commit b4b6d4a02fa8aa8187d426b508fb7f3b69df0dcc
author Andrew Scull <ascull@google.com> Wed Jan 02 15:54:55 2019 +0000
committer Andrew Scull <ascull@google.com> Wed Jan 02 15:54:55 2019 +0000
tree fdf4498bc30cb80757eaf20b46ea866b23141a93

v4.19.13 snapshot.

arch/x86/kernel/cpu/scattered.c

diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
new file mode 100644
index 0000000..772c219
--- /dev/null
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -0,0 +1,82 @@
+/*
+ *	Routines to identify additional cpu features that are scattered in
+ *	cpuid space.
+ */
+#include <linux/cpu.h>
+
+#include <asm/pat.h>
+#include <asm/processor.h>
+
+#include <asm/apic.h>
+
+struct cpuid_bit {
+	u16 feature;
+	u8 reg;
+	u8 bit;
+	u32 level;
+	u32 sub_leaf;
+};
+
+/* Please keep the leaf sorted by cpuid_bit.level for faster search. */
+static const struct cpuid_bit cpuid_bits[] = {
+	{ X86_FEATURE_APERFMPERF,       CPUID_ECX,  0, 0x00000006, 0 },
+	{ X86_FEATURE_EPB,		CPUID_ECX,  3, 0x00000006, 0 },
+	{ X86_FEATURE_CAT_L3,		CPUID_EBX,  1, 0x00000010, 0 },
+	{ X86_FEATURE_CAT_L2,		CPUID_EBX,  2, 0x00000010, 0 },
+	{ X86_FEATURE_CDP_L3,		CPUID_ECX,  2, 0x00000010, 1 },
+	{ X86_FEATURE_CDP_L2,		CPUID_ECX,  2, 0x00000010, 2 },
+	{ X86_FEATURE_MBA,		CPUID_EBX,  3, 0x00000010, 0 },
+	{ X86_FEATURE_HW_PSTATE,	CPUID_EDX,  7, 0x80000007, 0 },
+	{ X86_FEATURE_CPB,		CPUID_EDX,  9, 0x80000007, 0 },
+	{ X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },
+	{ X86_FEATURE_SME,		CPUID_EAX,  0, 0x8000001f, 0 },
+	{ X86_FEATURE_SEV,		CPUID_EAX,  1, 0x8000001f, 0 },
+	{ 0, 0, 0, 0, 0 }
+};
+
+void init_scattered_cpuid_features(struct cpuinfo_x86 *c)
+{
+	u32 max_level;
+	u32 regs[4];
+	const struct cpuid_bit *cb;
+
+	for (cb = cpuid_bits; cb->feature; cb++) {
+
+		/* Verify that the level is valid */
+		max_level = cpuid_eax(cb->level & 0xffff0000);
+		if (max_level < cb->level ||
+		    max_level > (cb->level | 0xffff))
+			continue;
+
+		cpuid_count(cb->level, cb->sub_leaf, &regs[CPUID_EAX],
+			    &regs[CPUID_EBX], &regs[CPUID_ECX],
+			    &regs[CPUID_EDX]);
+
+		if (regs[cb->reg] & (1 << cb->bit))
+			set_cpu_cap(c, cb->feature);
+	}
+}
+
+u32 get_scattered_cpuid_leaf(unsigned int level, unsigned int sub_leaf,
+			     enum cpuid_regs_idx reg)
+{
+	const struct cpuid_bit *cb;
+	u32 cpuid_val = 0;
+
+	for (cb = cpuid_bits; cb->feature; cb++) {
+
+		if (level > cb->level)
+			continue;
+
+		if (level < cb->level)
+			break;
+
+		if (reg == cb->reg && sub_leaf == cb->sub_leaf) {
+			if (cpu_has(&boot_cpu_data, cb->feature))
+				cpuid_val |= BIT(cb->bit);
+		}
+	}
+
+	return cpuid_val;
+}
+EXPORT_SYMBOL_GPL(get_scattered_cpuid_leaf);