1 files changed, 91 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
new file mode 100644
index 000000000..ad6776081
--- /dev/null
+++ b/arch/x86/kernel/cpu/match.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/cpu_device_id.h>
+#include <asm/cpufeature.h>
+#include <linux/cpu.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+
+/**
+ * x86_match_cpu - match current CPU again an array of x86_cpu_ids
+ * @match: Pointer to array of x86_cpu_ids. Last entry terminated with
+ *         {}.
+ *
+ * Return the entry if the current CPU matches the entries in the
+ * passed x86_cpu_id match table. Otherwise NULL.  The match table
+ * contains vendor (X86_VENDOR_*), family, model and feature bits or
+ * respective wildcard entries.
+ *
+ * A typical table entry would be to match a specific CPU
+ *
+ * X86_MATCH_VENDOR_FAM_MODEL_FEATURE(INTEL, 6, INTEL_FAM6_BROADWELL,
+ *				      X86_FEATURE_ANY, NULL);
+ *
+ * Fields can be wildcarded with %X86_VENDOR_ANY, %X86_FAMILY_ANY,
+ * %X86_MODEL_ANY, %X86_FEATURE_ANY (except for vendor)
+ *
+ * asm/cpu_device_id.h contains a set of useful macros which are shortcuts
+ * for various common selections. The above can be shortened to:
+ *
+ * X86_MATCH_INTEL_FAM6_MODEL(BROADWELL, NULL);
+ *
+ * Arrays used to match for this should also be declared using
+ * MODULE_DEVICE_TABLE(x86cpu, ...)
+ *
+ * This always matches against the boot cpu, assuming models and features are
+ * consistent over all CPUs.
+ */
+const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
+{
+	const struct x86_cpu_id *m;
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	for (m = match;
+	     m->vendor | m->family | m->model | m->steppings | m->feature;
+	     m++) {
+		if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
+			continue;
+		if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
+			continue;
+		if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
+			continue;
+		if (m->steppings != X86_STEPPING_ANY &&
+		    !(BIT(c->x86_stepping) & m->steppings))
+			continue;
+		if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
+			continue;
+		return m;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(x86_match_cpu);
+
+static const struct x86_cpu_desc *
+x86_match_cpu_with_stepping(const struct x86_cpu_desc *match)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	const struct x86_cpu_desc *m;
+
+	for (m = match; m->x86_family | m->x86_model; m++) {
+		if (c->x86_vendor != m->x86_vendor)
+			continue;
+		if (c->x86 != m->x86_family)
+			continue;
+		if (c->x86_model != m->x86_model)
+			continue;
+		if (c->x86_stepping != m->x86_stepping)
+			continue;
+		return m;
+	}
+	return NULL;
+}
+
+bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table)
+{
+	const struct x86_cpu_desc *res = x86_match_cpu_with_stepping(table);
+
+	if (!res || res->x86_microcode_rev > boot_cpu_data.microcode)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(x86_cpu_has_min_microcode_rev);