linux-kernel - Re: [PATCH 1/3] ARM: Generalize fncpy implementation

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Message-ID: <20170616115834.GZ23750@n2100.armlinux.org.uk>
Date:   Fri, 16 Jun 2017 12:58:34 +0100
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:GENERIC INCLUDE/ASM HEADER FILES" 
        <linux-arch@...r.kernel.org>, Dave Gerlach <d-gerlach@...com>,
        Tony Lindgren <tony@...mide.com>, Keerthy J <j-keerthy@...com>,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        linux-omap@...r.kernel.org, Shawn Guo <shawnguo@...nel.org>
Subject: Re: [PATCH 1/3] ARM: Generalize fncpy implementation

On Thu, Jun 15, 2017 at 04:21:15PM -0700, Florian Fainelli wrote:
> ARM's fncpy implementation is actually suitable for a large number of
> platforms since the only assumption it makes is just the function's
> alignment (8 bytes) which also happens to fulfil other architectures,
> including but not limited to ARM64.

NAK.  This is really not "generic" because the whole point of this is
that it encapsulates architecture specific knowledge - in the case of
ARM, the fact that bit 1 is used to indicate whether the code is to be
run in Thumb mode or ARM mode.

That clearly does not belong in an asm-generic version of this.

I'm not saying "don't provide an asm-generic" version, I'm saying don't
use the ARM version as an asm-generic implementation, because it is
nothing of the sort.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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