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From: Nathan Chancellor <nathan@kernel.org>
To: Paul Walmsley <pjw@kernel.org>
Cc: Alexandre Ghiti <alex@ghiti.fr>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Craig Topper <craig.topper@sifive.com>,
	linux-riscv@lists.infradead.org, llvm@lists.linux.dev,
	patches@lists.linux.dev
Subject: Re: [PATCH RFC v2] riscv: Use 64-bit variable for output in __get_user_asm
Date: Thu, 15 Jan 2026 22:10:11 -0700	[thread overview]
Message-ID: <20260116051011.GB1452322@ax162> (raw)
In-Reply-To: <7bc39d4d-6e2d-f0af-9787-5fd2c92bfd4e@kernel.org>

On Wed, Jan 14, 2026 at 06:02:46PM -0700, Paul Walmsley wrote:
> I'm assuming this would be a temporary patch, and that we might be able to 
> remove it at some point (years, I guess?)

Yes, ideally this would be short lived but unfortunately, I am not
really sure what the plan to fix this on the LLVM side is :/ Maybe Craig
or Bill can comment on that.

> Might be worth adding a comment in the code to explain why a temporary 
> variable is needed.

I will insert:

/*
 * Use a temporary variable for the output of the asm goto to avoid a
 * triggering an LLVM assertion due to sign extending the output when
 * it is used in function calls:
 * https://github.com/llvm/llvm-project/issues/143795
 */

I will send v3 either tomorrow or Monday.

Cheers,
Nathan

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      reply	other threads:[~2026-01-16  5:10 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-14  0:09 [PATCH RFC v2] riscv: Use 64-bit variable for output in __get_user_asm Nathan Chancellor
2026-01-15  1:02 ` Paul Walmsley
2026-01-16  5:10   ` Nathan Chancellor [this message]

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