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Date:   Wed, 24 Jul 2019 17:16:48 +0000
From:   Luis Chamberlain <mcgrof@kernel.org>
To:     Alexandre Ghiti <alex@ghiti.fr>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Russell King <linux@armlinux.org.uk>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        James Hogan <jhogan@kernel.org>,
        Palmer Dabbelt <palmer@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Kees Cook <keescook@chromium.org>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH REBASE v4 12/14] mips: Replace arch specific way to
 determine 32bit task with generic version
Message-ID: <20190724171648.GW19023@42.do-not-panic.com>
References: <20190724055850.6232-1-alex@ghiti.fr>
 <20190724055850.6232-13-alex@ghiti.fr>
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On Wed, Jul 24, 2019 at 01:58:48AM -0400, Alexandre Ghiti wrote:
> Mips uses TASK_IS_32BIT_ADDR to determine if a task is 32bit, but
> this define is mips specific and other arches do not have it: instead,
> use !IS_ENABLED(CONFIG_64BIT) || is_compat_task() condition.
> 
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/mips/mm/mmap.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
> index faa5aa615389..d4eafbb82789 100644
> --- a/arch/mips/mm/mmap.c
> +++ b/arch/mips/mm/mmap.c
> @@ -17,6 +17,7 @@
>  #include <linux/sched/signal.h>
>  #include <linux/sched/mm.h>
>  #include <linux/sizes.h>
> +#include <linux/compat.h>
>  
>  unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
>  EXPORT_SYMBOL(shm_align_mask);
> @@ -191,7 +192,7 @@ static inline unsigned long brk_rnd(void)
>  
>  	rnd = rnd << PAGE_SHIFT;
>  	/* 32MB for 32bit, 1GB for 64bit */
> -	if (TASK_IS_32BIT_ADDR)
> +	if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task())
>  		rnd = rnd & SZ_32M;
>  	else
>  		rnd = rnd & SZ_1G;
> -- 

Since there are at least two users why not just create an inline for
this which describes what we are looking for and remove the comments?

  Luis