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	x86/mm: implement free pmd/pte page interfaces
Implement pud_free_pmd_page() and pmd_free_pte_page() on x86, which
clear a given pud/pmd entry and free up lower level page table(s).
The address range associated with the pud/pmd entry must have been
purged by INVLPG.
Link: http://lkml.kernel.org/r/20180314180155.19492-3-toshi.kani@hpe.com
Fixes: e61ce6ade4 ("mm: change ioremap to set up huge I/O mappings")
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Reported-by: Lei Li <lious.lilei@hisilicon.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
			
			
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					 1 changed files with 26 additions and 2 deletions
				
			
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					@ -712,7 +712,22 @@ int pmd_clear_huge(pmd_t *pmd)
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 */
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					 */
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int pud_free_pmd_page(pud_t *pud)
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					int pud_free_pmd_page(pud_t *pud)
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{
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					{
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	return pud_none(*pud);
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						pmd_t *pmd;
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						int i;
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						if (pud_none(*pud))
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							return 1;
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						pmd = (pmd_t *)pud_page_vaddr(*pud);
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						for (i = 0; i < PTRS_PER_PMD; i++)
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							if (!pmd_free_pte_page(&pmd[i]))
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								return 0;
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						pud_clear(pud);
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						free_page((unsigned long)pmd);
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						return 1;
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}
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					}
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/**
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					/**
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					@ -724,6 +739,15 @@ int pud_free_pmd_page(pud_t *pud)
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 */
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					 */
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int pmd_free_pte_page(pmd_t *pmd)
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					int pmd_free_pte_page(pmd_t *pmd)
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{
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					{
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	return pmd_none(*pmd);
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						pte_t *pte;
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						if (pmd_none(*pmd))
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							return 1;
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						pte = (pte_t *)pmd_page_vaddr(*pmd);
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						pmd_clear(pmd);
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						free_page((unsigned long)pte);
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						return 1;
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}
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					}
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#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
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					#endif	/* CONFIG_HAVE_ARCH_HUGE_VMAP */
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