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Date: Thu, 30 May 2024 20:05:50 +0200
From: "Arnd Bergmann" <arnd@arndb.de>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: "Russell King" <linux@armlinux.org.uk>,
 "Naresh Kamboju" <naresh.kamboju@linaro.org>,
 "open list" <linux-kernel@vger.kernel.org>,
 "Linux ARM" <linux-arm-kernel@lists.infradead.org>,
 lkft-triage@lists.linaro.org,
 "Linux Regressions" <regressions@lists.linux.dev>, rcu <rcu@vger.kernel.org>,
 "Dan Carpenter" <dan.carpenter@linaro.org>,
 "Joel Fernandes" <joel@joelfernandes.org>, eeraj.upadhyay@kernel.org,
 "John Ogness" <john.ogness@linutronix.de>, "Mark Brown" <broonie@kernel.org>
Subject: Re: arm-linux-gnueabihf-ld: kernel/rcu/update.o:update.c:(.text+0x1cc4): more
 undefined references to `__bad_cmpxchg' follow
Content-Type: text/plain

On Thu, May 30, 2024, at 19:24, Paul E. McKenney wrote:
> On Thu, May 30, 2024 at 09:37:21AM -0700, Paul E. McKenney wrote:
>> On Thu, May 30, 2024 at 03:27:58PM +0200, Arnd Bergmann wrote:

> And for an untested first attempt at a fix.
>
> What did I mess up this time?  ;-)
>

I think only the comment:

> 
>  	switch (size) {
> -#ifndef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */
> +#ifdef CONFIG_CPU_V6	/* min ARCH >= ARMv6K */
> +	case 1:
> +		oldval = cmpxchg_emu_u8((volatile u8 *)ptr, old, new);
> +		break;
> +#else

"min ARCH >= ARMv6K" now applies to the #else side, while the
#if side is the early ARMv6 (pre-v6K).

     Arnd