1 files changed, 50 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/addon_cpuid_features.c b/arch/x86/kernel/cpu/addon_cpuid_features.c
new file mode 100644
index 0000000..3e91d3ee
--- /dev/null
+++ b/arch/x86/kernel/cpu/addon_cpuid_features.c
@@ -0,0 +1,50 @@
+
+/*
+ *	Routines to indentify additional cpu features that are scattered in
+ *	cpuid space.
+ */
+
+#include <linux/cpu.h>
+
+#include <asm/processor.h>
+
+struct cpuid_bit {
+	u16 feature;
+	u8 reg;
+	u8 bit;
+	u32 level;
+};
+
+enum cpuid_regs {
+	CR_EAX = 0,
+	CR_ECX,
+	CR_EDX,
+	CR_EBX
+};
+
+void __cpuinit init_scattered_cpuid_features(struct cpuinfo_x86 *c)
+{
+	u32 max_level;
+	u32 regs[4];
+	const struct cpuid_bit *cb;
+
+	static const struct cpuid_bit cpuid_bits[] = {
+		{ X86_FEATURE_IDA, CR_EAX, 1, 0x00000006 },
+		{ 0, 0, 0, 0 }
+	};
+
+	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(cb->level, &regs[CR_EAX], &regs[CR_EBX],
+			&regs[CR_ECX], &regs[CR_EDX]);
+
+		if (regs[cb->reg] & (1 << cb->bit))
+			set_bit(cb->feature, c->x86_capability);
+	}
+}