linux-kernel - Re: [PATCH V6 4/7] sparc/mm: Enable ARCH_HAS_VM_GET_PAGE

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Message-ID: <c3619877-32db-aaa3-5dd9-4917c067bc42@csgroup.eu>
Date:   Wed, 13 Apr 2022 06:13:40 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Anshuman Khandual <anshuman.khandual@....com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
CC:     "catalin.marinas@....com" <catalin.marinas@....com>,
        Christoph Hellwig <hch@...radead.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "sparclinux@...r.kernel.org" <sparclinux@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Khalid Aziz <khalid.aziz@...cle.com>
Subject: Re: [PATCH V6 4/7] sparc/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT



Le 13/04/2022 à 07:58, Anshuman Khandual a écrit :
> This defines and exports a platform specific custom vm_get_page_prot() via
> subscribing ARCH_HAS_VM_GET_PAGE_PROT. It localizes arch_vm_get_page_prot()
> as sparc_vm_get_page_prot() and moves near vm_get_page_prot().
> 
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: Khalid Aziz <khalid.aziz@...cle.com>
> Cc: sparclinux@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Reviewed-by: Khalid Aziz <khalid.aziz@...cle.com>
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
>   arch/sparc/Kconfig            |  1 +
>   arch/sparc/include/asm/mman.h |  6 ------
>   arch/sparc/mm/init_64.c       | 13 +++++++++++++
>   3 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index 9200bc04701c..85b573643af6 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -84,6 +84,7 @@ config SPARC64
>   	select PERF_USE_VMALLOC
>   	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>   	select HAVE_C_RECORDMCOUNT
> +	select ARCH_HAS_VM_GET_PAGE_PROT
>   	select HAVE_ARCH_AUDITSYSCALL
>   	select ARCH_SUPPORTS_ATOMIC_RMW
>   	select ARCH_SUPPORTS_DEBUG_PAGEALLOC
> diff --git a/arch/sparc/include/asm/mman.h b/arch/sparc/include/asm/mman.h
> index 274217e7ed70..af9c10c83dc5 100644
> --- a/arch/sparc/include/asm/mman.h
> +++ b/arch/sparc/include/asm/mman.h
> @@ -46,12 +46,6 @@ static inline unsigned long sparc_calc_vm_prot_bits(unsigned long prot)
>   	}
>   }
>   
> -#define arch_vm_get_page_prot(vm_flags) sparc_vm_get_page_prot(vm_flags)
> -static inline pgprot_t sparc_vm_get_page_prot(unsigned long vm_flags)
> -{
> -	return (vm_flags & VM_SPARC_ADI) ? __pgprot(_PAGE_MCD_4V) : __pgprot(0);
> -}
> -
>   #define arch_validate_prot(prot, addr) sparc_validate_prot(prot, addr)
>   static inline int sparc_validate_prot(unsigned long prot, unsigned long addr)
>   {
> diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
> index 8b1911591581..dcb17763c1f2 100644
> --- a/arch/sparc/mm/init_64.c
> +++ b/arch/sparc/mm/init_64.c
> @@ -3184,3 +3184,16 @@ void copy_highpage(struct page *to, struct page *from)
>   	}
>   }
>   EXPORT_SYMBOL(copy_highpage);
> +
> +static pgprot_t sparc_vm_get_page_prot(unsigned long vm_flags)
> +{
> +	return (vm_flags & VM_SPARC_ADI) ? __pgprot(_PAGE_MCD_4V) : __pgprot(0);
> +}
> +
> +pgprot_t vm_get_page_prot(unsigned long vm_flags)
> +{
> +	return __pgprot(pgprot_val(protection_map[vm_flags &
> +			(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) |
> +			pgprot_val(sparc_vm_get_page_prot(vm_flags)));
> +}
> +EXPORT_SYMBOL(vm_get_page_prot);


sparc is now the only one with two functions. You can most likely do 
like you did for ARM and POWERPC: merge into a single function:

pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
	unsigned long prot = pgprot_val(protection_map[vm_flags &
		(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);

	if (vm_flags & VM_SPARC_ADI)
		prot |= _PAGE_MCD_4V;

	return __pgprot(prot);
}
EXPORT_SYMBOL(vm_get_page_prot);