[tip:x86/microcode] x86/microcode/intel: Drop orig_sum from ext signature checksum

[tip-bot for Borislav Petkov]

Commit-ID:  4ace2e7a48ab426eaa9745ace4c50c6a7adb3992
Gitweb:     http://git.kernel.org/tip/4ace2e7a48ab426eaa9745ace4c50c6a7adb3992
Author:     Borislav Petkov <bp@xxxxxxx>
AuthorDate: Mon, 7 Mar 2016 11:10:04 +0100
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 8 Mar 2016 09:08:45 +0100

x86/microcode/intel: Drop orig_sum from ext signature checksum

It is 0 because for !0 values we would have exited already.

Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: http://lkml.kernel.org/r/1457345404-28884-6-git-send-email-bp@xxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/microcode/intel_lib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/intel_lib.c b/arch/x86/kernel/cpu/microcode/intel_lib.c
index 23b1d92..2ce1a7d 100644
--- a/arch/x86/kernel/cpu/microcode/intel_lib.c
+++ b/arch/x86/kernel/cpu/microcode/intel_lib.c
@@ -130,9 +130,9 @@ int microcode_sanity_check(void *mc, int print_err)
 	for (i = 0; i < ext_sigcount; i++) {
 		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
 			  EXT_SIGNATURE_SIZE * i;
-		sum = orig_sum
-			- (mc_header->sig + mc_header->pf + mc_header->cksum)
-			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
+
+		sum = (mc_header->sig + mc_header->pf + mc_header->cksum) -
+		      (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
 		if (sum) {
 			if (print_err)
 				pr_err("Bad extended signature checksum, aborting.\n");