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x86: corruption check: move the corruption checks into their own file
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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>
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Arjan van de Ven authored and Ingo Molnar committed Oct 27, 2008
1 parent 04d2aac commit 6784f7d
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Showing 4 changed files with 163 additions and 152 deletions.
4 changes: 4 additions & 0 deletions arch/x86/include/asm/setup.h
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Expand Up @@ -8,6 +8,10 @@
/* Interrupt control for vSMPowered x86_64 systems */
void vsmp_init(void);


void setup_bios_corruption_check(void);


#ifdef CONFIG_X86_VISWS
extern void visws_early_detect(void);
extern int is_visws_box(void);
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1 change: 1 addition & 0 deletions arch/x86/kernel/Makefile
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Expand Up @@ -35,6 +35,7 @@ obj-y += bootflag.o e820.o
obj-y += pci-dma.o quirks.o i8237.o topology.o kdebugfs.o
obj-y += alternative.o i8253.o pci-nommu.o
obj-y += tsc.o io_delay.o rtc.o
obj-y += check.o

obj-$(CONFIG_X86_TRAMPOLINE) += trampoline.o
obj-y += process.o
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158 changes: 158 additions & 0 deletions arch/x86/kernel/check.c
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@@ -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

152 changes: 0 additions & 152 deletions arch/x86/kernel/setup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -587,158 +587,6 @@ 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 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);


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;

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

static int __init dmi_low_memory_corruption(const struct dmi_system_id *d)
{
printk(KERN_NOTICE
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