Some CPUs have implementation dependent rdhwr registers.  Allow them
to be enabled on a per CPU basis.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
 #define cpu_scache_line_size() cpu_data[0].scache.linesz
 #endif
 
+#ifndef cpu_hwrena_impl_bits
+#define cpu_hwrena_impl_bits           0
+#endif
+
 #endif /* __ASM_CPU_FEATURES_H */
 
                         status_set);
 
        if (cpu_has_mips_r2) {
-               unsigned int enable = 0x0000000f;
+               unsigned int enable = 0x0000000f | cpu_hwrena_impl_bits;
 
                if (!noulri && cpu_has_userlocal)
                        enable |= (1 << 29);