This source file includes following definitions.
- set_corruption_check
- set_corruption_check_period
- set_corruption_check_size
- setup_bios_corruption_check
- check_for_bios_corruption
- check_corruption
- start_periodic_check_for_corruption
1
2
3 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
4
5 #include <linux/init.h>
6 #include <linux/sched.h>
7 #include <linux/kthread.h>
8 #include <linux/workqueue.h>
9 #include <linux/memblock.h>
10
11 #include <asm/proto.h>
12 #include <asm/setup.h>
13
14
15
16
17
18
19
20 #define MAX_SCAN_AREAS 8
21
22 static int __read_mostly memory_corruption_check = -1;
23
24 static unsigned __read_mostly corruption_check_size = 64*1024;
25 static unsigned __read_mostly corruption_check_period = 60;
26
27 static struct scan_area {
28 u64 addr;
29 u64 size;
30 } scan_areas[MAX_SCAN_AREAS];
31 static int num_scan_areas;
32
33 static __init int set_corruption_check(char *arg)
34 {
35 ssize_t ret;
36 unsigned long val;
37
38 if (!arg) {
39 pr_err("memory_corruption_check config string not provided\n");
40 return -EINVAL;
41 }
42
43 ret = kstrtoul(arg, 10, &val);
44 if (ret)
45 return ret;
46
47 memory_corruption_check = val;
48
49 return 0;
50 }
51 early_param("memory_corruption_check", set_corruption_check);
52
53 static __init int set_corruption_check_period(char *arg)
54 {
55 ssize_t ret;
56 unsigned long val;
57
58 if (!arg) {
59 pr_err("memory_corruption_check_period config string not provided\n");
60 return -EINVAL;
61 }
62
63 ret = kstrtoul(arg, 10, &val);
64 if (ret)
65 return ret;
66
67 corruption_check_period = val;
68 return 0;
69 }
70 early_param("memory_corruption_check_period", set_corruption_check_period);
71
72 static __init int set_corruption_check_size(char *arg)
73 {
74 char *end;
75 unsigned size;
76
77 if (!arg) {
78 pr_err("memory_corruption_check_size config string not provided\n");
79 return -EINVAL;
80 }
81
82 size = memparse(arg, &end);
83
84 if (*end == '\0')
85 corruption_check_size = size;
86
87 return (size == corruption_check_size) ? 0 : -EINVAL;
88 }
89 early_param("memory_corruption_check_size", set_corruption_check_size);
90
91
92 void __init setup_bios_corruption_check(void)
93 {
94 phys_addr_t start, end;
95 u64 i;
96
97 if (memory_corruption_check == -1) {
98 memory_corruption_check =
99 #ifdef CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
100 1
101 #else
102 0
103 #endif
104 ;
105 }
106
107 if (corruption_check_size == 0)
108 memory_corruption_check = 0;
109
110 if (!memory_corruption_check)
111 return;
112
113 corruption_check_size = round_up(corruption_check_size, PAGE_SIZE);
114
115 for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end,
116 NULL) {
117 start = clamp_t(phys_addr_t, round_up(start, PAGE_SIZE),
118 PAGE_SIZE, corruption_check_size);
119 end = clamp_t(phys_addr_t, round_down(end, PAGE_SIZE),
120 PAGE_SIZE, corruption_check_size);
121 if (start >= end)
122 continue;
123
124 memblock_reserve(start, end - start);
125 scan_areas[num_scan_areas].addr = start;
126 scan_areas[num_scan_areas].size = end - start;
127
128
129 memset(__va(start), 0, end - start);
130
131 if (++num_scan_areas >= MAX_SCAN_AREAS)
132 break;
133 }
134
135 if (num_scan_areas)
136 pr_info("Scanning %d areas for low memory corruption\n", num_scan_areas);
137 }
138
139
140 static void check_for_bios_corruption(void)
141 {
142 int i;
143 int corruption = 0;
144
145 if (!memory_corruption_check)
146 return;
147
148 for (i = 0; i < num_scan_areas; i++) {
149 unsigned long *addr = __va(scan_areas[i].addr);
150 unsigned long size = scan_areas[i].size;
151
152 for (; size; addr++, size -= sizeof(unsigned long)) {
153 if (!*addr)
154 continue;
155 pr_err("Corrupted low memory at %p (%lx phys) = %08lx\n", addr, __pa(addr), *addr);
156 corruption = 1;
157 *addr = 0;
158 }
159 }
160
161 WARN_ONCE(corruption, KERN_ERR "Memory corruption detected in low memory\n");
162 }
163
164 static void check_corruption(struct work_struct *dummy);
165 static DECLARE_DELAYED_WORK(bios_check_work, check_corruption);
166
167 static void check_corruption(struct work_struct *dummy)
168 {
169 check_for_bios_corruption();
170 schedule_delayed_work(&bios_check_work,
171 round_jiffies_relative(corruption_check_period*HZ));
172 }
173
174 static int start_periodic_check_for_corruption(void)
175 {
176 if (!num_scan_areas || !memory_corruption_check || corruption_check_period == 0)
177 return 0;
178
179 pr_info("Scanning for low memory corruption every %d seconds\n", corruption_check_period);
180
181
182 schedule_delayed_work(&bios_check_work, 0);
183
184 return 0;
185 }
186 device_initcall(start_periodic_check_for_corruption);
187