arm64: hugetlb: Use __set_ptes_anysz() and __ptep_get_and_clear_anysz()

Refactor the huge_pte helpers to use the new common __set_ptes_anysz()
and __ptep_get_and_clear_anysz() APIs.

This provides 2 benefits; First, when page_table_check=on, hugetlb is
now properly/fully checked. Previously only the first page of a hugetlb
folio was checked. Second, instead of having to call __set_ptes(nr=1)
for each pte in a loop, the whole contiguous batch can now be set in one
go, which enables some efficiencies and cleans up the code.

One detail to note is that huge_ptep_clear_flush() was previously
calling ptep_clear_flush() for a non-contiguous pte (i.e. a pud or pmd
block mapping). This has a couple of disadvantages; first
ptep_clear_flush() calls ptep_get_and_clear() which transparently
handles contpte. Given we only call for non-contiguous ptes, it would be
safe, but a waste of effort. It's preferable to go straight to the layer
below. However, more problematic is that ptep_get_and_clear() is for
PAGE_SIZE entries so it calls page_table_check_pte_clear() and would not
clear the whole hugetlb folio. So let's stop special-casing the non-cont
case and just rely on get_clear_contig_flush() to do the right thing for
non-cont entries.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Luiz Capitulino <luizcap@redhat.com>
Link: https://lore.kernel.org/r/20250422081822.1836315-6-ryan.roberts@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 087fc43381c6328903dbca862b6e1f2e200af2ce..d34703846ef47eb8d420d54844c4de5575a6e409 100644 (file)
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -159,12 +159,11 @@ static pte_t get_clear_contig(struct mm_struct *mm,
        pte_t pte, tmp_pte;
        bool present;
 
-       pte = __ptep_get_and_clear(mm, addr, ptep);
+       pte = __ptep_get_and_clear_anysz(mm, ptep, pgsize);
        present = pte_present(pte);
        while (--ncontig) {
                ptep++;
-               addr += pgsize;
-               tmp_pte = __ptep_get_and_clear(mm, addr, ptep);
+               tmp_pte = __ptep_get_and_clear_anysz(mm, ptep, pgsize);
                if (present) {
                        if (pte_dirty(tmp_pte))
                                pte = pte_mkdirty(pte);
@@ -208,7 +207,7 @@ static void clear_flush(struct mm_struct *mm,
        unsigned long i, saddr = addr;
 
        for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
-               __ptep_get_and_clear(mm, addr, ptep);
+               __ptep_get_and_clear_anysz(mm, ptep, pgsize);
 
        __flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, true);
 }
@@ -219,32 +218,20 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
        size_t pgsize;
        int i;
        int ncontig;
-       unsigned long pfn, dpfn;
-       pgprot_t hugeprot;
 
        ncontig = num_contig_ptes(sz, &pgsize);
 
        if (!pte_present(pte)) {
                for (i = 0; i < ncontig; i++, ptep++, addr += pgsize)
-                       __set_ptes(mm, addr, ptep, pte, 1);
+                       __set_ptes_anysz(mm, ptep, pte, 1, pgsize);
                return;
        }
 
-       if (!pte_cont(pte)) {
-               __set_ptes(mm, addr, ptep, pte, 1);
-               return;
-       }
-
-       pfn = pte_pfn(pte);
-       dpfn = pgsize >> PAGE_SHIFT;
-       hugeprot = pte_pgprot(pte);
-
        /* Only need to "break" if transitioning valid -> valid. */
-       if (pte_valid(__ptep_get(ptep)))
+       if (pte_cont(pte) && pte_valid(__ptep_get(ptep)))
                clear_flush(mm, addr, ptep, pgsize, ncontig);
 
-       for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
-               __set_ptes(mm, addr, ptep, pfn_pte(pfn, hugeprot), 1);
+       __set_ptes_anysz(mm, ptep, pte, ncontig, pgsize);
 }
 
 pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -434,11 +421,9 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
                               unsigned long addr, pte_t *ptep,
                               pte_t pte, int dirty)
 {
-       int ncontig, i;
+       int ncontig;
        size_t pgsize = 0;
-       unsigned long pfn = pte_pfn(pte), dpfn;
        struct mm_struct *mm = vma->vm_mm;
-       pgprot_t hugeprot;
        pte_t orig_pte;
 
        VM_WARN_ON(!pte_present(pte));
@@ -447,7 +432,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
                return __ptep_set_access_flags(vma, addr, ptep, pte, dirty);
 
        ncontig = num_contig_ptes(huge_page_size(hstate_vma(vma)), &pgsize);
-       dpfn = pgsize >> PAGE_SHIFT;
 
        if (!__cont_access_flags_changed(ptep, pte, ncontig))
                return 0;
@@ -462,19 +446,14 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
        if (pte_young(orig_pte))
                pte = pte_mkyoung(pte);
 
-       hugeprot = pte_pgprot(pte);
-       for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
-               __set_ptes(mm, addr, ptep, pfn_pte(pfn, hugeprot), 1);
-
+       __set_ptes_anysz(mm, ptep, pte, ncontig, pgsize);
        return 1;
 }
 
 void huge_ptep_set_wrprotect(struct mm_struct *mm,
                             unsigned long addr, pte_t *ptep)
 {
-       unsigned long pfn, dpfn;
-       pgprot_t hugeprot;
-       int ncontig, i;
+       int ncontig;
        size_t pgsize;
        pte_t pte;
 
@@ -487,16 +466,11 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
        }
 
        ncontig = find_num_contig(mm, addr, ptep, &pgsize);
-       dpfn = pgsize >> PAGE_SHIFT;
 
        pte = get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
        pte = pte_wrprotect(pte);
 
-       hugeprot = pte_pgprot(pte);
-       pfn = pte_pfn(pte);
-
-       for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
-               __set_ptes(mm, addr, ptep, pfn_pte(pfn, hugeprot), 1);
+       __set_ptes_anysz(mm, ptep, pte, ncontig, pgsize);
 }
 
 pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
@@ -505,13 +479,6 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
        struct mm_struct *mm = vma->vm_mm;
        size_t pgsize;
        int ncontig;
-       pte_t pte;
-
-       pte = __ptep_get(ptep);
-       VM_WARN_ON(!pte_present(pte));
-
-       if (!pte_cont(pte))
-               return ptep_clear_flush(vma, addr, ptep);
 
        ncontig = num_contig_ptes(huge_page_size(hstate_vma(vma)), &pgsize);
        return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);