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SubjectRe: [PATCH -fixes 1/2] riscv: Fix huge_ptep_set_wrprotect when PTE is a NAPOT
On Fri, Apr 28, 2023 at 02:01:19PM +0200, Alexandre Ghiti wrote:
> We need to avoid inconsistencies across the PTEs that form a NAPOT
> region, so when we write protect such a region, we should clear and flush
> all the PTEs to make sure that any of those PTEs is not cached which would
> result in such inconsistencies (arm64 does the same).
>
> Fixes: f2aeb0118ddd ("riscv: mm: support Svnapot in hugetlb page")
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
> arch/riscv/mm/hugetlbpage.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
> index a163a3e0f0d4..238d00bdac14 100644
> --- a/arch/riscv/mm/hugetlbpage.c
> +++ b/arch/riscv/mm/hugetlbpage.c
> @@ -218,6 +218,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
> {
> pte_t pte = ptep_get(ptep);
> unsigned long order;
> + pte_t orig_pte;
> int i, pte_num;
>
> if (!pte_napot(pte)) {
> @@ -228,9 +229,12 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
> order = napot_cont_order(pte);
> pte_num = napot_pte_num(order);
> ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
> + orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
> +
> + orig_pte = pte_wrprotect(orig_pte);
>
> for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
> - ptep_set_wrprotect(mm, addr, ptep);
> + set_pte_at(mm, addr, ptep, orig_pte);
> }
>
> pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
> --
> 2.37.2
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>

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