On 3/15/23 10:44, Matthew Wilcox (Oracle) wrote:
> Most architectures can just define set_pte() and PFN_PTE_SHIFT to
> use this definition. It's also a handy spot to document the guarantees
> provided by the MM.
>
> Suggested-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> include/linux/pgtable.h | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index c5a51481bbb9..a755fe94b4b4 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -172,6 +172,43 @@ static inline int pmd_young(pmd_t pmd)
> }
> #endif
>
> +#ifndef set_ptes
> +#ifdef PFN_PTE_SHIFT
> +/**
> + * set_ptes - Map consecutive pages to a contiguous range of addresses.
> + * @mm: Address space to map the pages into.
> + * @addr: Address to map the first page at.
> + * @ptep: Page table pointer for the first entry.
> + * @pte: Page table entry for the first page.
> + * @nr: Number of pages to map.
> + *
> + * May be overridden by the architecture, or the architecture can define
> + * set_pte() and PFN_PTE_SHIFT.
> + *
> + * Context: The caller holds the page table lock. The pages all belong
> + * to the same folio. The PTEs are all in the same PMD.
> + */
> +static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
> + pte_t *ptep, pte_t pte, unsigned int nr)
> +{
> + page_table_check_ptes_set(mm, addr, ptep, pte, nr);
> +
> + for (;;) {
> + set_pte(ptep, pte);
> + if (--nr == 0)
> + break;
> + ptep++;
> + pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
> + }
> +}
> +#ifndef set_pte_at
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif
Should not there be a build phase call out when both set_ptes() and PFN_PTE_SHIFT
are not defined on a given platform ?
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -204,6 +204,8 @@ static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
#ifndef set_pte_at
#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
#endif
+#else
+#error "You should define PFN_PTE_SHIFT"
#endif
#else
#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif> +#else
> +#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
> +#endif
> +
> #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
> extern int ptep_set_access_flags(struct vm_area_struct *vma,
> unsigned long address, pte_t *ptep,
