x86: corruption check: move the corruption checks into their own file
Impact: cleanup
The corruption check code is rather sizable and it's likely to grow over
time when we add checks for more types of corruptions (there's a few
candidates in kerneloops.org that I want to add checks for)... so lets move
it to its own file
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c
new file mode 100644
index 0000000..5056703
--- /dev/null
+++ b/arch/x86/kernel/check.c
@@ -0,0 +1,158 @@
+#include <linux/module.h>
+#include <linux/sched.h>
+
+#include <asm/e820.h>
+#include <asm/proto.h>
+
+/*
+ * Some BIOSes seem to corrupt the low 64k of memory during events
+ * like suspend/resume and unplugging an HDMI cable. Reserve all
+ * remaining free memory in that area and fill it with a distinct
+ * pattern.
+ */
+#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
+#define MAX_SCAN_AREAS 8
+
+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 */
+
+static struct e820entry scan_areas[MAX_SCAN_AREAS];
+static int num_scan_areas;
+
+
+static int set_corruption_check(char *arg)
+{
+ char *end;
+
+ memory_corruption_check = simple_strtol(arg, &end, 10);
+
+ return (*end == 0) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check", set_corruption_check);
+
+static int set_corruption_check_period(char *arg)
+{
+ char *end;
+
+ corruption_check_period = simple_strtoul(arg, &end, 10);
+
+ return (*end == 0) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check_period", set_corruption_check_period);
+
+static int set_corruption_check_size(char *arg)
+{
+ char *end;
+ unsigned size;
+
+ size = memparse(arg, &end);
+
+ if (*end == '\0')
+ corruption_check_size = size;
+
+ return (size == corruption_check_size) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check_size", set_corruption_check_size);
+
+
+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;
+
+ if (!memory_corruption_check)
+ return;
+
+ corruption_check_size = round_up(corruption_check_size, PAGE_SIZE);
+
+ while (addr < corruption_check_size && num_scan_areas < MAX_SCAN_AREAS) {
+ u64 size;
+ addr = find_e820_area_size(addr, &size, PAGE_SIZE);
+
+ if (addr == 0)
+ break;
+
+ if ((addr + size) > corruption_check_size)
+ size = corruption_check_size - addr;
+
+ if (size == 0)
+ break;
+
+ e820_update_range(addr, size, E820_RAM, E820_RESERVED);
+ scan_areas[num_scan_areas].addr = addr;
+ scan_areas[num_scan_areas].size = size;
+ num_scan_areas++;
+
+ /* Assume we've already mapped this early memory */
+ memset(__va(addr), 0, size);
+
+ addr += size;
+ }
+
+ printk(KERN_INFO "Scanning %d areas for low memory corruption\n",
+ num_scan_areas);
+ update_e820();
+}
+
+static struct timer_list periodic_check_timer;
+
+void check_for_bios_corruption(void)
+{
+ int i;
+ int corruption = 0;
+
+ if (!memory_corruption_check)
+ return;
+
+ for (i = 0; i < num_scan_areas; i++) {
+ unsigned long *addr = __va(scan_areas[i].addr);
+ unsigned long size = scan_areas[i].size;
+
+ for (; size; addr++, size -= sizeof(unsigned long)) {
+ if (!*addr)
+ continue;
+ printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
+ addr, __pa(addr), *addr);
+ corruption = 1;
+ *addr = 0;
+ }
+ }
+
+ WARN(corruption, KERN_ERR "Memory corruption detected in low memory\n");
+}
+
+static void periodic_check_for_corruption(unsigned long data)
+{
+ check_for_bios_corruption();
+ mod_timer(&periodic_check_timer,
+ round_jiffies(jiffies + corruption_check_period*HZ));
+}
+
+void start_periodic_check_for_corruption(void)
+{
+ if (!memory_corruption_check || corruption_check_period == 0)
+ return;
+
+ printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n",
+ corruption_check_period);
+
+ init_timer(&periodic_check_timer);
+ periodic_check_timer.function = &periodic_check_for_corruption;
+ periodic_check_for_corruption(0);
+}
+#endif
+