MIPS: Separate XPA CPU feature into LPA and MVH

XPA (eXtended Physical Addressing) should be detected as a combination
of two architectural features:
- Large Physical Address (as per Config3.LPA). With XPA this will be set
  on MIPS32r5 cores, but it may also be set for MIPS64r2 cores too.
- MTHC0/MFHC0 instructions (as per Config5.MVH). With XPA this will be
  set, but it may also be set in VZ guest context even when Config3.LPA
  in the guest context has been cleared by the hypervisor.

As such, XPA is only usable if both bits are set. Update CPU features to
separate these two features, with cpu_has_xpa requiring both to be set.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13112/
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/cpu-features.h

@@ -145,8 +145,14 @@
 # endif
 #endif
 
+#ifndef cpu_has_lpa
+#define cpu_has_lpa		(cpu_data[0].options & MIPS_CPU_LPA)
+#endif
+#ifndef cpu_has_mvh
+#define cpu_has_mvh		(cpu_data[0].options & MIPS_CPU_MVH)
+#endif
 #ifndef cpu_has_xpa
-#define cpu_has_xpa		(cpu_data[0].options & MIPS_CPU_XPA)
+#define cpu_has_xpa		(cpu_has_lpa && cpu_has_mvh)
 #endif
 #ifndef cpu_has_vtag_icache
 #define cpu_has_vtag_icache	(cpu_data[0].icache.flags & MIPS_CACHE_VTAG)

arch/mips/include/asm/cpu.h

@@ -394,7 +394,7 @@ enum cpu_type_enum {
 #define MIPS_CPU_MAAR		MBIT_ULL(30)	/* MAAR(I) registers are present */
 #define MIPS_CPU_FRE		MBIT_ULL(31)	/* FRE & UFE bits implemented */
 #define MIPS_CPU_RW_LLB		MBIT_ULL(32)	/* LLADDR/LLB writes are allowed */
-#define MIPS_CPU_XPA		MBIT_ULL(33)	/* CPU supports Extended Physical Addressing */
+#define MIPS_CPU_LPA		MBIT_ULL(33)	/* CPU supports Large Physical Addressing */
 #define MIPS_CPU_CDMM		MBIT_ULL(34)	/* CPU has Common Device Memory Map */
 #define MIPS_CPU_BP_GHIST	MBIT_ULL(35)	/* R12K+ Branch Prediction Global History */
 #define MIPS_CPU_SP		MBIT_ULL(36)	/* Small (1KB) page support */
@@ -403,6 +403,7 @@ enum cpu_type_enum {
 #define MIPS_CPU_NAN_2008	MBIT_ULL(39)	/* 2008 NaN implemented */
 #define MIPS_CPU_VP		MBIT_ULL(40)	/* MIPSr6 Virtual Processors (multi-threading) */
 #define MIPS_CPU_LDPTE		MBIT_ULL(41)	/* CPU has ldpte/lddir instructions */
+#define MIPS_CPU_MVH		MBIT_ULL(42)	/* CPU supports MFHC0/MTHC0 */
 
 /*
  * CPU ASE encodings

arch/mips/kernel/cpu-probe.c

@@ -702,6 +702,8 @@ static inline unsigned int decode_config3(struct cpuinfo_mips *c)
 		c->options |= MIPS_CPU_VINT;
 	if (config3 & MIPS_CONF3_VEIC)
 		c->options |= MIPS_CPU_VEIC;
+	if (config3 & MIPS_CONF3_LPA)
+		c->options |= MIPS_CPU_LPA;
 	if (config3 & MIPS_CONF3_MT)
 		c->ases |= MIPS_ASE_MIPSMT;
 	if (config3 & MIPS_CONF3_ULRI)