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[v2,0/5] x86 Heterogeneous design identification

Message ID 20241022034608.32396-1-mario.limonciello@amd.com
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Series x86 Heterogeneous design identification | expand

Message

Mario Limonciello Oct. 22, 2024, 3:46 a.m. UTC
This series adds topology identification for Intel and AMD processors and
uses this identification in the AMD CPPC code to identify the boost
numerator.

This series was previously submitted as [1], but this was based on some
patches in linux-pm/linux-next that will be dropped.

Instead the series is now based on tip/master.

This also pulls one patch from Pawan's series [2] and adjusts it for all
feedback while adding AMD support at the same time.

[1] https://lore.kernel.org/all/20241021175509.2079-5-mario.limonciello@amd.com/T/
[2] https://lore.kernel.org/all/20240930-add-cpu-type-v4-0-104892b7ab5f@linux.intel.com/

Mario Limonciello (2):
  x86/cpufeatures: Rename X86_FEATURE_FAST_CPPC to have AMD prefix
  x86/amd: Use heterogeneous core topology for identifying boost
    numerator

Pawan Gupta (1):
  x86/cpu: Add CPU type to struct cpuinfo_topology

Perry Yuan (2):
  x86/cpufeatures: Add feature bits for AMD heterogeneous processor
  x86/cpu: Enable SD_ASYM_PACKING for PKG Domain on AMD Processors

 arch/x86/include/asm/cpu.h               | 19 +++++++++++++++++++
 arch/x86/include/asm/cpufeatures.h       |  3 ++-
 arch/x86/include/asm/processor.h         | 18 ++++++++++++++++++
 arch/x86/include/asm/topology.h          |  8 ++++++++
 arch/x86/kernel/acpi/cppc.c              | 23 +++++++++++++++++++++++
 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/scattered.c          |  3 ++-
 arch/x86/kernel/cpu/topology_amd.c       |  3 +++
 arch/x86/kernel/cpu/topology_common.c    | 13 +++++++++++++
 arch/x86/kernel/smpboot.c                |  5 +++--
 drivers/cpufreq/amd-pstate.c             |  2 +-
 tools/arch/x86/include/asm/cpufeatures.h |  2 +-
 14 files changed, 126 insertions(+), 6 deletions(-)


base-commit: 21f0d4005e7eb71b95cf6b55041fd525bdb11c1f

Comments

Borislav Petkov Oct. 22, 2024, 11:57 a.m. UTC | #1
On Mon, Oct 21, 2024 at 10:46:07PM -0500, Mario Limonciello wrote:
> * Take this patch from Pawan's series and fix up for feedback left on it.
> * Add in AMD case as well

Yah, this one is adding way more boilerplate code than it should. IOW, I'm
thinking of something simpler like this:

---

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 98eced5084ca..44122b077932 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -53,6 +53,7 @@ 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);
+enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c);
 #else
 static inline u8 get_this_hybrid_cpu_type(void)
 {
@@ -63,6 +64,18 @@ static inline u32 get_this_hybrid_cpu_native_id(void)
 {
 	return 0;
 }
+static enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	return TOPO_CPU_TYPE_UNKNOWN;
+}
+#endif
+#ifdef CONFIG_CPU_SUP_AMD
+enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c);
+#else
+static inline enum x86_topology_cpu_type get_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 4a686f0e5dbf..c0975815980c 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_eff_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 aef70336d624..c43d4b3324bc 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;
 
+const char *get_topology_cpu_type_name(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 fab5caec0b72..7d8d62fdc112 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1205,3 +1205,12 @@ 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 get_amd_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.amd_type) {
+	case 0:	return TOPO_CPU_TYPE_PERFORMANCE;
+	case 1:	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 3baf3e435834..10719aba6276 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:            %s\n", get_topology_cpu_type_name(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 d1de300af173..7b1011d0b369 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -907,3 +907,12 @@ u32 get_this_hybrid_cpu_native_id(void)
 	return cpuid_eax(0x0000001a) &
 	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
 }
+
+enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
+{
+	switch (c->topo.intel_type) {
+	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
+	case 0x40: 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 7d476fa697ca..03b3c9c3a45e 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 9a6069e7133c..38220b64c6b3 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -27,6 +27,23 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
 	}
 }
 
+const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
+{
+	enum x86_topology_cpu_type type;
+
+	if (c->x86_vendor == X86_VENDOR_INTEL)
+		type = get_intel_cpu_type(c);
+	if (c->x86_vendor == X86_VENDOR_AMD)
+		type = get_amd_cpu_type(c);
+
+	if (type == TOPO_CPU_TYPE_PERFORMANCE)
+		return "performance";
+	else if (type == TOPO_CPU_TYPE_EFFICIENCY)
+		return "efficiency";
+	else
+		return "unknown";
+}
+
 static unsigned int __maybe_unused parse_num_cores_legacy(struct cpuinfo_x86 *c)
 {
 	struct {
@@ -87,6 +104,7 @@ 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 +150,8 @@ 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))
Mario Limonciello Oct. 22, 2024, 3:41 p.m. UTC | #2
On 10/22/2024 07:03, Borislav Petkov wrote:
> On Tue, Oct 22, 2024 at 01:57:20PM +0200, Borislav Petkov wrote:
>> diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
>> index 9a6069e7133c..38220b64c6b3 100644
>> --- a/arch/x86/kernel/cpu/topology_common.c
>> +++ b/arch/x86/kernel/cpu/topology_common.c
>> @@ -27,6 +27,23 @@ void topology_set_dom(struct topo_scan *tscan, enum x86_topology_domains dom,
>>   	}
>>   }
>>   
>> +const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
>> +{
>> +	enum x86_topology_cpu_type type;
>> +
>> +	if (c->x86_vendor == X86_VENDOR_INTEL)
>> +		type = get_intel_cpu_type(c);
>> +	if (c->x86_vendor == X86_VENDOR_AMD)
>> +		type = get_amd_cpu_type(c);
>> +
>> +	if (type == TOPO_CPU_TYPE_PERFORMANCE)
>> +		return "performance";
>> +	else if (type == TOPO_CPU_TYPE_EFFICIENCY)
>> +		return "efficiency";
>> +	else
>> +		return "unknown";
>> +}
> 
> I guess you still need topology_cpu_type() in your next patch but that's easy
> - you simply call it in get_topology_cpu_type_name().
> 
> The point being debugfs will dump the name of the core type and not some magic
> number which no one knows.

Yeah; makes sense.  I'll pull your suggestions in.
Mario Limonciello Oct. 22, 2024, 4:13 p.m. UTC | #3
On 10/22/2024 11:03, Dave Hansen wrote:
> On 10/22/24 04:57, Borislav Petkov wrote:
>> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
>> +{
>> +	switch (c->topo.intel_type) {
>> +	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
>> +	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
>> +	}
>> +	return TOPO_CPU_TYPE_UNKNOWN;
>> +}
> 
> This makes me feel a _bit_ uneasy.  0x20 here really does mean "Atom
> microarchitecture" and 0x40 means "Core microarchitecture".
> 
> We want to encourage folks to use this new ABI when they want to find
> the fastest core to run on.  But we don't want them to use it to bind to
> a CPU and then deploy Atom-specific optimizations.
> 
> We *also* don't want the in-kernel code to do be doing things like:
> 
> 	if (get_intel_cpu_type() == TOPO_CPU_TYPE_EFFICIENCY)
> 		setup_force_cpu_bug(FOO);
> 
> That would fall over if Intel ever mixed fast and slow core types with
> the same microarchitecture, which is what AMD is doing today.
> 
> Having:
> 
> 	TOPO_CPU_TYPE_EFFICIENCY, and
> 	TOPO_CPU_TYPE_PERFORMANCE
> 
> is totally fine in generic code.  But we also need to preserve the:
> 
> 	TOPO_HW_CPU_TYPE_INTEL_ATOM
> 	TOPO_HW_CPU_TYPE_INTEL_CORE
> 
> values also for use in vendor-specific code.

What you're suggesting is to keep an enum in the intel.c code and any 
code that needs to match atom vs core can directly use

c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM

Right?

> 
> In the ABI, I think we should probably make this an explicit
> power/performance interface rather than "cpu_type".  As much as I like
> the human readable "performance" and "efficiency", I'm worried it won't
> be flexible enough for future maniacal hardware designers.  To be 100%
> clear, all the hardware designs that I know of would fit in a two-bucket
> ("performance" and "efficiency") scheme.  But we've got to decide
> whether to commit to that forever.

As it stands today none of this is exported anywhere but debugfs; so I 
wouldn't say we have ABI concerns (yet).  Could we wait until the one 
that breaks the mold shows up?
Dave Hansen Oct. 22, 2024, 5:09 p.m. UTC | #4
On 10/22/24 09:13, Mario Limonciello wrote:
> On 10/22/2024 11:03, Dave Hansen wrote:
...
>> Having:
>>
>>     TOPO_CPU_TYPE_EFFICIENCY, and
>>     TOPO_CPU_TYPE_PERFORMANCE
>>
>> is totally fine in generic code.  But we also need to preserve the:
>>
>>     TOPO_HW_CPU_TYPE_INTEL_ATOM
>>     TOPO_HW_CPU_TYPE_INTEL_CORE
>>
>> values also for use in vendor-specific code.
> 
> What you're suggesting is to keep an enum in the intel.c code and any
> code that needs to match atom vs core can directly use
> 
> c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM
> 
> Right?

Yep, exactly.

> As it stands today none of this is exported anywhere but debugfs; so
> I wouldn't say we have ABI concerns (yet).  Could we wait until the
> one that breaks the mold shows up?

Oh, debugfs is fine.  I was, for some reason, assuming that the strings
were getting spit out in sysfs proper somewhere, not debugfs.  Sorry for
the noise.
Pawan Gupta Oct. 23, 2024, 3:58 a.m. UTC | #5
On Tue, Oct 22, 2024 at 11:13:00AM -0500, Mario Limonciello wrote:
> > This makes me feel a _bit_ uneasy.  0x20 here really does mean "Atom
> > microarchitecture" and 0x40 means "Core microarchitecture".
> > 
> > We want to encourage folks to use this new ABI when they want to find
> > the fastest core to run on.  But we don't want them to use it to bind to
> > a CPU and then deploy Atom-specific optimizations.
> > 
> > We *also* don't want the in-kernel code to do be doing things like:
> > 
> > 	if (get_intel_cpu_type() == TOPO_CPU_TYPE_EFFICIENCY)
> > 		setup_force_cpu_bug(FOO);
> > 
> > That would fall over if Intel ever mixed fast and slow core types with
> > the same microarchitecture, which is what AMD is doing today.
> > 
> > Having:
> > 
> > 	TOPO_CPU_TYPE_EFFICIENCY, and
> > 	TOPO_CPU_TYPE_PERFORMANCE
> > 
> > is totally fine in generic code.  But we also need to preserve the:
> > 
> > 	TOPO_HW_CPU_TYPE_INTEL_ATOM
> > 	TOPO_HW_CPU_TYPE_INTEL_CORE
> > 
> > values also for use in vendor-specific code.
> 
> What you're suggesting is to keep an enum in the intel.c code and any code
> that needs to match atom vs core can directly use
> 
> c->topo.intel_type == TOPO_HW_CPU_TYPE_INTEL_ATOM

To be able to match ATOM and CORE in the affected processor table, the
enums need to be defined in a way that they can be used in the common code.
Specially for !CONFIG_CPU_SUP_INTEL case.
Pawan Gupta Oct. 23, 2024, 4:40 a.m. UTC | #6
On Tue, Oct 22, 2024 at 01:57:20PM +0200, Borislav Petkov wrote:
> On Mon, Oct 21, 2024 at 10:46:07PM -0500, Mario Limonciello wrote:
> > * Take this patch from Pawan's series and fix up for feedback left on it.
> > * Add in AMD case as well
> 
> Yah, this one is adding way more boilerplate code than it should. IOW, I'm
> thinking of something simpler like this:
> 
> ---
> 
> diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
> index 98eced5084ca..44122b077932 100644
> --- a/arch/x86/include/asm/cpu.h
> +++ b/arch/x86/include/asm/cpu.h
> @@ -53,6 +53,7 @@ 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);
> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c);
>  #else
>  static inline u8 get_this_hybrid_cpu_type(void)
>  {
> @@ -63,6 +64,18 @@ static inline u32 get_this_hybrid_cpu_native_id(void)
>  {
>  	return 0;
>  }
> +static enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}
> +#endif
> +#ifdef CONFIG_CPU_SUP_AMD
> +enum x86_topology_cpu_type get_amd_cpu_type(struct cpuinfo_x86 *c);
> +#else
> +static inline enum x86_topology_cpu_type get_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 4a686f0e5dbf..c0975815980c 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_eff_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 aef70336d624..c43d4b3324bc 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;
>  
> +const char *get_topology_cpu_type_name(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 fab5caec0b72..7d8d62fdc112 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -1205,3 +1205,12 @@ 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 get_amd_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	switch (c->topo.amd_type) {
> +	case 0:	return TOPO_CPU_TYPE_PERFORMANCE;
> +	case 1:	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 3baf3e435834..10719aba6276 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:            %s\n", get_topology_cpu_type_name(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 d1de300af173..7b1011d0b369 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -907,3 +907,12 @@ u32 get_this_hybrid_cpu_native_id(void)
>  	return cpuid_eax(0x0000001a) &
>  	       (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
>  }
> +
> +enum x86_topology_cpu_type get_intel_cpu_type(struct cpuinfo_x86 *c)
> +{
> +	switch (c->topo.intel_type) {
> +	case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
> +	case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
> +	}
> +	return TOPO_CPU_TYPE_UNKNOWN;
> +}

The name of the function is a bit misleading, as it suggests that it
returns the Intel specific CPU type(ATOM/CORE), but it actually returns
the performance/efficiency generic types.

I would suggest to name the function based on what it returns, like:

get_generic_cpu_type(struct cpuinfo_x86 *c)
{
     enum x86_topology_cpu_type type;

	if (c->x86_vendor == X86_VENDOR_INTEL) {
	     switch (c->topo.intel_type) {
		     case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
		     case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
	}
	if (c->x86_vendor == X86_VENDOR_AMD) {
	     switch (c->topo.amd_type) {
		     case 0: return TOPO_CPU_TYPE_PERFORMANCE;
		     case 1: return TOPO_CPU_TYPE_EFFICIENCY;
	}

	return TOPO_CPU_TYPE_UNKNOWN;
}

get_intel_cpu_type(struct cpuinfo_x86 *c)
{
	return c->topo.intel_type;
}

get_amd_cpu_type(struct cpuinfo_x86 *c)
{
	return c->topo.amd_type;
}
Borislav Petkov Oct. 23, 2024, 3:59 p.m. UTC | #7
On Tue, Oct 22, 2024 at 09:40:15PM -0700, Pawan Gupta wrote:
> get_generic_cpu_type(struct cpuinfo_x86 *c)
> {
>      enum x86_topology_cpu_type type;
> 
> 	if (c->x86_vendor == X86_VENDOR_INTEL) {
> 	     switch (c->topo.intel_type) {
> 		     case 0x20: return TOPO_CPU_TYPE_EFFICIENCY;
> 		     case 0x40: return TOPO_CPU_TYPE_PERFORMANCE;
> 	}
> 	if (c->x86_vendor == X86_VENDOR_AMD) {
> 	     switch (c->topo.amd_type) {
> 		     case 0: return TOPO_CPU_TYPE_PERFORMANCE;
> 		     case 1: return TOPO_CPU_TYPE_EFFICIENCY;
> 	}
> 
> 	return TOPO_CPU_TYPE_UNKNOWN;
> }

Ok...

> get_intel_cpu_type(struct cpuinfo_x86 *c)
> {
> 	return c->topo.intel_type;
> }
> 
> get_amd_cpu_type(struct cpuinfo_x86 *c)
> {
> 	return c->topo.amd_type;

... except those silly wrappers can go. There's a reason cpuinfo_x86 has
well-defined members which can be used directly.