x86: enable memory tester support on 32-bit

only supports memory below max_low_pfn.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 96e0c2e..03980cb 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -447,7 +447,6 @@
 
 config MEMTEST
 	bool "Memtest"
-	depends on X86_64
 	help
 	  This option adds a kernel parameter 'memtest', which allows memtest
 	  to be set.
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 9689a51..3eeab6d 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -844,6 +844,9 @@
 		reserve_early(table_start << PAGE_SHIFT,
 				 table_end << PAGE_SHIFT, "PGTABLE");
 
+	if (!after_init_bootmem)
+		early_memtest(start, end);
+
 	return end >> PAGE_SHIFT;
 }