x86: add periodic corruption check

Perodically check for corruption in low phusical memory.  Don't bother
checking at fault time, since it won't show anything useful.

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

5 files changed, 22 insertions, 2 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ee89ebc5aabc..c239b3780973 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -623,6 +623,7 @@ static void __init setup_bios_corruption_check(void)
 }
 
 static int __read_mostly bios_corruption_check = 1;
+static struct timer_list periodic_check_timer;
 
 void check_for_bios_corruption(void)
 {
@@ -650,6 +651,22 @@ void check_for_bios_corruption(void)
                 dump_stack();
 }
 
+static void periodic_check_for_corruption(unsigned long data)
+{
+        check_for_bios_corruption();
+        mod_timer(&periodic_check_timer, jiffies + 60*HZ);
+}
+
+void start_periodic_check_for_corruption(void)
+{
+        if (!bios_corruption_check)
+                return;
+
+        init_timer(&periodic_check_timer);
+        periodic_check_timer.function = &periodic_check_for_corruption;
+        periodic_check_for_corruption(0);
+}
+
 static int set_bios_corruption_check(char *arg)
 {
         char *end;
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 5140bdf03020..455f3fe67b42 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -848,8 +848,6 @@ no_context:
  * Oops. The kernel tried to access some bad page. We'll have to
  * terminate things with extreme prejudice.
  */
-        check_for_bios_corruption();
-
 #ifdef CONFIG_X86_32
         bust_spinlocks(1);
 #else
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index d37f29376b0c..657a16ad61ba 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -907,6 +907,8 @@ void __init mem_init(void)
         int codesize, reservedpages, datasize, initsize;
         int tmp;
 
+        start_periodic_check_for_corruption();
+
 #ifdef CONFIG_FLATMEM
         BUG_ON(!mem_map);
 #endif
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index d3746efb060d..f4db5276fa21 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -769,6 +769,8 @@ void __init mem_init(void)
 {
         long codesize, reservedpages, datasize, initsize;
 
+        start_periodic_check_for_corruption();
+
         pci_iommu_alloc();
 
         /* clear_bss() already clear the empty_zero_page */
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 8017129e6b63..00bb251c6451 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -246,6 +246,7 @@ extern int root_mountflags;
  * able to scatter it around anywhere in the kernel.
  */
 void check_for_bios_corruption(void);
+void start_periodic_check_for_corruption(void);
 #else
 static inline void check_for_bios_corruption(void)
 {