diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index df48af505d15466b9f2312cda9feb7135ad5155c..6a2629d00598989182d523f1701de6beb90c7401 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -360,11 +360,6 @@ and is between 256 and 4096 characters. It is defined in the file
Format: <io>,<irq>,<mode>
See header of drivers/net/hamradio/baycom_ser_hdx.c.
- bios_corruption_check=0/1 [X86]
- Some BIOSes seem to corrupt the first 64k of memory
- when doing things like suspend/resume. Setting this
- option will scan the memory looking for corruption.
-
boot_delay= Milliseconds to delay each printk during boot.
Values larger than 10 seconds (10000) are changed to
no delay (0).
@@ -1233,6 +1228,29 @@ and is between 256 and 4096 characters. It is defined in the file
or
memmap=0x10000$0x18690000
+ memory_corruption_check=0/1 [X86]
+ Some BIOSes seem to corrupt the first 64k of
+ memory when doing things like suspend/resume.
+ Setting this option will scan the memory
+ looking for corruption. Enabling this will
+ both detect corruption and prevent the kernel
+ from using the memory being corrupted.
+ However, its intended as a diagnostic tool; if
+ repeatable BIOS-originated corruption always
+ affects the same memory, you can use memmap=
+ to prevent the kernel from using that memory.
+
+ memory_corruption_check_size=size [X86]
+ By default it checks for corruption in the low
+ 64k, making this memory unavailable for normal
+ use. Use this parameter to scan for
+ corruption in more or less memory.
+
+ memory_corruption_check_period=seconds [X86]
+ By default it checks for corruption every 60
+ seconds. Use this parameter to check at some
+ other rate. 0 disables periodic checking.
+
memtest= [KNL,X86] Enable memtest
Format: <integer>
range: 0,4 : pattern number
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1bb52e2ca02e710c3604d7531c4931d14a08afcb..cbee4199689ce4e94c4418216aca57f7290d682e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -201,9 +201,6 @@ 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"
@@ -1062,6 +1059,29 @@ config HIGHPTE
low memory. Setting this option will put user-space page table
entries in high memory.
+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
+ configuration, it is disabled at runtime. Enable it by
+ setting "memory_corruption_check=1" on the kernel command
+ line. By default it scans the low 64k of memory every 60
+ seconds; see the memory_corruption_check_size and
+ memory_corruption_check_period parameters in
+ Documentation/kernel-parameters.txt to adjust this.
+
+ When enabled with the default parameters, this option has
+ almost no overhead, as it reserves a relatively small amount
+ of memory and scans it infrequently. It both detects corruption
+ and prevents it from affecting the running system.
+
+ It is, however, intended as a diagnostic tool; if repeatable
+ BIOS-originated corruption always affects the same memory,
+ you can use memmap= to prevent the kernel from using that
+ memory.
+
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 c239b378097395d3270eab23d64a08b92474375f..27ae912888555b559caeeaad02bc98a92ee38ee0 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -586,22 +586,71 @@ 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 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);
+
+
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) {
+ 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) > 0x10000)
- size = 0x10000 - addr;
+ if ((addr + size) > corruption_check_size)
+ size = corruption_check_size - addr;
if (size == 0)
break;
@@ -617,12 +666,11 @@ static void __init setup_bios_corruption_check(void)
addr += size;
}
- printk(KERN_INFO "scanning %d areas for BIOS corruption\n",
+ printk(KERN_INFO "Scanning %d areas for low memory corruption\n",
num_scan_areas);
update_e820();
}
-static int __read_mostly bios_corruption_check = 1;
static struct timer_list periodic_check_timer;
void check_for_bios_corruption(void)
@@ -630,7 +678,7 @@ void check_for_bios_corruption(void)
int i;
int corruption = 0;
- if (!bios_corruption_check)
+ if (!memory_corruption_check)
return;
for(i = 0; i < num_scan_areas; i++) {
@@ -647,35 +695,27 @@ void check_for_bios_corruption(void)
}
}
- if (corruption)
- dump_stack();
+ 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, jiffies + 60*HZ);
+ mod_timer(&periodic_check_timer, jiffies + corruption_check_period*HZ);
}
void start_periodic_check_for_corruption(void)
{
- if (!bios_corruption_check)
+ 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);
}
-
-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
/*