Re: [External] Re: [PATCH v2 1/2] selftests: proc: Fix proc-empty-vm build error on non x86_64

[Punit Agrawal <punit.agrawal@bytedance.com>]

Hi Shuah,

Shuah Khan <skhan@linuxfoundation.org> writes:

> On 11/9/22 15:11, Punit Agrawal wrote:
>> The proc-empty-vm test is implemented for x86_64 and fails to build
>> for other architectures. Rather then emitting a compiler error it
>> would be preferable to only build the test on supported architectures.
>> Mark proc-empty-vm as a test for x86_64 and customise the Makefile
>> to
>> build it only when building for this target architecture.
>> Fixes: 5bc73bb3451b ("proc: test how it holds up with mapping'less
>> process")
>> Signed-off-by: Punit Agrawal <punit.agrawal@bytedance.com>
>> ---
>> v1 -> v2
>> * Fixed missing compilation on x86_64
>> Previous version
>> * https://lore.kernel.org/all/20221109110621.1791999-1-punit.agrawal@bytedance.com/
>> tools/testing/selftests/proc/Makefile | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>> diff --git a/tools/testing/selftests/proc/Makefile
>> b/tools/testing/selftests/proc/Makefile
>> index cd95369254c0..743aaa0cdd52 100644
>> --- a/tools/testing/selftests/proc/Makefile
>> +++ b/tools/testing/selftests/proc/Makefile
>> @@ -1,14 +1,16 @@
>>   # SPDX-License-Identifier: GPL-2.0-only
>> +
>> +# When ARCH not overridden for crosscompiling, lookup machine
>> +ARCH ?= $(shell uname -m 2>/dev/null || echo not)
>> +
>>   CFLAGS += -Wall -O2 -Wno-unused-function
>>   CFLAGS += -D_GNU_SOURCE
>>   LDFLAGS += -pthread
>>   -TEST_GEN_PROGS :=
>>   TEST_GEN_PROGS += fd-001-lookup
>>   TEST_GEN_PROGS += fd-002-posix-eq
>>   TEST_GEN_PROGS += fd-003-kthread
>>   TEST_GEN_PROGS += proc-loadavg-001
>> -TEST_GEN_PROGS += proc-empty-vm
>>   TEST_GEN_PROGS += proc-pid-vm
>>   TEST_GEN_PROGS += proc-self-map-files-001
>>   TEST_GEN_PROGS += proc-self-map-files-002
>> @@ -26,4 +28,8 @@ TEST_GEN_PROGS += thread-self
>>   TEST_GEN_PROGS += proc-multiple-procfs
>>   TEST_GEN_PROGS += proc-fsconfig-hidepid
>>   +TEST_GEN_PROGS_x86_64 += proc-empty-vm
>
> Why do you need this? You already have conditional compiles.
> Conditionally add proc-empty-vm to TEST_GEN_PROGS like other
> tests do.

I copied this approach from KVM tests. Looks like we've got a few
different ways of disabling compilation within selftests.

I can respin to conditionally compile as suggested if that is the way
forward.

>> +
>> +TEST_GEN_PROGS += $(TEST_GEN_PROGS_$(ARCH))
>> +
>>   include ../lib.mk
>
> Same question Andrews asked you. What does it take to get this
> to work on other architectures. proc and vm tests should be
> arch. agnostic as a rule unless it is absolutely necessary to
> have them acrh. aware.

Please see my reply elsewhere in the thread for an assessment of the
architecture dependencies.