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