Re: [PATCH RFC v3 06/21] mm/pgtable: define (pgd|p4d|pud)_leaf() for folded page tables

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The patch accidentally resurrects the `p4d_ERROR` and `pud_ERROR` macros, which reference a non-existent `pgd_ERROR` macro.
--

commit 1ad6d2e7fa6f4d648ec4866410881fd66f3c3298
Author: David Hildenbrand (Arm) <david@kernel.org>

mm/pgtable: define (pgd|p4d|pud)_leaf() for folded page tables
    
Define (pgd|p4d|pud)_leaf(), hard-coding it to "false". Note
that it's missed to define pud_leaf() before, allowing architectures to
unknowingly overwrite it.

> diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
> index 1cf739ee38aa1..c6a5a43899b50 100644
> --- a/include/asm-generic/pgtable-nop4d.h
> +++ b/include/asm-generic/pgtable-nop4d.h
> @@ -22,6 +22,9 @@ 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 void pgd_clear(pgd_t *pgd)	{ }
> +static inline bool pgd_leaf(pgd_t pgd)		{ return false; }
> +#define pgd_leaf pgd_leaf
> +#define p4d_ERROR(p4d)				(pgd_ERROR((p4d).pgd))

[Severity: Low]
Does this resurrect a broken macro? pgd_ERROR does not appear to exist in the
codebase anymore, so if a developer attempts to use p4d_ERROR in the future,
would it result in a build failure due to an undefined symbol?

[ ... ]

> diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
> index eedee8e3ad68f..6c9bca78047c4 100644
> --- a/include/asm-generic/pgtable-nopud.h
> +++ b/include/asm-generic/pgtable-nopud.h
> @@ -29,6 +29,9 @@ 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 void p4d_clear(p4d_t *p4d)	{ }
> +static inline bool p4d_leaf(p4d_t p4d)		{ return false; }
> +#define p4d_leaf p4d_leaf
> +#define pud_ERROR(pud)				(p4d_ERROR((pud).p4d))

[Severity: Low]
Since p4d_ERROR relies on the non-existent pgd_ERROR as noted above, does this
also mean pud_ERROR is broken in the same way?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260902-dummy_ptxp3-v3-0-5d8f5b17c25c@arm.com?part=6