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Date:   Fri, 11 Feb 2022 09:17:26 +0900
From:   Stafford Horne <shorne@gmail.com>
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Michal Simek <michal.simek@xilinx.com>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Mark Rutland <mark.rutland@arm.com>
Subject: Re: [PATCH] microblaze: remove CONFIG_SET_FS
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On Thu, Feb 10, 2022 at 08:31:05AM +0900, Stafford Horne wrote:
> On Wed, Feb 09, 2022 at 03:54:54PM +0100, Arnd Bergmann wrote:
> > On Wed, Feb 9, 2022 at 3:44 PM Michal Simek <michal.simek@xilinx.com> wrote:
> > > On 2/9/22 15:40, Arnd Bergmann wrote:
> > > > On Wed, Feb 9, 2022 at 2:50 PM Michal Simek <monstr@monstr.eu> wrote:
> > > >>
> > > >> Hi Arnd,
> > > >>
> > > >> po 17. 1. 2022 v 14:28 odes?latel Arnd Bergmann <arnd@kernel.org> napsal:
> > > >>>
> > > >>> From: Arnd Bergmann <arnd@arndb.de>
> > > >>>
> > > >>> I picked microblaze as one of the architectures that still
> > > >>> use set_fs() and converted it not to.
> > > >>
> > > >> Can you please update the commit message because what is above is not
> > > >> the right one?
> > > >
> > > > Ah, sorry about that. I think you can copy from the openrisc patch,
> > > > see https://lore.kernel.org/lkml/20220208064905.199632-1-shorne@gmail.com/
> > >
> > > Please do it. You are the author of this patch and we should follow the process.
> > 
> > Done.
> > 
> > Looking at it again, I wonder if it would help to use the __get_kernel_nofault()
> > and __get_kernel_nofault() helpers as the default in
> > include/asm-generic/uaccess.h.
> 
> That would make sense.  Perhaps also the __range_ok() function from OpenRISC
> could move there as I think other architectures would also want to use that.
> 
> > I see it's identical to the openrisc version and would probably be the same
> > for some of the other architectures that have no other use for
> > set_fs(). That may
> > help to do a bulk remove of set_fs for alpha, arc, csky, h8300, hexagon, nds32,
> > nios2, um and extensa, leaving only ia64, sparc and sh.
> 
> If you could add it into include/asm-generic/uaccess.h I can test changing my
> patch to use it.

Note, I would be happy to do the work to move these into include/asm-generic/uaccess.h.
But as I see it the existing include/asm-generic/uaccess.h is for NOMMU.  How
should we go about having an MMU and NOMMU version?  Should we move uaccess.h to
uaccess-nommu.h?  Or add more ifdefs to uaccess.h?

-Stafford