LXR linux/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
   7static 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
  28static 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
  35static 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
  66static 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 */
  84static unsigned int memtest_pattern __initdata;
  85
  86static 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
  98early_param("memtest", parse_memtest);
  99
 100void __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}
 114