LXR linux/mm/memtest.c

   1#include <linux/kernel.h>
   2#include <linux/types.h>
   3#include <linux/init.h>
   4#include <linux/memblock.h>
   5
   6static 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
  27static 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
  34static 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
  65static 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 */
  83static unsigned int memtest_pattern __initdata;
  84
  85static 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
  97early_param("memtest", parse_memtest);
  98
  99void __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}
 113