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

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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>
This commit is contained in:
Ryan Roberts 2025-04-22 09:18:13 +01:00 committed by Will Deacon
parent ef493d2343
commit a899b7d067
1 changed files with 10 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
arch/arm64/mm/hugetlbpage.c
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@ -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);