linux-kernel - Re: [PATCH v2] sh: Implement __get_user_u64() required for 64-bit get

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Date:   Wed, 3 Jun 2020 09:20:08 +0200
From:   John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>
To:     linux-sh@...r.kernel.org
Cc:     Rich Felker <dalias@...c.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Michael Karcher <kernel@...rcher.dialup.fu-berlin.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] sh: Implement __get_user_u64() required for 64-bit
 get_user()

Hi!

On 5/31/20 12:47 PM, John Paul Adrian Glaubitz wrote:
>  Changes since v1:
>  - Replace single mov instruction for exception handling
>    in case of invalid load

Yutaka Niibe has had a look at my patch and he says, we might have to add
an entry for the fault handling of the upper word.

Quote:

> (1) I think that there is possibility that the second access to user
> space fails (while the first access succeeds).  IIUC, it's good have
> an entry in __ex_tables for the second access too, like:
>     ".long 1b+2, 3b\n\t"
> I don't know if the expression "1b+2" is correct, my intention is
> detecting the failure in the seccond access.

Comments?

@Sato-san: Can you comment on the patch as well?

Thanks,
Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@...ian.org
`. `'   Freie Universitaet Berlin - glaubitz@...sik.fu-berlin.de
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