linux-kernel - Re: [RFC][PATCH 5/5] arch: Sanitize atomic

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Message-ID: <CAMuHMdV8BtrwfPWToxX5dUhtSQ4HP+UhWh10LM2voQ82pqcA+Q@mail.gmail.com>
Date:	Thu, 6 Feb 2014 15:43:19 +0100
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Linux-Arch <linux-arch@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>,
	Will Deacon <will.deacon@....com>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>
Subject: Re: [RFC][PATCH 5/5] arch: Sanitize atomic_t bitwise ops

On Thu, Feb 6, 2014 at 2:48 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> --- a/arch/m68k/include/asm/atomic.h
> +++ b/arch/m68k/include/asm/atomic.h
> @@ -76,6 +76,9 @@ static inline int atomic_##op##_return(i
>
>  ATOMIC_OP(add, +=)
>  ATOMIC_OP(sub, -=)
> +ATOMIC_OP(and, &=)
> +ATOMIC_OP(or , |=)
> +ATOMIC_OP(xor, ^=)

This last one ain't gonna fly. Given

static inline void atomic_##op(int i, atomic_t *v)                     \
{                                                                      \
       __asm__ __volatile__(#op "l %1,%0" : "+m" (*v) : ASM_DI (i));   \
}

from the previous patch, it'll generate the "xorl" mnemonic, which
IIRC does not exist. It's called "eorl".

Verified with m68k-linux-gnu-as:

Error: Unknown operator -- statement `xorl %d0,%d1' ignored

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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