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SubjectRe: [PATCH 1/2] x86, microcode: Do Intel microcode revision check signed
On Fri, Dec 06, 2013 at 01:04:02PM -0800, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> The Intel SDM Vol 3 9.11.1 Microcode update states that
> the update revision field is signed. However we do the comparison
> unsigned, as the comparison gets promoted.
>
> Use a cast to really do a signed comparison of the microcode
> revision.

Why not just update the struct?
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
> arch/x86/kernel/microcode_intel_lib.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/microcode_intel_lib.c b/arch/x86/kernel/microcode_intel_lib.c
> index ce69320..68503d1 100644
> --- a/arch/x86/kernel/microcode_intel_lib.c
> +++ b/arch/x86/kernel/microcode_intel_lib.c
> @@ -41,7 +41,7 @@ update_match_cpu(unsigned int csig, unsigned int cpf,
> int
> update_match_revision(struct microcode_header_intel *mc_header, int rev)
> {
> - return (mc_header->rev <= rev) ? 0 : 1;
> + return ((int)mc_header->rev <= rev) ? 0 : 1;
> }
>
> int microcode_sanity_check(void *mc, int print_err)
> --
> 1.8.3.1
>
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