lkml.org 
[lkml]   [2018]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 1/1] MIPS: Add Kconfig variable for CPUs with unaligned load/store instructions
From
Date
Hi Paul,

On Wed, 2018-09-26 at 22:18 +0000, Paul Burton wrote:
> Hi Yasha,
>
> On Wed, Sep 26, 2018 at 02:16:15PM +0300, Yasha Cherikovsky wrote:
> > MIPSR6 CPUs do not support unaligned load/store instructions
> > (LWL, LWR, SWL, SWR and LDL, LDR, SDL, SDR for 64bit).
> >
> > Currently the MIPS tree has some special cases to avoid these
> > instructions, and the code is testing for !CONFIG_CPU_MIPSR6.
> >
> > This patch declares a new Kconfig variable:
> > CONFIG_CPU_HAS_LOAD_STORE_LR.
> > This variable indicates that the CPU supports these instructions.
> >
> > Then, the patch does the following:
> > - Carefully selects this option on all CPUs except MIPSR6.
> > - Switches all the special cases to test for the new variable,
> > and inverts the logic:
> > '#ifndef CONFIG_CPU_MIPSR6' turns into
> > '#ifdef CONFIG_CPU_HAS_LOAD_STORE_LR'
> > and vice-versa.
> >
> > Also, when this variable is NOT selected (e.g. MIPSR6),
> > CONFIG_GENERIC_CSUM will default to 'y', to compile generic
> > C checksum code (instead of special assembly code that uses the
> > unsupported instructions).
> >
> > This commit should not affect any existing CPU, and is required
> > for future Lexra CPU support, that misses these instructions too.
> >
> > Signed-off-by: Yasha Cherikovsky <yasha.che3@gmail.com>
> > Cc: Ralf Baechle <ralf@linux-mips.org>
> > Cc: Paul Burton <paul.burton@mips.com>
> > Cc: James Hogan <jhogan@kernel.org>
> > Cc: linux-mips@linux-mips.org
> > Cc: linux-kernel@vger.kernel.org
> > ---
> > arch/mips/Kconfig | 35 +++++++++++++++++++++++++--
> > arch/mips/kernel/unaligned.c | 47 ++++++++++++++++++------------------
> > arch/mips/lib/memcpy.S | 10 ++++----
> > arch/mips/lib/memset.S | 12 ++++-----
> > 4 files changed, 67 insertions(+), 37 deletions(-)
>
> Thanks - applied to mips-next for 4.20.
>
> Paul

Thanks!

Yasha

\
 
 \ /
  Last update: 2018-09-27 00:32    [W:0.034 / U:0.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site