1 files changed, 123 insertions, 0 deletions

diff --git a/arch/x86/mm/memtest.c b/arch/x86/mm/memtest.c
new file mode 100644
index 000000000000..672e17f8262a
--- /dev/null
+++ b/arch/x86/mm/memtest.c
@@ -0,0 +1,123 @@
+#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 <asm/e820.h>
+
+static void __init memtest(unsigned long start_phys, unsigned long size,
+                                 unsigned pattern)
+{
+        unsigned long i;
+        unsigned long *start;
+        unsigned long start_bad;
+        unsigned long last_bad;
+        unsigned long val;
+        unsigned long start_phys_aligned;
+        unsigned long count;
+        unsigned long incr;
+
+        switch (pattern) {
+        case 0:
+                val = 0UL;
+                break;
+        case 1:
+                val = -1UL;
+                break;
+        case 2:
+#ifdef CONFIG_X86_64
+                val = 0x5555555555555555UL;
+#else
+                val = 0x55555555UL;
+#endif
+                break;
+        case 3:
+#ifdef CONFIG_X86_64
+                val = 0xaaaaaaaaaaaaaaaaUL;
+#else
+                val = 0xaaaaaaaaUL;
+#endif
+                break;
+        default:
+                return;
+        }
+
+        incr = sizeof(unsigned long);
+        start_phys_aligned = ALIGN(start_phys, incr);
+        count = (size - (start_phys_aligned - start_phys))/incr;
+        start = __va(start_phys_aligned);
+        start_bad = 0;
+        last_bad = 0;
+
+        for (i = 0; i < count; i++)
+                start[i] = val;
+        for (i = 0; i < count; i++, start++, start_phys_aligned += incr) {
+                if (*start != val) {
+                        if (start_phys_aligned == last_bad + incr) {
+                                last_bad += incr;
+                        } else {
+                                if (start_bad) {
+                                        printk(KERN_CONT "\n  %010lx bad mem addr %010lx - %010lx reserved",
+                                                val, start_bad, last_bad + incr);
+                                        reserve_early(start_bad, last_bad - start_bad, "BAD RAM");
+                                }
+                                start_bad = last_bad = start_phys_aligned;
+                        }
+                }
+        }
+        if (start_bad) {
+                printk(KERN_CONT "\n  %016lx bad mem addr %010lx - %010lx reserved",
+                        val, start_bad, last_bad + incr);
+                reserve_early(start_bad, last_bad - start_bad, "BAD RAM");
+        }
+
+}
+
+/* default is disabled */
+static int memtest_pattern __initdata;
+
+static int __init parse_memtest(char *arg)
+{
+        if (arg)
+                memtest_pattern = simple_strtoul(arg, NULL, 0);
+        return 0;
+}
+
+early_param("memtest", parse_memtest);
+
+void __init early_memtest(unsigned long start, unsigned long end)
+{
+        u64 t_start, t_size;
+        unsigned pattern;
+
+        if (!memtest_pattern)
+                return;
+
+        printk(KERN_INFO "early_memtest: pattern num %d", memtest_pattern);
+        for (pattern = 0; pattern < memtest_pattern; pattern++) {
+                t_start = start;
+                t_size = 0;
+                while (t_start < end) {
+                        t_start = find_e820_area_size(t_start, &t_size, 1);
+
+                        /* done ? */
+                        if (t_start >= end)
+                                break;
+                        if (t_start + t_size > end)
+                                t_size = end - t_start;
+
+                        printk(KERN_CONT "\n  %010llx - %010llx pattern %d",
+                                (unsigned long long)t_start,
+                                (unsigned long long)t_start + t_size, pattern);
+
+                        memtest(t_start, t_size, pattern);
+
+                        t_start += t_size;
+                }
+        }
+        printk(KERN_CONT "\n");
+}