LoongArch: Rework CPU feature probe from CPUCFG/IOCSR

Probe ISA level, TLB, IOCSR information from CPUCFG to improve kernel
resilience to different core implementations.

BTW, IOCSR register definition appears to be a platform-specific spec
instead of an architecture spec, even for the Loongson CPUs there is no
guarantee that IOCSR will always present.

Thus it's dangerous to perform IOCSR probing without checking CPU type
and instruction availability.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

6 files changed, 100 insertions, 64 deletions

diff --git a/arch/loongarch/include/asm/cpu-features.h b/arch/loongarch/include/asm/cpu-features.h
index 16a716f88a5c..fc83bb32f9f0 100644
--- a/arch/loongarch/include/asm/cpu-features.h
+++ b/arch/loongarch/include/asm/cpu-features.h
@@ -51,6 +51,7 @@
 #define cpu_has_lbt_mips	cpu_opt(LOONGARCH_CPU_LBT_MIPS)
 #define cpu_has_lbt		(cpu_has_lbt_x86|cpu_has_lbt_arm|cpu_has_lbt_mips)
 #define cpu_has_csr		cpu_opt(LOONGARCH_CPU_CSR)
+#define cpu_has_iocsr		cpu_opt(LOONGARCH_CPU_IOCSR)
 #define cpu_has_tlb		cpu_opt(LOONGARCH_CPU_TLB)
 #define cpu_has_watch		cpu_opt(LOONGARCH_CPU_WATCH)
 #define cpu_has_vint		cpu_opt(LOONGARCH_CPU_VINT)
@@ -65,6 +66,7 @@
 #define cpu_has_guestid		cpu_opt(LOONGARCH_CPU_GUESTID)
 #define cpu_has_hypervisor	cpu_opt(LOONGARCH_CPU_HYPERVISOR)
 #define cpu_has_ptw		cpu_opt(LOONGARCH_CPU_PTW)
+#define cpu_has_lspw		cpu_opt(LOONGARCH_CPU_LSPW)
 #define cpu_has_avecint		cpu_opt(LOONGARCH_CPU_AVECINT)
 
 #endif /* __ASM_CPU_FEATURES_H */
diff --git a/arch/loongarch/include/asm/cpu.h b/arch/loongarch/include/asm/cpu.h
index 843f9c4ec980..98cf4d7b4b0a 100644
--- a/arch/loongarch/include/asm/cpu.h
+++ b/arch/loongarch/include/asm/cpu.h
@@ -87,19 +87,21 @@ enum cpu_type_enum {
 #define CPU_FEATURE_LBT_MIPS		12	/* CPU has MIPS Binary Translation */
 #define CPU_FEATURE_TLB			13	/* CPU has TLB */
 #define CPU_FEATURE_CSR			14	/* CPU has CSR */
-#define CPU_FEATURE_WATCH		15	/* CPU has watchpoint registers */
-#define CPU_FEATURE_VINT		16	/* CPU has vectored interrupts */
-#define CPU_FEATURE_CSRIPI		17	/* CPU has CSR-IPI */
-#define CPU_FEATURE_EXTIOI		18	/* CPU has EXT-IOI */
-#define CPU_FEATURE_PREFETCH		19	/* CPU has prefetch instructions */
-#define CPU_FEATURE_PMP			20	/* CPU has perfermance counter */
-#define CPU_FEATURE_SCALEFREQ		21	/* CPU supports cpufreq scaling */
-#define CPU_FEATURE_FLATMODE		22	/* CPU has flat mode */
-#define CPU_FEATURE_EIODECODE		23	/* CPU has EXTIOI interrupt pin decode mode */
-#define CPU_FEATURE_GUESTID		24	/* CPU has GuestID feature */
-#define CPU_FEATURE_HYPERVISOR		25	/* CPU has hypervisor (running in VM) */
-#define CPU_FEATURE_PTW			26	/* CPU has hardware page table walker */
-#define CPU_FEATURE_AVECINT		27	/* CPU has avec interrupt */
+#define CPU_FEATURE_IOCSR		15	/* CPU has IOCSR */
+#define CPU_FEATURE_WATCH		16	/* CPU has watchpoint registers */
+#define CPU_FEATURE_VINT		17	/* CPU has vectored interrupts */
+#define CPU_FEATURE_CSRIPI		18	/* CPU has CSR-IPI */
+#define CPU_FEATURE_EXTIOI		19	/* CPU has EXT-IOI */
+#define CPU_FEATURE_PREFETCH		20	/* CPU has prefetch instructions */
+#define CPU_FEATURE_PMP			21	/* CPU has perfermance counter */
+#define CPU_FEATURE_SCALEFREQ		22	/* CPU supports cpufreq scaling */
+#define CPU_FEATURE_FLATMODE		23	/* CPU has flat mode */
+#define CPU_FEATURE_EIODECODE		24	/* CPU has EXTIOI interrupt pin decode mode */
+#define CPU_FEATURE_GUESTID		25	/* CPU has GuestID feature */
+#define CPU_FEATURE_HYPERVISOR		26	/* CPU has hypervisor (running in VM) */
+#define CPU_FEATURE_PTW			27	/* CPU has hardware page table walker */
+#define CPU_FEATURE_LSPW		28	/* CPU has LSPW (lddir/ldpte instructions) */
+#define CPU_FEATURE_AVECINT		29	/* CPU has AVEC interrupt */
 
 #define LOONGARCH_CPU_CPUCFG		BIT_ULL(CPU_FEATURE_CPUCFG)
 #define LOONGARCH_CPU_LAM		BIT_ULL(CPU_FEATURE_LAM)
@@ -115,6 +117,7 @@ enum cpu_type_enum {
 #define LOONGARCH_CPU_LBT_ARM		BIT_ULL(CPU_FEATURE_LBT_ARM)
 #define LOONGARCH_CPU_LBT_MIPS		BIT_ULL(CPU_FEATURE_LBT_MIPS)
 #define LOONGARCH_CPU_TLB		BIT_ULL(CPU_FEATURE_TLB)
+#define LOONGARCH_CPU_IOCSR		BIT_ULL(CPU_FEATURE_IOCSR)
 #define LOONGARCH_CPU_CSR		BIT_ULL(CPU_FEATURE_CSR)
 #define LOONGARCH_CPU_WATCH		BIT_ULL(CPU_FEATURE_WATCH)
 #define LOONGARCH_CPU_VINT		BIT_ULL(CPU_FEATURE_VINT)
@@ -128,6 +131,7 @@ enum cpu_type_enum {
 #define LOONGARCH_CPU_GUESTID		BIT_ULL(CPU_FEATURE_GUESTID)
 #define LOONGARCH_CPU_HYPERVISOR	BIT_ULL(CPU_FEATURE_HYPERVISOR)
 #define LOONGARCH_CPU_PTW		BIT_ULL(CPU_FEATURE_PTW)
+#define LOONGARCH_CPU_LSPW		BIT_ULL(CPU_FEATURE_LSPW)
 #define LOONGARCH_CPU_AVECINT		BIT_ULL(CPU_FEATURE_AVECINT)
 
 #endif /* _ASM_CPU_H */
diff --git a/arch/loongarch/include/asm/loongarch.h b/arch/loongarch/include/asm/loongarch.h
index 631d249b3ef2..4084cb64ba06 100644
--- a/arch/loongarch/include/asm/loongarch.h
+++ b/arch/loongarch/include/asm/loongarch.h
@@ -62,6 +62,7 @@
 #define LOONGARCH_CPUCFG1		0x1
 #define  CPUCFG1_ISGR32			BIT(0)
 #define  CPUCFG1_ISGR64			BIT(1)
+#define  CPUCFG1_ISA			GENMASK(1, 0)
 #define  CPUCFG1_PAGING			BIT(2)
 #define  CPUCFG1_IOCSR			BIT(3)
 #define  CPUCFG1_PABITS			GENMASK(11, 4)
diff --git a/arch/loongarch/include/uapi/asm/hwcap.h b/arch/loongarch/include/uapi/asm/hwcap.h
index 6955a7cb2c65..2b34e56cfa9e 100644
--- a/arch/loongarch/include/uapi/asm/hwcap.h
+++ b/arch/loongarch/include/uapi/asm/hwcap.h
@@ -17,5 +17,6 @@
 #define HWCAP_LOONGARCH_LBT_ARM		(1 << 11)
 #define HWCAP_LOONGARCH_LBT_MIPS	(1 << 12)
 #define HWCAP_LOONGARCH_PTW		(1 << 13)
+#define HWCAP_LOONGARCH_LSPW		(1 << 14)
 
 #endif /* _UAPI_ASM_HWCAP_H */
diff --git a/arch/loongarch/kernel/cpu-probe.c b/arch/loongarch/kernel/cpu-probe.c
index 14f0449f5452..cbce099037b2 100644
--- a/arch/loongarch/kernel/cpu-probe.c
+++ b/arch/loongarch/kernel/cpu-probe.c
@@ -91,12 +91,30 @@ static void cpu_probe_common(struct cpuinfo_loongarch *c)
 	unsigned int config;
 	unsigned long asid_mask;
 
-	c->options = LOONGARCH_CPU_CPUCFG | LOONGARCH_CPU_CSR |
-		     LOONGARCH_CPU_TLB | LOONGARCH_CPU_VINT | LOONGARCH_CPU_WATCH;
+	c->options = LOONGARCH_CPU_CPUCFG | LOONGARCH_CPU_CSR | LOONGARCH_CPU_VINT;
 
 	elf_hwcap = HWCAP_LOONGARCH_CPUCFG;
 
 	config = read_cpucfg(LOONGARCH_CPUCFG1);
+
+	switch (config & CPUCFG1_ISA) {
+	case 0:
+		set_isa(c, LOONGARCH_CPU_ISA_LA32R);
+		break;
+	case 1:
+		set_isa(c, LOONGARCH_CPU_ISA_LA32S);
+		break;
+	case 2:
+		set_isa(c, LOONGARCH_CPU_ISA_LA64);
+		break;
+	default:
+		pr_warn("Warning: unknown ISA level\n");
+	}
+
+	if (config & CPUCFG1_PAGING)
+		c->options |= LOONGARCH_CPU_TLB;
+	if (config & CPUCFG1_IOCSR)
+		c->options |= LOONGARCH_CPU_IOCSR;
 	if (config & CPUCFG1_UAL) {
 		c->options |= LOONGARCH_CPU_UAL;
 		elf_hwcap |= HWCAP_LOONGARCH_UAL;
@@ -139,6 +157,10 @@ static void cpu_probe_common(struct cpuinfo_loongarch *c)
 		c->options |= LOONGARCH_CPU_PTW;
 		elf_hwcap |= HWCAP_LOONGARCH_PTW;
 	}
+	if (config & CPUCFG2_LSPW) {
+		c->options |= LOONGARCH_CPU_LSPW;
+		elf_hwcap |= HWCAP_LOONGARCH_LSPW;
+	}
 	if (config & CPUCFG2_LVZP) {
 		c->options |= LOONGARCH_CPU_LVZ;
 		elf_hwcap |= HWCAP_LOONGARCH_LVZ;
@@ -162,22 +184,6 @@ static void cpu_probe_common(struct cpuinfo_loongarch *c)
 	if (config & CPUCFG6_PMP)
 		c->options |= LOONGARCH_CPU_PMP;
 
-	config = iocsr_read32(LOONGARCH_IOCSR_FEATURES);
-	if (config & IOCSRF_CSRIPI)
-		c->options |= LOONGARCH_CPU_CSRIPI;
-	if (config & IOCSRF_EXTIOI)
-		c->options |= LOONGARCH_CPU_EXTIOI;
-	if (config & IOCSRF_FREQSCALE)
-		c->options |= LOONGARCH_CPU_SCALEFREQ;
-	if (config & IOCSRF_FLATMODE)
-		c->options |= LOONGARCH_CPU_FLATMODE;
-	if (config & IOCSRF_EIODECODE)
-		c->options |= LOONGARCH_CPU_EIODECODE;
-	if (config & IOCSRF_AVEC)
-		c->options |= LOONGARCH_CPU_AVECINT;
-	if (config & IOCSRF_VM)
-		c->options |= LOONGARCH_CPU_HYPERVISOR;
-
 	config = csr_read32(LOONGARCH_CSR_ASID);
 	config = (config & CSR_ASID_BIT) >> CSR_ASID_BIT_SHIFT;
 	asid_mask = GENMASK(config - 1, 0);
@@ -210,6 +216,9 @@ static void cpu_probe_common(struct cpuinfo_loongarch *c)
 	default:
 		pr_warn("Warning: unknown TLB type\n");
 	}
+
+	if (get_num_brps() + get_num_wrps())
+		c->options |= LOONGARCH_CPU_WATCH;
 }
 
 #define MAX_NAME_LEN	32
@@ -220,52 +229,67 @@ static char cpu_full_name[MAX_NAME_LEN] = "        -        ";
 
 static inline void cpu_probe_loongson(struct cpuinfo_loongarch *c, unsigned int cpu)
 {
+	uint32_t config;
 	uint64_t *vendor = (void *)(&cpu_full_name[VENDOR_OFFSET]);
 	uint64_t *cpuname = (void *)(&cpu_full_name[CPUNAME_OFFSET]);
+	const char *core_name = "Unknown";
 
-	if (!__cpu_full_name[cpu])
-		__cpu_full_name[cpu] = cpu_full_name;
-
-	*vendor = iocsr_read64(LOONGARCH_IOCSR_VENDOR);
-	*cpuname = iocsr_read64(LOONGARCH_IOCSR_CPUNAME);
-
-	switch (c->processor_id & PRID_SERIES_MASK) {
-	case PRID_SERIES_LA132:
+	switch (BIT(fls(c->isa_level) - 1)) {
+	case LOONGARCH_CPU_ISA_LA32R:
+	case LOONGARCH_CPU_ISA_LA32S:
 		c->cputype = CPU_LOONGSON32;
-		set_isa(c, LOONGARCH_CPU_ISA_LA32S);
 		__cpu_family[cpu] = "Loongson-32bit";
-		pr_info("32-bit Loongson Processor probed (LA132 Core)\n");
 		break;
-	case PRID_SERIES_LA264:
+	case LOONGARCH_CPU_ISA_LA64:
 		c->cputype = CPU_LOONGSON64;
-		set_isa(c, LOONGARCH_CPU_ISA_LA64);
 		__cpu_family[cpu] = "Loongson-64bit";
-		pr_info("64-bit Loongson Processor probed (LA264 Core)\n");
+		break;
+	}
+
+	switch (c->processor_id & PRID_SERIES_MASK) {
+	case PRID_SERIES_LA132:
+		core_name = "LA132";
+		break;
+	case PRID_SERIES_LA264:
+		core_name = "LA264";
 		break;
 	case PRID_SERIES_LA364:
-		c->cputype = CPU_LOONGSON64;
-		set_isa(c, LOONGARCH_CPU_ISA_LA64);
-		__cpu_family[cpu] = "Loongson-64bit";
-		pr_info("64-bit Loongson Processor probed (LA364 Core)\n");
+		core_name = "LA364";
 		break;
 	case PRID_SERIES_LA464:
-		c->cputype = CPU_LOONGSON64;
-		set_isa(c, LOONGARCH_CPU_ISA_LA64);
-		__cpu_family[cpu] = "Loongson-64bit";
-		pr_info("64-bit Loongson Processor probed (LA464 Core)\n");
+		core_name = "LA464";
 		break;
 	case PRID_SERIES_LA664:
-		c->cputype = CPU_LOONGSON64;
-		set_isa(c, LOONGARCH_CPU_ISA_LA64);
-		__cpu_family[cpu] = "Loongson-64bit";
-		pr_info("64-bit Loongson Processor probed (LA664 Core)\n");
+		core_name = "LA664";
 		break;
-	default: /* Default to 64 bit */
-		c->cputype = CPU_LOONGSON64;
-		set_isa(c, LOONGARCH_CPU_ISA_LA64);
-		__cpu_family[cpu] = "Loongson-64bit";
-		pr_info("64-bit Loongson Processor probed (Unknown Core)\n");
 	}
+
+	pr_info("%s Processor probed (%s Core)\n", __cpu_family[cpu], core_name);
+
+	if (!cpu_has_iocsr)
+		return;
+
+	if (!__cpu_full_name[cpu])
+		__cpu_full_name[cpu] = cpu_full_name;
+
+	*vendor = iocsr_read64(LOONGARCH_IOCSR_VENDOR);
+	*cpuname = iocsr_read64(LOONGARCH_IOCSR_CPUNAME);
+
+	config = iocsr_read32(LOONGARCH_IOCSR_FEATURES);
+	if (config & IOCSRF_CSRIPI)
+		c->options |= LOONGARCH_CPU_CSRIPI;
+	if (config & IOCSRF_EXTIOI)
+		c->options |= LOONGARCH_CPU_EXTIOI;
+	if (config & IOCSRF_FREQSCALE)
+		c->options |= LOONGARCH_CPU_SCALEFREQ;
+	if (config & IOCSRF_FLATMODE)
+		c->options |= LOONGARCH_CPU_FLATMODE;
+	if (config & IOCSRF_EIODECODE)
+		c->options |= LOONGARCH_CPU_EIODECODE;
+	if (config & IOCSRF_AVEC)
+		c->options |= LOONGARCH_CPU_AVECINT;
+	if (config & IOCSRF_VM)
+		c->options |= LOONGARCH_CPU_HYPERVISOR;
 }
 
 #ifdef CONFIG_64BIT
diff --git a/arch/loongarch/kernel/proc.c b/arch/loongarch/kernel/proc.c
index 0d33cbc47e51..6ce46d92f1f1 100644
--- a/arch/loongarch/kernel/proc.c
+++ b/arch/loongarch/kernel/proc.c
@@ -31,6 +31,7 @@ int proc_cpuinfo_notifier_call_chain(unsigned long val, void *v)
 static int show_cpuinfo(struct seq_file *m, void *v)
 {
 	unsigned long n = (unsigned long) v - 1;
+	unsigned int isa = cpu_data[n].isa_level;
 	unsigned int version = cpu_data[n].processor_id & 0xff;
 	unsigned int fp_version = cpu_data[n].fpu_vers;
 	struct proc_cpuinfo_notifier_args proc_cpuinfo_notifier_args;
@@ -64,9 +65,11 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 		      cpu_pabits + 1, cpu_vabits + 1);
 
 	seq_printf(m, "ISA\t\t\t:");
-	if (cpu_has_loongarch32)
-		seq_printf(m, " loongarch32");
-	if (cpu_has_loongarch64)
+	if (isa & LOONGARCH_CPU_ISA_LA32R)
+		seq_printf(m, " loongarch32r");
+	if (isa & LOONGARCH_CPU_ISA_LA32S)
+		seq_printf(m, " loongarch32s");
+	if (isa & LOONGARCH_CPU_ISA_LA64)
 		seq_printf(m, " loongarch64");
 	seq_printf(m, "\n");
 
@@ -81,6 +84,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 	if (cpu_has_complex)	seq_printf(m, " complex");
 	if (cpu_has_crypto)	seq_printf(m, " crypto");
 	if (cpu_has_ptw)	seq_printf(m, " ptw");
+	if (cpu_has_lspw)	seq_printf(m, " lspw");
 	if (cpu_has_lvz)	seq_printf(m, " lvz");
 	if (cpu_has_lbt_x86)	seq_printf(m, " lbt_x86");
 	if (cpu_has_lbt_arm)	seq_printf(m, " lbt_arm");