objtool: Add Function to get the name of a CPU feature

Add a function to get the name of a CPU feature. The function is
architecture dependent and currently only implemented for x86. The
feature names are automatically generated from the cpufeatures.h
include file.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://patch.msgid.link/20251121095340.464045-27-alexandre.chartre@oracle.com

1 files changed, 34 insertions, 0 deletions

diff --git a/tools/arch/x86/tools/gen-cpu-feature-names-x86.awk b/tools/arch/x86/tools/gen-cpu-feature-names-x86.awk
new file mode 100644
index 000000000000..cc4c7a3e6c2e
--- /dev/null
+++ b/tools/arch/x86/tools/gen-cpu-feature-names-x86.awk
@@ -0,0 +1,34 @@
+#!/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Copyright (c) 2025, Oracle and/or its affiliates.
+#
+# Usage: awk -f gen-cpu-feature-names-x86.awk cpufeatures.h > cpu-feature-names.c
+#
+
+BEGIN {
+	print "/* cpu feature name array generated from cpufeatures.h */"
+	print "/* Do not change this code. */"
+	print
+	print "static const char *cpu_feature_names[(NCAPINTS+NBUGINTS)*32] = {"
+
+	value_expr = "\\([0-9*+ ]+\\)"
+}
+
+/^#define X86_FEATURE_/ {
+	if (match($0, value_expr)) {
+		value = substr($0, RSTART + 1, RLENGTH - 2)
+		print "\t[" value "] = \"" $2 "\","
+	}
+}
+
+/^#define X86_BUG_/ {
+	if (match($0, value_expr)) {
+		value = substr($0, RSTART + 1, RLENGTH - 2)
+		print "\t[NCAPINTS*32+(" value ")] = \"" $2 "\","
+	}
+}
+
+END {
+	print "};"
+}