On Thu, Jul 04, 2024 at 08:30:05AM +0200, Christophe Leroy wrote:
> Commit 2c8a81dc0cc5 ("riscv/mm: fix two page table check related
> issues") added pud_leaf() in include/asm-generic/pgtable-nopmd.h
>
> Do the same for p4d_leaf() and pgd_leaf() to avoid getting them
> erroneously defined by architectures that do not implement the
> related page level.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> include/asm-generic/pgtable-nop4d.h | 1 +
> include/asm-generic/pgtable-nopud.h | 1 +
> include/linux/pgtable.h | 6 +++---
> 3 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
> index 03b7dae47dd4..75c96bbc5a96 100644
> --- a/include/asm-generic/pgtable-nop4d.h
> +++ b/include/asm-generic/pgtable-nop4d.h
> @@ -21,6 +21,7 @@ typedef struct { pgd_t pgd; } p4d_t;
> static inline int pgd_none(pgd_t pgd) { return 0; }
> static inline int pgd_bad(pgd_t pgd) { return 0; }
> static inline int pgd_present(pgd_t pgd) { return 1; }
> +static inline int pgd_leaf(pgd_t pgd) { return 0; }
> static inline void pgd_clear(pgd_t *pgd) { }
> #define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd))
>
> diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
> index eb70c6d7ceff..14aeb8ef2d8a 100644
> --- a/include/asm-generic/pgtable-nopud.h
> +++ b/include/asm-generic/pgtable-nopud.h
> @@ -28,6 +28,7 @@ typedef struct { p4d_t p4d; } pud_t;
> static inline int p4d_none(p4d_t p4d) { return 0; }
> static inline int p4d_bad(p4d_t p4d) { return 0; }
> static inline int p4d_present(p4d_t p4d) { return 1; }
> +static inline int p4d_leaf(p4d_t p4d) { return 0; }
> static inline void p4d_clear(p4d_t *p4d) { }
> #define pud_ERROR(pud) (p4d_ERROR((pud).p4d))
>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 2a6a3cccfc36..b27e66f542d6 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1882,13 +1882,13 @@ typedef unsigned int pgtbl_mod_mask;
> * - It should cover all kinds of huge mappings (e.g., pXd_trans_huge(),
> * pXd_devmap(), or hugetlb mappings).
> */
> -#ifndef pgd_leaf
> +#if !defined(__PAGETABLE_P4D_FOLDED) && !defined(pgd_leaf)
> #define pgd_leaf(x) false
> #endif
> -#ifndef p4d_leaf
> +#if !defined(__PAGETABLE_PUD_FOLDED) && !defined(p4d_leaf)
> #define p4d_leaf(x) false
> #endif
> -#ifndef pud_leaf
> +#if !defined(__PAGETABLE_PMD_FOLDED) && !defined(pud_leaf)
> #define pud_leaf(x) false
> #endif
> #ifndef pmd_leaf
Is it possible to do it the other way round, so that we can still rely on
"ifdef pxx_leaf" to decide whether to provide a fallback, and define them
properly when needed?
IMHO it was a neat way to avoid worrying on any macro defined; it'll be as
simple as "if function xxx not defined, let's define a fallback for xxx".
Per my limited experience it helped a lot on avoid compile issues here and
there..
Thanks,
--
Peter Xu
