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 void __init memtest(unsigned long start_phys, unsigned long size,
  13                                  unsigned pattern)
  14 {
  15         unsigned long i;
  16         unsigned long *start;
  17         unsigned long start_bad;
  18         unsigned long last_bad;
  19         unsigned long val;
  20         unsigned long start_phys_aligned;
  21         unsigned long count;
  22         unsigned long incr;
  23
  24         switch (pattern) {
  25         case 0:
  26                 val = 0UL;
  27                 break;
  28         case 1:
  29                 val = -1UL;
  30                 break;
  31         case 2:
  32 #ifdef CONFIG_X86_64
  33                 val = 0x5555555555555555UL;
  34 #else
  35                 val = 0x55555555UL;
  36 #endif
  37                 break;
  38         case 3:
  39 #ifdef CONFIG_X86_64
  40                 val = 0xaaaaaaaaaaaaaaaaUL;
  41 #else
  42                 val = 0xaaaaaaaaUL;
  43 #endif
  44                 break;
  45         default:
  46                 return;
  47         }
  48
  49         incr = sizeof(unsigned long);
  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] = val;
  58         for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
  59                 if (*start != val) {
  60                         if (start_phys_aligned == last_bad + incr) {
  61                                 last_bad += incr;
  62                         } else {
  63                                 if (start_bad) {
  64                                         printk(KERN_CONT "\n  %010lx bad mem addr %010lx - %010lx reserved",
  65                                                 val, start_bad, last_bad + incr);
  66                                         reserve_early(start_bad, last_bad - start_bad, "BAD RAM");
  67                                 }
  68                                 start_bad = last_bad = start_phys_aligned;
  69                         }
  70                 }
  71         }
  72         if (start_bad) {
  73                 printk(KERN_CONT "\n  %016lx bad mem addr %010lx - %010lx reserved",
  74                         val, start_bad, last_bad + incr);
  75                 reserve_early(start_bad, last_bad - start_bad, "BAD RAM");
  76         }
  77
  78 }
  79
  80 /* default is disabled */
  81 static int memtest_pattern __initdata;
  82
  83 static int __init parse_memtest(char *arg)
  84 {
  85         if (arg)
  86                 memtest_pattern = simple_strtoul(arg, NULL, 0);
  87         return 0;
  88 }
  89
  90 early_param("memtest", parse_memtest);
  91
  92 void __init early_memtest(unsigned long start, unsigned long end)
  93 {
  94         u64 t_start, t_size;
  95         unsigned pattern;
  96
  97         if (!memtest_pattern)
  98                 return;
  99
 100         printk(KERN_INFO "early_memtest: pattern num %d", memtest_pattern);
 101         for (pattern = 0; pattern < memtest_pattern; pattern++) {
 102                 t_start = start;
 103                 t_size = 0;
 104                 while (t_start < end) {
 105                         t_start = find_e820_area_size(t_start, &t_size, 1);
 106
 107                         /* done ? */
 108                         if (t_start >= end)
 109                                 break;
 110                         if (t_start + t_size > end)
 111                                 t_size = end - t_start;
 112
 113                         printk(KERN_CONT "\n  %010llx - %010llx pattern %d",
 114                                 (unsigned long long)t_start,
 115                                 (unsigned long long)t_start + t_size, pattern);
 116
 117                         memtest(t_start, t_size, pattern);
 118
 119                         t_start += t_size;
 120                 }
 121         }
 122         printk(KERN_CONT "\n");
 123 }