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: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index dba9ca22eb5cf4081cfff4b8215681482ed6f040..d618dc1e366e2a3684dcdffe00c5ddcae2b9e066 100644 (file)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -688,7 +688,7 @@ 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)) &&