From: Segher Boessenkool <segher@kernel.crashing.org>
To: richard clark <richard.xnu.clark@gmail.com>
Cc: Xi Ruoyao <xry111@xry111.site>,
Mark Rutland <mark.rutland@arm.com>,
gcc-help@gcc.gnu.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: undefined reference to `__aarch64_cas4_sync' error on arm64 native build
Date: Wed, 10 Jan 2024 08:10:05 -0600 [thread overview]
Message-ID: <20240110141005.GL19790@gate.crashing.org> (raw)
In-Reply-To: <CAJNi4rM_w5JKjug1PtV+tHyk11DUhRJ-K1pSDE6P1x8KSU2wrg@mail.gmail.com>
On Wed, Jan 10, 2024 at 01:59:53PM +0800, richard clark wrote:
> A ported driver in linux kernel calls '__sync_val_compare_and_swap',
That is a builtin function. It does not necessarily expand to an actual
function call. aarch64 will typically expand it to inline code.
> the cross-compiler 'aarch64-linux-gnu-gcc' doesn't complain
> '__aarch64_cas1_sync' undefined reference, but the native compiler
> will complain. As Mark mentioned, I double check that both cross and
> native compiler should have ''-moutline-atomics' option enabled, do
> you know the reason for that?
Ah, so you are requesting external functions.
I am no aarch64 expert, but apparently there were some problems in
GCC 11, maybe that is what you saw? Or with some distros, anyway.
It also matters if you have ARMv8.1-A enabled, the LSE instructions.
Open a GCC bug report if you have more details? Thanks,
Segher
next prev parent reply other threads:[~2024-01-10 14:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-02 3:29 richard clark
2024-01-02 8:53 ` richard clark
2024-01-04 18:18 ` Mark Rutland
2024-01-08 1:28 ` richard clark
2024-01-08 10:51 ` Mark Rutland
2024-01-08 10:56 ` Xi Ruoyao
2024-01-09 2:55 ` richard clark
2024-01-09 3:05 ` Xi Ruoyao
2024-01-09 6:04 ` richard clark
2024-01-09 7:48 ` Segher Boessenkool
2024-01-09 8:09 ` Xi Ruoyao
2024-01-09 8:26 ` Segher Boessenkool
2024-01-10 5:59 ` richard clark
2024-01-10 14:10 ` Segher Boessenkool [this message]
2024-01-11 1:42 ` richard clark
2024-01-11 11:26 ` Mark Rutland
2024-01-15 9:23 ` richard clark
2024-01-09 2:52 ` richard clark
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