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Commit 722bc6b1 authored by WANG Cong's avatar WANG Cong Committed by Ingo Molnar
Browse files

x86/mm: Fix the size calculation of mapping tables 



For machines that enable PSE, the first 2/4M memory region still uses
4K pages, so needs more PTEs in this case, but
find_early_table_space() doesn't count this.

This patch fixes it.

The bug was found via code review, no misbehavior of the kernel
was observed.

Signed-off-by: default avatarWANG Cong <xiyou.wangcong@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: <ianfang.cn@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-kq6a00qe33h7c7ais2xsywnh@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 550cf00d

arch/x86/mm/init.c

+12 −9
Original line number Diff line number Diff line
@@ -30,8 +30,14 @@ int direct_gbpages 
#endif

;



static void __init find_early_table_space(unsigned long end, int use_pse,

					  int use_gbpages)

struct map_range {

	unsigned long start;

	unsigned long end;

	unsigned page_size_mask;

};



static void __init find_early_table_space(struct map_range *mr, unsigned long end,

					  int use_pse, int use_gbpages)

{

	unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;

	phys_addr_t base;
@@ -56,6 +62,9 @@ static void __init find_early_table_space(unsigned long end, int use_pse, 
#ifdef CONFIG_X86_32

		extra += PMD_SIZE;

#endif

		/* The first 2/4M doesn't use large pages. */

		extra += mr->end - mr->start;



		ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;

	} else

		ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
@@ -85,12 +94,6 @@ void __init native_pagetable_reserve(u64 start, u64 end) 
	memblock_reserve(start, end - start);

}



struct map_range {

	unsigned long start;

	unsigned long end;

	unsigned page_size_mask;

};



#ifdef CONFIG_X86_32

#define NR_RANGE_MR 3

#else /* CONFIG_X86_64 */
@@ -262,7 +265,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, 
	 * nodes are discovered.

	 */

	if (!after_bootmem)

		find_early_table_space(end, use_pse, use_gbpages);

		find_early_table_space(&mr[0], end, use_pse, use_gbpages);



	for (i = 0; i < nr_range; i++)

		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,