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Commit 0fc59d3a authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

x86: fix init_memory_mapping() to handle small ranges 



Impact: fix failed EFI bootup in certain circumstances

Ying Huang found init_memory_mapping() has problem with small ranges
less than 2M when he tried to direct map the EFI runtime code out of
max_low_pfn_mapped.

It turns out we never considered that case and didn't check the range...

Reported-by: default avatarYing Huang <ying.huang@intel.com>
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Cc: Brian Maly <bmaly@redhat.com>
LKML-Reference: <49ACDDED.1060508@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2450cf51

arch/x86/mm/init_64.c

+2 −0
Original line number Diff line number Diff line
@@ -714,6 +714,8 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, 
	pos = start_pfn << PAGE_SHIFT;

	end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)

			<< (PMD_SHIFT - PAGE_SHIFT);

	if (end_pfn > (end >> PAGE_SHIFT))

		end_pfn = end >> PAGE_SHIFT;

	if (start_pfn < end_pfn) {

		nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);

		pos = end_pfn << PAGE_SHIFT;