x86: early memtest to find bad ram
do simple memtest after init_memory_mapping
use find_e820_area_size to find all ram range that is not reserved.
and do some simple bits test to find some bad ram.
if find some bad ram, use reserve_early to exclude that range.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 255e51f..52f54ee 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -427,6 +427,106 @@
direct_gbpages = 0;
}
+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:
+ val = 0x5555555555555555UL;
+ break;
+ case 3:
+ val = 0xaaaaaaaaaaaaaaaaUL;
+ 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_INFO " %016lxx bad mem addr %016lx - %016lx reserved\n",
+ 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_INFO " %016lx bad mem addr %016lx - %016lx reserved\n",
+ val, start_bad, last_bad + incr);
+ reserve_early(start_bad, last_bad - start_bad, "BAD RAM");
+ }
+
+}
+
+static int __initdata memtest_pattern;
+static int __init parse_memtest(char *arg)
+{
+ if (arg)
+ memtest_pattern = simple_strtoul(arg, NULL, 0) + 1;
+ return 0;
+}
+
+early_param("memtest", parse_memtest);
+
+static void __init early_memtest(unsigned long start, unsigned long end)
+{
+ unsigned long t_start, t_size;
+ unsigned pattern;
+
+ if (memtest_pattern)
+ 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 %016lx - %016lx pattern %d",
+ t_start, t_start + t_size, pattern);
+
+ memtest(t_start, t_size, pattern);
+
+ t_start += t_size;
+ }
+ }
+ if (memtest_pattern)
+ printk(KERN_CONT "\n");
+}
+
/*
* Setup the direct mapping of the physical memory at PAGE_OFFSET.
* This runs before bootmem is initialized and gets pages directly from
@@ -435,8 +535,9 @@
void __init_refok init_memory_mapping(unsigned long start, unsigned long end)
{
unsigned long next;
+ unsigned long start_phys = start, end_phys = end;
- pr_debug("init_memory_mapping\n");
+ printk(KERN_INFO "init_memory_mapping\n");
/*
* Find space for the kernel direct mapping tables.
@@ -479,6 +580,9 @@
if (!after_bootmem)
reserve_early(table_start << PAGE_SHIFT,
table_end << PAGE_SHIFT, "PGTABLE");
+
+ if (!after_bootmem)
+ early_memtest(start_phys, end_phys);
}
#ifndef CONFIG_NUMA