xref: /openbmc/linux/mm/memtest.c (revision f1d93b2a)
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 
8 static bool early_memtest_done;
9 static phys_addr_t early_memtest_bad_size;
10 
11 static 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 
reserve_bad_mem(u64 pattern,phys_addr_t start_bad,phys_addr_t end_bad)32 static 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 
memtest(u64 pattern,phys_addr_t start_phys,phys_addr_t size)40 static 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 
do_one_pass(u64 pattern,phys_addr_t start,phys_addr_t end)73 static 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 */
91 static unsigned int memtest_pattern __initdata;
92 
parse_memtest(char * arg)93 static 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 
105 early_param("memtest", parse_memtest);
106 
early_memtest(phys_addr_t start,phys_addr_t end)107 void __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 
memtest_report_meminfo(struct seq_file * m)122 void 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