Message-ID: <525C1469.4000906@gmail.com>
Date: Mon, 14 Oct 2013 23:57:29 +0800
From: Jiang Liu <liuj97@gmail.com>
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To: Russell King - ARM Linux <linux@arm.linux.org.uk>
CC: Steven Rostedt <rostedt@goodmis.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Sandeepa Prabhu <sandeepa.prabhu@linaro.org>,
        Jiang Liu <jiang.liu@huawei.com>, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/7] Optimize jump label implementation on ARM64
References: <1381675827-1610-1-git-send-email-liuj97@gmail.com> <20131014154044.GR25034@n2100.arm.linux.org.uk>
In-Reply-To: <20131014154044.GR25034@n2100.arm.linux.org.uk>
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On 10/14/2013 11:40 PM, Russell King - ARM Linux wrote:
> On Sun, Oct 13, 2013 at 10:50:20PM +0800, Jiang Liu wrote:
>> To enable this feature, your toolchain must support "asm goto" extension
>> and "%c" constraint extesion. Current GCC for AARCH64 doesn't support
>> "%c", so you need a GCC patch similiar to this:
> 
> Oh god, not that again.  I've no idea why ARM stuff has such a problem with
> supporting this very useful "%c" GCC constraint.  Aarch32 didn't for ages
> consequently we now have horrid hacks around it in the kernel source
> because our compilers suck.  Seems Aarch64 is doomed to repeat the same
> stupid mistakes. :(
> 
We need to do the same trick for ARM64 too:)
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