/arch/x86/mm/memtest.c

  1#include <linux/kernel.h>
  2#include <linux/errno.h>
  3#include <linux/string.h>
  4#include <linux/types.h>
  5#include <linux/mm.h>
  6#include <linux/smp.h>
  7#include <linux/init.h>
  8#include <linux/pfn.h>
  9#include <linux/memblock.h>
 10
 11static u64 patterns[] __initdata = {
 12	0,
 13	0xffffffffffffffffULL,
 14	0x5555555555555555ULL,
 15	0xaaaaaaaaaaaaaaaaULL,
 16	0x1111111111111111ULL,
 17	0x2222222222222222ULL,
 18	0x4444444444444444ULL,
 19	0x8888888888888888ULL,
 20	0x3333333333333333ULL,
 21	0x6666666666666666ULL,
 22	0x9999999999999999ULL,
 23	0xccccccccccccccccULL,
 24	0x7777777777777777ULL,
 25	0xbbbbbbbbbbbbbbbbULL,
 26	0xddddddddddddddddULL,
 27	0xeeeeeeeeeeeeeeeeULL,
 28	0x7a6c7258554e494cULL, /* yeah ;-) */
 29};
 30
 31static void __init reserve_bad_mem(u64 pattern, u64 start_bad, u64 end_bad)
 32{
 33	printk(KERN_INFO "  %016llx bad mem addr %010llx - %010llx reserved\n",
 34	       (unsigned long long) pattern,
 35	       (unsigned long long) start_bad,
 36	       (unsigned long long) end_bad);
 37	memblock_x86_reserve_range(start_bad, end_bad, "BAD RAM");
 38}
 39
 40static void __init memtest(u64 pattern, u64 start_phys, u64 size)
 41{
 42	u64 *p, *start, *end;
 43	u64 start_bad, last_bad;
 44	u64 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		*p = pattern;
 55
 56	for (p = start; p < end; p++, start_phys_aligned += incr) {
 57		if (*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
 71static void __init do_one_pass(u64 pattern, u64 start, u64 end)
 72{
 73	u64 size = 0;
 74
 75	while (start < end) {
 76		start = memblock_x86_find_in_range_size(start, &size, 1);
 77
 78		/* done ? */
 79		if (start >= end)
 80			break;
 81		if (start + size > end)
 82			size = end - start;
 83
 84		printk(KERN_INFO "  %010llx - %010llx pattern %016llx\n",
 85		       (unsigned long long) start,
 86		       (unsigned long long) start + size,
 87		       (unsigned long long) cpu_to_be64(pattern));
 88		memtest(pattern, start, size);
 89
 90		start += size;
 91	}
 92}
 93
 94/* default is disabled */
 95static int memtest_pattern __initdata;
 96
 97static int __init parse_memtest(char *arg)
 98{
 99	if (arg)
100		memtest_pattern = simple_strtoul(arg, NULL, 0);
101	else
102		memtest_pattern = ARRAY_SIZE(patterns);
103
104	return 0;
105}
106
107early_param("memtest", parse_memtest);
108
109void __init early_memtest(unsigned long start, unsigned long end)
110{
111	unsigned int i;
112	unsigned int idx = 0;
113
114	if (!memtest_pattern)
115		return;
116
117	printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
118	for (i = 0; i < memtest_pattern; i++) {
119		idx = i % ARRAY_SIZE(patterns);
120		do_one_pass(patterns[idx], start, end);
121	}
122
123	if (idx > 0) {
124		printk(KERN_INFO "early_memtest: wipe out "
125		       "test pattern from memory\n");
126		/* additional test with pattern 0 will do this */
127		do_one_pass(0, start, end);
128	}
129}