Re: [BUG 2.6.31-rc1] HIGHMEM64G causes hang in PCI init on 32-bit x86

Yinghai Lu
2009-06-30T20:06:32Z

H. Peter Anvin wrote:
> Yinghai Lu wrote:
>> agreed, that is why we change round_up to take u64.
>>
>
> round_up() is a macro, it doesn't "take" anything per se...
>
i mean
end = roundup(start, ram_alignment(start)) - 1;

static u64 ram_alignment(u64 pos)

and other calling to round_up

please check

[PATCH] x86: add boundary check for 32bit res before expand e820 resource to alignment -v2

fix hang with HIGHMEM_64G and 32bit resource.
according to hpa and Linus, use (resource_size_t)-1 to fend off big ranges.

analyzed by hpa

v2: use roundup instead

Reported-and-tested-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
arch/x86/kernel/e820.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

Index: linux-2.6/arch/x86/kernel/e820.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820.c
+++ linux-2.6/arch/x86/kernel/e820.c
@@ -1367,9 +1367,9 @@ void __init e820_reserve_resources(void)
}

/* How much should we pad RAM ending depending on where it is? */
-static unsigned long ram_alignment(resource_size_t pos)
+static u64 ram_alignment(u64 pos)
{
- unsigned long mb = pos >> 20;
+ u64 mb = pos >> 20;

/* To 64kB in the first megabyte */
if (!mb)
@@ -1383,6 +1383,8 @@ static unsigned long ram_alignment(resou
return 32*1024*1024;
}

+#define MAX_RESOURCE_SIZE ((resource_size_t)-1)
+
void __init e820_reserve_resources_late(void)
{
int i;
@@ -1400,17 +1402,19 @@ void __init e820_reserve_resources_late(
* avoid stolen RAM:
*/
for (i = 0; i < e820.nr_map; i++) {
- struct e820entry *entry = &e820_saved.map[i];
- resource_size_t start, end;
+ struct e820entry *entry = &e820.map[i];
+ u64 start, end;

if (entry->type != E820_RAM)
continue;
start = entry->addr + entry->size;
- end = round_up(start, ram_alignment(start));
- if (start == end)
+ end = roundup(start, ram_alignment(start)) - 1;
+ if (end > MAX_RESOURCE_SIZE)
+ end = MAX_RESOURCE_SIZE;
+ if (start > end)
continue;
- reserve_region_with_split(&iomem_resource, start,
- end - 1, "RAM buffer");
+ reserve_region_with_split(&iomem_resource, start, end,
+ "RAM buffer");
}
}