Re: [PATCH v2 3/3] openrisc: Fix issue with get_user for 64-bit values

From: Stafford Horne
Date: Sat Sep 05 2020 - 17:34:15 EST


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