[PATCH] powerpc: enable NAP only on cpus who support it to avoid memory corruption

This patch fixes incorrect setting of powersave_nap to 1 on all
PowerMacs, potentially causing memory corruption on some models. This
bug was introuced by me during the 32/64 bits merge.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 4 insertions, 9 deletions

diff --git a/arch/powerpc/platforms/powermac/feature.c b/arch/powerpc/platforms/powermac/feature.c
index 34714d3ea69a..bbe794891a20 100644
--- a/arch/powerpc/platforms/powermac/feature.c
+++ b/arch/powerpc/platforms/powermac/feature.c
@@ -2491,9 +2491,7 @@ found:
                         pmac_mb.model_id = PMAC_TYPE_COMET;
                 iounmap(mach_id_ptr);
         }
-#endif /* CONFIG_POWER4 */
 
-#ifdef CONFIG_6xx
         /* Set default value of powersave_nap on machines that support it.
          * It appears that uninorth rev 3 has a problem with it, we don't
          * enable it on those. In theory, the flush-on-lock property is
@@ -2522,10 +2520,11 @@ found:
          * NAP mode
          */
         powersave_lowspeed = 1;
-#endif /* CONFIG_6xx */
-#ifdef CONFIG_POWER4
+
+#else /* CONFIG_POWER4 */
         powersave_nap = 1;
-#endif
+#endif  /* CONFIG_POWER4 */
+
         /* Check for "mobile" machine */
         if (model && (strncmp(model, "PowerBook", 9) == 0
                    || strncmp(model, "iBook", 5) == 0))
diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 1955462f4082..29c2946f1c77 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/arch/powerpc/platforms/powermac/setup.c
@@ -621,10 +621,6 @@ static void __init pmac_init_early(void)
         /* Probe motherboard chipset */
         pmac_feature_init();
 
-        /* We can NAP */
-        powersave_nap = 1;
-        printk(KERN_INFO "Using native/NAP idle loop\n");
-
         /* Initialize debug stuff */
         udbg_scc_init(!!strstr(cmd_line, "sccdbg"));
         udbg_adb_init(!!strstr(cmd_line, "btextdbg"));