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x86: early memtest to find bad ram
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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>
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Yinghai Lu authored and Ingo Molnar committed Apr 17, 2008
1 parent a5ae1c3 commit 272b9ca
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Showing 3 changed files with 177 additions and 2 deletions.
70 changes: 69 additions & 1 deletion arch/x86/kernel/e820_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,40 @@ bad_addr(unsigned long *addrp, unsigned long size, unsigned long align)
return changed;
}

/* Check for already reserved areas */
static inline int
bad_addr_size(unsigned long *addrp, unsigned long *sizep, unsigned long align)
{
int i;
unsigned long addr = *addrp, last;
unsigned long size = *sizep;
int changed = 0;
again:
last = addr + size;
for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
struct early_res *r = &early_res[i];
if (last > r->start && addr < r->start) {
size = r->start - addr;
changed = 1;
goto again;
}
if (last > r->end && addr < r->end) {
addr = round_up(r->end, align);
size = last - addr;
changed = 1;
goto again;
}
if (last <= r->end && addr >= r->start) {
(*sizep)++;
return 0;
}
}
if (changed) {
*addrp = addr;
*sizep = size;
}
return changed;
}
/*
* This function checks if any part of the range <start,end> is mapped
* with type.
Expand Down Expand Up @@ -190,7 +224,7 @@ unsigned long __init find_e820_area(unsigned long start, unsigned long end,
ei_last = ei->addr + ei->size;
if (addr < start)
addr = round_up(start, align);
if (addr > ei_last)
if (addr >= ei_last)
continue;
while (bad_addr(&addr, size, align) && addr+size <= ei_last)
;
Expand All @@ -204,6 +238,40 @@ unsigned long __init find_e820_area(unsigned long start, unsigned long end,
return -1UL;
}

/*
* Find next free range after *start
*/
unsigned long __init find_e820_area_size(unsigned long start, unsigned long *sizep, unsigned long align)
{
int i;

for (i = 0; i < e820.nr_map; i++) {
struct e820entry *ei = &e820.map[i];
unsigned long addr, last;
unsigned long ei_last;

if (ei->type != E820_RAM)
continue;
addr = round_up(ei->addr, align);
ei_last = ei->addr + ei->size;
// printk(KERN_DEBUG "find_e820_area_size : e820 %d [%llx, %lx]\n", i, ei->addr, ei_last);
if (addr < start)
addr = round_up(start, align);
// printk(KERN_DEBUG "find_e820_area_size : 0 [%lx, %lx]\n", addr, ei_last);
if (addr >= ei_last)
continue;
*sizep = ei_last - addr;
while (bad_addr_size(&addr, sizep, align) && addr+ *sizep <= ei_last)
;
last = addr + *sizep;
// printk(KERN_DEBUG "find_e820_area_size : 1 [%lx, %lx]\n", addr, last);
if (last > ei_last)
continue;
return addr;
}
return -1UL;

}
/*
* Find the highest page frame number we have available
*/
Expand Down
106 changes: 105 additions & 1 deletion arch/x86/mm/init_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,106 @@ static void __init init_gbpages(void)
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
Expand All @@ -435,8 +535,9 @@ static void __init init_gbpages(void)
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.
Expand Down Expand Up @@ -479,6 +580,9 @@ void __init_refok init_memory_mapping(unsigned long start, unsigned long end)
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
Expand Down
3 changes: 3 additions & 0 deletions include/asm-x86/e820_64.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,9 @@
#ifndef __ASSEMBLY__
extern unsigned long find_e820_area(unsigned long start, unsigned long end,
unsigned long size, unsigned long align);
extern unsigned long find_e820_area_size(unsigned long start,
unsigned long *sizep,
unsigned long align);
extern void add_memory_region(unsigned long start, unsigned long size,
int type);
extern void update_memory_range(u64 start, u64 size, unsigned old_type,
Expand Down

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