From 498343967613183611ac37dccb2846496d954c06 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 6 May 2009 13:06:47 +0100 Subject: x86-64: finish cleanup_highmaps()'s job wrt. _brk_end With the introduction of the .brk section, special care must be taken that no unused page table entries remain if _brk_end and _end are separated by a 2M page boundary. cleanup_highmap() runs very early and hence cannot take care of that, hence potential entries needing to be removed past _brk_end must be cleared once the brk allocator has done its job. [ Impact: avoids undesirable TLB aliases ] Signed-off-by: Jan Beulich Signed-off-by: H. Peter Anvin --- arch/x86/mm/init.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index fd3da1dda1c9..ae4f7b5d7104 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -7,6 +7,7 @@ #include #include #include +#include #include #include @@ -304,8 +305,23 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, #endif #ifdef CONFIG_X86_64 - if (!after_bootmem) + if (!after_bootmem && !start) { + pud_t *pud; + pmd_t *pmd; + mmu_cr4_features = read_cr4(); + + /* + * _brk_end cannot change anymore, but it and _end may be + * located on different 2M pages. cleanup_highmap(), however, + * can only consider _end when it runs, so destroy any + * mappings beyond _brk_end here. + */ + pud = pud_offset(pgd_offset_k(_brk_end), _brk_end); + pmd = pmd_offset(pud, _brk_end - 1); + while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1)) + pmd_clear(pmd); + } #endif __flush_tlb_all(); -- cgit v1.2.3-59-g8ed1b