CVMX_SSO_PPX_GRP_MSK
old_group_mask = cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid));
cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid),
cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */
cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid), old_group_mask);
cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */