4.4-stable review patch. If anyone has any objections, please let me know.
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From: Toshi Kani toshi.kani@hpe.com
commit 28ee90fe6048fa7b7ceaeb8831c0e4e454a4cf89 upstream.
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: e61ce6ade404e ("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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/mm/pgtable.c | 28 ++++++++++++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-)
--- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -676,7 +676,22 @@ 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; }
/** @@ -688,6 +703,15 @@ 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 */