x86, microcode, AMD: Fix broken ucode patch size check
authorAndreas Herrmann <andreas.herrmann3@amd.com>
Tue, 31 Jul 2012 13:41:45 +0000 (15:41 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 14 Sep 2012 17:00:34 +0000 (10:00 -0700)
commit72961d91696071841fa013f11f686eaa7e2d0996
tree31813ab89c9cf0013c067e1525816d271c7ab33f
parentbbebafa0d9507206793a05fbeb010eafb1fdb0d0
x86, microcode, AMD: Fix broken ucode patch size check

commit 36bf50d7697be18c6bfd0401e037df10bff1e573 upstream.

This issue was recently observed on an AMD C-50 CPU where a patch of
maximum size was applied.

Commit be62adb49294 ("x86, microcode, AMD: Simplify ucode verification")
added current_size in get_matching_microcode(). This is calculated as
size of the ucode patch + 8 (ie. size of the header). Later this is
compared against the maximum possible ucode patch size for a CPU family.
And of course this fails if the patch has already maximum size.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1344361461-10076-1-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/microcode_amd.c