x86: default corruption check to off, but put parameter default in Kconfig

Default the low memory corruption check to off, but make the default setting of
the memory_corruption_check kernel parameter a config parameter.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 20 insertions, 2 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cbee4199689c..7820d447bb8d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1061,7 +1061,6 @@ config HIGHPTE
 
 config X86_CHECK_BIOS_CORRUPTION
         bool "Check for low memory corruption"
-        default y
         help
          Periodically check for memory corruption in low memory, which
          is suspected to be caused by BIOS.  Even when enabled in the
@@ -1082,6 +1081,14 @@ config X86_CHECK_BIOS_CORRUPTION
          you can use memmap= to prevent the kernel from using that
          memory.
 
+config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
+        bool "Set the default setting of memory_corruption_check"
+        depends on X86_CHECK_BIOS_CORRUPTION
+        default y
+        help
+         Set whether the default state of memory_corruption_check is
+         on or off.
+
 config MATH_EMULATION
         bool
         prompt "Math emulation" if X86_32
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 27ae91288855..ec7e56c1b984 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -587,7 +587,8 @@ struct x86_quirks *x86_quirks __initdata = &default_x86_quirks;
 #ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
 #define MAX_SCAN_AREAS  8
 
-static int __read_mostly memory_corruption_check = 0;
+static int __read_mostly memory_corruption_check = -1;
+
 static unsigned __read_mostly corruption_check_size = 64*1024;
 static unsigned __read_mostly corruption_check_period = 60; /* seconds */
 
@@ -634,6 +635,16 @@ static void __init setup_bios_corruption_check(void)
 {
         u64 addr = PAGE_SIZE;   /* assume first page is reserved anyway */
 
+        if (memory_corruption_check == -1) {
+                memory_corruption_check =
+#ifdef CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
+                        1
+#else
+                        0
+#endif
+                        ;
+        }
+
         if (corruption_check_size == 0)
                 memory_corruption_check = 0;