6784f7d0a5
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>
159 lines
3.6 KiB
C
159 lines
3.6 KiB
C
#include <linux/module.h>
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#include <linux/sched.h>
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#include <asm/e820.h>
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#include <asm/proto.h>
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/*
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* Some BIOSes seem to corrupt the low 64k of memory during events
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* like suspend/resume and unplugging an HDMI cable. Reserve all
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* remaining free memory in that area and fill it with a distinct
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* pattern.
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*/
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#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
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#define MAX_SCAN_AREAS 8
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static int __read_mostly memory_corruption_check = -1;
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static unsigned __read_mostly corruption_check_size = 64*1024;
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static unsigned __read_mostly corruption_check_period = 60; /* seconds */
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static struct e820entry scan_areas[MAX_SCAN_AREAS];
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static int num_scan_areas;
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static int set_corruption_check(char *arg)
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{
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char *end;
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memory_corruption_check = simple_strtol(arg, &end, 10);
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return (*end == 0) ? 0 : -EINVAL;
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}
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early_param("memory_corruption_check", set_corruption_check);
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static int set_corruption_check_period(char *arg)
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{
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char *end;
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corruption_check_period = simple_strtoul(arg, &end, 10);
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return (*end == 0) ? 0 : -EINVAL;
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}
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early_param("memory_corruption_check_period", set_corruption_check_period);
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static int set_corruption_check_size(char *arg)
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{
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char *end;
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unsigned size;
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size = memparse(arg, &end);
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if (*end == '\0')
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corruption_check_size = size;
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return (size == corruption_check_size) ? 0 : -EINVAL;
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}
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early_param("memory_corruption_check_size", set_corruption_check_size);
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void __init setup_bios_corruption_check(void)
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{
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u64 addr = PAGE_SIZE; /* assume first page is reserved anyway */
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if (memory_corruption_check == -1) {
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memory_corruption_check =
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#ifdef CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
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1
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#else
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0
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#endif
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;
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}
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if (corruption_check_size == 0)
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memory_corruption_check = 0;
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if (!memory_corruption_check)
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return;
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corruption_check_size = round_up(corruption_check_size, PAGE_SIZE);
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while (addr < corruption_check_size && num_scan_areas < MAX_SCAN_AREAS) {
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u64 size;
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addr = find_e820_area_size(addr, &size, PAGE_SIZE);
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if (addr == 0)
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break;
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if ((addr + size) > corruption_check_size)
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size = corruption_check_size - addr;
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if (size == 0)
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break;
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e820_update_range(addr, size, E820_RAM, E820_RESERVED);
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scan_areas[num_scan_areas].addr = addr;
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scan_areas[num_scan_areas].size = size;
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num_scan_areas++;
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/* Assume we've already mapped this early memory */
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memset(__va(addr), 0, size);
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addr += size;
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}
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printk(KERN_INFO "Scanning %d areas for low memory corruption\n",
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num_scan_areas);
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update_e820();
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}
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static struct timer_list periodic_check_timer;
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void check_for_bios_corruption(void)
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{
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int i;
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int corruption = 0;
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if (!memory_corruption_check)
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return;
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for (i = 0; i < num_scan_areas; i++) {
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unsigned long *addr = __va(scan_areas[i].addr);
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unsigned long size = scan_areas[i].size;
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for (; size; addr++, size -= sizeof(unsigned long)) {
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if (!*addr)
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continue;
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printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
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addr, __pa(addr), *addr);
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corruption = 1;
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*addr = 0;
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}
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}
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WARN(corruption, KERN_ERR "Memory corruption detected in low memory\n");
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}
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static void periodic_check_for_corruption(unsigned long data)
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{
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check_for_bios_corruption();
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mod_timer(&periodic_check_timer,
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round_jiffies(jiffies + corruption_check_period*HZ));
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}
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void start_periodic_check_for_corruption(void)
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{
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if (!memory_corruption_check || corruption_check_period == 0)
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return;
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printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n",
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corruption_check_period);
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init_timer(&periodic_check_timer);
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periodic_check_timer.function = &periodic_check_for_corruption;
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periodic_check_for_corruption(0);
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}
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#endif
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