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Date:   Tue, 27 Aug 2019 12:29:09 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Nicholas Piggin <npiggin@gmail.com>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Christophe Leroy <christophe.leroy@c-s.fr>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] powerpc: cleanup hw_irq.h
Message-ID: <20190827172909.GA31406@gate.crashing.org>
References: <0f7e164afb5d1b022441559fe5a999bb6d3c0a23.1566893505.git.christophe.leroy@c-s.fr> <81f39fa06ae582f4a783d26abd2b310204eba8f4.1566893505.git.christophe.leroy@c-s.fr> <1566909844.x4jee1jjda.astroid@bobo.none>
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On Tue, Aug 27, 2019 at 10:48:24PM +1000, Nicholas Piggin wrote:
> Christophe Leroy's on August 27, 2019 6:13 pm:
> > +#define wrtee(val)	asm volatile("wrtee %0" : : "r" (val) : "memory")
> > +#define wrteei(val)	asm volatile("wrteei %0" : : "i" (val) : "memory")
> 
> Can you implement just one macro that uses __builtin_constant_p to 
> select between the imm and reg versions? I forgot if there's some
> corner cases that prevent that working with inline asm i constraints.

static inline void wrtee(long val)
{
	asm volatile("wrtee%I0 %0" : : "n"(val) : "memory");
}

(This output modifier goes back to the dark ages, some 2.4 or something).


Segher