x86, cpu: Fix regression in AMD errata checking code

commit 07a7795ca2e6e66d00b184efb46bd0e23d90d3fe upstream.

A bug in the family-model-stepping matching code caused the presence of
errata to go undetected when OSVW was not used. This causes hangs on
some K8 systems because the E400 workaround is not enabled.

Signed-off-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
LKML-Reference: <1282141190-930137-1-git-send-email-hans.rosenfeld@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 1b52ec9461ad0bb29049bfc37afcc393c8535ee8..f893f73397c994d80fae51e7f63a63155402a5e8 100644 (file)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -689,7 +689,7 @@ bool cpu_has_amd_erratum(const int *erratum)
        }
 
        /* OSVW unavailable or ID unknown, match family-model-stepping range */
-       ms = (cpu->x86_model << 8) | cpu->x86_mask;
+       ms = (cpu->x86_model << 4) | cpu->x86_mask;
        while ((range = *erratum++))
                if ((cpu->x86 == AMD_MODEL_RANGE_FAMILY(range)) &&
                    (ms >= AMD_MODEL_RANGE_START(range)) &&