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 i, count;
  44         u64 *start;
  45         u64 start_bad, last_bad;
  46         u64 start_phys_aligned;
  47         size_t incr;
  48
  49         incr = sizeof(pattern);
  50         start_phys_aligned = ALIGN(start_phys, incr);
  51         count = (size - (start_phys_aligned - start_phys))/incr;
  52         start = __va(start_phys_aligned);
  53         start_bad = 0;
  54         last_bad = 0;
  55
  56         for (i = 0; i < count; i++)
  57                 start[i] = pattern;
  58         for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
  59                 if (*start == pattern)
  60                         continue;
  61                 if (start_phys_aligned == last_bad + incr) {
  62                         last_bad += incr;
  63                         continue;
  64                 }
  65                 if (start_bad)
  66                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  67                 start_bad = last_bad = start_phys_aligned;
  68         }
  69         if (start_bad)
  70                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  71 }
  72
  73 static void __init do_one_pass(u64 pattern, u64 start, u64 end)
  74 {
  75         u64 size = 0;
  76
  77         while (start < end) {
  78                 start = find_e820_area_size(start, &size, 1);
  79
  80                 /* done ? */
  81                 if (start >= end)
  82                         break;
  83                 if (start + size > end)
  84                         size = end - start;
  85
  86                 printk(KERN_INFO "  %010llx - %010llx pattern %016llx\n",
  87                        (unsigned long long) start,
  88                        (unsigned long long) start + size,
  89                        (unsigned long long) cpu_to_be64(pattern));
  90                 memtest(pattern, start, size);
  91
  92                 start += size;
  93         }
  94 }
  95
  96 /* default is disabled */
  97 static int memtest_pattern __initdata;
  98
  99 static int __init parse_memtest(char *arg)
 100 {
 101         if (arg)
 102                 memtest_pattern = simple_strtoul(arg, NULL, 0);
 103         return 0;
 104 }
 105
 106 early_param("memtest", parse_memtest);
 107
 108 void __init early_memtest(unsigned long start, unsigned long end)
 109 {
 110         unsigned int i;
 111         unsigned int idx = 0;
 112
 113         if (!memtest_pattern)
 114                 return;
 115
 116         printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
 117         for (i = 0; i < memtest_pattern; i++) {
 118                 idx = i % ARRAY_SIZE(patterns);
 119                 do_one_pass(patterns[idx], start, end);
 120         }
 121
 122         if (idx > 0) {
 123                 printk(KERN_INFO "early_memtest: wipe out "
 124                        "test pattern from memory\n");
 125                 /* additional test with pattern 0 will do this */
 126                 do_one_pass(0, start, end);
 127         }
 128 }