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 bool early_memtest_done;
   8 phys_addr_t early_memtest_bad_size;
   9
  10 static u64 patterns[] __initdata = {
  11         /* The first entry has to be 0 to leave memtest with zeroed memory */
  12         0,
  13         0xffffffffffffffffULL,
  14         0x5555555555555555ULL,
  15         0xaaaaaaaaaaaaaaaaULL,
  16         0x1111111111111111ULL,
  17         0x2222222222222222ULL,
  18         0x4444444444444444ULL,
  19         0x8888888888888888ULL,
  20         0x3333333333333333ULL,
  21         0x6666666666666666ULL,
  22         0x9999999999999999ULL,
  23         0xccccccccccccccccULL,
  24         0x7777777777777777ULL,
  25         0xbbbbbbbbbbbbbbbbULL,
  26         0xddddddddddddddddULL,
  27         0xeeeeeeeeeeeeeeeeULL,
  28         0x7a6c7258554e494cULL, /* yeah ;-) */
  29 };
  30
  31 static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
  32 {
  33         pr_info("  %016llx bad mem addr %pa - %pa reserved\n",
  34                 cpu_to_be64(pattern), &start_bad, &end_bad);
  35         memblock_reserve(start_bad, end_bad - start_bad);
  36         early_memtest_bad_size += (end_bad - start_bad);
  37 }
  38
  39 static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
  40 {
  41         u64 *p, *start, *end;
  42         phys_addr_t start_bad, last_bad;
  43         phys_addr_t start_phys_aligned;
  44         const size_t incr = sizeof(pattern);
  45
  46         start_phys_aligned = ALIGN(start_phys, incr);
  47         start = __va(start_phys_aligned);
  48         end = start + (size - (start_phys_aligned - start_phys)) / incr;
  49         start_bad = 0;
  50         last_bad = 0;
  51
  52         for (p = start; p < end; p++)
  53                 *p = pattern;
  54
  55         for (p = start; p < end; p++, start_phys_aligned += incr) {
  56                 if (*p == pattern)
  57                         continue;
  58                 if (start_phys_aligned == last_bad + incr) {
  59                         last_bad += incr;
  60                         continue;
  61                 }
  62                 if (start_bad)
  63                         reserve_bad_mem(pattern, start_bad, last_bad + incr);
  64                 start_bad = last_bad = start_phys_aligned;
  65         }
  66         if (start_bad)
  67                 reserve_bad_mem(pattern, start_bad, last_bad + incr);
  68
  69         early_memtest_done = true;
  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, MEMBLOCK_NONE, &this_start,
  78                                 &this_end, NULL) {
  79                 this_start = clamp(this_start, start, end);
  80                 this_end = clamp(this_end, start, end);
  81                 if (this_start < this_end) {
  82                         pr_info("  %pa - %pa pattern %016llx\n",
  83                                 &this_start, &this_end, cpu_to_be64(pattern));
  84                         memtest(pattern, this_start, this_end - this_start);
  85                 }
  86         }
  87 }
  88
  89 /* default is disabled */
  90 static unsigned int memtest_pattern __initdata;
  91
  92 static int __init parse_memtest(char *arg)
  93 {
  94         int ret = 0;
  95
  96         if (arg)
  97                 ret = kstrtouint(arg, 0, &memtest_pattern);
  98         else
  99                 memtest_pattern = ARRAY_SIZE(patterns);
 100
 101         return ret;
 102 }
 103
 104 early_param("memtest", parse_memtest);
 105
 106 void __init early_memtest(phys_addr_t start, phys_addr_t end)
 107 {
 108         unsigned int i;
 109         unsigned int idx = 0;
 110
 111         if (!memtest_pattern)
 112                 return;
 113
 114         pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
 115         for (i = memtest_pattern-1; i < UINT_MAX; --i) {
 116                 idx = i % ARRAY_SIZE(patterns);
 117                 do_one_pass(patterns[idx], start, end);
 118         }
 119 }