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

Yinghai Lu
2009-06-30T01:15:28Z

H. Peter Anvin wrote:
> Yinghai Lu wrote:
>> continue;
>> @@ -1409,8 +1409,10 @@ void __init e820_reserve_resources_late(
>> end = round_up(start, ram_alignment(start));
>> if (start == end)
>> continue;
>> - reserve_region_with_split(&iomem_resource, start,
>> - end - 1, "RAM buffer");
>> + if (end != (resource_size_t)end)
>> + continue;
>> + reserve_region_with_split(&iomem_resource, (resource_size_t)start,
>> + (resource_size_t)(end - 1), "RAM buffer");
>> }
>> }
>>
>
> That doesn't quite look right; for one thing it doesn't handle the
> (admittedly somewhat unlikely) case of end pointing to the end of the
> address space.
>
> Something like:
>
> if (start > (resource_size_t)end-1)
> continue;
>
> ... should work better.
>

ok this one?

---
arch/x86/kernel/e820.c | 16 ++++++++--------
1 file changed, 8 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)
@@ -1400,17 +1400,17 @@ 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 = round_up(start, ram_alignment(start)) - 1;
+ if (start > (resource_size_t)end)
continue;
- reserve_region_with_split(&iomem_resource, start,
- end - 1, "RAM buffer");
+ reserve_region_with_split(&iomem_resource, (resource_size_t)start,
+ (resource_size_t)end, "RAM buffer");
}
}