selftests/seccomp: Add m68k support

Add m68k seccomp definitions to seccomp_bpf self test code.

Tested on ARAnyM.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/20230112035529.13521-4-schmitzmic@gmail.comSigned-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

tools/testing/selftests/seccomp/seccomp_bpf.c

@@ -138,6 +138,8 @@ struct seccomp_data {
 #  define __NR_seccomp 337
 # elif defined(__sh__)
 #  define __NR_seccomp 372
+# elif defined(__mc68000__)
+#  define __NR_seccomp 380
 # else
 #  warning "seccomp syscall number unknown for this architecture"
 #  define __NR_seccomp 0xffff
@@ -1838,6 +1840,10 @@ TEST_F(TRACE_poke, getpid_runs_normally)
 # define ARCH_REGS		struct pt_regs
 # define SYSCALL_NUM(_regs)	(_regs).regs[3]
 # define SYSCALL_RET(_regs)	(_regs).regs[0]
+#elif defined(__mc68000__)
+# define ARCH_REGS		struct user_regs_struct
+# define SYSCALL_NUM(_regs)	(_regs).orig_d0
+# define SYSCALL_RET(_regs)	(_regs).d0
 #else
 # error "Do not know how to find your architecture's registers and syscalls"
 #endif
@@ -1902,7 +1908,7 @@ const bool ptrace_entry_set_syscall_ret =
  * Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for
  * architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux).
  */
-#if defined(__x86_64__) || defined(__i386__) || defined(__mips__)
+#if defined(__x86_64__) || defined(__i386__) || defined(__mips__) || defined(__mc68000__)
 # define ARCH_GETREGS(_regs)	ptrace(PTRACE_GETREGS, tracee, 0, &(_regs))
 # define ARCH_SETREGS(_regs)	ptrace(PTRACE_SETREGS, tracee, 0, &(_regs))
 #else