diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 078fb5533541..2d80653aa2af 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1636,7 +1636,7 @@ static int __init prom_find_machine_type(void)
 			   compat, sizeof(compat)-1);
 	if (len <= 0)
 		return PLATFORM_GENERIC;
-	if (strncmp(compat, RELOC("chrp"), 4))
+	if (strcmp(compat, RELOC("chrp")))
 		return PLATFORM_GENERIC;
 
 	/* Default to pSeries. We need to know if we are running LPAR */