arch/x86/mm/memtest.c

   1 #include <linux/kernel.h>
   2 #include <linux/errno.h>
   3 #include <linux/string.h>
   4 #include <linux/types.h>
   5 #include <linux/mm.h>
   6 #include <linux/smp.h>
   7 #include <linux/init.h>
   8 #include <linux/pfn.h>
   9
  10 #include <asm/e820.h>
  11
  12 static u64 patterns[] __initdata = {
  13         0,
  14         0xffffffffffffffffULL,
  15         0x5555555555555555ULL,
  16         0xaaaaaaaaaaaaaaaaULL,
  17         0x1111111111111111ULL,
  18         0x2222222222222222ULL,
  19         0x4444444444444444ULL,
  20         0x8888888888888888ULL,
  21         0x3333333333333333ULL,
  22         0x6666666666666666ULL,
  23         0x9999999999999999ULL,
  24         0xccccccccccccccccULL,
  25         0x7777777777777777ULL,
  26         0xbbbbbbbbbbbbbbbbULL,
  27         0xddddddddddddddddULL,
  28         0xeeeeeeeeeeeeeeeeULL,
  29         0x7a6c7258554e494cULL, /* yeah ;-) */
  30 };
  31
  32 static void __init reserve_bad_mem(u64 pattern, u64 start_bad, u64 end_bad)
  33 {
  34         printk(KERN_INFO "  %016llx bad mem addr %010llx - %010llx reserved\n",
  35                (unsigned long long) pattern,
  36                (unsigned long long) start_bad,
  37                (unsigned long long) end_bad);
  38         reserve_early(start_bad, end_bad, "BAD RAM");
  39 }
  40
  41 static void __init memtest(u64 pattern, u64 start_phys, u64 size)
  42 {
  43         u64 *p, *start, *end;
  44         u64 start_bad, last_bad;
  45         u64 start_phys_aligned;
  46         const size_t incr = sizeof(pattern);
  47
  48         start_phys_aligned = ALIGN(start_phys, incr);
  49         start = __va(start_phys_aligned);
  50         end = start + (size - (start_phys_aligned - start_phys)) / incr;
  51         start_bad = 0;
  52         last_bad = 0;
  53
  54         for (p = start; p < end; p++)
  55                 *p = pattern;
  56
  57         for (p = start; p < end; p++, start_phys_aligned += incr) {
  58                 if (*p == pattern)
  59                         continue;
  60                 if (start_phys_aligned == last_bad + incr) {
  61                         last_bad += incr;
  62                         continue;
  63                 }
  64                 if (start_bad)
  65                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  66                 start_bad = last_bad = start_phys_aligned;
  67         }
  68         if (start_bad)
  69                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  70 }
  71
  72 static void __init do_one_pass(u64 pattern, u64 start, u64 end)
  73 {
  74         u64 size = 0;
  75
  76         while (start < end) {
  77                 start = find_e820_area_size(start, &size, 1);
  78
  79                 /* done ? */
  80                 if (start >= end)
  81                         break;
  82                 if (start + size > end)
  83                         size = end - start;
  84
  85                 printk(KERN_INFO "  %010llx - %010llx pattern %016llx\n",
  86                        (unsigned long long) start,
  87                        (unsigned long long) start + size,
  88                        (unsigned long long) cpu_to_be64(pattern));
  89                 memtest(pattern, start, size);
  90
  91                 start += size;
  92         }
  93 }
  94
  95 /* default is disabled */
  96 static int memtest_pattern __initdata;
  97
  98 static int __init parse_memtest(char *arg)
  99 {
 100         if (arg)
 101                 memtest_pattern = simple_strtoul(arg, NULL, 0);
 102         else
 103                 memtest_pattern = ARRAY_SIZE(patterns);
 104
 105         return 0;
 106 }
 107
 108 early_param("memtest", parse_memtest);
 109
 110 void __init early_memtest(unsigned long start, unsigned long end)
 111 {
 112         unsigned int i;
 113         unsigned int idx = 0;
 114
 115         if (!memtest_pattern)
 116                 return;
 117
 118         printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
 119         for (i = 0; i < memtest_pattern; i++) {
 120                 idx = i % ARRAY_SIZE(patterns);
 121                 do_one_pass(patterns[idx], start, end);
 122         }
 123
 124         if (idx > 0) {
 125                 printk(KERN_INFO "early_memtest: wipe out "
 126                        "test pattern from memory\n");
 127                 /* additional test with pattern 0 will do this */
 128                 do_one_pass(0, start, end);
 129         }
 130 }