selftests: vDSO: fix the way vDSO functions are called for powerpc
vdso_test_correctness test fails on powerpc:
~ # ./vdso_test_correctness
...
[RUN] Testing clock_gettime for clock CLOCK_REALTIME_ALARM (8)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock CLOCK_BOOTTIME_ALARM (9)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock CLOCK_SGI_CYCLE (10)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
...
[RUN] Testing clock_gettime for clock invalid (-1)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock invalid (-
2147483648)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
[RUN] Testing clock_gettime for clock invalid (
2147483647)...
[FAIL] No such clock, but __vdso_clock_gettime returned 22
On powerpc, a call to a VDSO function is not an ordinary C function
call. Unlike several architectures which returns a negative error code
in case of an error, powerpc sets CR[SO] and returns the error code
as a positive value.
Define and use a macro called VDSO_CALL() which takes a pointer
to the function to call, the number of arguments and the arguments.
Also update ABI vdso documentation to reflect this subtlety.
Provide a specific version of VDSO_CALL() for powerpc that negates
the error code on return when CR[SO] is set.
Fixes:
c7e5789b24d3 ("kselftest: Move test_vdso to the vDSO test suite")
Fixes:
2e9a97256616 ("selftests: vdso: Add a selftest for vDSO getcpu()")
Fixes:
693f5ca08ca0 ("kselftest: Extend vDSO selftest")
Fixes:
b2f1c3db2887 ("kselftest: Extend vdso correctness test to clock_gettime64")
Fixes:
4920a2590e91 ("selftests/vDSO: add tests for vgetrandom")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>