Thanks for the feedback. No, I don' t see any changes in the /proc/iomem. I am trying to prevent a ioremap of a 4K size on a non aligned 4K address that is below the ISA_START_ADDRESS. The problem generates a oops about overlapping. I have a fix which instruct to not to do any re-map if the section name is "reserved". Which is not really clean. I am looking for a clean way to tell the ioremap function to not remap bios reserved memory. That' s why I thought the e820 would be a good start. I will continue looking into this. It does not crash the systems. A warning generates the oops. -Mathieu On Wed, May 19, 2010 at 10:43 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 05/19/2010 10:40 AM, Yinghai wrote: >> On 05/18/2010 10:35 PM, Mathieu Rondonneau wrote: >>> Does it make sense to prevent looking for stolen RAM below the ISA section. >>> >>> >>> Signed-off-by: Mathieu Rondonneau <mathieu.rondonneau@xxxxxxxxx> >>> --- >>> arch/x86/kernel/e820.c | 2 ++ >>> 1 files changed, 2 insertions(+), 0 deletions(-) >>> >>> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c >>> index 7bca3c6..322c9c3 100644 >>> --- a/arch/x86/kernel/e820.c >>> +++ b/arch/x86/kernel/e820.c >>> @@ -1156,6 +1156,8 @@ void __init e820_reserve_resources_late(void) >>> end = MAX_RESOURCE_SIZE; >>> if (start >= end) >>> continue; >>> + if (end < ISA_START_ADDRESS) >>> + continue; >>> printk(KERN_DEBUG "reserve RAM buffer: %016llx - %016llx ", >>> start, end); >>> reserve_region_with_split(&iomem_resource, start, end, >> >> do you notice any changes in /proc/iomem? >> > > It should be harmless to reserve memory which is already reserved, so > this patch is at best a no-op. Furthermore, it introduces another > instance of special address space (ISA_START_ADDRESS in this case) which > is never a good thing. > > -hpa > > -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html