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Commit 49834396 authored by Jan Beulich's avatar Jan Beulich Committed by H. Peter Anvin
Browse files

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: default avatarJan Beulich <jbeulich@novell.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 61438766

arch/x86/mm/init.c

+17 −1
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <asm/page.h>

#include <asm/page_types.h>

#include <asm/sections.h>

#include <asm/setup.h>

#include <asm/system.h>

#include <asm/tlbflush.h>
@@ -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();