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From: Palmer Dabbelt <palmer@dabbelt.com>
To: mcroce@linux.microsoft.com
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	aou@eecs.berkeley.edu, Atish Patra <Atish.Patra@wdc.com>,
	kernel@esmil.dk, akira.tsukamoto@gmail.com, drew@beagleboard.org,
	bmeng.cn@gmail.com, David.Laight@aculab.com, guoren@kernel.org,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v4 0/3] riscv: optimized mem* functions
Date: Thu, 07 Oct 2021 18:26:44 -0700 (PDT)	[thread overview]
Message-ID: <mhng-1ef62a9c-06e5-43cf-a4ec-8c18111e79d3@palmerdabbelt-glaptop> (raw)
In-Reply-To: <20210919192104.98592-1-mcroce@linux.microsoft.com>

On Sun, 19 Sep 2021 12:21:01 PDT (-0700), mcroce@linux.microsoft.com wrote:
> From: Matteo Croce <mcroce@microsoft.com>
>
> Replace the assembly mem{cpy,move,set} with C equivalent.
>
> Try to access RAM with the largest bit width possible, but without
> doing unaligned accesses.
>
> A further improvement could be to use multiple read and writes as the
> assembly version was trying to do.
>
> Tested on a BeagleV Starlight with a SiFive U74 core, where the
> improvement is noticeable.
>
> v3 -> v4:
> - incorporate changes from proposed generic version:
>   https://lore.kernel.org/lkml/20210617152754.17960-1-mcroce@linux.microsoft.com/
>
> v2 -> v3:
> - alias mem* to __mem* and not viceversa
> - use __alias instead of a tail call
>
> v1 -> v2:
> - reduce the threshold from 64 to 16 bytes
> - fix KASAN build
> - optimize memset
>
> Matteo Croce (3):
>   riscv: optimized memcpy
>   riscv: optimized memmove
>   riscv: optimized memset
>
>  arch/riscv/include/asm/string.h |  18 ++--
>  arch/riscv/kernel/Makefile      |   1 -
>  arch/riscv/kernel/riscv_ksyms.c |  17 ----
>  arch/riscv/lib/Makefile         |   4 +-
>  arch/riscv/lib/memcpy.S         | 108 ----------------------
>  arch/riscv/lib/memmove.S        |  64 -------------
>  arch/riscv/lib/memset.S         | 113 -----------------------
>  arch/riscv/lib/string.c         | 154 ++++++++++++++++++++++++++++++++
>  8 files changed, 164 insertions(+), 315 deletions(-)
>  delete mode 100644 arch/riscv/kernel/riscv_ksyms.c
>  delete mode 100644 arch/riscv/lib/memcpy.S
>  delete mode 100644 arch/riscv/lib/memmove.S
>  delete mode 100644 arch/riscv/lib/memset.S
>  create mode 100644 arch/riscv/lib/string.c

Thanks.  These generally look good, but they're failing to build for me.  
I'm getting errors along the lines of

    arch/riscv/lib/string.c:89:7: error: inlining failed in call to ‘always_inline’ ‘memcpy’: function body can be overwritten at link time
       89 | void *memcpy(void *dest, const void *src, size_t count) __weak __alias(__memcpy);      |       ^~~~~~
    arch/riscv/lib/string.c:99:10: note: called from here
       99 |   return memcpy(dest, src, count);
          |          ^~~~~~~~~~~~~~~~~~~~~~~~

I'm still a bit behind on email so I'm going to keep going through 
patches, but if there's no v5 by the time I get back here then I'll take 
a look.

  parent reply	other threads:[~2021-10-08  1:26 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-19 19:21 Matteo Croce
2021-09-19 19:21 ` [PATCH v4 1/3] riscv: optimized memcpy Matteo Croce
2021-09-19 19:21 ` [PATCH v4 2/3] riscv: optimized memmove Matteo Croce
2021-09-19 22:05   ` kernel test robot
2021-09-27 10:48     ` Matteo Croce
2021-09-29 17:04       ` Emil Renner Berthing
2021-09-19 19:21 ` [PATCH v4 3/3] riscv: optimized memset Matteo Croce
2021-09-19 22:00 ` [PATCH v4 0/3] riscv: optimized mem* functions Matteo Croce
2021-10-08  1:26 ` Palmer Dabbelt [this message]
2021-10-08  1:39   ` Matteo Croce

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