diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 397551cf2e7bc3235d4dcf4d55b22485a846d79e..09a51d091941be3aa75ae37b53b386714a6d3db5 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -561,15 +561,18 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c)
 	if (cpu_has_tlb) {
 		if (((config4 & MIPS_CONF4_IE) >> 29) == 2)
 			c->options |= MIPS_CPU_TLBINV;
+
 		/*
-		 * This is a bit ugly. R6 has dropped that field from
-		 * config4 and the only valid configuration is VTLB+FTLB so
-		 * set a good value for mmuextdef for that case.
+		 * R6 has dropped the MMUExtDef field from config4.
+		 * On R6 the fields always describe the FTLB, and only if it is
+		 * present according to Config.MT.
 		 */
-		if (cpu_has_mips_r6)
+		if (!cpu_has_mips_r6)
+			mmuextdef = config4 & MIPS_CONF4_MMUEXTDEF;
+		else if (cpu_has_ftlb)
 			mmuextdef = MIPS_CONF4_MMUEXTDEF_VTLBSIZEEXT;
 		else
-			mmuextdef = config4 & MIPS_CONF4_MMUEXTDEF;
+			mmuextdef = 0;
 
 		switch (mmuextdef) {
 		case MIPS_CONF4_MMUEXTDEF_MMUSIZEEXT: