linux-kernel - Re: [PATCH] mm: Remove pud_user() from asm-generic/pgtable-nopmd.h

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Message-ID: <cf90951d-0eee-4b51-a769-b657144dab7a@ghiti.fr>
Date: Tue, 12 Aug 2025 13:31:47 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Christophe Leroy <christophe.leroy@...roup.eu>,
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
 Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt
 <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
 Arnd Bergmann <arnd@...db.de>
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-riscv@...ts.infradead.org, linux-arch@...r.kernel.org,
 Peter Xu <peterx@...hat.com>, Oscar Salvador <osalvador@...e.de>
Subject: Re: [PATCH] mm: Remove pud_user() from asm-generic/pgtable-nopmd.h

Hi Christophe,

On 8/12/25 13:14, Christophe Leroy wrote:
> Commit 2c8a81dc0cc5 ("riscv/mm: fix two page table check related
> issues") added pud_user() in include/asm-generic/pgtable-nopmd.h
>
> But pud_user() only exists on ARM64 and RISCV and is not expected
> by any part of MM.
>
> Add the missing definition in arch/riscv/include/asm/pgtable-32.h
> and remove it from asm-generic/pgtable-nopmd.h
>
> A stub pud_user() is also required for ARM64 after
> commit ed928a3402d8 ("arm64/mm: fix page table check compile
> error for CONFIG_PGTABLE_LEVELS=2")
>
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> Reviewed-by: Peter Xu <peterx@...hat.com>
> Reviewed-by: Oscar Salvador <osalvador@...e.de>
> ---
>   arch/arm64/include/asm/pgtable.h    | 1 +
>   arch/riscv/include/asm/pgtable-32.h | 5 +++++
>   include/asm-generic/pgtable-nopmd.h | 1 -
>   3 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index abd2dee416b3b..fef7cc7a340d8 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -955,6 +955,7 @@ static inline pmd_t *pud_pgtable(pud_t pud)
>   
>   #define pud_valid(pud)		false
>   #define pud_page_paddr(pud)	({ BUILD_BUG(); 0; })
> +#define pud_user		false /* Always 0 with folding */
>   #define pud_user_exec(pud)	pud_user(pud) /* Always 0 with folding */
>   
>   /* Match pmd_offset folding in <asm/generic/pgtable-nopmd.h> */
> diff --git a/arch/riscv/include/asm/pgtable-32.h b/arch/riscv/include/asm/pgtable-32.h
> index 00f3369570a83..37878ef374668 100644
> --- a/arch/riscv/include/asm/pgtable-32.h
> +++ b/arch/riscv/include/asm/pgtable-32.h
> @@ -36,4 +36,9 @@
>   static const __maybe_unused int pgtable_l4_enabled;
>   static const __maybe_unused int pgtable_l5_enabled;
>   
> +static inline int pud_user(pud_t pud)
> +{
> +	return 0;
> +}
> +
>   #endif /* _ASM_RISCV_PGTABLE_32_H */
> diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h
> index 8ffd64e7a24cb..b01349a312fa7 100644
> --- a/include/asm-generic/pgtable-nopmd.h
> +++ b/include/asm-generic/pgtable-nopmd.h
> @@ -30,7 +30,6 @@ typedef struct { pud_t pud; } pmd_t;
>   static inline int pud_none(pud_t pud)		{ return 0; }
>   static inline int pud_bad(pud_t pud)		{ return 0; }
>   static inline int pud_present(pud_t pud)	{ return 1; }
> -static inline int pud_user(pud_t pud)		{ return 0; }
>   static inline int pud_leaf(pud_t pud)		{ return 0; }
>   static inline void pud_clear(pud_t *pud)	{ }
>   #define pmd_ERROR(pmd)				(pud_ERROR((pmd).pud))


Acked-by: Alexandre Ghiti <alexghiti@...osinc.com> # riscv

Thanks,

Alex