Re: [PATCH v6 09/20] xen/riscv: introduce io.h

[Jan Beulich <jbeulich@xxxxxxxx>]

On 22.03.2024 12:02, Oleksii wrote:
> On Thu, 2024-03-21 at 13:27 +0100, Jan Beulich wrote:
>> On 15.03.2024 19:06, Oleksii Kurochko wrote:
>>> --- /dev/null
>>> +++ b/xen/arch/riscv/include/asm/io.h
>>> @@ -0,0 +1,167 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +/*
>>> + *  The header taken form Linux 6.4.0-rc1 and is based on
>>> + *  arch/riscv/include/asm/mmio.h with the following changes:
>>> + *   - drop forcing of endianess for read*(), write*() functions
>>> as
>>> + *     no matter what CPU endianness, what endianness a particular
>>> device
>>> + *     (and hence its MMIO region(s)) is using is entirely
>>> independent.
>>> + *     Hence conversion, where necessary, needs to occur at a
>>> layer up.
>>> + *     Another one reason to drop endianess conversion is:
>>> + *    
>>> https://patchwork.kernel.org/project/linux-riscv/patch/20190411115623.5749-3-hch@xxxxxx/
>>> + *     One of the answers of the author of the commit:
>>> + *       And we don't know if Linux will be around if that ever
>>> changes.
>>> + *       The point is:
>>> + *        a) the current RISC-V spec is LE only
>>> + *        b) the current linux port is LE only except for this
>>> little bit
>>> + *       There is no point in leaving just this bitrotting code
>>> around.  It
>>> + *       just confuses developers, (very very slightly) slows down
>>> compiles
>>> + *      and will bitrot.  It also won't be any significant help to
>>> a future
>>> + *       developer down the road doing a hypothetical BE RISC-V
>>> Linux port.
>>> + *   - drop unused argument of __io_ar() macros.
>>> + *   - drop "#define _raw_{read,write}{b,w,l,d,q}
>>> _raw_{read,write}{b,w,l,d,q}"
>>
>> In the commit message I'm not worried as much, but at least here the
>> odd mention
>> of d as suffixes would better be purged.
> Probably, I use incorrect words, but what I meant that it was dropped:
>    #define _raw_{read,write}{b,w,l,d,q} _raw_{read,write}{b,w,l,d,q}
> before declaration/definition of inline functions (
> __raw_{read,write}{b,w,l,d,q} ).

But where did you find a raw_readd() or raw_writed() (with no matter how
many leading underscores)?

Jan