From: Ignacio Encinas <ignacio@iencinas.com>
To: Ben Dooks <ben.dooks@codethink.co.uk>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Alexandre Ghiti <alex@ghiti.fr>, Arnd Bergmann <arnd@arndb.de>
Cc: "Eric Biggers" <ebiggers@kernel.org>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linux.dev, skhan@linuxfoundation.org,
"Zhihang Shao" <zhihang.shao.iscas@gmail.com>,
"Björn Töpel" <bjorn@kernel.org>,
linux-arch@vger.kernel.org
Subject: Re: [PATCH v3 2/2] riscv: introduce asm/swab.h
Date: Fri, 4 Apr 2025 20:13:17 +0200 [thread overview]
Message-ID: <d03cb69d-d9a3-46fb-a283-d429a9389606@iencinas.com> (raw)
In-Reply-To: <99b7b45a-4b18-4f0d-a197-4dccbb6c2352@codethink.co.uk>
On 4/4/25 17:55, Ben Dooks wrote:
> On 03/04/2025 21:34, Ignacio Encinas wrote:
>> +#ifdef CONFIG_64BIT
>> +ARCH_SWAB(64)
>> +#define __arch_swab64 __arch_swab64
>> +#endif
>
> I suppose if we're 64bit we can't just rely on values being in one
> register so this'd need special casing here?
Oops... I somehow decided that __arch_swab64 wasn't worth having for
CONFIG_32BIT. I can't tell how useful it is to have it, but it is
doable and already present in the codebase (include/uapi/linux/swab.h):
__u32 h = val >> 32;
__u32 l = val & ((1ULL << 32) - 1);
return (((__u64)__fswab32(l)) << 32) | ((__u64)(__fswab32(h)));
I'll excuse myself on this one because I'm not sure I have ever used a
32 bit CPU (other than the very occasional and quick school project)
Thanks for catching this one! I'll make sure to add __arch_swab64 for
the 32BIT version mimicking the snippet from above.
next prev parent reply other threads:[~2025-04-04 18:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-03 20:34 [PATCH v3 0/2] Implement endianess swap macros for RISC-V Ignacio Encinas
2025-04-03 20:34 ` [PATCH v3 1/2] include/uapi/linux/swab.h: move default implementation for swab macros into asm-generic Ignacio Encinas
2025-04-04 15:31 ` kernel test robot
2025-04-03 20:34 ` [PATCH v3 2/2] riscv: introduce asm/swab.h Ignacio Encinas
2025-04-04 5:58 ` Arnd Bergmann
2025-04-04 15:54 ` Ben Dooks
2025-04-04 17:35 ` Ignacio Encinas
2025-04-23 11:08 ` Alexandre Ghiti
2025-04-24 17:27 ` Ignacio Encinas Rubio
2025-04-04 15:47 ` Ben Dooks
2025-04-04 17:53 ` Ignacio Encinas
2025-04-04 19:28 ` Eric Biggers
2025-04-04 15:55 ` Ben Dooks
2025-04-04 18:13 ` Ignacio Encinas [this message]
2025-04-04 15:56 ` [PATCH v3 0/2] Implement endianess swap macros for RISC-V Ben Dooks
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