The previous commit introduced the use of CLONE_NEWTIME without including
<sched.h> which contains its definition.

Add an explicit include of <sched.h> to ensure that CLONE_NEWTIME
is correctly defined before it is used.

Fixes: 2aec90036dcd ("selftests: vDSO: ensure vgetrandom works in a time namespace")
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Improve the error and skip condition messages to let the developer know
precisely where a test has failed. Also make better use of the ksft api
for this.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Rather than building on supported archs, build on all archs, and then
use the presence of the symbol in the vDSO to either skip the test or
move forward with it.

Note that this means that this test no longer checks whether the symbol
was correctly added to the kernel. But hopefully this will be clear
enough to developers and we'll cross our fingers that symbols aren't
removed by accident and not caught after this change.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Rather than using symlinks to find the vgetrandom-chacha.S file for each
arch, store this in a file that uses the compiler to determine
architecture, and then make use of weak symbols to skip the test on
architectures that don't provide the code.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

This prevents false sharing, which makes a large difference on machines
with several NUMA nodes, such as on a dual socket Intel(R) Xeon(R) Gold
6338 CPU @ 2.00GHz, where the "bench-multi" test goes from 2.7s down to
1.9s. While this is just test code, it also forms the basis of how folks
will wind up implementing this in libraries, so we should implement this
simple cache alignment improvement here.

Suggested-by: Florian Weimer <fweimer@redhat.com>
Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Pull kselftest fix from Shuah Khan:
 "One urgent fix to vDSO as automated testing is failing due to this
  bug"

* tag 'linux_kselftest-next-6.12-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: vDSO: align stack for O2-optimized memcpy

When switching on -O2, gcc generates SSE2 instructions that assume a
16-byte aligned stack, which the standalone test's start point wasn't
aligning. Fix this with the usual alignment sequence.

Fixes: ecb8bd70d51 ("selftests: vDSO: build tests with O2 optimization")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202409241558.98e13f6f-oliver.sang@intel.com
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Some archs -- arm64 and s390x -- implemented chacha using instructions
that are available most places, but aren't always available. The kernel
handles this just fine, but the selftest does not. Check the hwcaps
before running, and skip the test if the cpu doesn't support it. As
well, on s390x, always emit the fallback instructions of an alternative
block, to ensure maximum compatibility.

Co-developed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Provide the s390 specific vdso getrandom() architecture backend.

_vdso_rng_data required data is placed within the _vdso_data vvar page,
by using a hardcoded offset larger than vdso_data.

As required the chacha20 implementation does not write to the stack.

The implementation follows more or less the arm64 implementations and
makes use of vector instructions. It has a fallback to the getrandom()
system call for machines where the vector facility is not installed.

The check if the vector facility is installed, as well as an
optimization for machines with the vector-enhancements facility 2, is
implemented with alternatives, avoiding runtime checks.

Note that __kernel_getrandom() is implemented without the vdso user
wrapper which would setup a stack frame for odd cases (aka very old
glibc variants) where the caller has not done that. All callers of
__kernel_getrandom() are required to setup a stack frame, like the C ABI
requires it.

The vdso testcases vdso_test_getrandom and vdso_test_chacha pass.

Benchmark on a z16:

    $ ./vdso_test_getrandom bench-single
       vdso: 25000000 times in 0.493703559 seconds
    syscall: 25000000 times in 6.584025337 seconds

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Running vdso_test_correctness on s390x (aka s390 64 bit) emits a warning:

Warning: failed to find clock_gettime64 in vDSO

This is caused by the "#elif defined (__s390__)" check in vdso_config.h
which the defines VDSO_32BIT.

If __s390x__ is defined also __s390__ is defined. Therefore the correct
check must make sure that only __s390__ is defined.

Therefore add the missing !defined(__s390x__). Also use common
__s390x__ define instead of __s390X__.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Fixes: 693f5ca08ca0 ("kselftest: Extend vDSO selftest")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>