mm/memtest.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kernel.h>
   3 #include <linux/types.h>
   4 #include <linux/init.h>
   5 #include <linux/memblock.h>
   6
   7 static u64 patterns[] __initdata = {
   8         /* The first entry has to be 0 to leave memtest with zeroed memory */
   9         0,
  10         0xffffffffffffffffULL,
  11         0x5555555555555555ULL,
  12         0xaaaaaaaaaaaaaaaaULL,
  13         0x1111111111111111ULL,
  14         0x2222222222222222ULL,
  15         0x4444444444444444ULL,
  16         0x8888888888888888ULL,
  17         0x3333333333333333ULL,
  18         0x6666666666666666ULL,
  19         0x9999999999999999ULL,
  20         0xccccccccccccccccULL,
  21         0x7777777777777777ULL,
  22         0xbbbbbbbbbbbbbbbbULL,
  23         0xddddddddddddddddULL,
  24         0xeeeeeeeeeeeeeeeeULL,
  25         0x7a6c7258554e494cULL, /* yeah ;-) */
  26 };
  27
  28 static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
  29 {
  30         pr_info("  %016llx bad mem addr %pa - %pa reserved\n",
  31                 cpu_to_be64(pattern), &start_bad, &end_bad);
  32         memblock_reserve(start_bad, end_bad - start_bad);
  33 }
  34
  35 static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
  36 {
  37         u64 *p, *start, *end;
  38         phys_addr_t start_bad, last_bad;
  39         phys_addr_t start_phys_aligned;
  40         const size_t incr = sizeof(pattern);
  41
  42         start_phys_aligned = ALIGN(start_phys, incr);
  43         start = __va(start_phys_aligned);
  44         end = start + (size - (start_phys_aligned - start_phys)) / incr;
  45         start_bad = 0;
  46         last_bad = 0;
  47
  48         for (p = start; p < end; p++)
  49                 *p = pattern;
  50
  51         for (p = start; p < end; p++, start_phys_aligned += incr) {
  52                 if (*p == pattern)
  53                         continue;
  54                 if (start_phys_aligned == last_bad + incr) {
  55                         last_bad += incr;
  56                         continue;
  57                 }
  58                 if (start_bad)
  59                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  60                 start_bad = last_bad = start_phys_aligned;
  61         }
  62         if (start_bad)
  63                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  64 }
  65
  66 static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
  67 {
  68         u64 i;
  69         phys_addr_t this_start, this_end;
  70
  71         for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
  72                                 &this_end, NULL) {
  73                 this_start = clamp(this_start, start, end);
  74                 this_end = clamp(this_end, start, end);
  75                 if (this_start < this_end) {
  76                         pr_info("  %pa - %pa pattern %016llx\n",
  77                                 &this_start, &this_end, cpu_to_be64(pattern));
  78                         memtest(pattern, this_start, this_end - this_start);
  79                 }
  80         }
  81 }
  82
  83 /* default is disabled */
  84 static unsigned int memtest_pattern __initdata;
  85
  86 static int __init parse_memtest(char *arg)
  87 {
  88         int ret = 0;
  89
  90         if (arg)
  91                 ret = kstrtouint(arg, 0, &memtest_pattern);
  92         else
  93                 memtest_pattern = ARRAY_SIZE(patterns);
  94
  95         return ret;
  96 }
  97
  98 early_param("memtest", parse_memtest);
  99
 100 void __init early_memtest(phys_addr_t start, phys_addr_t end)
 101 {
 102         unsigned int i;
 103         unsigned int idx = 0;
 104
 105         if (!memtest_pattern)
 106                 return;
 107
 108         pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
 109         for (i = memtest_pattern-1; i < UINT_MAX; --i) {
 110                 idx = i % ARRAY_SIZE(patterns);
 111                 do_one_pass(patterns[idx], start, end);
 112         }
 113 }