linux-kernel - Re: [PATCH] x86/CPU: Use correct macros for Cyrix calls on Geode processors

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Date:   Wed, 6 Mar 2019 21:11:06 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Matthew Whitehead <tedheadster@...il.com>
cc:     linux-kernel@...r.kernel.org, mingo@...nel.org, luto@...nel.org
Subject: Re: [PATCH] x86/CPU: Use correct macros for Cyrix calls on Geode
 processors

Matthew,

On Wed, 6 Mar 2019, Matthew Whitehead wrote:

> There are comments in processor-cyrix.h advising you to _not_ make calls
> using the deprecated macros in this style:
> 
>   setCx86_old(CX86_CCR4, getCx86_old(CX86_CCR4) | 0x80);
> 
> This is because it expands the macro into a non-functioning calling
> sequence. The calling order must be:
> 
>   outb(CX86_CCR2, 0x22);
>   inb(0x23);
> 
> >From the comments:
> 
>  * When using the old macros a line like
>  *   setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88);
>  * gets expanded to:
>  *  do {
>  *    outb((CX86_CCR2), 0x22);
>  *    outb((({
>  *        outb((CX86_CCR2), 0x22);
>  *        inb(0x23);
>  *    }) | 0x88), 0x23);
>  *  } while (0);
> 
> The new macros fix this problem, so use them instead. Tested on an
> actual Geode processor.

Thanks for cleaning that up, but now the old macros are unused, so please
remove them entirely including the comment.

Thanks,

	tglx