Re: [PATCH] selftests: lib.mk Fix individual test builds

[Michael Ellerman]

Shuah Khan <shuahkh@xxxxxxxxxxxxxxx> writes:
> In commit a8ba798bc8ec ("selftests: enable O and KBUILD_OUTPUT"), added
> support to generate compile targets in a user specified directory. OUTPUT
> variable controls the location which is undefined when tests are built in
> the test directory or with "make -C tools/testing/selftests/x86".
>
> make -C tools/testing/selftests/x86/
> make: Entering directory '/lkml/linux_4.11/tools/testing/selftests/x86'
> Makefile:44: warning: overriding recipe for target 'clean'
> ../lib.mk:51: warning: ignoring old recipe for target 'clean'
> gcc -m64 -o /single_step_syscall_64 -O2 -g -std=gnu99 -pthread -Wall  single_step_syscall.c -lrt -ldl
> /usr/bin/ld: cannot open output file /single_step_syscall_64: Permission denied
> collect2: error: ld returned 1 exit status
> Makefile:50: recipe for target '/single_step_syscall_64' failed
> make: *** [/single_step_syscall_64] Error 1
> make: Leaving directory '/lkml/linux_4.11/tools/testing/selftests/x86'
>
> Same failure with "cd tools/testing/selftests/x86/;make" run.
>
> Fix this with a change to lib.mk to define OUTPUT to be the pwd when
> MAKELEVEL is 0. This covers both cases mentioned above.
>
> Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
> ---
>  tools/testing/selftests/lib.mk | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
> index ce96d80..775c589 100644
> --- a/tools/testing/selftests/lib.mk
> +++ b/tools/testing/selftests/lib.mk
> @@ -2,6 +2,10 @@
>  # Makefile can operate with or without the kbuild infrastructure.
>  CC := $(CROSS_COMPILE)gcc
>  
> +ifeq (0,$(MAKELEVEL))
> +OUTPUT := $(shell pwd)
> +endif

I preferred my version which just used =? rather than checking
MAKELEVEL, but I don't mind that much.

Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

cheers