[PATCH v2 4/5] x86/cpu: Add CPU type to struct cpuinfo_topology

[Mario Limonciello <mario.limonciello@amd.com>]

From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>

Sometimes it is required to take actions based on if a CPU is a performance
or efficiency core. As an example, intel_pstate driver uses the Intel
core-type to determine CPU scaling. Also, some CPU vulnerabilities only
affect a specific CPU type, like RFDS only affects Intel Atom. Hybrid
systems that have variants P+E, P-only(Core) and E-only(Atom), it is not
straightforward to identify which variant is affected by a type specific
vulnerability.

Such processors do have CPUID field that can uniquely identify them. Like,
P+E, P-only and E-only enumerates CPUID.1A.CORE_TYPE identification, while
P+E additionally enumerates CPUID.7.HYBRID. Based on this information, it
is possible for boot CPU to identify if a system has mixed CPU types.

Add a new field hw_cpu_type to struct cpuinfo_topology that stores the
hardware specific CPU type. This saves the overhead of IPIs to get the CPU
type of a different CPU. CPU type is populated early in the boot process,
before vulnerabilities are enumerated.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
* Take this patch from Pawan's series and fix up for feedback left on it.
* Add in AMD case as well
---
 arch/x86/include/asm/cpu.h            | 19 +++++++++++++++++++
 arch/x86/include/asm/processor.h      | 18 ++++++++++++++++++
 arch/x86/include/asm/topology.h       |  8 ++++++++
 arch/x86/kernel/cpu/amd.c             | 14 ++++++++++++++
 arch/x86/kernel/cpu/debugfs.c         |  1 +
 arch/x86/kernel/cpu/intel.c           | 18 ++++++++++++++++++
 arch/x86/kernel/cpu/topology_amd.c    |  3 +++
 arch/x86/kernel/cpu/topology_common.c | 13 +++++++++++++
 8 files changed, 94 insertions(+)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 98eced5084ca7..28bb177241131 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -53,6 +53,8 @@ static inline void bus_lock_init(void) {}
 #ifdef CONFIG_CPU_SUP_INTEL
 u8 get_this_hybrid_cpu_type(void);
 u32 get_this_hybrid_cpu_native_id(void);
+u32 intel_native_model_id(struct cpuinfo_x86 *c);
+enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c);
 #else
 static inline u8 get_this_hybrid_cpu_type(void)
 {
@@ -63,6 +65,23 @@ static inline u32 get_this_hybrid_cpu_native_id(void)
 {
 	return 0;
 }
+
+static u32 intel_native_model_id(struct cpuinfo_x86 *c)
+{
+	return 0;
+}
+static enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+#endif
+#ifdef CONFIG_CPU_SUP_AMD
+enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c);
+#else
+static inline enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
 #endif
 #ifdef CONFIG_IA32_FEAT_CTL
 void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4a686f0e5dbf6..872e5a429d00d 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -105,6 +105,24 @@ struct cpuinfo_topology {
 	// Cache level topology IDs
 	u32			llc_id;
 	u32			l2c_id;
+
+	// Hardware defined CPU-type
+	union {
+		u32		cpu_type;
+		struct {
+			// CPUID.1A.EAX[23-0]
+			u32	intel_native_model_id:24;
+			// CPUID.1A.EAX[31-24]
+			u32	intel_type:8;
+		};
+		struct {
+			// CPUID 0x80000026.EBX
+			u32  amd_num_processors             :16,
+			     amd_power_efficiency_ranking   :8,
+			     amd_native_model_id            :4,
+			     amd_type                       :4;
+		};
+	};
 };
 
 struct cpuinfo_x86 {
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index aef70336d6247..5b344ff81219d 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -114,6 +114,12 @@ enum x86_topology_domains {
 	TOPO_MAX_DOMAIN,
 };
 
+enum x86_topology_cpu_type {
+	TOPO_CPU_TYPE_PERFORMANCE,
+	TOPO_CPU_TYPE_EFFICIENCY,
+	TOPO_CPU_TYPE_UNKNOWN,
+};
+
 struct x86_topology_system {
 	unsigned int	dom_shifts[TOPO_MAX_DOMAIN];
 	unsigned int	dom_size[TOPO_MAX_DOMAIN];
@@ -149,6 +155,8 @@ extern unsigned int __max_threads_per_core;
 extern unsigned int __num_threads_per_package;
 extern unsigned int __num_cores_per_package;
 
+enum x86_topology_cpu_type topology_cpu_type(struct cpuinfo_x86 *c);
+
 static inline unsigned int topology_max_packages(void)
 {
 	return __max_logical_packages;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index fab5caec0b72e..779073e5a6468 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -29,6 +29,9 @@
 
 #include "cpu.h"
 
+#define TOPO_HW_CPU_TYPE_AMD_PERFORMANCE 0
+#define TOPO_HW_CPU_TYPE_AMD_EFFICIENCY  1
+
 static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
 {
 	u32 gprs[8] = { 0 };
@@ -1205,3 +1208,14 @@ void amd_check_microcode(void)
 	if (cpu_feature_enabled(X86_FEATURE_ZEN2))
 		on_each_cpu(zenbleed_check_cpu, NULL, 1);
 }
+
+enum x86_topology_cpu_type amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.amd_type) {
+	case TOPO_HW_CPU_TYPE_AMD_PERFORMANCE:
+		return TOPO_CPU_TYPE_PERFORMANCE;
+	case TOPO_HW_CPU_TYPE_AMD_EFFICIENCY:
+		return TOPO_CPU_TYPE_EFFICIENCY;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/debugfs.c b/arch/x86/kernel/cpu/debugfs.c
index 3baf3e4358347..c3361e496df99 100644
--- a/arch/x86/kernel/cpu/debugfs.c
+++ b/arch/x86/kernel/cpu/debugfs.c
@@ -22,6 +22,7 @@ static int cpu_debug_show(struct seq_file *m, void *p)
 	seq_printf(m, "die_id:              %u\n", c->topo.die_id);
 	seq_printf(m, "cu_id:               %u\n", c->topo.cu_id);
 	seq_printf(m, "core_id:             %u\n", c->topo.core_id);
+	seq_printf(m, "cpu_type:            %u\n", topology_cpu_type(c));
 	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);
 	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);
 	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index d1de300af1737..8887b5ed1fbca 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -878,6 +878,8 @@ static const struct cpu_dev intel_cpu_dev = {
 cpu_dev_register(intel_cpu_dev);
 
 #define X86_HYBRID_CPU_TYPE_ID_SHIFT	24
+#define TOPO_HW_CPU_TYPE_INTEL_ATOM	0x20
+#define TOPO_HW_CPU_TYPE_INTEL_CORE	0x40
 
 /**
  * get_this_hybrid_cpu_type() - Get the type of this hybrid CPU
@@ -907,3 +909,19 @@ u32 get_this_hybrid_cpu_native_id(void)
 	return cpuid_eax(0x0000001a) &
 	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
 }
+
+u32 intel_native_model_id(struct cpuinfo_x86 *c)
+{
+	return c->topo.intel_native_model_id;
+}
+
+enum x86_topology_cpu_type intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.intel_type) {
+	case TOPO_HW_CPU_TYPE_INTEL_ATOM:
+		return TOPO_CPU_TYPE_EFFICIENCY;
+	case TOPO_HW_CPU_TYPE_INTEL_CORE:
+		return TOPO_CPU_TYPE_PERFORMANCE;
+	}
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index 7d476fa697ca5..03b3c9c3a45e2 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -182,6 +182,9 @@ static void parse_topology_amd(struct topo_scan *tscan)
 	if (cpu_feature_enabled(X86_FEATURE_TOPOEXT))
 		has_topoext = cpu_parse_topology_ext(tscan);
 
+	if (cpu_feature_enabled(X86_FEATURE_AMD_HETEROGENEOUS_CORES))
+		tscan->c->topo.cpu_type = cpuid_ebx(0x80000026);
+
 	if (!has_topoext && !parse_8000_0008(tscan))
 		return;
 
diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index 9a6069e7133c9..04b012dffa473 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -27,6 +27,16 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
 	}
 }
 
+enum x86_topology_cpu_type topology_cpu_type(struct cpuinfo_x86 *c)
+{
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		return intel_cpu_type(c);
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		return amd_cpu_type(c);
+
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+
 static unsigned int __maybe_unused parse_num_cores_legacy(struct cpuinfo_x86 *c)
 {
 	struct {
@@ -87,6 +97,7 @@ static void parse_topology(struct topo_scan *tscan, bool early)
 		.cu_id			= 0xff,
 		.llc_id			= BAD_APICID,
 		.l2c_id			= BAD_APICID,
+		.cpu_type		= TOPO_CPU_TYPE_UNKNOWN,
 	};
 	struct cpuinfo_x86 *c = tscan->c;
 	struct {
@@ -132,6 +143,8 @@ static void parse_topology(struct topo_scan *tscan, bool early)
 	case X86_VENDOR_INTEL:
 		if (!IS_ENABLED(CONFIG_CPU_SUP_INTEL) || !cpu_parse_topology_ext(tscan))
 			parse_legacy(tscan);
+		if (c->cpuid_level >= 0x1a)
+			c->topo.cpu_type = cpuid_eax(0x1a);
 		break;
 	case X86_VENDOR_HYGON:
 		if (IS_ENABLED(CONFIG_CPU_SUP_HYGON))
-- 
2.43.0