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#include <linux/seq_file.h>
7
8static bool early_memtest_done;
9static phys_addr_t early_memtest_bad_size;
10
11static u64 patterns[] __initdata = {
12	/* The first entry has to be 0 to leave memtest with zeroed memory */
13	0,
14	0xffffffffffffffffULL,
15	0x5555555555555555ULL,
16	0xaaaaaaaaaaaaaaaaULL,
17	0x1111111111111111ULL,
18	0x2222222222222222ULL,
19	0x4444444444444444ULL,
20	0x8888888888888888ULL,
21	0x3333333333333333ULL,
22	0x6666666666666666ULL,
23	0x9999999999999999ULL,
24	0xccccccccccccccccULL,
25	0x7777777777777777ULL,
26	0xbbbbbbbbbbbbbbbbULL,
27	0xddddddddddddddddULL,
28	0xeeeeeeeeeeeeeeeeULL,
29	0x7a6c7258554e494cULL, /* yeah ;-) */
30};
31
32static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
33{
34	pr_info("  %016llx bad mem addr %pa - %pa reserved\n",
35		cpu_to_be64(pattern), &start_bad, &end_bad);
36	memblock_reserve(start_bad, end_bad - start_bad);
37	early_memtest_bad_size += (end_bad - start_bad);
38}
39
40static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
41{
42	u64 *p, *start, *end;
43	phys_addr_t start_bad, last_bad;
44	phys_addr_t start_phys_aligned;
45	const size_t incr = sizeof(pattern);
46
47	start_phys_aligned = ALIGN(start_phys, incr);
48	start = __va(start_phys_aligned);
49	end = start + (size - (start_phys_aligned - start_phys)) / incr;
50	start_bad = 0;
51	last_bad = 0;
52
53	for (p = start; p < end; p++)
54		WRITE_ONCE(*p, pattern);
55
56	for (p = start; p < end; p++, start_phys_aligned += incr) {
57		if (READ_ONCE(*p) == pattern)
58			continue;
59		if (start_phys_aligned == last_bad + incr) {
60			last_bad += incr;
61			continue;
62		}
63		if (start_bad)
64			reserve_bad_mem(pattern, start_bad, last_bad + incr);
65		start_bad = last_bad = start_phys_aligned;
66	}
67	if (start_bad)
68		reserve_bad_mem(pattern, start_bad, last_bad + incr);
69
70	early_memtest_done = true;
71}
72
73static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
74{
75	u64 i;
76	phys_addr_t this_start, this_end;
77
78	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &this_start,
79				&this_end, NULL) {
80		this_start = clamp(this_start, start, end);
81		this_end = clamp(this_end, start, end);
82		if (this_start < this_end) {
83			pr_info("  %pa - %pa pattern %016llx\n",
84				&this_start, &this_end, cpu_to_be64(pattern));
85			memtest(pattern, this_start, this_end - this_start);
86		}
87	}
88}
89
90/* default is disabled */
91static unsigned int memtest_pattern __initdata;
92
93static int __init parse_memtest(char *arg)
94{
95	int ret = 0;
96
97	if (arg)
98		ret = kstrtouint(arg, 0, &memtest_pattern);
99	else
100		memtest_pattern = ARRAY_SIZE(patterns);
101
102	return ret;
103}
104
105early_param("memtest", parse_memtest);
106
107void __init early_memtest(phys_addr_t start, phys_addr_t end)
108{
109	unsigned int i;
110	unsigned int idx = 0;
111
112	if (!memtest_pattern)
113		return;
114
115	pr_info("early_memtest: # of tests: %u\n", memtest_pattern);
116	for (i = memtest_pattern-1; i < UINT_MAX; --i) {
117		idx = i % ARRAY_SIZE(patterns);
118		do_one_pass(patterns[idx], start, end);
119	}
120}
121
122void memtest_report_meminfo(struct seq_file *m)
123{
124	unsigned long early_memtest_bad_size_kb;
125
126	if (!IS_ENABLED(CONFIG_PROC_FS))
127		return;
128
129	if (!early_memtest_done)
130		return;
131
132	early_memtest_bad_size_kb = early_memtest_bad_size >> 10;
133	if (early_memtest_bad_size && !early_memtest_bad_size_kb)
134		early_memtest_bad_size_kb = 1;
135	/* When 0 is reported, it means there actually was a successful test */
136	seq_printf(m, "EarlyMemtestBad:   %5lu kB\n", early_memtest_bad_size_kb);
137}
138