xref: /kernel/linux/linux-5.10/mm/memtest.c (revision 8c2ecf20) 
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