linux-toradex.git/tools/testing/selftests/nolibc, branch v6.3

selftests/nolibc: Add a "run-user" target to test the program in user land

2023-01-24T23:35:45+00:00

When developing tests, it is much faster to use the QEMU Linux
emulator instead of the system emulator, which among other things avoids
kernel-build latencies.  Although use of the QEMU Linux emulator does have
its limitations (please see below), it is sufficient to test startup code,
stdlib code, and syscall calling conventions.

However, the current mainline Linux-kernel nolibc setup does not
support this.  Therefore, add a "run-user" target that immediately
executes the prebuilt executable.

Again, this approach does have its limitations.  For example, the
executable runs with the user's privilege level, which can cause some
false-positive failures due to insufficient permissions.  In addition,
if the underlying kernel is old enough to lack some features that
nolibc relies on, the result will be false-positive failures in the
corresponding tests.  However, for nolibc changes not affected by these
limittions, the result is a much faster code-compile-test-debug cycle.

With this patch, running a userland test is as simple as issuing:

  make ARCH=xxx CROSS_COMPILE=xxx run-user

Signed-off-by: Willy Tarreau 
Tested-by: Ammar Faizi 
Signed-off-by: Paul E. McKenney

selftests/nolibc: Support "x86_64" for arch name

2023-01-24T23:35:16+00:00

Building the kernel with ARCH=x86_64 works fine, but nolibc-test
only supports "x86", which causes errors when reusing existing build
environment.  Let's permit this environment to be used as well by making
nolibc also accept ARCH=x86_64.

Signed-off-by: Willy Tarreau 
Tested-by: Ammar Faizi 
Signed-off-by: Paul E. McKenney

selftests/nolibc: Add `getpagesize(2)` selftest

2023-01-10T21:33:56+00:00

Test the getpagesize() function. Make sure it returns the correct
value.

Signed-off-by: Ammar Faizi 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: add s390 support

2023-01-09T17:36:06+00:00

Signed-off-by: Sven Schnelle 
Acked-by: Heiko Carstens 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: Always rebuild the sysroot when running a test

2022-10-28T22:17:22+00:00

Paul and I got trapped a few times by not seeing the effects of applying
a patch to the nolibc source code until a "make clean" was issued in
the nolibc directory. It's particularly annoying when trying to confirm
that a proposed patch really solves a problem (or that reverting it
reintroduces the problem).

The reason for the sysroot not being rebuilt was that it can be quite
slow. But in fact it's only slow after a "make clean" issued at the
kernel's topdir, because it's the main "make headers" that can take a
tens of seconds; as long as "usr/include" still contains headers, the
"headers_install" phase is only a quick "rsync", and rebuilding the
whole nolibc sysroot takes a bit less than one second, which is perfectly
acceptable for a test, even more once the time lost caused by misleading
results is factored in.

This patch marks the sysroot target as phony and starts by clearing
the previous sysroot for the current architecture before reinstalling
it. Thanks to this, applying a patch to nolibc makes the effect
immediately visible to "make nolibc-test":

  $ time make -j -C tools/testing/selftests/nolibc nolibc-test
  make: Entering directory '/k/tools/testing/selftests/nolibc'
    MKDIR   sysroot/x86/include
  make[1]: Entering directory '/k/tools/include/nolibc'
  make[2]: Entering directory '/k'
  make[2]: Leaving directory '/k'
  make[2]: Entering directory '/k'
    INSTALL /k/tools/testing/selftests/nolibc/sysroot/sysroot/include
  make[2]: Leaving directory '/k'
  make[1]: Leaving directory '/k/tools/include/nolibc'
    CC      nolibc-test
  make: Leaving directory '/k/tools/testing/selftests/nolibc'

  real    0m0.869s
  user    0m0.716s
  sys     0m0.149s

Cc: "Paul E. McKenney" 
Link: https://lore.kernel.org/all/20221021155645.GK5600@paulmck-ThinkPad-P17-Gen-1/
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: Add 7 tests for memcmp()

2022-10-28T22:17:22+00:00

This adds 7 combinations of input values for memcmp() using signed and
unsigned bytes, which will trigger on the original code before Rasmus'
fix. This is mostly aimed at helping backporters verify their work, and
showing how tests for corner cases can be added to the selftests suite.

Before the fix it reports:
  12 memcmp_20_20 = 0                      [OK]
  13 memcmp_20_60 = -64                    [OK]
  14 memcmp_60_20 = 64                     [OK]
  15 memcmp_20_e0 = 64                    [FAIL]
  16 memcmp_e0_20 = -64                   [FAIL]
  17 memcmp_80_e0 = -96                    [OK]
  18 memcmp_e0_80 = 96                     [OK]

And after:
  12 memcmp_20_20 = 0                      [OK]
  13 memcmp_20_60 = -64                    [OK]
  14 memcmp_60_20 = 64                     [OK]
  15 memcmp_20_e0 = -192                   [OK]
  16 memcmp_e0_20 = 192                    [OK]
  17 memcmp_80_e0 = -96                    [OK]
  18 memcmp_e0_80 = 96                     [OK]

Cc: Rasmus Villemoes 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: Avoid generated files being committed

2022-08-31T12:17:45+00:00

After running the nolibc tests, the "git status" is not clean because
the generated files are not ignored. Create a `.gitignore` inside the
selftests/nolibc directory to ignore them.

Cc: Ammar Faizi 
Cc: Fernanda Ma'rouf 
Signed-off-by: Fernanda Ma'rouf 
Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "help" target

2022-08-31T12:17:45+00:00

It presents the supported targets, and becomes the default target to
save the user from having to read the makefile. The "all" target was
placed after it and now points to "run" to do everything since it's
no longer the default one.

Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: "sysroot" target installs a local copy of the sysroot

2022-08-31T12:17:45+00:00

It's not convenient to rely on a sysroot built in another directory,
especially when running cross-compilation tests, where one has to
switch back and forth between directories.

Let's make it possible to install the sysroot directly in the test
directory. It's not big and even benefits from being copied by arch
so that it's easier to switch between archs if needed. The new
"sysroot" target does this, it just calls "headers_standalone" from
nolibc to install the sysroot right here.

Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney

selftests/nolibc: add a "run" target to start the kernel in QEMU

2022-08-31T12:17:45+00:00

The "run" target will build the kernel and start it in QEMU. The
"rerun" target will not have the kernel dependency and will just try
to start QEMU. The QEMU architecture used to start the kernel is
derived from the configured ARCH. This might need to be improved
for archs which include different variants under the same name
(mips vs mipsel, +/-64, riscv32 vs riscv64). This could be tested
for i386, x86, arm, arm64, mips and riscv (the later two reporting
issues on some tests).

It is possible to pass a test specification for nolibc-test in the TEST
variable, which will be passed as-is as NOLIBC_TEST.

On success, the number of successful tests is printed. On failure, failed
lines are individually printed.

Signed-off-by: Willy Tarreau 
Signed-off-by: Paul E. McKenney