On 10/21/2024 05:58, Borislav Petkov wrote:
On Thu, Oct 03, 2024 at 04:37:59PM -0500, Mario Limonciello wrote:
Subject: Re: [PATCH 2/2] CPPC: Use heterogeneous core topology for identifying boost numerator
The tip tree preferred format for patch subject prefixes is
'subsys/component:', e.g. 'x86/apic:', 'x86/mm/fault:', 'sched/fair:',
'genirq/core:'. Please do not use file names or complete file paths as
prefix. 'git log path/to/file' should give you a reasonable hint in most
cases.
The condensed patch description in the subject line should start with a
uppercase letter and should be written in imperative tone.
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 4a686f0e5dbf..d81a6efa81bb 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -691,6 +691,14 @@ static inline u32 per_cpu_l2c_id(unsigned int cpu)
return per_cpu(cpu_info.topo.l2c_id, cpu);
}
+/* defined by CPUID_Fn80000026_EBX BIT [31:28] */
+enum amd_core_type {
+ CPU_CORE_TYPE_NO_HETERO_SUP = -1,
Why?
Why isn't this the last value in the enum without explicitly enumerating them?
+ CPU_CORE_TYPE_PERFORMANCE = 0,
+ CPU_CORE_TYPE_EFFICIENCY = 1,
+ CPU_CORE_TYPE_UNDEFINED = 2,
+};
That thing goes...
+
#ifdef CONFIG_CPU_SUP_AMD
... in here.
/*
* Issue a DIV 0/1 insn to clear any division data from previous DIV
...
Ack; will drop a series momentarily fixing this and your other above
feedback.
Thx.
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 015971adadfc..8ad5f1385f0e 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1204,3 +1204,32 @@ void amd_check_microcode(void)
on_each_cpu(zenbleed_check_cpu, NULL, 1);
}
+
+/**
+ * amd_get_core_type - Heterogeneous core type identification
+ *
+ * Returns the CPU type [31:28] (i.e., performance or efficient) of
+ * a CPU in the processor.
+ *
+ * If the processor has no core type support, returns
+ * CPU_CORE_TYPE_NO_HETERO_SUP.
+ */
+enum amd_core_type amd_get_core_type(void)
+{
+ struct {
+ u32 num_processors :16,
+ power_efficiency_ranking :8,
+ native_model_id :4,
+ core_type :4;
+ } props;
So this thing wants to use this stuff here:
https://lore.kernel.org/r/20240930-add-cpu-type-v4-2-104892b7ab5f@xxxxxxxxxxxxxxx
and add the AMD part to the union. Instead of calling CPUID each time and
adding an ugly export...
Due to the cross tree landing complexity I'll rip this and the symbol
out after that one lands (probably next cycle).
+
+ if (!cpu_feature_enabled(X86_FEATURE_HETERO_CORE_TOPOLOGY))
+ return CPU_CORE_TYPE_NO_HETERO_SUP;
+
+ cpuid_leaf_reg(0x80000026, CPUID_EBX, &props);
+ if (props.core_type >= CPU_CORE_TYPE_UNDEFINED)
+ return CPU_CORE_TYPE_UNDEFINED;
+
+ return props.core_type;
+}
+EXPORT_SYMBOL_GPL(amd_get_core_type);
--
2.43.0
