kernel/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 #include <linux/memblock.h>
  10
  11 static u64 patterns[] __initdata = {
  12         /* The first entry has to be 0 to leave memtest with zeroed memory */
  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, phys_addr_t start_bad, phys_addr_t 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         memblock_reserve(start_bad, end_bad - start_bad);
  39 }
  40
  41 static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
  42 {
  43         u64 *p, *start, *end;
  44         phys_addr_t start_bad, last_bad;
  45         phys_addr_t 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, phys_addr_t start, phys_addr_t end)
  73 {
  74         u64 i;
  75         phys_addr_t this_start, this_end;
  76
  77         for_each_free_mem_range(i, NUMA_NO_NODE, &this_start, &this_end, NULL) {
  78                 this_start = clamp(this_start, start, end);
  79                 this_end = clamp(this_end, start, end);
  80                 if (this_start < this_end) {
  81                         printk(KERN_INFO "  %010llx - %010llx pattern %016llx\n",
  82                                (unsigned long long)this_start,
  83                                (unsigned long long)this_end,
  84                                (unsigned long long)cpu_to_be64(pattern));
  85                         memtest(pattern, this_start, this_end - this_start);
  86                 }
  87         }
  88 }
  89
  90 /* default is disabled */
  91 static int memtest_pattern __initdata;
  92
  93 static int __init parse_memtest(char *arg)
  94 {
  95         if (arg)
  96                 memtest_pattern = simple_strtoul(arg, NULL, 0);
  97         else
  98                 memtest_pattern = ARRAY_SIZE(patterns);
  99
 100         return 0;
 101 }
 102
 103 early_param("memtest", parse_memtest);
 104
 105 void __init early_memtest(phys_addr_t start, phys_addr_t end)
 106 {
 107         unsigned int i;
 108         unsigned int idx = 0;
 109
 110         if (!memtest_pattern)
 111                 return;
 112
 113         printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
 114         for (i = memtest_pattern-1; i < UINT_MAX; --i) {
 115                 idx = i % ARRAY_SIZE(patterns);
 116                 do_one_pass(patterns[idx], start, end);
 117         }
 118 }