linux-kernel - Re: [PATCH v3 1/5] arch/x86: Drop own definition of pgd,p4d

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Message-ID: <Z9i1oGaAR9c2MPbN@MiWiFi-R3L-srv>
Date: Tue, 18 Mar 2025 07:52:00 +0800
From: Baoquan He <bhe@...hat.com>
To: Christophe Leroy <christophe.leroy@...roup.eu>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	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>,
	Huacai Chen <chenhuacai@...nel.org>,
	WANG Xuerui <kernel@...0n.name>,
	Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-riscv@...ts.infradead.org, linux-arch@...r.kernel.org,
	loongarch@...ts.linux.dev, linux-mips@...r.kernel.org,
	Oscar Salvador <osalvador@...e.de>, Peter Xu <peterx@...hat.com>
Subject: Re: [PATCH v3 1/5] arch/x86: Drop own definition of pgd,p4d_leaf

On 07/13/24 at 09:08am, Christophe Leroy wrote:
> From: Oscar Salvador <osalvador@...e.de>
> 
> We provide generic definitions of pXd_leaf in pgtable.h when the arch
> do not define their own, where the generic pXd_leaf always return false.
> 
> Although x86 defines {pgd,p4d}_leaf, they end up being a no-op, so drop them
> and make them fallback to the generic one.
> 
> Signed-off-by: Oscar Salvador <osalvador@...e.de>
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> Reviewed-by: Peter Xu <peterx@...hat.com>
> ---
>  arch/x86/include/asm/pgtable.h | 10 ----------
>  1 file changed, 10 deletions(-)

Seems this series is missed. It does do a great clean up.

> 
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 65b8e5bb902c..772f778bac06 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -252,13 +252,6 @@ static inline unsigned long pgd_pfn(pgd_t pgd)
>  	return (pgd_val(pgd) & PTE_PFN_MASK) >> PAGE_SHIFT;
>  }
>  
> -#define p4d_leaf p4d_leaf
> -static inline bool p4d_leaf(p4d_t p4d)
> -{
> -	/* No 512 GiB pages yet */
> -	return 0;
> -}
> -
>  #define pte_page(pte)	pfn_to_page(pte_pfn(pte))
>  
>  #define pmd_leaf pmd_leaf
> @@ -1396,9 +1389,6 @@ static inline bool pgdp_maps_userspace(void *__ptr)
>  	return (((ptr & ~PAGE_MASK) / sizeof(pgd_t)) < PGD_KERNEL_START);
>  }
>  
> -#define pgd_leaf	pgd_leaf
> -static inline bool pgd_leaf(pgd_t pgd) { return false; }
> -
>  #ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
>  /*
>   * All top-level MITIGATION_PAGE_TABLE_ISOLATION page tables are order-1 pages
> -- 
> 2.44.0
> 
>