MIPS: Loongson: Fix cpu_probe_loongson() again

Commit 7db5e9e9e5e6c10d7d ("MIPS: loongson64: fix FTLB configuration")
move decode_configs() from the beginning of cpu_probe_loongson() to the
end in order to fix FTLB configuration. However, it breaks the CPUCFG
decoding because decode_configs() use "c->options = xxxx" rather than
"c->options |= xxxx", all information get from CPUCFG by decode_cpucfg()
is lost.

This causes error when creating a KVM guest on Loongson-3A4000:
Exception Code: 4 not handled @ PC: 0000000087ad5981, inst: 0xcb7a1898 BadVaddr: 0x0 Status: 0x0

Fix this by moving the c->cputype setting to the beginning and moving
decode_configs() after that.

Fixes: 7db5e9e9e5e6c10d7d ("MIPS: loongson64: fix FTLB configuration")
Cc: [e-mail]
Cc: Huang Pei <[e-mail]>
Signed-off-by: Huacai Chen <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/kernel/cpu-probe.c

···
 
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu)
 {
+	c->cputype = CPU_LOONGSON64;
+
 	/* All Loongson processors covered here define ExcCode 16 as GSExc. */
+	decode_configs(c);
 	c->options |= MIPS_CPU_GSEXCEX;
 
 	switch (c->processor_id & PRID_IMP_MASK) {
···
 		case PRID_REV_LOONGSON2K_R1_1:
 		case PRID_REV_LOONGSON2K_R1_2:
 		case PRID_REV_LOONGSON2K_R1_3:
-			c->cputype = CPU_LOONGSON64;
 			__cpu_name[cpu] = "Loongson-2K";
 			set_elf_platform(cpu, "gs264e");
 			set_isa(c, MIPS_CPU_ISA_M64R2);
···
 		switch (c->processor_id & PRID_REV_MASK) {
 		case PRID_REV_LOONGSON3A_R2_0:
 		case PRID_REV_LOONGSON3A_R2_1:
-			c->cputype = CPU_LOONGSON64;
 			__cpu_name[cpu] = "ICT Loongson-3";
 			set_elf_platform(cpu, "loongson3a");
 			set_isa(c, MIPS_CPU_ISA_M64R2);
 			break;
 		case PRID_REV_LOONGSON3A_R3_0:
 		case PRID_REV_LOONGSON3A_R3_1:
-			c->cputype = CPU_LOONGSON64;
 			__cpu_name[cpu] = "ICT Loongson-3";
 			set_elf_platform(cpu, "loongson3a");
 			set_isa(c, MIPS_CPU_ISA_M64R2);
···
 		c->ases &= ~MIPS_ASE_VZ; /* VZ of Loongson-3A2000/3000 is incomplete */
 		break;
 	case PRID_IMP_LOONGSON_64G:
-		c->cputype = CPU_LOONGSON64;
 		__cpu_name[cpu] = "ICT Loongson-3";
 		set_elf_platform(cpu, "loongson3a");
 		set_isa(c, MIPS_CPU_ISA_M64R2);
···
 		panic("Unknown Loongson Processor ID!");
 		break;
 	}
-
-	decode_configs(c);
 }
 #else
 static inline void cpu_probe_loongson(struct cpuinfo_mips *c, unsigned int cpu) { }