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SubjectRe: [tip:x86/urgent] x86, cpufeature: Catch duplicate CPU feature strings
On Mon, 25 Jun 2012 09:14:29 -0700, tip-bot for H. Peter Anvin wrote:
> Commit-ID: 55f6cb9d0b364e7e8cb65b51193f5e4743c44fde
> Gitweb: http://git.kernel.org/tip/55f6cb9d0b364e7e8cb65b51193f5e4743c44fde
> Author: H. Peter Anvin <hpa@linux.intel.com>
> AuthorDate: Fri, 22 Jun 2012 11:47:15 -0700
> Committer: H. Peter Anvin <hpa@linux.intel.com>
> CommitDate: Mon, 25 Jun 2012 09:02:13 -0700
>
> 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>
> ---
> arch/x86/kernel/cpu/mkcapflags.pl | 23 ++++++++++++++++++-----
> 1 files changed, 18 insertions(+), 5 deletions(-)
>
> 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 @@ 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;

You added an extra %s in the string, can't think of a good reason for
it. perl -w would have told you, I think we should add it.

Other than this, the code looks good and the improvement reasonable, so
you can add:

Acked-by: Jean Delvare <khali@linux-fr.org>

after fixing it.

> }
> }
> print OUT "};\n";
>
> close(IN);
> close(OUT);
> +
> +if ($err) {
> + unlink($out);
> + exit(1);
> +}
> +
> +exit(0);


--
Jean Delvare


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