it.
One reason why I wanted to clearly call this out as CUSTOM
program.

But it does make sense to reduce additional EXTRA_CLEAN by
just using TEST_GEN_PROGS.
> 
> I think if those are removed it should all still work? Regardless:
> 
diff Makefile
diff --git a/tools/testing/selftests/seccomp/Makefile 
b/tools/testing/selftests/seccomp/Makefile
index a0388fd2c3f2..d3d256654cb1 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -2,7 +2,7 @@
  CFLAGS += -Wl,-no-as-needed -Wall
  LDFLAGS += -lpthread

-.PHONY: all clean
+#.PHONY: all clean

  include ../lib.mk

@@ -11,5 +11,5 @@ TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf 
$(OUTPUT)/seccomp_benchmark

  $(TEST_GEN_PROGS): ../kselftest_harness.h

-all: $(TEST_GEN_PROGS)
+#$all: $(TEST_GEN_PROGS)

With this:

make
make: Nothing to be done for 'all'.

> Reviewed-by: Kees Cook <keescook@chromium.org>
> 

I am addressing your comment about other tests that de[end on
kselftest_harness.h. I have a few patches ready to be sent.

thanks,
-- Shuah

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Michael Ellerman]

Shuah Khan <skhan@linuxfoundation.org> writes:
> Fix seccomp relocatable builds. This is a simple fix to use the right
> lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
> header, and defining LDFLAGS for pthread lib.
>
> Removes custom clean rule which is no longer necessary with the use of
> TEST_GEN_PROGS. 
>
> Uses $(OUTPUT) defined in lib.mk to handle build relocation.
>
> The following use-cases work with this change:
>
> In seccomp directory:
> make all and make clean
>
> From top level from main Makefile:
> make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
>  CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
>
> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
> ---
>
> Changes since v2:
> -- Using TEST_GEN_PROGS is sufficient to generate objects.
>    Addresses review comments from Kees Cook.
>
>  tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
>  1 file changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
> index 1760b3e39730..a0388fd2c3f2 100644
> --- a/tools/testing/selftests/seccomp/Makefile
> +++ b/tools/testing/selftests/seccomp/Makefile
> @@ -1,17 +1,15 @@
>  # SPDX-License-Identifier: GPL-2.0
> -all:
> -
> -include ../lib.mk
> +CFLAGS += -Wl,-no-as-needed -Wall
> +LDFLAGS += -lpthread
>  
>  .PHONY: all clean
>  
> -BINARIES := seccomp_bpf seccomp_benchmark
> -CFLAGS += -Wl,-no-as-needed -Wall
> +include ../lib.mk
> +
> +# OUTPUT set by lib.mk
> +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
>  
> -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
> -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
> +$(TEST_GEN_PROGS): ../kselftest_harness.h
>  
> -TEST_PROGS += $(BINARIES)
> -EXTRA_CLEAN := $(BINARIES)
> +all: $(TEST_GEN_PROGS)
>  
> -all: $(BINARIES)


It shouldn't be that complicated. We just need to define TEST_GEN_PROGS
before including lib.mk, and then add the dependency on the harness
after we include lib.mk (so that TEST_GEN_PROGS has been updated to
prefix $(OUTPUT)).

eg:

  # SPDX-License-Identifier: GPL-2.0
  CFLAGS += -Wl,-no-as-needed -Wall
  LDFLAGS += -lpthread
  
  TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
  
  include ../lib.mk
  
  $(TEST_GEN_PROGS): ../kselftest_harness.h


Normal in-tree build:

  selftests$ make TARGETS=seccomp
  make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
  make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
  
  selftests$ ls -l seccomp/
  total 388
  -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
  -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:07 seccomp_benchmark*
  -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:07 seccomp_bpf*
  -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c


O= build:

  selftests$ make TARGETS=seccomp O=$PWD/build
  make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_benchmark
  make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
  
  selftests$ ls -l build/seccomp/
  total 280
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:05 seccomp_benchmark*
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:05 seccomp_bpf*


Build in the directory itself:
  selftests$ cd seccomp
  seccomp$ make
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
  gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
  
  seccomp$ ls -l
  total 388
  -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
  -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
  -rwxrwxr-x 1 michael michael  70824 Mar 16 23:06 seccomp_benchmark*
  -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
  -rwxrwxr-x 1 michael michael 290520 Mar 16 23:06 seccomp_bpf*
  -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c


cheers

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Kees Cook]

On Mon, Mar 16, 2020 at 11:12:57PM +1100, Michael Ellerman wrote:
> Shuah Khan <skhan@linuxfoundation.org> writes:
> > Fix seccomp relocatable builds. This is a simple fix to use the right
> > lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
> > header, and defining LDFLAGS for pthread lib.
> >
> > Removes custom clean rule which is no longer necessary with the use of
> > TEST_GEN_PROGS. 
> >
> > Uses $(OUTPUT) defined in lib.mk to handle build relocation.
> >
> > The following use-cases work with this change:
> >
> > In seccomp directory:
> > make all and make clean
> >
> > From top level from main Makefile:
> > make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
> >  CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
> >
> > Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
> > ---
> >
> > Changes since v2:
> > -- Using TEST_GEN_PROGS is sufficient to generate objects.
> >    Addresses review comments from Kees Cook.
> >
> >  tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
> >  1 file changed, 8 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
> > index 1760b3e39730..a0388fd2c3f2 100644
> > --- a/tools/testing/selftests/seccomp/Makefile
> > +++ b/tools/testing/selftests/seccomp/Makefile
> > @@ -1,17 +1,15 @@
> >  # SPDX-License-Identifier: GPL-2.0
> > -all:
> > -
> > -include ../lib.mk
> > +CFLAGS += -Wl,-no-as-needed -Wall
> > +LDFLAGS += -lpthread
> >  
> >  .PHONY: all clean
> >  
> > -BINARIES := seccomp_bpf seccomp_benchmark
> > -CFLAGS += -Wl,-no-as-needed -Wall
> > +include ../lib.mk
> > +
> > +# OUTPUT set by lib.mk
> > +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
> >  
> > -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
> > -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
> > +$(TEST_GEN_PROGS): ../kselftest_harness.h
> >  
> > -TEST_PROGS += $(BINARIES)
> > -EXTRA_CLEAN := $(BINARIES)
> > +all: $(TEST_GEN_PROGS)
> >  
> > -all: $(BINARIES)
> 
> 
> It shouldn't be that complicated. We just need to define TEST_GEN_PROGS
> before including lib.mk, and then add the dependency on the harness
> after we include lib.mk (so that TEST_GEN_PROGS has been updated to
> prefix $(OUTPUT)).
> 
> eg:
> 
>   # SPDX-License-Identifier: GPL-2.0
>   CFLAGS += -Wl,-no-as-needed -Wall
>   LDFLAGS += -lpthread
>   
>   TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
>   
>   include ../lib.mk
>   
>   $(TEST_GEN_PROGS): ../kselftest_harness.h

Exactly. This (with an extra comment) is precisely what I suggested during
v2 review:
https://lore.kernel.org/lkml/202003041815.B8C73DEC@keescook/

-Kees

> 
> 
> Normal in-tree build:
> 
>   selftests$ make TARGETS=seccomp
>   make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
>   make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
>   
>   selftests$ ls -l seccomp/
>   total 388
>   -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
>   -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
>   -rwxrwxr-x 1 michael michael  70824 Mar 16 23:07 seccomp_benchmark*
>   -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
>   -rwxrwxr-x 1 michael michael 290520 Mar 16 23:07 seccomp_bpf*
>   -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c
> 
> 
> O= build:
> 
>   selftests$ make TARGETS=seccomp O=$PWD/build
>   make[1]: Entering directory '/home/michael/linux/tools/testing/selftests/seccomp'
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_bpf
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/build/seccomp/seccomp_benchmark
>   make[1]: Leaving directory '/home/michael/linux/tools/testing/selftests/seccomp'
>   
>   selftests$ ls -l build/seccomp/
>   total 280
>   -rwxrwxr-x 1 michael michael  70824 Mar 16 23:05 seccomp_benchmark*
>   -rwxrwxr-x 1 michael michael 290520 Mar 16 23:05 seccomp_bpf*
> 
> 
> Build in the directory itself:
>   selftests$ cd seccomp
>   seccomp$ make
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_bpf
>   gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c ../kselftest_harness.h  -o /home/michael/linux/tools/testing/selftests/seccomp/seccomp_benchmark
>   
>   seccomp$ ls -l
>   total 388
>   -rw-rw-r-- 1 michael michael     41 Jan  9 12:00 config
>   -rw-rw-r-- 1 michael michael    201 Mar 16 23:04 Makefile
>   -rwxrwxr-x 1 michael michael  70824 Mar 16 23:06 seccomp_benchmark*
>   -rw-rw-r-- 1 michael michael   2289 Feb 17 21:39 seccomp_benchmark.c
>   -rwxrwxr-x 1 michael michael 290520 Mar 16 23:06 seccomp_bpf*
>   -rw-rw-r-- 1 michael michael  94778 Mar  5 23:33 seccomp_bpf.c
> 
> 
> cheers

-- 
Kees Cook

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Michael Ellerman]

Kees Cook <keescook@chromium.org> writes:
> On Mon, Mar 16, 2020 at 11:12:57PM +1100, Michael Ellerman wrote:
>> Shuah Khan <skhan@linuxfoundation.org> writes:
>> > Fix seccomp relocatable builds. This is a simple fix to use the right
>> > lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
>> > header, and defining LDFLAGS for pthread lib.
>> >
>> > Removes custom clean rule which is no longer necessary with the use of
>> > TEST_GEN_PROGS. 
>> >
>> > Uses $(OUTPUT) defined in lib.mk to handle build relocation.
>> >
>> > The following use-cases work with this change:
>> >
>> > In seccomp directory:
>> > make all and make clean
>> >
>> > From top level from main Makefile:
>> > make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
>> >  CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
>> >
>> > Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
>> > ---
>> >
>> > Changes since v2:
>> > -- Using TEST_GEN_PROGS is sufficient to generate objects.
>> >    Addresses review comments from Kees Cook.
>> >
>> >  tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
>> >  1 file changed, 8 insertions(+), 10 deletions(-)
>> >
>> > diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
>> > index 1760b3e39730..a0388fd2c3f2 100644
>> > --- a/tools/testing/selftests/seccomp/Makefile
>> > +++ b/tools/testing/selftests/seccomp/Makefile
>> > @@ -1,17 +1,15 @@
>> >  # SPDX-License-Identifier: GPL-2.0
>> > -all:
>> > -
>> > -include ../lib.mk
>> > +CFLAGS += -Wl,-no-as-needed -Wall
>> > +LDFLAGS += -lpthread
>> >  
>> >  .PHONY: all clean
>> >  
>> > -BINARIES := seccomp_bpf seccomp_benchmark
>> > -CFLAGS += -Wl,-no-as-needed -Wall
>> > +include ../lib.mk
>> > +
>> > +# OUTPUT set by lib.mk
>> > +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
>> >  
>> > -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
>> > -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
>> > +$(TEST_GEN_PROGS): ../kselftest_harness.h
>> >  
>> > -TEST_PROGS += $(BINARIES)
>> > -EXTRA_CLEAN := $(BINARIES)
>> > +all: $(TEST_GEN_PROGS)
>> >  
>> > -all: $(BINARIES)
>> 
>> 
>> It shouldn't be that complicated. We just need to define TEST_GEN_PROGS
>> before including lib.mk, and then add the dependency on the harness
>> after we include lib.mk (so that TEST_GEN_PROGS has been updated to
>> prefix $(OUTPUT)).
>> 
>> eg:
>> 
>>   # SPDX-License-Identifier: GPL-2.0
>>   CFLAGS += -Wl,-no-as-needed -Wall
>>   LDFLAGS += -lpthread
>>   
>>   TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
>>   
>>   include ../lib.mk
>>   
>>   $(TEST_GEN_PROGS): ../kselftest_harness.h
>
> Exactly. This (with an extra comment) is precisely what I suggested during
> v2 review:
> https://lore.kernel.org/lkml/202003041815.B8C73DEC@keescook/

Oh sorry, I missed that.

OK so I think we know what the right solution is.

cheers

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Shuah Khan]

Hi Michael and Kees,

On 3/18/20 9:15 PM, Michael Ellerman wrote:
> Kees Cook <keescook@chromium.org> writes:
>> On Mon, Mar 16, 2020 at 11:12:57PM +1100, Michael Ellerman wrote:
>>> Shuah Khan <skhan@linuxfoundation.org> writes:
>>>> Fix seccomp relocatable builds. This is a simple fix to use the right
>>>> lib.mk variable TEST_GEN_PROGS with dependency on kselftest_harness.h
>>>> header, and defining LDFLAGS for pthread lib.
>>>>
>>>> Removes custom clean rule which is no longer necessary with the use of
>>>> TEST_GEN_PROGS.
>>>>
>>>> Uses $(OUTPUT) defined in lib.mk to handle build relocation.
>>>>
>>>> The following use-cases work with this change:
>>>>
>>>> In seccomp directory:
>>>> make all and make clean
>>>>
>>>>  From top level from main Makefile:
>>>> make kselftest-install O=objdir ARCH=arm64 HOSTCC=gcc \
>>>>   CROSS_COMPILE=aarch64-linux-gnu- TARGETS=seccomp
>>>>
>>>> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
>>>> ---
>>>>
>>>> Changes since v2:
>>>> -- Using TEST_GEN_PROGS is sufficient to generate objects.
>>>>     Addresses review comments from Kees Cook.
>>>>
>>>>   tools/testing/selftests/seccomp/Makefile | 18 ++++++++----------
>>>>   1 file changed, 8 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
>>>> index 1760b3e39730..a0388fd2c3f2 100644
>>>> --- a/tools/testing/selftests/seccomp/Makefile
>>>> +++ b/tools/testing/selftests/seccomp/Makefile
>>>> @@ -1,17 +1,15 @@
>>>>   # SPDX-License-Identifier: GPL-2.0
>>>> -all:
>>>> -
>>>> -include ../lib.mk
>>>> +CFLAGS += -Wl,-no-as-needed -Wall
>>>> +LDFLAGS += -lpthread
>>>>   
>>>>   .PHONY: all clean
>>>>   
>>>> -BINARIES := seccomp_bpf seccomp_benchmark
>>>> -CFLAGS += -Wl,-no-as-needed -Wall
>>>> +include ../lib.mk
>>>> +
>>>> +# OUTPUT set by lib.mk
>>>> +TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
>>>>   
>>>> -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
>>>> -	$(CC) $(CFLAGS) $(LDFLAGS) $< -lpthread -o $@
>>>> +$(TEST_GEN_PROGS): ../kselftest_harness.h
>>>>   
>>>> -TEST_PROGS += $(BINARIES)
>>>> -EXTRA_CLEAN := $(BINARIES)
>>>> +all: $(TEST_GEN_PROGS)
>>>>   
>>>> -all: $(BINARIES)
>>>
>>>
>>> It shouldn't be that complicated. We just need to define TEST_GEN_PROGS
>>> before including lib.mk, and then add the dependency on the harness
>>> after we include lib.mk (so that TEST_GEN_PROGS has been updated to
>>> prefix $(OUTPUT)).
>>>
>>> eg:
>>>
>>>    # SPDX-License-Identifier: GPL-2.0
>>>    CFLAGS += -Wl,-no-as-needed -Wall
>>>    LDFLAGS += -lpthread
>>>    
>>>    TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
>>>    
>>>    include ../lib.mk
>>>    
>>>    $(TEST_GEN_PROGS): ../kselftest_harness.h
>>
>> Exactly. This (with an extra comment) is precisely what I suggested during
>> v2 review:
>> https://lore.kernel.org/lkml/202003041815.B8C73DEC@keescook/
> 
> Oh sorry, I missed that.

Sorry. I missed it as well.

> 
> OK so I think we know what the right solution is.
> 

I am picking this back up after time off.

The proposed change by you works for seccomp. There are at least 10+
tests that have dependencies on kselftest_harness.h and several that
have dependency on kselftest.h and kselftest_module.h

Enforcing this local header dependency in lib.mk makes sense so we
don't have to change the test make files.

Add dependency to libk.mk on local headers. This enforces the dependency
blindly even when a test doesn't include the file, with the benefit of a
simpler enforcement without requiring individual tests to have special
rule for it.

The following two changes work. You both have better make foo than
I do. Can you see any issues with this proposal? I can send patch
to do this, so we can do a larger test.

--------------------------------------------------------------
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 3ed0134a764d..54caa9a4ec8a 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -137,7 +137,7 @@ endif
  # Selftest makefiles can override those targets by setting
  # OVERRIDE_TARGETS = 1.
  ifeq ($(OVERRIDE_TARGETS),)
-$(OUTPUT)/%:%.c
+$(OUTPUT)/%:%.c ../kselftest_harness.h ../kselftest.h
         $(LINK.c) $^ $(LDLIBS) -o $@

  $(OUTPUT)/%.o:%.S


diff --git a/tools/testing/selftests/seccomp/Makefile 
b/tools/testing/selftests/seccomp/Makefile
index a0388fd2c3f2..0ebfe8b0e147 100644
--- a/tools/testing/selftests/seccomp/Makefile
+++ b/tools/testing/selftests/seccomp/Makefile
@@ -2,14 +2,5 @@
  CFLAGS += -Wl,-no-as-needed -Wall
  LDFLAGS += -lpthread

-.PHONY: all clean
-
+TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
  include ../lib.mk
-
-# OUTPUT set by lib.mk
-TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
-
-$(TEST_GEN_PROGS): ../kselftest_harness.h
-
-all: $(TEST_GEN_PROGS)
-
--------------------------------------------------------------

thanks,
-- Shuah

Re: [PATCH v3] selftests: Fix seccomp to support relocatable build (O=objdir)

[Kees Cook]

On Mon, Mar 23, 2020 at 02:18:29PM -0600, Shuah Khan wrote:
> The following two changes work. You both have better make foo than
> I do. Can you see any issues with this proposal? I can send patch
> to do this, so we can do a larger test.
> 
> --------------------------------------------------------------
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index 3ed0134a764d..54caa9a4ec8a 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -137,7 +137,7 @@ endif
>  # Selftest makefiles can override those targets by setting
>  # OVERRIDE_TARGETS = 1.
>  ifeq ($(OVERRIDE_TARGETS),)
> -$(OUTPUT)/%:%.c
> +$(OUTPUT)/%:%.c ../kselftest_harness.h ../kselftest.h
>         $(LINK.c) $^ $(LDLIBS) -o $@

I don't think this will work because some tests are in subdirectories.
The Makefile needs to know what the top-level directory of the selftest
tree is (which I think is $(selfdir) ?) I think this might be more
complete:

$(OUTPUT)/%: %.c $(selfdir)/kselftest_harness.h $(selfdir)/kselftest.h
	$(LINK.c) $^ $(LDLIBS) -o $@

> diff --git a/tools/testing/selftests/seccomp/Makefile
> b/tools/testing/selftests/seccomp/Makefile
> index a0388fd2c3f2..0ebfe8b0e147 100644
> --- a/tools/testing/selftests/seccomp/Makefile
> +++ b/tools/testing/selftests/seccomp/Makefile
> @@ -2,14 +2,5 @@
>  CFLAGS += -Wl,-no-as-needed -Wall
>  LDFLAGS += -lpthread
> 
> -.PHONY: all clean
> -
> +TEST_GEN_PROGS := seccomp_bpf seccomp_benchmark
>  include ../lib.mk
> -
> -# OUTPUT set by lib.mk
> -TEST_GEN_PROGS := $(OUTPUT)/seccomp_bpf $(OUTPUT)/seccomp_benchmark
> -
> -$(TEST_GEN_PROGS): ../kselftest_harness.h
> -
> -all: $(TEST_GEN_PROGS)
> -

This part looks right. :)

-- 
Kees Cook