Commit 28ee90fe authored Mar 22, 2018 by Toshi Kani Committed by Linus Torvalds Mar 22, 2018

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: e61ce6ad ("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>

parent b6bdb751

arch/x86/mm/pgtable.c

+26 −2

Original line number	Original line	Diff line number	Diff line
	@@ -712,7 +712,22 @@ int pmd_clear_huge(pmd_t *pmd)
	*/		*/
	int pud_free_pmd_page(pud_t *pud)		int pud_free_pmd_page(pud_t *pud)
	{		{
	return pud_none(*pud);		pmd_t *pmd;
			int i;

			if (pud_none(*pud))
			return 1;

			pmd = (pmd_t )pud_page_vaddr(pud);

			for (i = 0; i < PTRS_PER_PMD; i++)
			if (!pmd_free_pte_page(&pmd[i]))
			return 0;

			pud_clear(pud);
			free_page((unsigned long)pmd);

			return 1;
	}		}

	/**		/**
	@@ -724,6 +739,15 @@ int pud_free_pmd_page(pud_t *pud)
	*/		*/
	int pmd_free_pte_page(pmd_t *pmd)		int pmd_free_pte_page(pmd_t *pmd)
	{		{
	return pmd_none(*pmd);		pte_t *pte;

			if (pmd_none(*pmd))
			return 1;

			pte = (pte_t )pmd_page_vaddr(pmd);
			pmd_clear(pmd);
			free_page((unsigned long)pte);

			return 1;
	}		}
	#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */		#endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */