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Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig3
-rw-r--r--arch/x86/kernel/setup.c87
-rw-r--r--arch/x86/mm/fault.c2
3 files changed, 92 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ed92864d132..1bb52e2ca02 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -201,6 +201,9 @@ config X86_TRAMPOLINE
depends on X86_SMP || (X86_VOYAGER && SMP) || (64BIT && ACPI_SLEEP)
default y
+config X86_CHECK_BIOS_CORRUPTION
+ def_bool y
+
config KTIME_SCALAR
def_bool X86_32
source "init/Kconfig"
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 362d4e7f2d3..ee89ebc5aab 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -579,6 +579,89 @@ static struct x86_quirks default_x86_quirks __initdata;
struct x86_quirks *x86_quirks __initdata = &default_x86_quirks;
/*
+ * 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 struct e820entry scan_areas[MAX_SCAN_AREAS];
+static int num_scan_areas;
+
+static void __init setup_bios_corruption_check(void)
+{
+ u64 addr = PAGE_SIZE; /* assume first page is reserved anyway */
+
+ while(addr < 0x10000 && num_scan_areas < MAX_SCAN_AREAS) {
+ u64 size;
+ addr = find_e820_area_size(addr, &size, PAGE_SIZE);
+
+ if (addr == 0)
+ break;
+
+ if ((addr + size) > 0x10000)
+ size = 0x10000 - 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 BIOS corruption\n",
+ num_scan_areas);
+ update_e820();
+}
+
+static int __read_mostly bios_corruption_check = 1;
+
+void check_for_bios_corruption(void)
+{
+ int i;
+ int corruption = 0;
+
+ if (!bios_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;
+ }
+ }
+
+ if (corruption)
+ dump_stack();
+}
+
+static int set_bios_corruption_check(char *arg)
+{
+ char *end;
+
+ bios_corruption_check = simple_strtol(arg, &end, 10);
+
+ return (*end == 0) ? 0 : -EINVAL;
+}
+early_param("bios_corruption_check", set_bios_corruption_check);
+#endif
+
+/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
* for initialization. Note, the efi init code path is determined by the
@@ -750,6 +833,10 @@ void __init setup_arch(char **cmdline_p)
high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
#endif
+#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
+ setup_bios_corruption_check();
+#endif
+
/* max_pfn_mapped is updated here */
max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
max_pfn_mapped = max_low_pfn_mapped;
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 455f3fe67b4..5140bdf0302 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -848,6 +848,8 @@ 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