linux-kernel - Re: [PATCH] arm64/mm: Drop BUG_ON() from [pmd|pud]_set_huge()

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Message-ID: <CAKv+Gu-OSkPWUACCt=hzQJbbNArjYzt_nyYXit-oMOZy8t3fTQ@mail.gmail.com>
Date:   Mon, 27 May 2019 08:37:00 +0200
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>
Subject: Re: [PATCH] arm64/mm: Drop BUG_ON() from [pmd|pud]_set_huge()

On Mon, 27 May 2019 at 06:02, Anshuman Khandual
<anshuman.khandual@....com> wrote:
>
> There are no callers for the functions which will pass unaligned physical
> addresses. Hence just drop these BUG_ON() checks which are not required.
>

This might change in the future, right? Should we perhaps switch to
VM_BUG_ON() instead so they get compiled out unless CONFIG_VM_DEBUG is
enabled?

> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> Cc: Catalin Marinas <catalin.marinas@....com>
> Cc: Will Deacon <will.deacon@....com>
> Cc: Mark Rutland <mark.rutland@....com>
> ---
>  arch/arm64/mm/mmu.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index 22c2e4f0768f..629011c6238d 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -978,7 +978,6 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
>                                    pud_val(new_pud)))
>                 return 0;
>
> -       BUG_ON(phys & ~PUD_MASK);
>         set_pud(pudp, new_pud);
>         return 1;
>  }
> @@ -992,7 +991,6 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
>                                    pmd_val(new_pmd)))
>                 return 0;
>
> -       BUG_ON(phys & ~PMD_MASK);
>         set_pmd(pmdp, new_pmd);
>         return 1;
>  }
> --
> 2.20.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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