From 722bc6b16771ed80871e1fd81c86d3627dda2ac8 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Mon, 5 Mar 2012 15:05:13 -0800 Subject: [PATCH] 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: WANG Cong Cc: Yinghai Lu Cc: Tejun Heo Cc: Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/n/tip-kq6a00qe33h7c7ais2xsywnh@git.kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/init.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 6cabf65..2e92fdc 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -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, -- 2.7.4