From: Stafford Horne <shorne@gmail.com>
To: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Jonas Bonn <jonas@southpole.se>,
Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>,
Andrew Morton <akpm@linux-foundation.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Greentime Hu <green.hu@gmail.com>,
openrisc@lists.librecores.org
Subject: Re: [PATCH v2 3/3] openrisc: Fix issue with get_user for 64-bit values
Date: Sun, 6 Sep 2020 06:34:08 +0900 [thread overview]
Message-ID: <20200905213408.GI3562056@lianli.shorne-pla.net> (raw)
In-Reply-To: <20200905135714.74bsr5h423k7guw4@ltop.local>
On Sat, Sep 05, 2020 at 03:57:14PM +0200, Luc Van Oostenryck wrote:
> On Sat, Sep 05, 2020 at 10:19:35PM +0900, Stafford Horne wrote:
>
> Hi,
>
> The change for 64-bit get_user() looks good to me.
> But I wonder, given that openrisc is big-endian, what will happen
> you have the opposite situation:
> u32 *ptr;
> u64 val;
> ...
> get_user(val, ptr);
>
> Won't you end with the value in the most significant part of
> the register pair?
Hi Luc,
The get_user function uses the size of the ptr to determine how to do the load ,
so this case would not use the 64-bit pair register logic. I think it should be
ok, the end result would be the same as c code:
var = *ptr;
-Stafford
next prev parent reply other threads:[~2020-09-05 21:34 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-05 13:19 [PATCH v2 0/3] OpenRISC fixes for 5.9 Stafford Horne
2020-09-05 13:19 ` [PATCH v2 1/3] openrisc: Reserve memblock for initrd Stafford Horne
2020-09-05 13:25 ` Stafford Horne
2020-09-06 6:15 ` Mike Rapoport
2020-09-05 13:19 ` [PATCH v2 2/3] openrisc: Fix cache API compile issue when not inlining Stafford Horne
2020-09-05 13:19 ` [PATCH v2 3/3] openrisc: Fix issue with get_user for 64-bit values Stafford Horne
2020-09-05 13:57 ` Luc Van Oostenryck
2020-09-05 21:34 ` Stafford Horne [this message]
2020-09-06 0:22 ` [OpenRISC] " Luc Van Oostenryck
2020-09-06 21:00 ` Stafford Horne
2020-09-05 13:24 ` [PATCH v2 0/3] OpenRISC fixes for 5.9 Stafford Horne
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