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Message-ID: <20250905055103.3821518-4-baolu.lu@linux.intel.com>
Date: Fri, 5 Sep 2025 13:50:58 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Joerg Roedel <joro@...tes.org>,
Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Kevin Tian <kevin.tian@...el.com>,
Jason Gunthorpe <jgg@...dia.com>,
Jann Horn <jannh@...gle.com>,
Vasant Hegde <vasant.hegde@....com>,
Dave Hansen <dave.hansen@...el.com>,
Alistair Popple <apopple@...dia.com>,
Peter Zijlstra <peterz@...radead.org>,
Uladzislau Rezki <urezki@...il.com>,
Jean-Philippe Brucker <jean-philippe@...aro.org>,
Andy Lutomirski <luto@...nel.org>,
Yi Lai <yi1.lai@...el.com>
Cc: iommu@...ts.linux.dev,
security@...nel.org,
linux-kernel@...r.kernel.org,
Dave Hansen <dave.hansen@...ux.intel.com>,
Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v4 3/8] x86/mm: Use 'ptdesc' when freeing PMD pages
From: Dave Hansen <dave.hansen@...ux.intel.com>
There are a billion ways to refer to a physical memory address.
One of the x86 PMD freeing code location chooses to use a 'pte_t *' to
point to a PMD page and then call a PTE-specific freeing function for
it. That's a bit wonky.
Just use a 'struct ptdesc *' instead. Its entire purpose is to refer
to page table pages. It also means being able to remove an explicit
cast.
Right now, pte_free_kernel() is a one-liner that calls
pagetable_dtor_free(). Effectively, all this patch does is
remove one superfluous __pa(__va(paddr)) conversion and then
call pagetable_dtor_free() directly instead of through a helper.
Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
arch/x86/mm/pgtable.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index ddf248c3ee7d..2e5ecfdce73c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -729,7 +729,7 @@ int pmd_clear_huge(pmd_t *pmd)
int pud_free_pmd_page(pud_t *pud, unsigned long addr)
{
pmd_t *pmd, *pmd_sv;
- pte_t *pte;
+ struct ptdesc *pt;
int i;
pmd = pud_pgtable(*pud);
@@ -750,8 +750,8 @@ 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]);
- pte_free_kernel(&init_mm, pte);
+ pt = page_ptdesc(pmd_page(pmd_sv[i]));
+ pagetable_dtor_free(pt);
}
}
@@ -772,15 +772,15 @@ int pud_free_pmd_page(pud_t *pud, unsigned long addr)
*/
int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
{
- pte_t *pte;
+ struct ptdesc *pt;
- pte = (pte_t *)pmd_page_vaddr(*pmd);
+ pt = page_ptdesc(pmd_page(*pmd));
pmd_clear(pmd);
/* INVLPG to clear all paging-structure caches */
flush_tlb_kernel_range(addr, addr + PAGE_SIZE-1);
- pte_free_kernel(&init_mm, pte);
+ pagetable_dtor_free(pt);
return 1;
}
--
2.43.0
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