selftests/bpf: Add 6-argument syscall tracing test

Turns out splice() is one of the syscalls that's using current maximum
number of arguments (six). This is perfect for testing, so extend
bpf_syscall_macro selftest to also trace splice() syscall, using
BPF_KSYSCALL() macro. This makes sure all the syscall argument register
definitions are correct.

Suggested-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Alan Maguire <alan.maguire@oracle.com> # arm64
Tested-by: Ilya Leoshkevich <iii@linux.ibm.com> # s390x
Link: https://lore.kernel.org/bpf/20230120200914.3008030-25-andrii@kernel.org

selftests/bpf: use BPF_KSYSCALL and SEC("ksyscall") in selftests

Convert few selftest that used plain SEC("kprobe") with arch-specific
syscall wrapper prefix to ksyscall/kretsyscall and corresponding
BPF_KSYSCALL macro. test_probe_user.c is especially benefiting from this
simplification.

Tested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220714070755.3235561-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

selftests/bpf: Test BPF_KPROBE_SYSCALL macro

Add tests for the newly added BPF_KPROBE_SYSCALL macro.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220207143134.2977852-3-hengqi.chen@gmail.com

selftests/bpf: Skip test_bpf_syscall_macro's syscall_arg1 on arm64 and s390

These architectures can provide access to the first syscall argument
only through PT_REGS_PARM1_CORE_SYSCALL().

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-8-iii@linux.ibm.com

selftests/bpf: Use PT_REGS_SYSCALL_REGS in bpf_syscall_macro

Ensure that PT_REGS_SYSCALL_REGS works correctly.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-4-iii@linux.ibm.com

selftests/bpf: Fix an endianness issue in bpf_syscall_macro test

bpf_syscall_macro reads a long argument into an int variable, which
produces a wrong value on big-endian systems. Fix by reading the
argument into an intermediate long variable first.

Fixes: 77fc0330dfe5 ("selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220209021745.2215452-2-iii@linux.ibm.com

selftests/bpf: Add a test to confirm PT_REGS_PARM4_SYSCALL

Add a selftest to verify the behavior of PT_REGS_xxx
and the CORE variant.

Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220124141622.4378-4-Kenta.Tada@sony.com