1 files changed, 118 insertions, 0 deletions

diff --git a/mm/memtest.c b/mm/memtest.c
new file mode 100644
index 000000000000..1997d934b13b
--- /dev/null
+++ b/mm/memtest.c
@@ -0,0 +1,118 @@
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/init.h>
+#include <linux/pfn.h>
+#include <linux/memblock.h>
+
+static u64 patterns[] __initdata = {
+        /* The first entry has to be 0 to leave memtest with zeroed memory */
+        0,
+        0xffffffffffffffffULL,
+        0x5555555555555555ULL,
+        0xaaaaaaaaaaaaaaaaULL,
+        0x1111111111111111ULL,
+        0x2222222222222222ULL,
+        0x4444444444444444ULL,
+        0x8888888888888888ULL,
+        0x3333333333333333ULL,
+        0x6666666666666666ULL,
+        0x9999999999999999ULL,
+        0xccccccccccccccccULL,
+        0x7777777777777777ULL,
+        0xbbbbbbbbbbbbbbbbULL,
+        0xddddddddddddddddULL,
+        0xeeeeeeeeeeeeeeeeULL,
+        0x7a6c7258554e494cULL, /* yeah ;-) */
+};
+
+static void __init reserve_bad_mem(u64 pattern, phys_addr_t start_bad, phys_addr_t end_bad)
+{
+        printk(KERN_INFO "  %016llx bad mem addr %010llx - %010llx reserved\n",
+               (unsigned long long) pattern,
+               (unsigned long long) start_bad,
+               (unsigned long long) end_bad);
+        memblock_reserve(start_bad, end_bad - start_bad);
+}
+
+static void __init memtest(u64 pattern, phys_addr_t start_phys, phys_addr_t size)
+{
+        u64 *p, *start, *end;
+        phys_addr_t start_bad, last_bad;
+        phys_addr_t start_phys_aligned;
+        const size_t incr = sizeof(pattern);
+
+        start_phys_aligned = ALIGN(start_phys, incr);
+        start = __va(start_phys_aligned);
+        end = start + (size - (start_phys_aligned - start_phys)) / incr;
+        start_bad = 0;
+        last_bad = 0;
+
+        for (p = start; p < end; p++)
+                *p = pattern;
+
+        for (p = start; p < end; p++, start_phys_aligned += incr) {
+                if (*p == pattern)
+                        continue;
+                if (start_phys_aligned == last_bad + incr) {
+                        last_bad += incr;
+                        continue;
+                }
+                if (start_bad)
+                        reserve_bad_mem(pattern, start_bad, last_bad + incr);
+                start_bad = last_bad = start_phys_aligned;
+        }
+        if (start_bad)
+                reserve_bad_mem(pattern, start_bad, last_bad + incr);
+}
+
+static void __init do_one_pass(u64 pattern, phys_addr_t start, phys_addr_t end)
+{
+        u64 i;
+        phys_addr_t this_start, this_end;
+
+        for_each_free_mem_range(i, NUMA_NO_NODE, &this_start, &this_end, NULL) {
+                this_start = clamp(this_start, start, end);
+                this_end = clamp(this_end, start, end);
+                if (this_start < this_end) {
+                        printk(KERN_INFO "  %010llx - %010llx pattern %016llx\n",
+                               (unsigned long long)this_start,
+                               (unsigned long long)this_end,
+                               (unsigned long long)cpu_to_be64(pattern));
+                        memtest(pattern, this_start, this_end - this_start);
+                }
+        }
+}
+
+/* default is disabled */
+static int memtest_pattern __initdata;
+
+static int __init parse_memtest(char *arg)
+{
+        if (arg)
+                memtest_pattern = simple_strtoul(arg, NULL, 0);
+        else
+                memtest_pattern = ARRAY_SIZE(patterns);
+
+        return 0;
+}
+
+early_param("memtest", parse_memtest);
+
+void __init early_memtest(phys_addr_t start, phys_addr_t end)
+{
+        unsigned int i;
+        unsigned int idx = 0;
+
+        if (!memtest_pattern)
+                return;
+
+        printk(KERN_INFO "early_memtest: # of tests: %d\n", memtest_pattern);
+        for (i = memtest_pattern-1; i < UINT_MAX; --i) {
+                idx = i % ARRAY_SIZE(patterns);
+                do_one_pass(patterns[idx], start, end);
+        }
+}