1 #include <linux/kernel.h>
2 #include <linux/errno.h>
3 #include <linux/string.h>
4 #include <linux/types.h>
7 #include <linux/init.h>
12 static u64 patterns[] __initdata = {
14 0xffffffffffffffffULL,
15 0x5555555555555555ULL,
16 0xaaaaaaaaaaaaaaaaULL,
19 static void __init reserve_bad_mem(u64 pattern, u64 start_bad, u64 end_bad)
21 printk(KERN_INFO " %016llx bad mem addr %010llx - %010llx reserved\n",
22 (unsigned long long) pattern,
23 (unsigned long long) start_bad,
24 (unsigned long long) end_bad);
25 reserve_early(start_bad, end_bad, "BAD RAM");
28 static void __init memtest(u64 pattern, u64 start_phys, u64 size)
32 u64 start_bad, last_bad;
33 u64 start_phys_aligned;
36 incr = sizeof(pattern);
37 start_phys_aligned = ALIGN(start_phys, incr);
38 count = (size - (start_phys_aligned - start_phys))/incr;
39 start = __va(start_phys_aligned);
43 for (i = 0; i < count; i++)
45 for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
46 if (*start == pattern)
48 if (start_phys_aligned == last_bad + incr) {
53 reserve_bad_mem(pattern, start_bad, last_bad + incr);
54 start_bad = last_bad = start_phys_aligned;
57 reserve_bad_mem(pattern, start_bad, last_bad + incr);
60 static void __init do_one_pass(u64 pattern, u64 start, u64 end)
65 start = find_e820_area_size(start, &size, 1);
70 if (start + size > end)
73 printk(KERN_INFO " %010llx - %010llx pattern %016llx\n",
74 (unsigned long long) start,
75 (unsigned long long) start + size,
76 (unsigned long long) cpu_to_be64(pattern));
77 memtest(pattern, start, size);
83 /* default is disabled */
84 static int memtest_pattern __initdata;
86 static int __init parse_memtest(char *arg)
89 memtest_pattern = simple_strtoul(arg, NULL, 0);
93 early_param("memtest", parse_memtest);
95 void __init early_memtest(unsigned long start, unsigned long end)
100 if (!memtest_pattern)
103 printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
104 for (i = 0; i < memtest_pattern; i++) {
105 idx = i % ARRAY_SIZE(patterns);
106 do_one_pass(patterns[idx], start, end);
110 printk(KERN_INFO "early_memtest: wipe out "
111 "test pattern from memory\n");
112 /* additional test with pattern 0 will do this */
113 do_one_pass(0, start, end);