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Commit 55f6cb9d authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

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>
parent 4ad33411

arch/x86/kernel/cpu/mkcapflags.pl

+18 −5
Original line number Diff line number Diff line
@@ -11,22 +11,35 @@ open(OUT, "> $out\0") or die "$0: cannot create: $out: $!\n"; 
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);