mm/memtest.c

   1 #include <linux/kernel.h>
   2 #include <linux/types.h>
   3 #include <linux/init.h>
   4 #include <linux/memblock.h>
   5
   6 static u64 patterns[] __initdata = {
   7         /* The first entry has to be 0 to leave memtest with zeroed memory */
   8         0,
   9         0xffffffffffffffffULL,
  10         0x5555555555555555ULL,
  11         0xaaaaaaaaaaaaaaaaULL,
  12         0x1111111111111111ULL,
  13         0x2222222222222222ULL,
  14         0x4444444444444444ULL,
  15         0x8888888888888888ULL,
  16         0x3333333333333333ULL,
  17         0x6666666666666666ULL,
  18         0x9999999999999999ULL,
  19         0xccccccccccccccccULL,
  20         0x7777777777777777ULL,
  21         0xbbbbbbbbbbbbbbbbULL,
  22         0xddddddddddddddddULL,
  23         0xeeeeeeeeeeeeeeeeULL,
  24         0x7a6c7258554e494cULL, /* yeah ;-) */
  25 };
  26
  27 static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
  28 {
  29         pr_info("  %016llx bad mem addr %pa - %pa reserved\n",
  30                 cpu_to_be64(pattern), &start_bad, &end_bad);
  31         memblock_reserve(start_bad, end_bad - start_bad);
  32 }
  33
  34 static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
  35 {
  36         u64 *p, *start, *end;
  37         phys_addr_t start_bad, last_bad;
  38         phys_addr_t start_phys_aligned;
  39         const size_t incr = sizeof(pattern);
  40
  41         start_phys_aligned = ALIGN(start_phys, incr);
  42         start = __va(start_phys_aligned);
  43         end = start + (size - (start_phys_aligned - start_phys)) / incr;
  44         start_bad = 0;
  45         last_bad = 0;
  46
  47         for (p = start; p < end; p++)
  48                 *p = pattern;
  49
  50         for (p = start; p < end; p++, start_phys_aligned += incr) {
  51                 if (*p == pattern)
  52                         continue;
  53                 if (start_phys_aligned == last_bad + incr) {
  54                         last_bad += incr;
  55                         continue;
  56                 }
  57                 if (start_bad)
  58                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  59                 start_bad = last_bad = start_phys_aligned;
  60         }
  61         if (start_bad)
  62                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  63 }
  64
  65 static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
  66 {
  67         u64 i;
  68         phys_addr_t this_start, this_end;
  69
  70         for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
  71                                 &this_end, NULL) {
  72                 this_start = clamp(this_start, start, end);
  73                 this_end = clamp(this_end, start, end);
  74                 if (this_start < this_end) {
  75                         pr_info("  %pa - %pa pattern %016llx\n",
  76                                 &this_start, &this_end, cpu_to_be64(pattern));
  77                         memtest(pattern, this_start, this_end - this_start);
  78                 }
  79         }
  80 }
  81
  82 /* default is disabled */
  83 static unsigned int memtest_pattern __initdata;
  84
  85 static int __init parse_memtest(char *arg)
  86 {
  87         int ret = 0;
  88
  89         if (arg)
  90                 ret = kstrtouint(arg, 0, &memtest_pattern);
  91         else
  92                 memtest_pattern = ARRAY_SIZE(patterns);
  93
  94         return ret;
  95 }
  96
  97 early_param("memtest", parse_memtest);
  98
  99 void __init early_memtest(phys_addr_t start, phys_addr_t end)
 100 {
 101         unsigned int i;
 102         unsigned int idx = 0;
 103
 104         if (!memtest_pattern)
 105                 return;
 106
 107         pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
 108         for (i = memtest_pattern-1; i < UINT_MAX; --i) {
 109                 idx = i % ARRAY_SIZE(patterns);
 110                 do_one_pass(patterns[idx], start, end);
 111         }
 112 }