[PATCH v2 02/12] x86: pgtable: Always use pte_free_kernel()

Kevin Brodsky kevin.brodsky at arm.com
Tue Apr 8 02:52:12 PDT 2025


Page table pages are normally freed using the appropriate helper for
the given page table level. On x86, pud_free_pmd_page() and
pmd_free_pte_page() are an exception to the rule: they call
free_page() directly.

Constructor/destructor calls are about to be introduced for kernel
PTEs. To avoid missing dtor calls in those helpers, free the PTE
pages using pte_free_kernel() instead of free_page().

While at it also use pmd_free() instead of calling pagetable_dtor()
explicitly at the PMD level.

Signed-off-by: Kevin Brodsky <kevin.brodsky at arm.com>
---
 arch/x86/mm/pgtable.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 7930f234c5f6..1dee9bdbeea5 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -809,14 +809,13 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 	for (i = 0; i < PTRS_PER_PMD; i++) {
 		if (!pmd_none(pmd_sv[i])) {
 			pte = (pte_t *)pmd_page_vaddr(pmd_sv[i]);
-			free_page((unsigned long)pte);
+			pte_free_kernel(&init_mm, pte);
 		}
 	}
 
 	free_page((unsigned long)pmd_sv);
 
-	pagetable_dtor(virt_to_ptdesc(pmd));
-	free_page((unsigned long)pmd);
+	pmd_free(&init_mm, pmd);
 
 	return 1;
 }
@@ -839,7 +838,7 @@ int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 	/* INVLPG to clear all paging-structure caches */
 	flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
 
-	free_page((unsigned long)pte);
+	pte_free_kernel(&init_mm, pte);
 
 	return 1;
 }
-- 
2.47.0




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