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Message-ID: <20250205151003.88959-8-ryan.roberts@arm.com>
Date: Wed, 5 Feb 2025 15:09:47 +0000
From: Ryan Roberts <ryan.roberts@....com>
To: Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Muchun Song <muchun.song@...ux.dev>,
Pasha Tatashin <pasha.tatashin@...een.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Uladzislau Rezki <urezki@...il.com>,
Christoph Hellwig <hch@...radead.org>,
Mark Rutland <mark.rutland@....com>,
Ard Biesheuvel <ardb@...nel.org>,
Anshuman Khandual <anshuman.khandual@....com>,
Dev Jain <dev.jain@....com>,
Alexandre Ghiti <alexghiti@...osinc.com>,
Steve Capper <steve.capper@...aro.org>,
Kevin Brodsky <kevin.brodsky@....com>
Cc: Ryan Roberts <ryan.roberts@....com>,
linux-arm-kernel@...ts.infradead.org,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: [PATCH v1 07/16] arm64: hugetlb: Use ___set_ptes() and ___ptep_get_and_clear()
Refactor the huge_pte helpers to use the new generic ___set_ptes() and
___ptep_get_and_clear() 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 stright 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.
Signed-off-by: Ryan Roberts <ryan.roberts@....com>
---
arch/arm64/mm/hugetlbpage.c | 50 ++++++++-----------------------------
1 file changed, 11 insertions(+), 39 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index e870d01d12ea..02afee31444e 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -166,12 +166,12 @@ 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(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(mm, ptep, pgsize);
if (present) {
if (pte_dirty(tmp_pte))
pte = pte_mkdirty(pte);
@@ -215,7 +215,7 @@ 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(mm, ptep, pgsize);
__flush_hugetlb_tlb_range(&vma, saddr, addr, pgsize, true);
}
@@ -226,32 +226,20 @@ 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(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(mm, ptep, pte, ncontig, pgsize);
}
pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -441,11 +429,9 @@ 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));
@@ -454,7 +440,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
return __ptep_set_access_flags(vma, addr, ptep, pte, dirty);
ncontig = find_num_contig(mm, addr, ptep, &pgsize);
- dpfn = pgsize >> PAGE_SHIFT;
if (!__cont_access_flags_changed(ptep, pte, ncontig))
return 0;
@@ -469,19 +454,14 @@ 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(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;
@@ -494,16 +474,11 @@ 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(mm, ptep, pte, ncontig, pgsize);
}
pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
@@ -517,10 +492,7 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
pte = __ptep_get(ptep);
VM_WARN_ON(!pte_present(pte));
- if (!pte_cont(pte))
- return ptep_clear_flush(vma, addr, ptep);
-
- ncontig = find_num_contig(mm, addr, ptep, &pgsize);
+ ncontig = num_contig_ptes(page_size(pte_page(pte)), &pgsize);
return get_clear_contig_flush(mm, addr, ptep, pgsize, ncontig);
}
--
2.43.0
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