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riscv: Fix hugetlb retrieval of number of ptes in case of !present pte

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Ryan sent a fix [1] for arm64 that applies to riscv too: in some hugetlb
functions, we must not use the pte value to get the size of a mapping
because the pte may not be present.

So use the already present size parameter for huge_pte_clear() and the
newly introduced size parameter for huge_ptep_get_and_clear(). And make
sure to gather A/D bits only on present ptes.

Fixes: 82a1a1f3bf ("riscv: mm: support Svnapot in hugetlb page")
Link: https://lore.kernel.org/all/20250217140419.1702389-1-ryan.roberts@arm.com/ [1]
Link: https://lore.kernel.org/r/20250317072551.572169-1-alexghiti@rivosinc.com
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
This commit is contained in:
Alexandre Ghiti 2025-03-17 08:25:51 +01:00
parent a3313375e8
commit 83d78ac677
No known key found for this signature in database
GPG Key ID: 643FB2BC9285EF8A
1 changed files with 44 additions and 30 deletions
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74
arch/riscv/mm/hugetlbpage.c
View File

@ -148,22 +148,25 @@ unsigned long hugetlb_mask_last_page(struct hstate *h)
static pte_t get_clear_contig(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep,
unsigned long pte_num)
unsigned long ncontig)
{
pte_t orig_pte = ptep_get(ptep);
unsigned long i;
pte_t pte, tmp_pte;
bool present;
for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++) {
pte_t pte = ptep_get_and_clear(mm, addr, ptep);
if (pte_dirty(pte))
orig_pte = pte_mkdirty(orig_pte);
if (pte_young(pte))
orig_pte = pte_mkyoung(orig_pte);
pte = ptep_get_and_clear(mm, addr, ptep);
present = pte_present(pte);
while (--ncontig) {
ptep++;
addr += PAGE_SIZE;
tmp_pte = ptep_get_and_clear(mm, addr, ptep);
if (present) {
if (pte_dirty(tmp_pte))
pte = pte_mkdirty(pte);
if (pte_young(tmp_pte))
pte = pte_mkyoung(pte);
}
}
return orig_pte;
return pte;
}
static pte_t get_clear_contig_flush(struct mm_struct *mm,
@ -212,6 +215,26 @@ static void clear_flush(struct mm_struct *mm,
flush_tlb_range(&vma, saddr, addr);
}
static int num_contig_ptes_from_size(unsigned long sz, size_t *pgsize)
{
unsigned long hugepage_shift;
if (sz >= PGDIR_SIZE)
hugepage_shift = PGDIR_SHIFT;
else if (sz >= P4D_SIZE)
hugepage_shift = P4D_SHIFT;
else if (sz >= PUD_SIZE)
hugepage_shift = PUD_SHIFT;
else if (sz >= PMD_SIZE)
hugepage_shift = PMD_SHIFT;
else
hugepage_shift = PAGE_SHIFT;
*pgsize = 1 << hugepage_shift;
return sz >> hugepage_shift;
}
/*
* When dealing with NAPOT mappings, the privileged specification indicates that
* "if an update needs to be made, the OS generally should first mark all of the
@ -226,22 +249,10 @@ void set_huge_pte_at(struct mm_struct *mm,
pte_t pte,
unsigned long sz)
{
unsigned long hugepage_shift, pgsize;
size_t pgsize;
int i, pte_num;
if (sz >= PGDIR_SIZE)
hugepage_shift = PGDIR_SHIFT;
else if (sz >= P4D_SIZE)
hugepage_shift = P4D_SHIFT;
else if (sz >= PUD_SIZE)
hugepage_shift = PUD_SHIFT;
else if (sz >= PMD_SIZE)
hugepage_shift = PMD_SHIFT;
else
hugepage_shift = PAGE_SHIFT;
pte_num = sz >> hugepage_shift;
pgsize = 1 << hugepage_shift;
pte_num = num_contig_ptes_from_size(sz, &pgsize);
if (!pte_present(pte)) {
for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
@ -295,13 +306,14 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep, unsigned long sz)
{
size_t pgsize;
pte_t orig_pte = ptep_get(ptep);
int pte_num;
if (!pte_napot(orig_pte))
return ptep_get_and_clear(mm, addr, ptep);
pte_num = napot_pte_num(napot_cont_order(orig_pte));
pte_num = num_contig_ptes_from_size(sz, &pgsize);
return get_clear_contig(mm, addr, ptep, pte_num);
}
@ -351,6 +363,7 @@ void huge_pte_clear(struct mm_struct *mm,
pte_t *ptep,
unsigned long sz)
{
size_t pgsize;
pte_t pte = ptep_get(ptep);
int i, pte_num;
@ -359,8 +372,9 @@ void huge_pte_clear(struct mm_struct *mm,
return;
}
pte_num = napot_pte_num(napot_cont_order(pte));
for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
pte_num = num_contig_ptes_from_size(sz, &pgsize);
for (i = 0; i < pte_num; i++, addr += pgsize, ptep++)
pte_clear(mm, addr, ptep);
}