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}