[PATCH v1 00/17] selftests/nolibc: allow run with minimal kernel config

[Zhangjin Wu]

Hi, Willy

This patchset mainly allows speed up the nolibc test with a minimal
kernel config.

As the nolibc supported architectures become more and more, the 'run'
test with DEFCONFIG may cost several hours, which is not friendly to
develop testing and even for release testing, so, smaller kernel configs
may be required, and firstly, we should let nolibc-test work with less
kernel config options, this patchset aims to this goal.

This patchset mainly remove the dependency from procfs, tmpfs, net and
memfd_create, many failures have been fixed up.

When CONFIG_TMPFS and CONFIG_SHMEM are disabled, kernel will provide a
ramfs based tmpfs (mm/shmem.c), it will be used as a choice to fix up
some failures and also allow skip less tests.

Besides, it also adds musl support, improves glibc support and fixes up
a kernel cmdline passing use case.

This is based on the dev.2023.06.14a branch of linux-rcu [1], all of the
supported architectures are tested (with local minimal configs, [5]
pasted the one for i386) without failures:

           arch/board | result
          ------------|------------
      arm/vexpress-a9 | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/arm-vexpress-a9-nolibc-test.log
         aarch64/virt | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/aarch64-virt-nolibc-test.log
          ppc/g3beige | not supported
              i386/pc | 136 test(s) passed, 3 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/i386-pc-nolibc-test.log
            x86_64/pc | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/x86_64-pc-nolibc-test.log
         mipsel/malta | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/mipsel-malta-nolibc-test.log
     loongarch64/virt | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/loongarch64-virt-nolibc-test.log
         riscv64/virt | 136 test(s) passed, 3 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/riscv64-virt-nolibc-test.log
         riscv32/virt | no test log found
s390x/s390-ccw-virtio | 138 test(s) passed, 1 skipped, 0 failed. See all results in /labs/linux-lab/logging/nolibc/s390x-s390-ccw-virtio-nolibc-test.log

Notes:
  * The skipped ones are -fstackprotector, chmod_self and chown_self

    The -fstackprotector skip is due to gcc version.
    chmod_self and chmod_self skips are due to procfs not enabled

  * ppc/g3beige support is added locally, but not added in this patchset

    will send ppc support as a new patchset, it depends on v2 test
    report patchset [3] and the v5 rv32 support, require changes on
    Makefile

  * riscv32/virt support is still in review, see v5 rv32 support [4]

This patchset doesn't depends on any of my other nolibc patch series,
but the new rmdir() routine added in this patchset may be requird to
apply the __sysret() from our v4 syscall helper series [2] after that
series being merged, currently, we use the old method to let it compile
without any dependency.

Here explains all of the patches:

* selftests/nolibc: stat_fault: silence NULL argument warning with glibc
  selftests/nolibc: gettid: restore for glibc and musl
  selftests/nolibc: add _LARGEFILE64_SOURCE for musl

  The above 3 patches adds musl compile support and improve glibc support.

  It is able to build and run nolibc-test with musl libc now, but there
  are some failures/skips due to the musl its own issues/requirements:

    $ sudo ./nolibc-test  | grep -E 'FAIL|SKIP'
    8 sbrk = 1 ENOMEM                                               [FAIL]
    9 brk = -1 ENOMEM                                               [FAIL]
    46 limit_int_fast16_min = -2147483648                           [FAIL]
    47 limit_int_fast16_max = 2147483647                            [FAIL]
    49 limit_int_fast32_min = -2147483648                           [FAIL]
    50 limit_int_fast32_max = 2147483647                            [FAIL]
    0 -fstackprotector not supported                                [SKIPPED]

  musl disabled sbrk and brk for some conflicts with its malloc and the
  fast version of int types are defined in 32bit, which differs from nolibc
  and glibc. musl reserved the sbrk(0) to allow get current brk, we
  added a test for this in the v4 __sysret() helper series [2].

* selftests/nolibc: fix up kernel parameters support

  kernel cmdline allows pass two types of parameters, one is without
  '=', another is with '=', the first one is passed as init arguments,
  the sencond one is passed as init environment variables.

  Our nolibc-test prefer arguments to environment variables, this not
  work when users add such parameters in the kernel cmdline:

    noapic NOLIBC_TEST=syscall

  So, this patch will verify the setting from arguments at first, if it
  is no valid, will try the environment variables instead.

* selftests/nolibc: stat_timestamps: remove procfs dependency

  Use '/' instead of /proc/self, or we can add a 'has_proc' condition
  for this test case, but it is not that necessary to skip the whole
  stat_timestamps tests for such a subtest binding to /proc/self.

  Welcome suggestion from Thomas.

* tools/nolibc: add rmdir() support
  selftests/nolibc: add a new rmdir() test case

  rmdir() routine and test case are added for the coming requirement.

  Note, if the __sysret() patchset [2] is applied before us, this patch
  should be rebased on it and apply the __sysret() helper.

* selftests/nolibc: fix up failures when there is no procfs

  call rmdir() to remove /proc completely to rework the checking of
  /proc, before, the existing of /proc not means the procfs is really
  mounted.

* selftests/nolibc: rename proc variable to has_proc
  selftests/nolibc: rename euid0 variable to is_root

  align with the has_gettid, has_xxx variables.

* selftests/nolibc: prepare tmpfs and hugetlbfs
  selftests/nolibc: rename chmod_net to chmod_good
  selftests/nolibc: link_cross: support tmpfs
  selftests/nolibc: rename chroot_exe to chroot_file

  use file from /tmp instead of file from /proc when there is no procfs
  this avoid skipping the chmod_net, link_cross, chroot_exe tests

* selftests/nolibc: vfprintf: silence memfd_create() warning
  selftests/nolibc: vfprintf: skip if neither tmpfs nor hugetlbfs
  selftests/nolibc: vfprintf: support tmpfs and hugetlbfs

  memfd_create from kernel >= v6.2 forcely warn on missing
  MFD_NOEXEC_SEAL flag, the first one silence it with such flag, for
  older kernels, use 0 flag as before.

  since memfd_create() depends on TMPFS or HUGETLBFS, the second one
  skip the whole vfprintf instead of simply fail if memfd_create() not
  work.

  the 3rd one futher try the ramfs based tmpfs even when memfd_create()
  not work.

At last, let's simply discuss about the configs, I have prepared minimal
configs for all of the nolibc supported architectures but not sure where
should we put them, what about tools/testing/selftests/nolibc/configs ?

Thanks!

Best regards,
Zhangjin
---

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git/
[2]: https://lore.kernel.org/linux-riscv/cover.1687187451.git.falcon@xxxxxxxxxxx/
[3]: https://lore.kernel.org/lkml/cover.1687156559.git.falcon@xxxxxxxxxxx/
[4]: https://lore.kernel.org/linux-riscv/cover.1687176996.git.falcon@xxxxxxxxxxx/
[5]: https://pastebin.com/5jq0Vxbz 

Zhangjin Wu (17):
  selftests/nolibc: stat_fault: silence NULL argument warning with glibc
  selftests/nolibc: gettid: restore for glibc and musl
  selftests/nolibc: add _LARGEFILE64_SOURCE for musl
  selftests/nolibc: fix up kernel parameters support
  selftests/nolibc: stat_timestamps: remove procfs dependency
  tools/nolibc: add rmdir() support
  selftests/nolibc: add a new rmdir() test case
  selftests/nolibc: fix up failures when there is no procfs
  selftests/nolibc: rename proc variable to has_proc
  selftests/nolibc: rename euid0 variable to is_root
  selftests/nolibc: prepare tmpfs and hugetlbfs
  selftests/nolibc: rename chmod_net to chmod_good
  selftests/nolibc: link_cross: support tmpfs
  selftests/nolibc: rename chroot_exe to chroot_file
  selftests/nolibc: vfprintf: silence memfd_create() warning
  selftests/nolibc: vfprintf: skip if neither tmpfs nor hugetlbfs
  selftests/nolibc: vfprintf: support tmpfs and hugetlbfs

 tools/include/nolibc/sys.h                   |  28 ++++
 tools/testing/selftests/nolibc/nolibc-test.c | 132 +++++++++++++++----
 2 files changed, 138 insertions(+), 22 deletions(-)

-- 
2.25.1