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 };
  18
  19 static void __init reserve_bad_mem(u64 pattern, unsigned long start_bad,
  20                             unsigned long end_bad)
  21 {
  22         printk(KERN_CONT "\n  %016llx bad mem addr "
  23                "%010lx - %010lx reserved",
  24                (unsigned long long) pattern, start_bad, end_bad);
  25         reserve_early(start_bad, end_bad, "BAD RAM");
  26 }
  27
  28 static void __init memtest(unsigned long start_phys, unsigned long size,
  29                            u64 pattern)
  30 {
  31         unsigned long i;
  32         u64 *start;
  33         unsigned long start_bad;
  34         unsigned long last_bad;
  35         unsigned long start_phys_aligned;
  36         unsigned long count;
  37         unsigned long incr;
  38
  39         incr = sizeof(pattern);
  40         start_phys_aligned = ALIGN(start_phys, incr);
  41         count = (size - (start_phys_aligned - start_phys))/incr;
  42         start = __va(start_phys_aligned);
  43         start_bad = 0;
  44         last_bad = 0;
  45
  46         for (i = 0; i < count; i++)
  47                 start[i] = pattern;
  48         for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
  49                 if (*start == pattern)
  50                         continue;
  51                 if (start_phys_aligned == last_bad + incr) {
  52                         last_bad += incr;
  53                         continue;
  54                 }
  55                 if (start_bad)
  56                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  57                 start_bad = last_bad = start_phys_aligned;
  58         }
  59         if (start_bad)
  60                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  61 }
  62
  63 /* default is disabled */
  64 static int memtest_pattern __initdata;
  65
  66 static int __init parse_memtest(char *arg)
  67 {
  68         if (arg)
  69                 memtest_pattern = simple_strtoul(arg, NULL, 0);
  70         return 0;
  71 }
  72
  73 early_param("memtest", parse_memtest);
  74
  75 void __init early_memtest(unsigned long start, unsigned long end)
  76 {
  77         u64 t_start, t_size;
  78         unsigned int i;
  79         u64 pattern;
  80
  81         if (!memtest_pattern)
  82                 return;
  83
  84         printk(KERN_INFO "early_memtest: pattern num %d", memtest_pattern);
  85         for (i = 0; i < memtest_pattern; i++) {
  86                 unsigned int idx = i % ARRAY_SIZE(patterns);
  87                 pattern = patterns[idx];
  88                 t_start = start;
  89                 t_size = 0;
  90                 while (t_start < end) {
  91                         t_start = find_e820_area_size(t_start, &t_size, 1);
  92
  93                         /* done ? */
  94                         if (t_start >= end)
  95                                 break;
  96                         if (t_start + t_size > end)
  97                                 t_size = end - t_start;
  98
  99                         printk(KERN_CONT "\n  %010llx - %010llx pattern %d",
 100                                (unsigned long long)t_start,
 101                                (unsigned long long)t_start + t_size, idx);
 102
 103                         memtest(t_start, t_size, pattern);
 104
 105                         t_start += t_size;
 106                 }
 107         }
 108         printk(KERN_CONT "\n");
 109 }