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Subject: Re: [PATCH v3 22/23] powerpc/vdso: Migrate native signals to generic
 vdso_base
To:     Dmitry Safonov <dima@arista.com>, linux-kernel@vger.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Guo Ren <guoren@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Ingo Molnar <mingo@redhat.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Russell King <linux@armlinux.org.uk>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Will Deacon <will@kernel.org>, x86@kernel.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>
References: <20210611180242.711399-1-dima@arista.com>
 <20210611180242.711399-23-dima@arista.com>
From:   Christophe Leroy <christophe.leroy@csgroup.eu>
Message-ID: <4500e70f-19bc-588c-df8f-d5b5b304ee49@csgroup.eu>
Date:   Thu, 17 Jun 2021 08:30:26 +0200
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Le 11/06/2021 à 20:02, Dmitry Safonov a écrit :
> Generic way to track the land vma area.
> Stat speaks for itself.
> 
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Mackerras <paulus@samba.org>
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---

> diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
> index 4bc45d3ed8b0..71dedeac7fdb 100644
> --- a/arch/powerpc/include/asm/mmu_context.h
> +++ b/arch/powerpc/include/asm/mmu_context.h
> @@ -260,15 +260,6 @@ static inline void enter_lazy_tlb(struct mm_struct *mm,
>   
>   extern void arch_exit_mmap(struct mm_struct *mm);
>   
> -static inline void arch_unmap(struct mm_struct *mm,
> -			      unsigned long start, unsigned long end)
> -{
> -	unsigned long vdso_base = (unsigned long)mm->context.vdso;
> -
> -	if (start <= vdso_base && vdso_base < end)
> -		mm->context.vdso = NULL;
> -}
> -
>   #ifdef CONFIG_PPC_MEM_KEYS
>   bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write,
>   			       bool execute, bool foreign);

powerpc was the only user of arch_unmap().

We should get rid of it completely (Remove the stubs in arch/x86/include/asm/mmu_context.h and 
include/asm-generic/mm_hooks.h and remove call in mm/mmap.c)