x86, cpufeature: Catch duplicate CPU feature strings
We had a case of duplicate CPU feature strings, a user space ABI
violation, for almost two years. Make it a build error so that
doesn't happen again.
Link: http://lkml.kernel.org/r/4FE34BCB.5050305@linux.intel.com
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jean Delvare <khali@linux-fr.org>
diff --git a/arch/x86/kernel/cpu/mkcapflags.pl b/arch/x86/kernel/cpu/mkcapflags.pl
index dfea390..0c5b549 100644
--- a/arch/x86/kernel/cpu/mkcapflags.pl
+++ b/arch/x86/kernel/cpu/mkcapflags.pl
@@ -11,22 +11,35 @@
print OUT "#include <asm/cpufeature.h>\n\n";
print OUT "const char * const x86_cap_flags[NCAPINTS*32] = {\n";
+%features = ();
+$err = 0;
+
while (defined($line = <IN>)) {
if ($line =~ /^\s*\#\s*define\s+(X86_FEATURE_(\S+))\s+(.*)$/) {
$macro = $1;
- $feature = $2;
+ $feature = "\L$2";
$tail = $3;
if ($tail =~ /\/\*\s*\"([^"]*)\".*\*\//) {
- $feature = $1;
+ $feature = "\L$1";
}
- if ($feature ne '') {
- printf OUT "\t%-32s = \"%s\",\n",
- "[$macro]", "\L$feature";
+ next if ($feature eq '');
+
+ if ($features{$feature}++) {
+ print STDERR "$in: duplicate feature name: $feature\n";
+ $err++;
}
+ printf OUT "\t%-32s = \"%s\",%s\n", "[$macro]", $feature;
}
}
print OUT "};\n";
close(IN);
close(OUT);
+
+if ($err) {
+ unlink($out);
+ exit(1);
+}
+
+exit(0);