Re: [PATCH v2 2/2] selftests/powerpc: Add test to verify rfi flush across a system call

[Michael Ellerman]

"Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> writes:
> diff --git a/tools/testing/selftests/powerpc/security/rfi_flush.c 
> b/tools/testing/selftests/powerpc/security/rfi_flush.c
> new file mode 100644
> index 000000000000..a20fe8eca161
> --- /dev/null
> +++ b/tools/testing/selftests/powerpc/security/rfi_flush.c
> @@ -0,0 +1,132 @@
...
> +
> +int rfi_flush_test(void)
> +{
> +     char *p;
> +     int repetitions = 10;
> +     int fd, passes = 0, iter, rc = 0;
> +     struct perf_event_read v;
> +     uint64_t l1d_misses_total = 0;
> +     unsigned long iterations = 100000, zero_size = 24*1024;
> +     int rfi_flush_org, rfi_flush;
> +
> +     SKIP_IF(geteuid() != 0);
> +
> +     if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
> +             perror("error reading powerpc/rfi_flush debugfs file");
> +             printf("unable to determine current rfi_flush setting");
> +             return 1;
> +     }

This leads to a hard error on old kernels, which I don't want (breaks my CI).

So I changed it to:

        if (read_debugfs_file("powerpc/rfi_flush", &rfi_flush_org)) {
                perror("Unable to read powerpc/rfi_flush debugfs file");
                SKIP_IF(1);
        }

cheers