ptrace:get_set_sud in ubuntu_kernel_selftests failed on M-gcp arm64

[Po-Hsu Lin]

Issue found on GCP ARM64 instance t2a-standard-4, since M-gcp-1008

Test log:
 Running 'make run_tests -C ptrace TEST_PROGS=get_set_sud TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/ptrace'
 TAP version 13
 1..1
 # timeout set to 45
 # selftests: ptrace: get_set_sud
 # TAP version 13
 # 1..1
 # # Starting 1 tests from 1 test cases.
 # # RUN global.get_set_sud ...
 # # get_set_sud.c:43:get_set_sud:Expected ret (-1) == 0 (0)
 # # get_set_sud: Test terminated by assertion
 # # FAIL global.get_set_sud
 # not ok 1 global.get_set_sud
 # # FAILED: 0 / 1 tests passed.
 # # Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0
 not ok 1 selftests: ptrace: get_set_sud # exit=1
 make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/ptrace'

The cause is yet to be determined.

[Masahiro Yamada (myamada)]

To support PTRACE_SET_SYSCALL_USER_DISPATCH_CONFIG and PTRACE_GET_SYSCALL_USER_DISPATCH_CONFIG,
CONFIG_GENERIC_ENTRY must be selected. (see ptrace_request())

As of writing (v6.8 kernel), GENERIC_ENTRY is only selected by x86, s390, riscv, loongarch.

In my opinion, this test should be skipped for architectures that do not select GENERIC_ENTRY.
It is tedious to give a hint to every arm, arm64, ppc, platform.

[Masahiro Yamada (myamada)]

A patch.