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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>
hifive-unleashed-5.1
Toshi Kani 2018-03-22 16:17:24 -07:00 committed by Linus Torvalds
parent b6bdb7517c
commit 28ee90fe60
1 changed files with 26 additions and 2 deletions
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28
arch/x86/mm/pgtable.c
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@ -712,7 +712,22 @@ int pmd_clear_huge(pmd_t *pmd)
*/
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)
{
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 */